巴西专利BR112016008578B1 tire condition analysis method and device

专利PDF首页>>巴西专利

专利附录

专利说明

权利要求

类似技术

同族专利

引用文献

法律状态

优先权

专利摘要:
METHOD AND DEVICE FOR TIRE CONDITION ANALYSIS. It is a system for measuring the depth of a tire (5) on a wheel (2) of a vehicle (1) while the wheel rotates and moves along the ground. A camera (3) captures images while the tire spins over at least most of its circumference. The light sources (L1 to L4) are spaced longitudinally and are directed at an acute angle to the tire's path, to illuminate the tire while images are captured. The images are analyzed by a data processing device (8) and the streak depth is determined from the length of shadows (12, 13) in the gaps (11) between the streak blocks (10). The light sources are activated and deactivated sequentially according to signals from longitudinally spaced sensors (S1 to S4) that detect the presence of the tire, so that when an image is captured from a portion of the tire stripe, only one source light is activated to illuminate the tire streak portion.
公开号:BR112016008578B1
申请号:R112016008578-7
申请日:2014-10-21
公开日:2021-01-12
发明作者:Paul Michael Taylor；William James Bradley；Willem Paul Beeker；Alexander Paul Codd
申请人:Wheelright Limited；
IPC主号:

专利说明:

[0001] The present invention relates to a method and apparatus for assessing a condition of a vehicle tire on a wheel while the wheel turns and the vehicle moves. In particular, the invention concerns the measurement of the groove depth in the tire.
[0002] A system is disclosed in U.S. No. 5987978 to measure a tire's tread depth. In one embodiment, a light source is used to illuminate a tire in an oblique manner, such that shadows are formed within the lower portions of the streak pattern. A second light source is provided to illuminate the tire from a different direction. The first and second light sources can be arranged to operate in an alternating sequence and can be arranged in such a way that the light they produce comes from opposite directions. Those portions of the tire that are illuminated will reflect a greater intensity of light than the portions at the bottom of the streaks that are in a shaded region. By comparing the patterns of reflected light when the tire is illuminated on each side, it is possible to establish the depth of the groove. It is said that, as the tire wears, the depth of the groove grooves decreases and, eventually, they wear out to a point where the light can reflect from the bottom of the grooves. It is stated that, once this occurs, the width of the shadow is directly related to the depth of the streak. The reflected light is directed to a camera, where the image is captured and sent to a data processor for processing. The apparatus of document No. U.S. 5987978 does not measure the tread depth of a tire in multiple positions around its circumference, as the tire rotates and moves along a surface. Instead, the tire can be rotated on a test bed, such as a moving track-type road, or a sensor can be moved around the periphery of a tire, for example, during a roadside inspection.
[0003] Document No. 8542881 discloses an automated tire inspection system aided by computer vision for inspection, in motion, of vehicle tires. A camera at an image acquisition station captures digital images of an oncoming vehicle's tires and, in particular, the grooves and side walls as the vehicle passes through an inspection station. There is a light in the image acquisition station and this can also be physically separated from the image acquisition station. Sufficient images are captured to cover an entire tire revolution. It is said that the images are analyzed to determine the tire groove depth. There is no disclosure of how the groove depth is measured using images.
[0004] An objective of the present invention is to provide an effective system for measuring the tire groove depth in multiple positions around its circumference, while the tire rotates and moves longitudinally on a base.
[0005] According to one aspect, the present invention provides a method for assessing the condition of a tire on a wheel that is mounted on a vehicle, while the vehicle moves and the tire is rotated and moves longitudinally along a movement path on a base, where the periphery of the tire has groove portions separated by groove gaps; wherein the method comprises using an imaging device to capture images of a plurality of different portions of the tire's periphery while the tire completes at least a major part of a complete revolution, with the images being captured while a light source is activated to illuminate the periphery portions of the tire; and the images are analyzed to determine the depth of the streak gaps; on what
[0006] a series of a plurality of light sources is positioned on one side of the tire's movement path, where each light source is a point source of non-collimated light and which directs light at an acute angle to the path tire movement; in which the light sources are spaced apart in a longitudinal direction;
[0007] a control system is configured to activate the light sources sequentially while the tire moves along said movement path, so that only one of the said light sources in the series illuminates the tire when images are being captured by the device;
[0008] when a light source is activated to illuminate a portion of the tire's periphery, the light source causes shadows to be cast in the groove gaps between the groove portions; the imaging device is operated to collect an image of at least part of the illuminated portion of the tire's periphery; and the image is analyzed by the data processing apparatus which determines the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap.
[0009] According to another aspect, the present invention provides an apparatus for assessing the condition of a vehicle tire on a wheel, while the tire rotates and moves longitudinally along a movement path on a base, in which the the tire periphery has groove portions separated by groove gaps; wherein the apparatus comprises an imaging device and a light source, the imaging device being arranged to capture images of a plurality of different portions of the tire's periphery while the tire completes at least a major part of a complete revolution, in which images are captured while the light source is activated to illuminate the periphery portions of the tire; and a data processing system configured to process the images to allow the depth of the streak gaps to be determined; on what
[0010] a series of a plurality of light sources is positioned on one side of the tire's movement path, where each light source is a point source of non-collimated light and which directs light at an acute angle to the path tire movement; in which the light sources are spaced apart in a longitudinal direction;
[0011] a control system is configured to activate the light sources sequentially while the tire moves along said movement path, so that only one of the said light sources in the series illuminates the tire when images are being captured by the device;
[0012] when a light source is activated to illuminate a portion of the tire's periphery, the light source causes shadows to be cast in the groove gaps between the groove portions; wherein the imaging device is arranged to collect an image of at least part of the illuminated portion of the tire's periphery; and the data processing system is configured to analyze the image in order to determine the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap.
[0013] In this way, the images are obtained from the surface of the tire as the wheel and the tire move along the movement path, which can be either towards the imaging device and the light sources or in the opposite direction to them , for at least a greater portion of the circumference of the wheel, that is, at least about one half. During the imaging process, there will be a considerable change in distance between the imaging device and the surface that is imaged. For example, if a tire has a diameter of about one meter, half the circumference would be more than 1.5 m. The imaging device will be arranged to collect images, in focus, of the rotating tire as the tire moves towards or in the opposite direction to the imaging device over that distance. For larger tires and / or to collect images over a larger portion of the tire, the imaging device will collect images as the tire moves towards or away from the imaging device over a greater distance. Being able to collect multiple images, in preferred modes that cover the entire circumference of the tire, while the vehicle is moving, is a considerable advantage in terms of system usability, unlike that of U.S. No. 5987978.
[0014] The use of a plurality of light sources that are spaced longitudinally and activated sequentially as the wheel moves along said movement path so that when an image is captured, only one light source illuminates the tire, it means that there is always sufficient illumination of the tire so that a satisfactory image can be obtained, while the use of only a single point source of light means that well-defined shadows can be obtained and analyzed to determine the groove depth. Each light source provides a lighting zone and the movement path of the wheel extends through the plurality of zones, moving from one to the next. In a preferred mode, the lighting zones overlap. When the wheel is completely within a first zone, a first light source is activated and the second light source is not activated. When the wheel has entered the overlap area with the second zone, the first light source is disabled and the second light source is activated. Similarly, when the wheel has entered the overlap area with a third zone, the second light source is disabled and the third light source is activated. This continues until the penultimate light source in the series is deactivated and the final light source is activated. When a wheel is said to have entered the overlapping area, this includes acting as the wheel enters the zone, immediately after the wheel enters the zone, or at any other appropriate time when the wheel is in the overlapping zone.
[0015] It will be verified that if the lighting zones do not overlap, there will be a region on the periphery of the tire that will not be well lit during its trajectory through the system, so there will be a gap in high quality images if the intention is to capture images around the entire periphery of the tire.
[0016] A lighting zone will generally be (in two dimensions) in the form of a segment that is centered around the main direction in which the light source exit is directed. In three dimensions, the lighting zone could be conical, but it may be preferable to shape the light source output so that the cross section is not circular, but is, for example, elliptical.
[0017] When it is said that the light sources are spaced longitudinally, this does not imply that all light sources rest on a line that is parallel to the movement path of the tire, although, in some modalities, the light sources rest on such line or one that is generally parallel to the tire's movement path. However, light sources may rest on a line that is somewhat slanted in relation to the parallel direction, or light sources may not rest on a line at all. The light sources in the series can be evenly spaced or generally evenly spaced, or there may be a variation in spacing.
[0018] According to the invention, the method does not involve the use of a laser or other collimated light to illuminate the tire. Instead, the system uses properly directed non-collimated lighting, which illuminates a significant portion of the tire's periphery rather than providing a sweeping line. The light source is preferably chosen to be clear enough to be the dominant light source that illuminates the stria, taking into account the ambient background light. In some embodiments, a light source that offers several thousand lumens is preferred. Such as a metal halide lamp or a light-emitting diode (LED) or several LEDs that are mounted together so that they act as a substantially point source of light. In general, the term “point source” encompasses a plurality of light sources that are arranged adjacent to each other and, for the purposes of lighting the tire and creating a well-defined shadow, operate effectively as a source of point light .
[0019] Light sources should be the dominant light source, but in many cases there will be ambient light such as daylight. Providing ambient light can assist in controlling the contrast in images. This can be achieved by ensuring that there is sufficient daylight, or by providing sufficient background lighting through general artificial lighting, particularly if the system is used under cover, such as indoors, or the system is used during the night or at a time when there is insufficient daylight. In some cases, it may be desirable to use a secondary light source that is a lower intensity than each light source in the series.
[0020] The imaging device must have sufficient depth of field and frame rate so that the surface of the tire can be imaged multiple times as the tire rotates forward. The ability to imagine the tire will depend on the geometry of the tires and the location of the camera; vehicle speed; the resolution of the imaging device; the field of view of the imaging device; exposure time; lighting conditions and environmental conditions. The captured images can be colored or grayscale. If color images are captured, in subsequent assessment of the streak depth, grayscale images can be used in some modalities.
[0021] The operation of the imaging device will typically begin when the wheel reaches a trigger point that can be detected by any known detector system, mechanical, optical, magnetic, electrical or other different. The trigger point can also be used to initiate sequential activation of the light sources.
[0022] If the vehicle speed is determined, the sequence of activation and deactivation of the light sources sequentially can be based on time. In a preferred embodiment, however, there are sensors to detect when a tire is in a suitable position for one light source to be deactivated and the next light source to be activated. In some cases, it may be necessary to have an adjacent light source activated together, so that there are overlapping lighting zones. This can happen if, for example, there is a vehicle such as a heavy goods vehicle tractor unit that has a geometry axis spacing that is approximately the same as the distance between the sensors that activate / deactivate the light sources, so that a front wheel and a rear wheel operate the sensors at approximately the same time. This could result in adjacent light sources being activated at the same time, but the light sources are operated in a controlled manner so that the tire is not in the overlapping illumination region when images are captured. For example, a first light source would be deactivated before the tire enters the overlap region. This can restrict the amount of tire circumference on the rear wheel that is imaged or imaged effectively.
[0023] Typically, the imaging device is a conventional camera that is used to take a series of still images and, preferably, a digital camera. However, a video camera could be used and individual frames inspected, or a specialized imaging device could be used.
[0024] It has been found that the overall imaging resolution is dependent on the resolution of the imaging device, the distance between the imaging device and the target, the viewing angle, curvature distortion and blurring by movement. Moving the camera closer to the target improves the “best” resolution, but worsens the “worst” resolution. Moving the camera in the opposite direction achieves more consistent performance.
[0025] Blurring by movement increases as the target moves up the tire, in the opposite direction to the surface, but the surface resolution improves due to the angle of the tire surface.
[0026] A high resolution camera will provide a higher resolution per image, but may be unable to take images fast enough to cover the entire periphery of the tire in one pass.
[0027] The highest resolution of the tire surface will be when the camera is closest to the tire. However, if the camera is well focused when close, the focus farther away will be poor. For best medium resolution, it may be preferable to have a minimum focal length, but a better depth of field.
[0028] A smaller aperture will provide a greater depth of field. However, stronger lighting and / or longer exposure time will be required - which increases blurring by movement.
[0029] It was determined that when using a camera it is not easy to automatically focus and use the zoom between shots, particularly if the illumination is through a strobe light or a flash and the tire is dark between shots. It is therefore preferable, in some modalities, to have a fixed focal length lens, with an aperture that is set small enough to give a depth of field that covers the distance the vehicle travels for at least one revolution of the wheel, or another distance traveled while images are being captured. The exposure needs to be short enough to avoid blurring by movement, and for this it is necessary to use a very bright light source.
[0030] In some modalities, the imaging device is operated to collect multiple images while the tire completes at least approximately 50% of a complete revolution of the tire; or at least approximately 55% of a complete tire revolution; or at least approximately 60% of a complete tire revolution; or at least approximately 65% of a complete tire revolution; or at least approximately 70% of a complete tire revolution; or at least approximately 75% of a complete tire revolution; or at least approximately 80% of a complete tire revolution; or at least approximately 85% of a complete tire revolution; or at least approximately 90% of a complete tire revolution; or at least approximately 95% of a complete tire revolution; or at least a complete tire revolution.
[0031] When it is stated that the images are collected from different portions spaced around the said external surface of the tire, this does not imply that there is necessarily a continuous series of images covering the entire periphery of the external surface of the tire, although this is a feature of a preferred embodiment of the invention and, in that embodiment of the invention, there are sufficient images to provide a continuous series that covers the outer periphery of the outer surface of the tire. The images can be of overlapping portions of the outer surface of the tire. In an alternative embodiment, the images may be in relation to circumferentially spaced portions of the outer surface of the tire, so that there is a discontinuous series of images around the periphery of the outer surface of the tire. In such an arrangement, the images between them cover at least approximately 50% of the tire's periphery; or at least approximately 55% of the periphery of the tire; or at least approximately 60% of the periphery of the tire; or at least approximately 65% of the periphery of the tire; or at least approximately 70% of the periphery of the tire; or at least approximately 75% of the periphery of the tire; or at least approximately 80% of the periphery of the tire; or at least approximately 85% of the periphery of the tire; or at least approximately 90% of the periphery of the tire; or at least approximately 95% of the periphery of the tire.
[0032] In some embodiments of the invention, images are not collected completely until a revolution has been completed and there may be a gap in the final image collected at the end of the revolution. In preferred modes, images are collected over a continuous period that covers at least approximately 50% of a complete tire revolution; or at least approximately 55% of a complete tire revolution; or at least approximately 60% of a complete tire revolution; or at least approximately 65% of a complete tire revolution; or at least approximately 70% of a complete tire revolution; or at least approximately 75% of a complete tire revolution; or at least approximately 80% of a complete tire revolution; or at least approximately 85% of a complete tire revolution; or at least approximately 90% of a complete tire revolution; or at least approximately 95% of a complete tire revolution; or at least a complete tire revolution.
[0033] It will be verified that in some circumstances it will not be possible to imagine 50% of the periphery of a tire, for example, when a tire is obscured by another tire to the front, or the side and / or there is a vehicle structure that obscures the tire. The amount of tire circumference that can be imaged can be as low as 10% or even less. In that case, the method of the invention is only applicable to other tires on the vehicle that are not so obscured. The device of the invention is still capable of collecting sufficient images of a tire, even if one or more tires of a vehicle cannot be imaged sufficiently, or at all, even if none of the tires of a particular vehicle can be imaged sufficiently, or no way.
[0034] In modes where images are collected over a continuous period that covers less than a complete revolution of the tire, the images will cover only a portion of the entire periphery of the tire. The images can cover the entire periphery of the tire during this part of the tire revolution and the images can overlap. In an alternative arrangement, the images may be in relation to circumferentially spaced portions of the outer surface of that portion of the periphery of the tire, so that there is a discontinuous series of images around that portion of the periphery of the outer surface of the tire. In such an arrangement, the images between them preferably cover at least approximately 50% of that portion of the periphery of the tire; or at least approximately 55% of that portion of the tire periphery; or at least approximately 60% of that portion of the tire periphery; or at least approximately 65% of that portion of the tire periphery; or at least approximately 70% of that portion of the periphery of the tire; or at least approximately 75% of that portion of the periphery of the tire; or at least approximately 80% of that portion of the tire periphery; or at least approximately 85% of that portion of the tire periphery; or at least approximately 90% of that portion of the periphery of the tire; or at least approximately 95% of that portion of the tire periphery.
[0035] Where it is said that each image is in relation to different portions around the periphery of the tire, this does not exclude the possibility that two images can be taken in a very rapid succession so that, in reality, they are, substantially, in relation to the same portion of the tire.
[0036] Where there is a reference to an image of a portion of the periphery of the outer surface of the tire, this does not imply that the entire width of the outer surface of the tire is imaged; and / or that a groove depth indication is provided in relation to the entire width of the outer surface of the tire. This is, however, a feature of a preferred embodiment of the invention. In another embodiment, only a portion of the width of the outer surface of the tire is imaged and / or an indication of the groove depth is provided relative to only a portion of the width of the outer surface of the tire. That portion of the width of the outer surface of the base tire could be a percentage of the outer surface of the tire that will be in contact with the base. This could be at least the percentage established by any relevant legislation. For example, in the United Kingdom it is necessary to have a minimum groove depth specified over the central 75% of the groove. Thus, for example, the imaged and analyzed width can be at least the central 75% of the streak that will be in contact with the base, or at least approximately the central 80% of the streak, or at least approximately the central 85% of the streak. , or at least approximately the central 90% of the streak, or at least approximately the central 95% of the streak. Expressed in another way, the imaged and analyzed width can be at least the central 75% of the outer surface of the tire that will be used to make contact with the base, or at least approximately the central 80% of the outer surface of the tire that will be used to make contact with the base, or at least approximately the central 85% of the outer surface of the tire that will be used to make contact with the base, or at least approximately the central 90% of the outer surface of the tire that will be used to make contact with the base base, or at least approximately the central 95% of the outer surface of the tire that will be used to make contact with the base.
[0037] In some modalities, images are used to detect defects in the groove along the outer surface of the tire, such as cuts, regions where there are holes and protuberances. This can be done by manual inspection or using the data processing device. Additionally or alternatively, the images may include portions of the two sidewalls of the tire, one on each side of the outer surface of the tire that is in contact with the base. The images can then be used to detect defects in the tire sidewalls such as cuts or bumps. Again, this can be done by manual inspection or using the data processing device.
[0038] According to the invention, the light source is moved at an acute angle to one side of said movement path in order to be able to create shadows in the tire groove gaps. The light source can be moved to either side of the movement path. The imaging device can also be moved at an acute angle to one side of said movement path. In this case, the imaging device can be moved to the same side of the motion path as the light source, to the other side of the motion path. It would also be possible for the imaging device to face the movement path along it. In that case, the tire would normally be driven over the imaging device, which could, for example, be spring-loaded or mounted under a transparent plate or under a prism so that it would not be damaged when the tire passed over.
[0039] A potential advantage of an imaging device that faces the tire, is that it may be possible for a single imaging device to capture images of both sidewalls of the tire. However, it may be necessary for mirrors to be provided to make the side walls visible.
[0040] In some modalities, a supplementary imaging device is used to capture images of portions of a sidewall of the tire. It may be possible to provide a supplementary light source for the supplementary imaging device, but if both this and the light sources in the series are operated simultaneously, the arrangement should be such that they do not interfere with each other in such a way as to remove or diminish the shadows that are necessary to put the invention into operation.
[0041] In some embodiments, two supplementary imaging devices are used, one on each side of the outer surface of the tire. The images can then be used to detect defects in the tire sidewalls. Again, this can be done by manual inspection or using the data processing device.
[0042] In a preferred arrangement, the imaging device is arranged to mark a part of the tire adjacent to the base on which the tire moves and extends upwards by a distance from that base. This is to avoid obstruction by portions of bodywork or other items such as mudguards.
[0043] The imaging device can operate to capture images of the front of the tire as it moves towards the imaging device, or capture images of the rear side of the tire as it moves in the opposite direction to the imaging device. In some arrangements, it would be possible to have two imaging devices, one to capture images of the rear side of the tire and one to capture images of the front of the tire. The two series of images could be used together, for example, through images of tire portions captured by the rear camera interspersed with images of portions captured by the front camera, with the tire portions captured by the rear camera being different from the tire portions captured by the front camera.
[0044] Vehicles will have a plurality of tires on one side and it would be possible to have a plurality of imaging devices that could capture images of different tires simultaneously. This can be useful when there are geometry axes with close spacing, as in some heavy goods vehicles.
[0045] In a preferred arrangement, tires on both sides of a vehicle can be inspected at the same time. Thus, preferably, the arrangement of an imaging device and a light source, or a plurality thereof, for imaging wheels on one side of a vehicle is repeated on the other side of the vehicle, for example, being mirrored.
[0046] All the features discussed above in relation to tires on one side of a vehicle are equally applicable to tires on opposite sides of the vehicle.
[0047] In some cases, a single geometry axis may have two wheels on one side of the vehicle and two wheels on the other side of the vehicle. In this case the outer wheel of a pair may obstruct the inner wheel of the pair. To deal with such an arrangement, it may be desirable to have a first array of light source and imaging device for capturing images of the outer wheel and a second array of light source and imaging device for capturing images of the inner wheel. Again, this could be duplicated on both sides of the vehicle. If two tires are mounted next to each other on a geometric axis, it may not be possible to imagine the side walls facing each other, at least completely.
[0048] In a preferred mode, the imaging device and the series of light sources are on opposite sides of the movement path of the wheel / tire, that is, one of the imaging device and the series of light sources is located on one side of the wheel / tire movement path and the other is located on the other side of the movement path. In this way, the light sources could be arranged on one side, in addition to the vehicle, while the imaging device is positioned in line with the vehicle; or the reverse arrangement could be used. If the tires on both sides of the vehicle are analyzed at the same time, the arrangement could be reproduced on the other side of the vehicle. In a preferred arrangement in which the tires on both sides of a vehicle are analyzed, two imaging devices are provided in positions that will be within the outline of the vehicle, while light sources are provided to the sides, outside the outline of the vehicle . Alternatively, imaging devices could be provided on the sides, outside the vehicle outline, while light sources are provided in positions that will be within the vehicle outline.
[0049] In embodiments of the invention, the angle of light that hits the tire will affect the amount of shadow. If the lighting path is approximately perpendicular to the tire surface, there will be little or no shadow cast and the entire groove gap will be illuminated. If the light illuminates through the tire's surface, the full streak gap will be in darkness.
[0050] If the light extends at an appropriate angle to the groove gap, a shadow will be cast that extends to the side of the groove gap and across the base of the groove gap. The deeper the groove gap, the longer the shadow extends to the side of the groove gap and the longer the shadow extends across the base of the groove gap, in the opposite direction to the base of the side wall. The length of the shadow for the side of the groove gap can be analyzed. An absolute depth measurement can be provided, or merely an indication as to whether it complies with a minimum depth requirement. Additionally or alternatively, the extent of the shadow across the base of the streak gap can be analyzed.
[0051] In preferred embodiments of the invention, the analysis of an image determines the location of a combination of wheel and tire and then determines the center of the wheel. This can then be the basis for calculating distances and angles. When putting the invention into operation it must be borne in mind that the distance to the tire from the imaging device changes continuously, so that the scale of the images will change and this must be taken into account when the actual length of a shadow is calculated. This could be done by having in each image an item that is of known size that can be evaluated to establish the scale, such as the diameter or radius of the wheel, or the diameter or radius of the tire and the location of the center of the wheel will assist in that. The tire or wheel dimension can be known in advance, or it can be determined by comparing the dimension of the item to a scale mounted at a known distance from the camera, the item and the scale that appears in an image. Thus, in general, a scale factor is applied by reference to an item of known real size that is present in each image. The item can be at least a part of the wheel. The dimension of the wheel can be known and stored. Alternatively the dimension of the wheel is measured. The dimension of the wheel could be measured against the scale that appears in an image with the wheel, where the wheel and the scale are at the same distance from the imaging device.
[0052] An alternative and preferred arrangement is to use a calibration step, in which an item that has known dimensions is positioned at a known distance from the imaging device. The item could be a graph with markings on it. By viewing a graphic image or other item at that known distance, a scale factor can be applied that, for example, will relate the number of pixels in the image in a particular direction to a real distance. In practice, the known distance of the imaging device will be the same distance as that of a device to trigger the start of a series of images. In this way, the tire distance from the imaging device, at the time of the first image, will be known.
[0053] Where the imaging device is moved sideways from the movement path, geometric calculations can be performed to determine the distance to the tire for subsequent images. The angle of the imaging device in relation to the movement path is fixed. As the vehicle moves along the movement path, the position of an item in the vehicle, such as a tire or wheel, will deviate across the field of view of the imaging device. Through a calibration step or other means, the amount of deviation of the item across the field of view - for example, measured in pixels - can be related to the distance traveled along the movement path. In this way, with the use of geometric calculations, it is possible to calculate the distance to the tire just by inspecting the images, as long as there has been adequate calibration.
[0054] One must also take into account distortions caused by the geometry of the arrangement, with the camera moved to the side of the vehicle that is in motion. The camera can be tilted upward on the tire, but its path may not be perpendicular to the tire's surface. The tire will have a curved surface and the curvature will depend on the radius of the tire
[0055] In some modalities, the general procedure involves the following steps:
[0056] 1) Measure the distance between the tire and the imaging device in a known geometry.
[0057] 2) Capture images, while operating light sources sequentially as described above.
[0058] 3) Filter images to try to eliminate variations in lighting,
[0059] 4) Filter images to try to detect valid groove shadows unlike other dark areas.
[0060] 5) Integrate shadow values.
[0061] 6) Convert to real shadow size.
[0062] 7) Calculate groove depth from the shadow size.
[0063] In some embodiments of the invention, the vehicle can travel up to approximately 20 miles per hour (32 km / h or more generally up to approximately 30 kilometers per hour), with preferred speeds being up to approximately 5 miles per hour (8 km / h or more generally up to approximately 10 kilometers per hour) or up to approximately 10 miles per hour (16 km / h or more generally up to approximately 15 kilometers per hour) or up to approximately 15 miles per hour (24 km / h or more generally up to approximately 25 kilometers per hour). In some modalities the vehicle should travel at least approximately 5 miles per hour (8 km / h or more generally at least approximately 10 kilometers per hour).
[0064] In some embodiments of the invention, a sensor detects the presence of the vehicle and triggers the operation of the imaging device (s) and the light source (s). There may be a sensor or sensors to detect the speed of the vehicle, or the images can be inspected to calculate the speed of the vehicle.
[0065] Some modalities will now be described by way of example and with reference to the attached drawings, in which:
[0066] Figure 1 is a diagram of a modality of a system used to carry out the invention;
[0067] Figure 2 is a side view of a tire that is imaged.
[0068] Figure 3 is a front view of a tire that is imaged.
[0069] Figure 4 shows a portion of a vehicle tire;
[0070] Figure 5 shows how a shadow is formed;
[0071] Figure 6 shows an alternative configuration for mounting an imaging device;
[0072] Figure 7 is a diagram illustrating a distance measurement system; and
[0073] Figure 8 shows in detail the arrangement of light sources, the imaging device and sensors.
[0074] Referring now to the Figures showing an apparatus for putting aspects of the invention into operation, Figure 1 is an illustration of a first modality of a system, in diagrammatic form. A truck 1 has ten wheels indicated in 2 and travels in a direction indicated by the arrow A. Positioned below the level of the truck body are two imaging devices in the form of fixed digital cameras 3 and 4, respectively directed at an acute angle on the wheels on the left side of the truck and on the right side of the truck. A first series of light sources L1, L2, L3 and L4 are spaced longitudinally along a line that generally runs parallel to the truck's movement path, off the left side of the truck. A second series of light sources L5, L6, L7 and L8 are spaced longitudinally along a line that generally runs parallel to the truck's movement path, off the right side of the truck. Each light source comprises several grouped LED elements and operates efficiently as a point source of non-collimated light.
[0075] With reference to Figure 2, wheel 2 is equipped with a pneumatic rubber tire 5 and rotates in the direction of arrow B, while moving in a longitudinal direction on a base 6 as indicated by arrow A. Both cameras image a region 7 of the tire under the bodywork of truck 1. In Figure 2, the right side of the vehicle is illustrated diagrammatically, with camera 4 shown; the other side corresponds. Figure 3 illustrates the left side diagrammatically, showing how the L4 light source is used to illuminate region 7 of the tire, while camera 3 captures an image. The operation of the light sources, such as L4 shown in Figure 3 and the cameras, such as camera 3 shown in Figure 3, are controlled by a data processing unit 8, which also receives image data from the cameras and can manipulate the data and calculate the groove depths. The image data and other data can be displayed on a screen 9.
[0076] Figure 4 shows a portion of tire 5, which has groove blocks 10 separated by gaps 11. Figure 5 shows how shadows are formed when the surface of tire 5 is illuminated by a light source such as L1. There is a shadow portion 12 that extends to the side of the groove gap 11 and a shadow portion 13 that extends partially across the base. As the depth of the groove gap 11 becomes smaller, with tire wear, both shadows shorten.
[0077] As the wheel rotates, different portions of the tire surface come successively into the fields of view of cameras 3 and 4. The light sources are operated sequentially, as described below with reference to Figure 8, under the control of data processing unit 8.
[0078] Figure 6 shows an alternative arrangement similar to Figure 2, in which the camera 4 is lowered below the surface 6. The camera can be covered by a window 14 of tempered glass or similar, so that it will not be damaged by the wheel and the tire that goes over it.
[0079] Figure 7 illustrates a system for detecting the distance of an object O. An OP observation plane is arranged at an acute angle 0 for the motion path B of a tire. The distance D1 from the observation plane to a starting point, P1, at which the imaging is triggered, is known from a calibration step. When object O has moved along the path of movement A to a point P2, the distance D2 from the object of the OP observation plane is related to the distance L through the observation plane OP through the following: D2 = D1 - L x cotan 0
[0080] Consequently, if the distance L is measured, the distance D2 can be calculated. In practice, a camera will be positioned on the observation plane and the actual distance L will be related to the apparent distance in the image, such as a number of pixels. The direction in which the camera lens is turned will be at angle 0 for the movement path B. Object O could be anything suitable, such as the center of the wheel, as identified in the images.
[0081] Figure 8 shows the arrangement of camera 3 and light sources L1 to L4 in more detail. The arrangement for camera 4 and light sources L5 to L8 corresponds. The trajectory of a tire that is imaged is indicated in C. The camera's field of view is indicated by segment 15 and is arranged so that, over a considerable length of its trajectory or course, the tire is within that field. eyesight. The light sources L1 to L2 are positioned at equal spacing along a line 16 that is parallel to the tire's line C and shifted to the left of that line. The light sources L1, L2, L3 and L4, illuminate segments such as 17, 18, 19 and 20. respectively. These lighting segments overlap and are directed at acute angles to the path of the tire. Among them, the lighting segments cover the entire trajectory of the tire that falls within the camera's field of view.
[0082] Also supplied at spaced intervals along a line parallel to the tire's trajectory path are sensors S1, S2, S3 and S4 that detect the presence of the wheel / tire. The sensors are all in communication with data processing 8. Initially, light sources L1 to L4 are not activated. As the tire enters the system, it activates the S1 sensor. This communicates with the data processing unit and activates the L1 light source. As the tire moves forward, this triggers the S2 sensor, which causes the L1 light source to be disabled and the L2 light source to be activated. This can be right at the moment or after the point when the tire enters the lighting segment 18 of the L2 light source, where there is an overlap with the lighting segment 17 of the L1 light source. As the tire moves further forward, this triggers the S3 sensor, which causes the L2 light source to be deactivated and the L3 light source to be activated. This can be right at the moment or after the point when the tire enters the lighting segment 19 of the L3 light source, where there is an overlap with the lighting segment 18 of the L2 light source. As the tire moves further forward, this triggers the S4 sensor, which causes the L3 light source to be deactivated and the L4 light source to be activated. This can be right at the moment or after the point when the tire enters the lighting segment 20 of the L4 light source, where there is an overlap with the lighting segment 19 of the L3 light source.
[0083] Finally, a fifth S5 sensor is provided that detects the presence of the wheel / tire as it leaves the region where images are being captured. This disables the L4 light source and can also disable the camera's operation.
[0084] It will be verified that the distance between the geometric axes in a vehicle can be such that while the images are being taken from the front wheel, the next wheel can move to the regions where the images are being captured. This second wheel will activate the first sensor S1 and that, in turn, will activate the first light source L1. The light source must be arranged so that, at that moment, the light source L2 is deactivated. The L3 light source may still be activated while images are being captured from the front wheel, but the arrangement is such that the lighting segment of the L3 light source does not overlap with the lighting segment of the L1 light source.
[0085] Thus, in general where there are wheels spaced longitudinally from a vehicle, a front wheel may still be within the lighting zone of a light source and may be illuminated by that light source, while a rear wheel may be within the lighting zone of a previous light source in the series and may be illuminated by that previous light source, as long as there is no overlap between the lighting zones of a light source and the previous light source.
[0086] In addition to measuring the tire groove depth, the system can also check for anomalies in the tire image. To do this, in one mode, the system generates a rectangular gray “flattened” image of the tire's periphery, which corresponds exactly to a complete tire revolution. Using deterministic methods, the system identifies anomalies in the streak. The system can use a set of a plurality of anomaly types, for example, ten different types. For each anomaly identified in the stria there is a given classification for the type of anomaly as well as the limit of the area of the anomaly.
[0087] The analysis and interpretation of anomalies consist of several specialized detectors that work sequentially, trying to classify the anomalies. For example, as a first step, the system can search for uncovered cables by detecting any long, narrow anomalies that show pixel values of intensities significantly greater than their surroundings. Once the uncovered cables are removed, the system tries to detect the area limits of each anomaly, looking at different thresholds of what will be considered “abnormal” and counting the connected regions that this produces. For example, a detector that looks for cuts in the tire detects any anomalies that are long and narrow and that have darker pixel values in the original image than in its surroundings.
[0088] In one embodiment, an algorithm consists of two parts. Firstly, a synthetic image is created from the tire stripe pattern from the rectangular gray-toned image mentioned above. This is subtracted from the input image to give an anomaly detection image.
[0089] Second, the anomalies revealed in this image are analyzed and interpreted and the anomalies are classified.
[0090] As noted above, in a first stage the system generates a rectangular "flattened" gray tone image of the tire periphery, which corresponds exactly to a complete revolution of the tire, that is, the rib is unrolled effectively in a strip. To create the synthetic image of the tire stripe, in one mode, each vertical column A of pixels in the original image, in the region of the anomaly, is replaced by a similar column B, of pixels from a different part of the image, which contains the same part of the trail pattern, but without anomalies. To do this, B is the column of pixels that is most similar to A (in terms of the squared error of the pixel values), but is even further away from A than a certain threshold. Optimizations of this include considering separate row blocks between tire grooves.
[0091] Subtracting this synthetic image from the original, the streak pattern is largely removed from the image and only anomalies are left. These remaining anomalies are then finally classified into a set of permanently encoded groups, depending on the size, shape and are covered / located within a groove groove. An improvement on this will be to use a Neural network approach to use data of registered defective types to automatically determine the categorization of the anomaly.
[0092] This procedure is used independently, without the particular system described for measuring the groove depth and independently of the system used to obtain an image of the entire periphery of the tire.
[0093] The invention can be viewed from several different aspects. Seen from another aspect of the invention, an apparatus is provided to assess the condition of a vehicle tire, the periphery of the tire being provided with groove portions separated by groove gaps; wherein the apparatus comprises a light source which is moved to one side of the tire in order to illuminate a portion of the tire's periphery, the light source causing shadows to be cast into the groove gaps between groove portions; and the apparatus further comprises an imaging device which is operable to collect an image from at least part of the illuminated periphery portion of the tire; and the data processing apparatus that is configured to analyze the image in order to determine the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap; and the apparatus is arranged to repeat this process for at least another portion of the periphery of the tire; where the tire is arranged to rotate and move longitudinally along a movement path on a base, the light source and the imaging device are fixed, the light source is displaced at an acute angle in the opposite direction to that movement path and the distance between the tire and the imaging device varies as the tire moves along said movement path; and the apparatus is arranged so that images are collected by the imaging device in relation to a plurality of different portions of the periphery of the tire while the tire completes at least approximately half of a complete revolution, with each image being collected as the respective portion is turned in one direction along the movement path. Preferably, a second light source is provided and the arrangement is such that they cannot interfere with one another in such a way as to remove or reduce the shadows that are necessary to put the invention into operation. Preferably, a plurality of light sources are positioned to one side of the tire's movement path, with each light source being a point source of non-collimated light and directing light at an acute angle to the tire's movement path; the light sources being spaced from each other in a direction that is generally parallel to the tire's movement path; and a control system is configured to activate the light sources sequentially while the tire moves along said movement path so that only one light source illuminates the tire when images are being captured by the imaging device.
[0094] Seen from another aspect of the invention an apparatus is provided to assess the condition of a vehicle tire on a wheel, while the wheel rotates and the wheel moves longitudinally along a movement path on a base, in that the apparatus comprises a light source displaced at an acute angle to one side of said movement path in order to illuminate the portions of the outer surface of the tire which are turned in one direction along the movement path; an imaging device and a control unit that controls the imaging device to collect multiple, substantially in focus, portions of the outer surface of the tire, while the tire rotates and completes at least approximately half a complete revolution, each of which the image is of different portions spaced around said external surface of the tire and each image is collected while the respective portion is turned along the movement path; the light source is controlled by the control unit to be operated while the imaging device is operated to collect each image, the light source causes shadows to be cast in the streak gaps between streak portions; and the apparatus includes the data processing apparatus which is controlled to analyze the multiple images, at least some of which include said shadow, the data processing apparatus which determines the extent of the shadow in a streak gap in order to provide an indication of tire groove depth in different positions spaced around the outer surface of the tire. Preferably, a second light source is provided and the arrangement is such that they cannot interfere with one another in such a way as to remove or reduce the shadows that are necessary to put the invention into operation. Preferably, a plurality of light sources are positioned to one side of the tire's movement path, with each light source being a point source of non-collimated light and directing light at an acute angle to the tire's movement path; the light sources being spaced from each other in a direction that is generally parallel to the tire's movement path; and a control system is configured to activate the light sources sequentially while the tire moves along said movement path so that only one light source illuminates the tire when images are being captured by the imaging device.
[0095] Seen from another aspect, the invention provides a process for assessing the condition of a vehicle tire, the periphery of the tire being provided with streak portions separately by streak gaps; wherein a light source is moved to one side of the tire in order to illuminate a portion of the periphery of the tire, with the light source causing shadows to be cast in the groove gaps between groove portions; an imaging device is operated to collect an image of at least part of the illuminated portion of the tire's periphery; and the image is analyzed by the data processing apparatus which determines the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap; and the process is repeated for at least another portion of the tire periphery; in which the tire rotates and moves longitudinally along a movement path on a base, the light source and the imaging device are fixed, the light source is displaced at an acute angle in the direction opposite to the said movement path and the distance between the tire and the imaging device varies as the tire moves along said movement path; and images are collected by the imaging device in relation to a plurality of different portions of the periphery of the tire while the tire completes at least approximately half a complete revolution, with each image being collected while the respective portion is turned in one direction along of the movement path. Preferably, a second light source is provided and the arrangement is such that they cannot interfere with one another in such a way as to remove or reduce the shadows that are necessary to put the invention into operation. Preferably, a plurality of light sources are positioned to one side of the tire's movement path, with each light source being a point source of non-collimated light and directing light at an acute angle to the tire's movement path; the light sources being spaced from each other in a direction that is generally parallel to the tire's movement path; and a control system is configured to activate the light sources sequentially while the tire moves along said movement path so that only one light source illuminates the tire when images are being captured by the imaging device.
[0096] Seen from another aspect, the invention provides a method to evaluate the condition of a vehicle tire on a wheel, while the wheel rotates and the wheel moves longitudinally along a movement path on a base, being that the tire has an external surface that makes contact with the base, and the external surface contains portions of groove; wherein a light source is moved at an acute angle to one side of said movement path in order to illuminate the portions of the outer surface of the tire that are turned along the movement path; an imaging device is operated to collect multiple images, substantially in focus, of the portions of the outer surface of the tire, while the tire rotates and completes at least approximately half a complete revolution, with each image being of different portions spaced around the said external tire surface and each image is collected while the respective portion is turned along the movement path; the light source is operated while the imaging device is operated to collect each image, with the light source causing shadows to be cast into the streak gaps between streak portions; and the multiple images, at least some of which include a said shadow, are analyzed by the data processing apparatus that determines the extent of the shadow in a tread gap in order to provide an indication of tire tread depth at different spaced positions around the outer surface of the tire. Preferably, a second light source is provided and the arrangement is such that they cannot interfere with one another in such a way as to remove or reduce the shadows that are necessary to put the invention into operation. Preferably, a plurality of light sources are positioned to one side of the tire's movement path, with each light source being a point source of non-collimated light and directing light at an acute angle to the tire's movement path; the light sources being spaced from each other in a direction that is generally parallel to the tire's movement path; and a control system is configured to activate the light sources sequentially while the tire moves along said movement path so that only one light source illuminates the tire when images are being captured by the imaging device.
[0097] Seen from another aspect, the invention provides a method to assess the condition of a tire on a wheel that is mounted on a vehicle, while the vehicle moves and the tire rotates and moves longitudinally along a path of movement on a base, the periphery of the tire having groove portions separated by groove gaps; wherein the method comprises using an imaging device to capture images of a plurality of different portions of the tire's periphery while the tire completes at least a major part of a complete revolution; there being a plurality of longitudinally spaced light sources, which illuminate different portions of the tire periphery respectively as it moves; and the images are analyzed to determine the depth of the streak gaps; wherein each light source directs light at an acute angle to the tire's movement path; when a light source is activated to illuminate a portion of the tire's periphery, the light source causes shadows to be cast into the groove gaps between groove portions; the imaging device is operated to collect an image of at least part of the illuminated portion of the tire's periphery; and the image is analyzed by the data processing apparatus which determines the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap; and where a control system activates the light sources sequentially while the tire moves along said movement path, so that the light sources do not interfere with each other in such a way as to remove or reduce the shadows cast on the streak gaps between streak portions.
[0098] Seen from another point of view, the invention provides a method of assessing the condition of a tire on a wheel that is mounted on a vehicle, as the vehicle moves and the tire rotates and moves longitudinally along a trajectory of movement on a base, with the periphery of the tire having groove portions separated by groove gaps; wherein the method comprises the use of an imaging device to capture images of a plurality of different portions of the tire's periphery while the tire completes at least a major part of a complete revolution, the images being captured as a light source it is activated to illuminate the periphery portions of the tire; and the images are analyzed to determine the depth of the streak gaps; wherein a series of a plurality of light sources is positioned to one side of the tire's movement path, with each light source directing light at an acute angle to the tire's movement path; the light sources being spaced from one another in a longitudinal direction; a control system is configured to activate the light sources sequentially while the tire moves along said movement path, so that only one of the said light sources in the series illuminates the tire when images are being captured by the imaging; when a light source is reached to illuminate a portion of the tire's periphery, the light source causes shadows to be cast into the groove gaps between groove portions; the imaging device is operated to collect an image of at least part of the illuminated portion of the tire's periphery; and the image is analyzed by the data processing apparatus which determines the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap.
[0099] Preferably, each light source is a non-collimated light source. Preferably, each light source is a point light source. In the embodiments of this aspect of the invention, each point light source is provided by a plurality of light emitting sources that are grouped together to function as a point light source.
[00100] In preferred embodiments of the invention, a system is provided to measure the tire depth of a tire on a vehicle wheel as the wheel rotates and moves along the ground. An imaging device, such as a camera, captures images while the tire spins over at least most of its circumference. The light sources are spaced longitudinally and are directed at an acute angle to the tire's path, to illuminate the tire while images are captured. The images are analyzed by a data processing device and the depth of the streak is determined from the length of shadows in the gaps between the streak blocks. The light sources are activated and deactivated sequentially, for example, according to signals from longitudinally spaced sensors that detect the presence of the tire, so that when an image is captured from a portion of the tire stripe, only one source of light is activated to illuminate the portion of the tire streak.
[00101] It will be verified that, when it is stated that, according to a broad aspect of the invention, only one of the light sources in a series illuminates the tire when images are being captured by the imaging device, in a general sense this can meaning that when an image is captured of a portion of the tire tread, for use in analyzing the depth of the tread, only one light source is activated to illuminate that portion of the tire tread. There could be another source of light that illuminates another portion of the tire or another portion of the tire groove, as long as two light sources, in different positions, do not illuminate the same portion of the tire groove while an image is being captured of that portion that is used when the tire groove depth is analyzed. The light sources do not interfere with each other in such a way that they remove or diminish the shadows cast in the streak gaps between streak portions while an image is being captured.

权利要求:
Claims (13)
[0001]
1. Method for assessing the condition of a tire (5) on a wheel (2) that is mounted on a vehicle (1), while the vehicle (1) moves and the tire (5) is rotated and moves longitudinally along a movement path on a base, where the periphery of the tire (5) has groove portions (10) separated by groove gaps (11); wherein the method comprises using an imaging device (3) to capture images of a plurality of different portions of the periphery of the tire (5) while the tire (5) completes at least a major part of a complete revolution, the images being they are captured while a light source (L1, L2, L3, L4) is activated to illuminate the periphery portions of the tire (5); and the images are analyzed to determine the depth of the groove gaps (11); characterized by the fact that a series of a plurality of light sources (L1, L2, L3, L4) is positioned on one side of the tire's movement path (5), where each light source (L1, L2, L3 , L4) is a point source of non-collimated light that directs the light at an acute angle to the movement path of the tire (5); where the light sources (L1, L2, L3, L4) are spaced apart in a longitudinal direction; a control system (8) is configured to activate the light sources (L1, L2, L3, L4) sequentially while the tire (5) moves along said movement path, so that only one of the said sources of light (L1, L2, L3, L4) of the series illuminate a portion of the periphery of the tire (5) when an image is being captured by the imaging device (3) of that portion of the periphery of the tire (5); when a light source (L4) is activated to illuminate a portion (7) of the tire periphery (5), the light source (L4) causes shadows (12, 13) to be cast in the groove gaps (11) between the streak portions (10); the imaging device (3) is operated to collect an image of at least part of the illuminated portion of the tire periphery (5); and the image is analyzed by the data processing apparatus (8) which determines the extent of the shadow (13) in a groove gap (11) in order to provide an indication of the depth of the groove gap (11).
[0002]
2. Method, according to claim 1, characterized by the fact that the imaging device (3) captures images of adjacent portions of the periphery of the tire (5) while the tire (5) completes a complete revolution, so that there is a continuous series of images covering the entire periphery of the outer surface of the tire (5).
[0003]
3. Method, according to claim 1 or 2, characterized by the fact that each light source (L1, L2, L3, L4) provides a lighting zone (17, 18, 19, 20) and the movement path the tire (5) extends through the plurality of zones (17, 18, 19, 20), so that the tire moves from one lighting zone to the next, in series; and the lighting zones (17, 18, 19, 20) overlap.
[0004]
4. Method, according to claim 3, characterized by the fact that the tire (5) is in a lighting zone (17) of a light source (L1), the light source (L1) being activated ; the tire (5) moves to a region where there is an overlap between said lighting zone (17) and the subsequent lighting zone (18) of a subsequent light source (L2); and said light source (L1) is deactivated and the second light source (L2) is activated.
[0005]
5. Method, according to claim 4, characterized by the fact that a series of sensors (S1, S2, S3, S4, S5) is provided, in which each sensor communicates with the control system for the purpose of controlling the activation and deactivation of light sources (L1, L2, L3, L4); wherein a first of said sensors (S1) detects the movement of a tire (5) in the lighting zone (17) of the first light source (L1) in the series; where subsequent sensors (S2, S3, S4) detect the movement of the tire (5) in overlapping regions between the lighting zones (17, 18, 19, 20) of light sources (L1, L2, L3, L4) ; and in which a final sensor (S5) detects the movement of the tire (5) to a position where the imaging is finished.
[0006]
6. Method according to claim 3, 4 or 5, characterized by the fact that it is repeated for a second tire (5) on a second wheel (2) mounted on the vehicle (1), spaced longitudinally from the first wheel (2 ); where the second tire is in a first lighting zone (17) of a first light source (L1) in the series of light sources (L1, L2, L3, L4), while that first light source (L1) is activated; and the first tire is in a subsequent lighting zone (20) of a subsequent light source (L4) in the series of light sources (L1, L2, L3, L4), while that subsequent light source (L4) is activated ; the subsequent lighting zone (20) not overlapping the first lighting zone (17).
[0007]
7. Method according to any of the preceding claims, characterized by the fact that the imaging device (3) is positioned on one side of the tire's movement path (5), and is directed at an acute angle to the path of movement of the tire (5).
[0008]
8. Method, according to claim 7, characterized by the fact that the imaging device (3) is positioned on one side of the tire's movement path (5), and the plurality of light sources (L1, L2, L3, L4) is positioned on the side opposite the tire's movement path (5).
[0009]
9. Method according to claim 8, characterized by the fact that the imaging device (3) is moved inwards from one side of the vehicle (1), and the light sources (L1, L2, L3, L4) are displaced out of said one side of the vehicle (1).
[0010]
10. Method according to any one of the preceding claims, characterized by the fact that the method is repeated for another tire on another wheel mounted on the vehicle (1), the first tire being on one side of the vehicle and said other tire is on the other side of the vehicle, in which said other tire is illuminated by a second series of light sources (L5, L6, L7, L8) for said other side of the vehicle (1), and in which images of said another tire are captured by a second imaging device (4) for said other side of the vehicle.
[0011]
11. Apparatus to assess the condition of a vehicle tire (5) on a wheel (2), while the tire (5) rotates and moves longitudinally along a movement path on a base, in which the periphery of the tire (5) has groove portions (10) separated by groove gaps (11); wherein the apparatus comprises an imaging device (3) and a light source (L1, L2, L3, L4), the imaging device (3) being arranged to capture images from a plurality of different portions of the periphery of the tire (5) while tire (5) completes at least a major part of a complete revolution, in which images are captured while the light source (L1, L2, L3, L4) is activated to illuminate the portions (7) the periphery of the tire (5); and a data processing system (8) configured to process the images to allow the depth of the streak gaps (11) to be determined; characterized by the fact that: a series of a plurality of light sources (L1, L2, L3, L4) is positioned on one side of the tire's movement path (5), where each light source is a point source of non-collimated light that directs the light at an acute angle to the tire's movement path (5); where the light sources (L1, L2, L3, L4) are spaced apart in a longitudinal direction; a control system (8) is configured to activate the light sources (L1, L2, L3, L4) sequentially while the tire (5) moves along said movement path, so that only one of the said sources light (L1, L2, L3, L4) of the series illuminate a portion (7) of the tire periphery (5) when an image is being captured by the imaging device (3) of that portion of the tire periphery; the device being configured so that when a light source (L4) is activated to illuminate a portion (7) of the tire periphery (5), the light source (L4) causes shadows (12, 13) to be cast in the groove gaps (11) between the groove portions (10); wherein the imaging device (3) is arranged to collect an image of at least part of the illuminated portion (7) of the tire periphery (5); and the data processing system (8) is configured to analyze the image in order to determine the extent of the shadow (13) in a groove gap (11) in order to provide an indication of the depth of the groove gap (11) .
[0012]
12. Apparatus according to claim 11, characterized by the fact that it is to further assess the condition of a second tire on a second wheel (2) that is mounted on the opposite side of the vehicle (1), while the vehicle moves and the second tire is rotated and moves longitudinally along a second movement path on a base, where the periphery of the second tire has groove portions separated by groove gaps; wherein the apparatus comprises a second imaging device (4) and a second series of a plurality of second light sources (L5, L6, L7, L8), the second imaging device (4) being arranged to capture images of a plurality of different portions of the periphery of the second tire while the second tire completes at least a major part of a complete revolution, in which images are captured while a second light source (L8) is activated to illuminate the portions of the periphery of the second tire; and a data processing system (8) is configured to process the images to allow the depth of the streak gaps to be determined; where the second series of a plurality of second light sources (L5, L6, L7, L8) is positioned on one side of the second movement path of the second tire, where each light source is a point source of non-collimated light and that directs the light at an acute angle to the second movement path of the second tire; wherein the second light sources (L5, L6, L7, L8) are spaced apart in a direction that is generally parallel to the second path of movement of the tire; a second control system is configured to activate the second light sources (L5, L6, L7, L8) sequentially while the second tire moves along said second movement path so that only one of said second light sources (L5, L6, L7, L8) illuminate the second tire when an image is captured by the second imaging device (4); the device being configured so that when a second light source (L8) is activated to illuminate a portion of the periphery of the second tire, the second light source causes shadows to be cast in the groove gaps between the groove portions of the second tire; the second imaging device (4) being arranged to collect an image of at least part of the illuminated portion of the periphery of the second tire; and a second data processing system is configured to analyze the image in order to determine the extent of the shadow in a groove gap in order to provide an indication of the depth of the groove gap of the second tire.
[0013]
13. Apparatus according to claim 12, characterized by the fact that the second control system and the second data processing system are the same used in relation to the first tire.

类似技术:

公开号 | 公开日 | 专利标题

BR112016008578B1|2021-01-12|tire condition analysis method and device

JP6765728B2|2020-10-07|Tire condition analysis

JP2010532870A|2010-10-14|Optical inspection method and inspection apparatus for object surface

KR20140109990A|2014-09-16|Determining a vertical profile of a vehicle environment by means of a 3d camera

CN103038601A|2013-04-10|Device and method for inspecting tyre shape

US20130258108A1|2013-10-03|Road Surface Shape Recognition System and Autonomous Mobile Apparatus Using Same

BR112019016740A2|2020-04-07|broken wheel detection system

JP6317892B2|2018-04-25|Appearance inspection apparatus and appearance inspection method

KR101870229B1|2018-06-22|System and method for determinig lane road position of vehicle

JP4398282B2|2010-01-13|Pantograph slip board inspection device.

CN105556241B|2019-05-10|The measurement of walking mechanism under ambient light

US20220036576A1|2022-02-03|Detection of broken or flawed wheels

JP4216784B2|2009-01-28|Pantograph sliding plate inspection device

JP3666826B2|2005-06-29|Appearance inspection method of transparent circular body

US10724920B2|2020-07-28|Method of analyzing a light distribution of a vehicle headlight

WO2020086698A1|2020-04-30|Methods and systems used to measure tire treads

同族专利:

公开号 | 公开日

GB201318824D0|2013-12-11|

US20160258842A1|2016-09-08|

PL3060899T3|2018-06-29|

EP3060899A1|2016-08-31|

CA2928508C|2021-07-27|

WO2015059457A1|2015-04-30|

JP6302059B2|2018-03-28|

CN110057601A|2019-07-26|

ZA201603468B|2017-08-30|

AU2014338756B2|2018-07-19|

CA2928508A1|2015-04-30|

EP3060899B1|2017-12-27|

US10859468B2|2020-12-08|

CN110057601B|2021-11-16|

JP2017500540A|2017-01-05|

KR20160075660A|2016-06-29|

KR102311403B1|2021-10-08|

AU2014338756A1|2016-06-09|

CN105849524A|2016-08-10|

ES2661651T3|2018-04-02|

引用文献:

公开号 | 申请日 | 公开日 | 申请人 | 专利标题

DE1809459A1|1968-11-18|1970-06-11|Dr Ekkehard Fuchs|Method and arrangement for measuring the tread depth of motor vehicle tires and for evaluating the measurement results|

US4095464A|1976-06-21|1978-06-20|The Goodyear Tire & Rubber Company|Method and apparatus for tire tread analysis|

US4604648A|1984-10-12|1986-08-05|Kley Victor B|Electronic viewing system for integrated circuit packages|

FR2665255A1|1990-07-24|1992-01-31|Inrets|DEVICE FOR EVALUATING THE DEGREE OF WEAR OF TIRES OF VEHICLES.|

US5245867A|1991-12-16|1993-09-21|Bridgestone Corporation|Method and apparatus for measuring tire parameters|

DE4316984A1|1993-05-21|1994-08-18|Daimler Benz Ag|Method and a device for automatically determining the tread depth of vehicle tyres|

GB9418091D0|1994-09-08|1994-10-26|Russell Malcom B|Tyre surface scanner|

GB9516968D0|1995-08-18|1995-10-18|Mot Technologies Ltd|Automated system for vehicle condition evaluation|

US5936737A|1996-02-07|1999-08-10|Simmons Machine Tool Corporation|Wheelset sensing system|

US5987978A|1997-04-02|1999-11-23|Assembly Technology & Test Ltd.|Apparatus for testing tire tread depth|

US6674531B2|2001-08-17|2004-01-06|Maehner Bernward|Method and apparatus for testing objects|

US6768551B2|2001-10-17|2004-07-27|International Electronic Machines Corp.|Contactless wheel measurement system and method|

DE10313191A1|2003-03-25|2004-10-07|Gutehoffnungshütte Radsatz Gmbh|Method for contactless, dynamic detection of the profile of a solid|

DE10319099B4|2003-04-28|2005-09-08|Steinbichler Optotechnik Gmbh|Method for interference measurement of an object, in particular a tire|

DE50300973D1|2003-09-04|2005-09-15|Snap On Equip Srl Unico Socio|Optical scanning of the condition of a pneumatic tire of a vehicle wheel |

US7269997B2|2004-06-03|2007-09-18|Snap-On Incorporated|Non-contact method and system for tire analysis|

US7561569B2|2005-07-11|2009-07-14|Battelle Memorial Institute|Packet flow monitoring tool and method|

US7564569B2|2005-09-16|2009-07-21|International Electronic Machines Corp.|Optical wheel evaluation|

AT429627T|2005-11-22|2009-05-15|Yarayan Ali|DEVICE FOR TESTING TIRE PROFILE DEPTH AND TYPE, SPEED AND BODY FREQUENCY ON VEHICLES DURING THE RIDE|

DE102006007948B3|2006-02-21|2007-10-04|Stähle, Kurt|Vehicle`s e.g. lorry, tire tread depth measuring method, involves guiding measuring head to measuring bar, and measuring tread depth in two tracks during forward or backward movement of head from or to starting position, respectively|

DE102006062447B4|2006-12-28|2009-08-20|Chronos Vision Gmbh|Method and device for detecting the three-dimensional surface of an object, in particular a vehicle tire|

JP2008185511A|2007-01-31|2008-08-14|Bridgestone Corp|Tire rro measurement method and its device|

JP5046688B2|2007-03-08|2012-10-10|株式会社神戸製鋼所|Tire shape detection device and tire shape detection method|

US7578180B2|2007-06-29|2009-08-25|The Goodyear Tire & Rubber Company|Tread depth sensing device and method for measuring same|

DE102007054156A1|2007-11-12|2009-05-14|Ventech Gmbh|Method for determining the pressure and the tread depth in a vehicle tire|

JP5176517B2|2007-12-07|2013-04-03|横浜ゴム株式会社|Tire tread measuring device|

FR2925706B1|2007-12-19|2010-01-15|Soc Tech Michelin|DEVICE FOR EVALUATING THE SURFACE OF A TIRE.|

US7975540B2|2008-04-24|2011-07-12|Rite-Solutions, Inc.|Methods and apparatus for tire tread measurement|

EP2141475B1|2008-07-03|2013-03-27|Snap-on Equipment Srl a unico socio|Apparatus for determining the condition of a tire tread of a vehicle wheel|

FR2938330A1|2008-11-07|2010-05-14|Michelin Soc Tech|EVALUATION OF THE SURFACE SURFACE OF A PNEUMATIC BY STEREOVISION ACTIVE|

DE102009016498A1|2009-04-08|2010-10-21|Ventech Gmbh|Method and device for determining the tread depth of a vehicle tire|

US8171783B2|2009-11-02|2012-05-08|Tire Measurements, Inc.|Tire tread scanner drive-over unit|

US8542881B2|2010-07-26|2013-09-24|Nascent Technology, Llc|Computer vision aided automated tire inspection system for in-motion inspection of vehicle tires|

JP5833317B2|2011-01-27|2015-12-16|株式会社ブリヂストン|Tire shape measuring method and tire shape measuring apparatus|

DE102012202271A1|2011-07-11|2013-01-17|Robert Bosch Gmbh|Apparatus and method for tire testing|

KR101332650B1|2011-11-17|2013-11-26|한국타이어 주식회사|Dynamic displacement measuring apparatus of tire tread|

KR101299571B1|2012-07-06|2013-08-23|세반코주식회사|Irregularity inspection method for tire|

NO2833907T3|2012-11-02|2018-07-28|

DE102012224260A1|2012-12-21|2014-06-26|Robert Bosch Gmbh|Device and method for measuring the tread depth of a tire|ES2659171T3|2014-01-27|2018-03-14|Texa S.P.A.|Method and tool to determine the state of deterioration of a brake disc|

EP3237834B1|2014-12-22|2020-02-19|Pirelli Tyre S.p.A.|Apparatus for controlling tyres in a production line|

JP6279163B1|2014-12-22|2018-02-14|ピレリ・タイヤ・ソチエタ・ペル・アツィオーニ|Method and apparatus for detecting tire defects in a tire manufacturing process|

MX2017007772A|2014-12-22|2017-10-02|Pirelli|Method and apparatus for checking tyres in a production line.|

US9921133B2|2015-07-29|2018-03-20|Hon Hai Precision Industry Co., Ltd.|Tread depth measuring system|

GB201517926D0|2015-10-09|2015-11-25|Wheelright Ltd|Tyre condition analysis|

MX2018006593A|2015-12-16|2018-11-09|Pirelli|Method and device for checking tyres.|

GB2546344A|2016-01-12|2017-07-19|Gobotix Ltd|Vehicle underframe examination system|

US10789773B2|2016-03-04|2020-09-29|TIREAUDIT.COM, Inc.|Mesh registration system and method for diagnosing tread wear|

WO2017152179A1|2016-03-04|2017-09-08|TIREAUDIT.COM, Inc.|Mesh registration system and method for diagnosing tread wear|

BR112019001466A2|2016-07-26|2019-05-07|Pirelli Tyre S.P.A.|method for checking a tire and checking station|

CN106915303B|2017-01-22|2018-11-16|西安科技大学|Automobile A-column blind area perspective method based on depth data and fish eye images|

KR20190126807A|2017-02-13|2019-11-12|휠라이트 리미티드|Tread line scanner|

JP6614746B2|2017-10-12|2019-12-04|中央海産株式会社|Tire profile information acquisition device|

KR20190051140A|2017-11-06|2019-05-15|금호타이어 주식회사|For CUT and CHIP level quantification analysis of tire tread part|

EP3495767B1|2017-12-11|2022-01-05|Butler Engineering & Marketing S.p.A.|Unit for detecting geometric characteristics of a component of a tired wheel of a vehicle|

JP6987020B2|2018-05-25|2021-12-22|株式会社ブリヂストン|Tire Trauma Detection System and Tire Trauma Detection Program|

FR3103555B1|2019-11-27|2021-12-24|Michelin & Cie|Tire surface condition assessment system|

US20210357645A1|2020-05-18|2021-11-18|Moj.Io, Inc.|Compute system with wear detection mechanism and method of operation thereof|

法律状态:
2020-07-21| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|

2020-11-24| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|

2021-01-12| B16A| Patent or certificate of addition of invention granted [chapter 16.1 patent gazette]|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 21/10/2014, OBSERVADAS AS CONDICOES LEGAIS. |

优先权:

申请号 | 申请日 | 专利标题

GBGB1318824.8A|GB201318824D0|2013-10-24|2013-10-24|Tyre condition analysis|

GB1318824.8|2013-10-24|

PCT/GB2014/053132|WO2015059457A1|2013-10-24|2014-10-21|Method and device for tyre condition analysis|

[返回顶部]