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    • 专利摘要:
    methods for segmenting the surface of a tire, and for detecting defects on a surface of a tire, and equipment for segmenting the surface of a tire. the present invention relates to a method for segmenting the surface (5a, 5b) of a tire (p) including at least one groove (4). the method comprises: irradiating a portion (100) of the surface (5a, 5b) of the tire (p) by means of electromagnetic radiation having a wavelength in the visible spectrum; acquires an image (100a) of the radiated portion (100) of the surface; and image processor (100a) in order to segment it into regions (101, 102) corresponding to regions of the tire that belong or not to at least one groove (4). additionally, image processing (100a) in order to segment it includes: calculating a statistical quantity associated with electromagnetic radiation irradiation for each region (101, 102) of the image (100a); and determining whether the region (101, 102) of the image belongs or not to at least one groove (4) according to the value of the statistical quantity. the invention also relates to an equipment (1) for segmenting a surface (5a, 5b) of a tire (p) including at least one groove (4).
    公开号:BR112015001413B1
    申请号:R112015001413-5
    申请日:2013-07-23
    公开日:2020-12-15
    发明作者:Vincenzo Boffa；Marco Gallo；Bartolomeo Montrucchio
    申请人:Pirelli Tyre S.P.A；
    IPC主号:
    专利说明:

    [001] The present invention relates to a method for segmenting the surface of a tire and to equipment that operates according to this method. The method and equipment according to the invention can be used to accurately and accurately detect areas on the tire surface having different characteristics, and consequently to segment the tire surface into groups of areas or pixels having similar properties.
    [002] Tires, particularly top-of-the-range models, but also those not classified as high-performance, are usually carefully inspected after fabrication and / or after vulcanization, in order to measure or verify a plurality of tire characteristics, whose values can, for example, lead to tire rejection or acceptance. For example, the tire surface is carefully examined for any defects, non-uniformities or other flaws, and the tire is considered to be acceptable if these measured parameters fall within certain acceptable ranges, or if they are found to be absent or present. These value ranges vary with the type, model, size and intended use of the tires.
    [003] A tire generally comprises a carcass structure, in the form of a toroidal ring, including one or more carcass linings, reinforced with reinforcement cords located in radial planes (in which case they are known as radial tires), in other words on planes containing the tire's axis of rotation. The ends of each carcass tarpaulin are attached to at least one metallic ring structure, usually known as the bead core, which reinforces the beads, in other words, the radially internal ends of said tire, which serve to fit the tire on a corresponding mounting ring. A band of elastomeric material, called the tread, is placed over the crown of said carcass structure, and a relief design for contact with the ground is formed on this tread at the end of the curing and molding stages. A reinforcement structure, usually known as the belt structure, is placed between the carcass structure and the tread. In the case of car tires, this belt structure usually comprises at least two radially superimposed strips of rubberized fabric provided with reinforcement cords, usually metallic, positioned parallel to each other on each strip and crossing the cords of the adjacent strip, the cords preferably being positioned symmetrically around the equatorial plane of the tire. Preferably, said belt structure also comprises a third layer of fabric or metal cord placed circumferentially (at 0 degrees) in a radially external position, at least on the ends of the underlying strips.
    [004] Flanks of elastomeric material are also applied to the corresponding side surfaces of the carcass structure, each extending from one of the lateral edges of the tread to the position of the corresponding annular fixing structure to the beads.
    [005] Q Vgtoq "groove" * go wo rpgw + fgpqVc wo undercut formed on one of the tire surfaces, not necessarily on the tread surface, but also, for example, on the radially internal surface of the tire. In the specific case of the tread, a groove is defined as a recess forming part of the tread design defined above, which preferably separates two blocks from the tread. Since the groove is a recess, it is possible to identify a bottom surface and a top surface, where the top surface essentially coincides with the radially outer surface of the blocks separated by the groove, and the bottom surface is defined as a portion of the tire surface spaced radially from the top surface and in a radially internal position with respect to the latter. The bottom and top surfaces are preferably continuously interconnected by side walls, which can be essentially perpendicular to a plane locally tangent to the top surface, or inclined with respect to them. The bottom surface and the side walls are considered to belong to the groove, while the top surfaces are considered to not belong to the groove. On the tire surface, therefore, it is possible to define portions of surface belonging to a groove, in other words portions of surface belonging to either the bottom surface or side walls, and portions of surface not belonging to a groove, in other words those that are part of the top surface.
    [006] Generally, a groove extends in a direction called the longitudinal direction, and in particular it has a longitudinal extension greater than its transverse dimension, although other geometries can be found.
    [007] Wo “f gfgkVq” go wo rpgw fi woc ectceVgtiuVkec fq rpgw swg fi unwanted, although it does not necessarily lead to the rejection of the tire. Examples of defect types are foreign bodies on the cover under vulcanization, open joints, defects within the grooves such as bubbles under a tread, burrs and steps on the tread, and exposed cords on the tread.
    [008] The Vgtoq “eqtfqpgl expouVq” fgpqVc wo fghgkVq fq rpgw go than a textile or metal cord, for example (but not necessarily) wo eqnqecfq c 2 itcw. fi “expouVq” rgnq ocVgtkcn glcuVqofitkeq, qw fi rgnq less visible under the material, in a tire groove, because the elastomeric material is very thin. The elastomeric material above the cordon has a “gneqtfqcfc” crctêpekc * fci q pqog + swg fi pcrtieulcπiig'ntg fkfiekn fg identify.
    [009] Q Vgtoq "fqnVg fg tcfkc>« q gngVtqocinfiVkec "fgpqVc woc qw more than a variety of radiation sources, including, but not limited to, LED-based sources (using one or more LEDs as defined below), incandescent sources (for example, filament lamps or halogen lamps), fluorescent sources, phosphorescent sources, discharge sources, lasers, and others.
    [0010] The radiation source can be configured to generate electromagnetic radiation within the visible spectrum, outside the visible spectrum, or in codq fguVgUo C gzrtguu «q“ hqnVg fg tcfkc> «q nwokpquc gokvkpfq tcfkc>« q pq gurgeVtq xku ukipkfiec woc hqpVg swg goiVg tcfkc> «the ow pq visible spectrum only, or in the visible spectrum and in other spectra as well. Since it is specifically dealing with radiation sources in gurgeVtq xkuixgn in rtgugnVg eonVgzVo.ou Vgtoou “tafka>« q ”g“ Iwz ”u« q wuafou interchangeably. In addition, a radiation source may include one or more filters, lenses or other optical components.
    [0011] C gzrtguu «q tafka>« q “VgngeênVtkea” ukinkhkea woa hqnVg fg radiation that emits electromagnetic radiation in the form of a plurality of rays essentially parallel to each other.
    [0012] The expression tafka> «q“ swaug VgngeênVtkea ”ukinkfiea woa hqnVg of radiation that emits electromagnetic radiation in the form of a plurality of rays making an angle of less than about ± 10 ° to each other. EqnugswgnVgognVg.hqnVgu “swaug VgngeênVtkeau knenwgo hqnVgu Vglecentric.
    [0013] Radiation is also described as essentially scratching with respect to a surface when the rays that constitute the radiation make an angle of no more than about ± 15 °, or more preferably about ± 5 °, with the surface.
    [0014] The termq “gurgeVtq” fgxg ugt knVgtrtgVafq eqoq ug tghgtknfq to one or more radiation frequencies produced by a radiation source. Q Vgtoq “gurgeVtq xkuixgn” igtanognVg fgnqVa tafka> «q nwoknqua Vgnfq w wavelength in the range of about 380 nm to about 760 nm.
    [0015] Q Vgtoq “eot” fg woc tcfkc> «q fi wucfc cswk knVgtecodkcxgnogntg eoo Vgtoo“ gurgeVto ”Rotfio, Vgtoo“ eot ”fi wucfo primarily to refer to a radiation property that can be perceived by an observer.
    [0016] In the following text, the term “NGF” tghgtg refers to light-emitting diodes of any type that are configured to emit radiation in a specified spectrum. An LED therefore includes, but is not limited to, a semiconductor structure that emits radiation in response to a current. Organic semiconductor structures (eg OLEDs) are also included in this definition.
    [0017] Q Vgtoo “NGFu fg eot fkhgtgpVg” rotVcpVo fgpoVc NGFu emitting radiation with separate spectra, in other words spectra having different bandwidths g1ow eooropgpVgu gurgeVtcku0 ocu c tcfkc> «o * ow“ nwz ”. interpreted as having the same meaning) emitted by the LEDs may also be within the infrared range, the ultraviolet range or a combination of them with visible light.
    [0018] The description of a radiation source, for example an LED, and the “dtcpec”. "Xgtognjc". gVe0. fgxg ugt kpVgtrtgVcfc eooo ukipkhkecpfo woc lontg gmiVkpfo tcfkc> «o rtgfookpanVgogpVg rgtegdkfc eooo“ dtcnec ”,“ xgtognjc ”g cuuko go fkcpVg. godotc c hopVg rouuc Vcodfio gokVkt owVtc radiation.
    [0019] US 2010/0002244 describes a method for inspecting the surface of a tire capable of reliably discriminating rubber parts having a different quality than that of the tire, these parts being incorporated into the tire surface as a result of the vulcanization of the tire. A first lighting unit includes two light projectors that project light from two opposite sides to a target line on a tire. A second lighting unit includes a pair of second projectors that project light from opposite sides to the objective line in a direction other than that in which the first lighting unit projects light. The first and second units operate alternately. A linear video camera forms an image of part of the tire surface corresponding to the objective line in synchronization with the lighting process of the first and second lighting units. The images are analyzed for the inspection of the tire surface.
    [0020] US 2011/0018999 describes a device for evaluating the appearance of a tire surface, comprising a color linear video camera including means for separating a beam of light reflected by the surface of said tire and entering the video camera in at least two primary colors having given wavelengths, such that the light beam is directed to a series of sensors in such a way that a basic gray scale camera is obtained for each primary color. The device also includes a number of means of illumination equal to the number of primary colors, said means of illumination being oriented in order to illuminate the surface to be evaluated at different angles. The device is characterized by the fact that each means of illumination emits a colored light that is different from that emitted by the other means of illumination, and whose wavelength corresponds essentially to the wavelength of one of the primary colors selected by the video camera.
    [0021] WO 2012/052301 describes a method for inspecting a tire tread having a tread design formed by the set of circumferentially juxtaposed elements separated by extremes having formed identical known and a reduced number of basic patterns placed in sequence of a predetermined way.
    [0022] The applicant noted that the systems for processing images of the tire surface used in the field are generally not sufficiently accurate to detect all defects and / or features of interest.
    [0023] As is known, the final color of a tire is usually black, due to the presence of carbon black. The design on the tread is produced by forming a plurality of grooves, which are essentially recesses in the tread. In particular, in a typical structural configuration, a tire comprises a tread on which a plurality of grooves is defined extending circumferentially and transversely, delimiting a corresponding structural block. In the case of winter tires, a plurality of small transverse notches known as "ncogncu". fi Vcodfio fotocfc go ecfc wo fqu dnqeqUo
    [0024] The applicant realized that, according to the documents mentioned above, the tire surface is inspected by irradiation with electromagnetic radiation, with the production of images, such as digital images, of the light reflected by the tire. However, the color black, with the inevitable “gxcpguekogpVo” g fkfètgp> cu fg kpVgpukfcfg fg eot. c rtgugp> c fg woc plurality of recesses having different dimensions and orientations on the surface fo rpgw. swg igtco “uoodtcu” g owVtou hgp »ogpou, c ewtxcVwtc fc uwrgtfiekg of the tread, and the existence of a plurality of positioning surface, as well as dust, oil and other substances that can contaminate the tread surface, combine to make the analysis and processing of acquired images extremely complicated and difficult, and in particular to make it difficult to avoid errors, fault identification, medk> õgu kpeottgVcu. ow “fcnuou roukvkxou”
    [0025] The applicant therefore wishes to provide a method and equipment that can improve efficiency in terms of tire inspection accuracy, thereby enabling defects and parameters caused by its surface to be detected while reducing errors.
    [0026] However, the applicant found that, in order to achieve this, it is not enough to improve the method of illuminating the tire surface, since, even with the best lighting possible, the images of the tire surface to be examined are difficult to process for the reasons mentioned above.
    [0027] In fact, the applicant realized it is necessary not only ognjqtct c knwokpc> «q. ocu Vcodfio rtqxgt “rtfi-rtqeguucogpVq” fcu kocigpu acquired before the inspection can be conducted with the required degree of reliability.
    [0028] Finally, the applicant found that this pre-processing must include segmentation of the images acquired in areas having similar characteristics; in other words, it includes image segmentation in "fg groove" g "p« q fg groove ". fg oqfq c fkxkfkt c kocigo acquired in areas of the tire surface corresponding to the presence of a groove (or part of it) and areas of the tire surface that are outside the grooves.
    [0029] This segmentation preferably takes place by means of appropriate statistical analysis of the characteristics of the various regions, such as for example areas of pixels, forming the acquired images.
    [0030] In particular, in a first aspect, the invention relates to a method for segmenting the surface of a tire including at least one groove.
    [0031] Preferably, said method comprises irradiating a portion of said surface of said tire with electromagnetic radiation having a wavelength in the visible spectrum.
    [0032] Preferably, the method comprises acquiring an image of said portion of the irradiated surface.
    [0033] Preferably, provision is made to process said image in order to segment it into regions corresponding to regions of the tire that belong or not to said at least one groove.
    [0034] Preferably, processing includes calculating a statistical amount associated with irradiation by said electromagnetic radiation for each region of said image.
    [0035] Preferably, processing comprises determining whether said region of said image belongs or not to said at least one groove according to the value of said statistical quantity.
    [0036] The applicant believes that a division of the image into separate regions allows the image processing to be continued afterwards in a simplified way. When divided into regions, the image allows the examination to be limited, for example, to the regions of the image corresponding to the groove, or to those corresponding to regions outside the groove. Excluding non-relevant regions eliminates many of the causes of processing errors.
    [0037] For example, dividing the images acquired from the surface of the rpgw go “tgikõgu fg groove” g “tgikõgu p« q fg groove ”g crnkecnfq cliqtkVoqu known for the detection of defects, non-uniformities or other characteristics of one or other of these two groups, the applicant noted that the degree of accuracy is improved by comparison with the application of these algorithms without this upstream segmentation, and that, in particular, it is possible to identify defects that cannot be detected with other solutions.
    [0038] According to a second aspect, the invention relates to a method for detecting defects on a tire surface, including the method for segmenting the surface of a tire according to the first aspect, comprising: processing at least one of said regions of said image belonging to said at least one groove, for the detection of defects within it.
    [0039] The applicant therefore believes that, following the segmentation described above, a plurality of analyzes known in the art can be conducted out with greater precision and accuracy, thus reducing the error rate and allowing a particularly detailed inspection of the tire to be carried out. .
    [0040] According to a third aspect, the invention relates to an equipment to segment the surface of a tire including at least one groove.
    [0041] Preferably, said equipment comprises a source of electromagnetic radiation capable of irradiating a portion of said tire surface with electromagnetic radiation having a wavelength in the visible spectrum.
    [0042] Preferably, a light sensor capable of acquiring an image of said portion of the radiated surface of said tire is provided.
    [0043] Preferably, a processor is provided, this processor being able to process said image by dividing it into regions corresponding to regions of the tire that belong or not to said at least one groove.
    [0044] Preferably, said processor comprises a calculator capable of calculating a statistical quantity associated with irradiation by said electromagnetic radiation for each region of said image.
    [0045] Preferably, said processor comprises a selector capable of determining whether said region of said image belongs or not to said at least one groove according to the value of said statistical quantity.
    [0046] The applicant believes that the equipment mentioned above can allow automatic inspection of the tire surface that overcomes the above mentioned drawbacks of the prior art.
    [0047] In at least one of the aspects mentioned above, the present invention can have at least one of the following preferred characteristics.
    [0048] In a preferred example, irradiating a portion of said surface includes: using an almost telecentric source of said electromagnetic radiation to irradiate said portion.
    [0049] In fact, the applicant noted that, depending on the type of characteristic and / or defect to be observed on the tire surface, the type of lighting to be provided on the tire is significant. For example, it has been observed that, for the detection of certain types of defects, lighting with a beam of essentially parallel rays, in other words with an almost telecentric device, is the solution that gives the greatest precision.
    [0050] Additionally or alternatively, in addition, radiating a portion of said surface includes the fact that said electromagnetic radiation is essentially scratching with respect to a bottom surface of said at least one groove.
    [0051] Depending on the type of defect or characteristic that is sought, the angle between the incident device and the tire surface can be varied, thus making the identification of the defect or characteristic as simple as possible in the acquired image. For some defects or characteristics located within the grooves, the best radiation is one that is essentially level with respect to the bottom surface of the groove.
    [0052] Preferably, the invention includes: detecting an identification code of said tire; placing said tire for said irradiation operation according to said identification code.
    [0053] As is well known, tires have variable tread sizes and designs. The arrangement and depth of the grooves can therefore vary considerably between one tire model and another. In order to simplify the processing of the acquired images, it is therefore preferable to know the type of tire on which the segmentation is conducted, for example by reading a tire identification code such as a bar code, in order to check the characteristics of the tire and position the light radiation source and / or the light sensor in the most convenient way with respect to the surface of the tire to be irradiated.
    [0054] In a preferred example, irradiating a portion of said tire surface by electromagnetic radiation includes: irradiating said portion by means of radiation having one of a plurality of main irradiation directions, and selecting a radiation having a different main direction from among this plurality.
    [0055] As stated above, a characteristic or defect of the tire surface is more or less evident in the image of the tire surface that is acquired, according to the type of radiation incident on the tire surface. In more detail, a defect or characteristic can be more or less accentuated in the acquired image, the irradiated portion of the surface, according to the main propagation direction of electromagnetic radiation. According to the invention, provision is made in a preferred example to introduce a plurality of radiation sources, each of which emits electromagnetic radiation incident on the tire surface, with wo âpiwnq fg kpekfêpekc fkhgtgnVg fg woc fonVg c qwVtCo Cuuko. “CVkxanfq” qw “fgucVkxcnfq” c fonVg „vkoc rctc q vkrq fg ectceVgtiuVkec qw fgfekVq gnxqnxkfq. it is possible to perform a plurality of processing operations in a limited time to make a complete inspection of the tire surface.
    [0056] Additionally, positioning said tire includes rotating and / or translating said tire so as to radiate said portion in a predetermined direction.
    [0057] Preferably, the radiation source includes an LED.
    [0058] Even more preferably, the radiation source includes a linear group of LEDs.
    [0059] The applicant noted that the use of LEDs allows lighting to be provided in the required direction in a flexible and relatively economical way.
    [0060] Preferably, this source of electromagnetic radiation is almost telecentric.
    [0061] Preferably, a plurality of sources of electromagnetic radiation are provided, these sources being able to radiate with electromagnetic radiation, and each source having a main radiation direction that differs from the other sources of the plurality.
    [0062] Preferably, this light sensor includes a linear scanning video camera.
    [0063] Preferably, the equipment according to the invention includes a movement device capable of causing the movement of said tire surface in relation to said source of electromagnetic radiation.
    [0064] Preferably, the equipment comprises movement devices to provide relative movement of at least two among said source, said light sensor and said tire.
    [0065] In a preferred example, at least one between said light sensor and said source is moved by a robotic arm.
    [0066] Even more preferably, said light sensor and said source are fixed together and moved by the same robotic arm.
    [0067] Thus the tire is positioned in the best way for the aforementioned processing.
    [0068] Preferably, devices are provided for translating and / or rotating said tire in such a way that said portion of said surface is irradiated by said source.
    [0069] In an exemplary embodiment, said electromagnetic radiation includes radiation having a wavelength in the range of 495 nm to 570 nm.
    [0070] It was observed that when certain defects or characteristics of the tire must be detected and the goal is to make them more apparent in the groove images, the light that gives rise to the least errors is the green light.
    [0071] Advantageously, when a main longitudinal direction is defined in said groove, said operation of segmenting said image in said regions includes segmenting said image in regions that are essentially parallel to said main longitudinal direction.
    [0072] Generally, a groove has a main direction along which it extends and a transverse dimension, also called width. The applicant found that segmenting the image in regions that are parallel to the main direction of the groove simplifies the process of segmenting the surface. Essentially, where a digital image formed by pixels is involved, the examination is conducted by dividing the image into areas of pixels that u «q guugpekcnogpVg“ eonwpcu ”fg pixels parallel to the direction of extension of the groove. fg oqfq swg c atg fíec qw “Vofc fgpVtq” qw “Vofc fotc” was grooved, except in the case of border regions.
    [0073] Preferably, the size of said groove is not less than about 2 mm.
    [0074] Preferably, determining whether said region of said image belongs to said groove or not includes dividing said image into a plurality of regions; calculate a value of said statistical quantity for each region of said plurality; calculating the ratio between two values of said statistical quantity of two separate regions of said plurality; wherein one of the two regions of said plurality belongs to said groove and one does not belong to said groove when said ratio has a value outside a predetermined range.
    [0075] Additionally or alternatively, two regions of said plurality both belong to said groove or both do not belong to said groove when said ratio has a value within said predetermined range.
    [0076] The applicant found that segmenting the image in groove regions and regions outside the groove can be performed in a relatively simple way by analyzing a statistical quantity related to separate regions of the image. In other words, the applicant found that there are statistical quantities that differ markedly from each other in ceqtfq eqo ug gncu u «q ecnewncfcu go woc tgik« q fg "groove" qw go woc rgik "q" p «q fg groove" Rqrtcptq swcpfq c taz «q gpttg gutcu fwcu swcptkfcfgu fi sufficiently different from the unit, this means that the two regions of the image under examination belong to different groups, one belonging to the groove regions and one to the non-groove regions. However, if the reason is close to the unit, both regions investigated belong to the same group.
    [0077] Preferably, said statistical quantity is a standard deviation, said predetermined range extending from about 0.8 to about 1.25.
    [0078] The applicant found that, if the standard deviation is chosen as the statistical quantity, the predetermined range most suitable to allow segmentation of the image is that given above.
    [0079] Preferably, calculating said statistical quantity for each region of said image includes calculating a value of the dispersion of the data in relation to a variable related to a luminous intensity of each region of the image of said portion of the acquired irradiated surface.
    [0080] The applicant found that this difference between groove and non-groove areas is particularly pronounced when the dispersion of the data correlated with the light intensity of the groove and non-groove regions is calculated. It can be seen that the data dispersion is greater in the case of non-furrow areas, allowing these areas to be identified based on the difference between the observed values and those for the furrow regions where the dispersion is less.
    [0081] More preferably, calculating said statistical quantity for each region of said image includes calculating the standard deviation of the data in relation to a variable related to the luminous intensity of each region of the image of said portion of the acquired irradiated surface.
    [0082] Even more preferably, calculating said statistical quantity for each region of said image includes calculating the standard deviation of the luminance of each region of the image of said portion of the acquired irradiated surface.
    [0083] In an exemplary embodiment, calculating a statistical quantity associated with irradiation for each region of said image includes: calculating said statistical quantity for a region of said image including a column of pixels having a width of at least one pixel.
    [0084] As stated above, the acquired image, usually a digital image, is an image formed by a plurality of pixels. It is rqrtcpVq rtqeguucfc rtqeguucnfq "ágcu fg pixels eqnVinwqu" swg u «q preferably columns of pixels having a base width of at least one pixel.
    [0085] Preferably, an average of said statistical quantity is calculated for at least three columns of pixels.
    [0086] In other words, for example, the regions of the image can be composed of columns with a width of 3 pixels and a height depending on the average dimensions of the groove, so that the statistical reference quantities are calculated. When the desired statistical quantity has been calculated for a first region, the calculation is repeated for woc qwttc tgik «q fq oguoq tcocnhq,“ fgunqecfc rqt wo rkzgn ”with respect to the first region, and so on. Therefore, for each column of pixels with a width of one pixel, there are three values of the statistical quantity involved, and the average of these is taken. However, other averages with a different number of data can be calculated and are included in the present invention.
    [0087] The grooves present on the tire surface can be in any position and can be of any type, either on the radially internal surface or on the radially external surface of the tire.
    [0088] Preferably, said at least one groove is present on a tread of said tire.
    [0089] Even more preferably, said at least one groove is present over a shoulder area of said tire.
    [0090] The applicant stressed that the pre-processing that is conducted, in other words the division of the image into groove areas and non-groove areas, simplifies any subsequent processing, such as processing to identify defects in the tire grooves.
    [0091] Preferably, said equipment includes another processor capable of processing at least one of said regions belonging to said at least one groove, for the detection of defects within it
    [0092] The other processor can also match the main processor; in other words, a single processor can perform all calculations relating to the method of the invention.
    [0093] More preferably, said other processor is capable of processing defects having a size of not less than about 0.5 mm.
    [0094] Even more preferably, said other processor is capable of processing defects comprising an exposed cord.
    [0095] Preferably, processing said region belonging to said groove includes using a small wave transform and / or a morphological operator.
    [0096] In order to identify known defects, methods and algorithms are used, for example small wave transforms, morphological operators, and the like. An example of methods and algorithms that can be used for the purposes of the present invention can be found at Go To Iqpzcngz. To Yqqfu. “Digital Image Processing RtgpVkeg Jcn. 422:
    [0097] The characteristics and advantages of the invention will become clearer by the detailed description of the same preferred example of embodiment, illustrated, for the purposes of guidance and in a non-limiting manner, with reference to the attached drawings, in which :
    [0098] Figure 1 is an axonometric view of an exemplary embodiment of equipment for segmenting a tire.
    [0099] Figure 2 is an enlarged perspective view from above of a component of the equipment in Figure 1.
    [00100] Figure 3 is an enlarged perspective view of another component of the equipment in Figure 1.
    [00101] Figure 4 is a perspective view from above of a portion of a tire to which the method according to the invention is applied.
    [00102] Figure 5 is a partial perspective view of a groove belonging to a tire.
    [00103] Figures 6a and 6b are, respectively, an enlarged view of part of the image of figure 4 and a histogram of the luminance calculated over the area enclosed by the region shown in broken lines in figure 6a, which is located outside the groove in this case .
    [00104] Figures 7a and 7b are, respectively, an enlarged view of part of the image in figure 4 and a histogram of the luminance calculated over the area enclosed by the region shown in broken lines in figure 7a, which is located within a groove in this case;
    [00105] Figures 8a and 8b are, respectively, an enlarged view of part of the image in figure 4 and a histogram of the calculated luminance over the area enclosed by the region shown in broken lines in figure 8a, which is located in the extreme left outline of the groove in this case.
    [00106] Figure 9 is a graph showing the variation of the standard deviation of the luminance as a function of the number of pixels (the longitudinal coordinate);
    [00107] Figures 10a, 10b and 10c show three images corresponding to three successive operations of processing a region of the image of figure 4 according to three steps of the method of the invention.
    [00108] Figure 11 is a diagram of a detail of the equipment of the invention shown in figure 1.
    [00109] With initial reference to figures 1 and 2, the number 1 indicates all the equipment to segment the surface of a tire P.
    [00110] In detail, the tire P, shown schematically in figures 1 and 2, defines a Z axis, substantially coinciding with its own axis of rotation, and an X plane, the tracing of which can be seen in figure 2, which is the plane equatorial angle of the tire, in other words the median plane perpendicular to the axis of rotation Z. The tire comprises a carcass structure 2 including at least one carcass tarpaulin (not shown in the drawings) which is associated for operation with a pair of annular structures of fixation (one of which is visible in figure 1 and is indicated by 1a), a tread 3 in a position radially external to said carcass structure, and a belt structure (not shown) interposed between the carcass structure and the tread 3. Planes containing the tire's axis of rotation are indicated as radial planes.
    [00111] In the text below, the tire P will be described with reference to its equatorial plane X and its radial planes, and therefore references to “czkcnogpVg kptgππVgztgrpq” qw “tcfkcnogpVg kpVgmqlgzVgmq” fgxgo ugt reference with interpreted plane and the axis of rotation Z respectively. Surfaces delimiting the tire, such as a radially internal surface 5b, which for example can coincide with an airtight component called a liner, and a radially external surface 5a, typically the outer surface of the tread 3, are therefore defined on the tire .
    [00112] A plurality of grooves are formed on the tread 3, all these grooves being generically indicated by 4, delimiting a plurality of blocks 5 (visible only in figure 4, where an enlarged portion of the tire is shown), and being arranged in succession along a circumferential direction of the tread 2.
    [00113] Grooves 4 may be circumferential, in other words, extend over the entire length of the circumference of the tire P, or it may extend over a portion of the circumference only. Additionally, they can extend along said circumferential direction, along a direction essentially perpendicular to the circumferential direction (in the case of transverse grooves), or along an inclined direction with respect to both of these. For example, figure 4 shows a circumferential groove and a plurality of transverse grooves that are essentially perpendicular to the circumferential groove.
    [00114] In addition, the grooves can have an essentially straight shape, or in other words they can essentially extend along a main longitudinal direction, or a curved, wavy or zigzag shape, meaning that projections on axes perpendicular to the direction main extension will be non-zero.
    [00115] In the case of winter tires, one or more sipes 6 can be formed in each block 5, as shown in figure 4, these sipes extending, in the preferred example described here, along a perpendicular direction with respect to circumferential direction of the tire P. However, the arrangement and configuration of the sipes, if present, is not significant for the purposes of the present invention.
    [00116] It should be understood that alternative embodiments, in which the shape of the blocks 5 and the arrangement of the grooves 4 and any lamellae 6 are designed differently on the tread 3 in order to meet specific functional requirements, can easily be produced by persons specialized in the technique.
    [00117] Each groove 4 can be blunt, in other words completely separate from the other grooves in the tread 3, or it can be opened, at one or both of its opposite longitudinal ends 6a, 6b, in an additional groove 4 or a pair additional grooves delimiting the block 5, as for example in figure 4, in order to pass through the block from side to side.
    [00118] With reference to figure 5, which is an enlarged schematic representation of a groove, groove 4 extends between a top surface 17 of the groove, which opens over the tread surface 3, and a surface of bottom 18 of the groove, in a radially internal position in the tread 3 with respect to the top surface 17. Groove 4 separates one from the other a first and a second block, which are again identified by the number 5, and which are spaced for a distance that preferably remains essentially constant along the longitudinal extent of the groove 4 and is equal to the width of the latter. This width is preferably greater than about 2 mm. However, grooves 4 having a variable width along their longitudinal extent are also included in the present invention.
    [00119] Groove 4 defines a wall 9 of the first block and a wall 10 of the second block, these walls facing each other and extending from the top surface 17 to the bottom surface 18. The walls 9 and 10 are identified as groove side walls 4.
    [00120] The two walls 9 and 10 are essentially flat, and therefore have a profile with an essentially straight extension. However, curved walls, in the case of a groove 4 having a non-straight longitudinal extension, are also possible and are covered by the invention.
    [00121] A typical groove depth 4, in other words the radial distance between the bottom wall 18 and the top wall 17, is for example in the range of about 4 mm to about 12 mm, depending on the use of the tire P (racing tire, winter tire, etc.).
    [00122] The bottom wall 18, and also the top wall 17, can be considered to be essentially flat locally, in the sense that, although the curvature due to the tire's toroidal geometry makes the entire tire surface convex, points within a sufficiently small area they can be considered to be on a plane tangent to the tire surface.
    [00123] In the description above, reference is made to a groove 4 formed on the tread surface 3. A similar groove, with a bottom wall 18 and a top wall 17 defined in the same way, can be present in the radially internal part 5b of tire P. According to the invention, equipment 1 is used to segment a portion of the inner or outer surface 5a, 5b of tire P, preferably, but not necessarily, for the purpose of detecting defects and / or characteristics of the tire on this examined portion of the surface. A defect or characteristic that should preferably be detected, regardless of its type, is identified below by the number 70.
    [00124] Equipment 1, shown schematically in figure 1, on which the tire P described above is placed, comprises, for example, a base 40 on which the tire rests. As shown in figure 1, the tire P can be laid flat on the base 40, in other words with its equatorial X plane parallel to the base, or alternatively the base can be perpendicular to the equatorial plane and the tire P can be held in a position vertical by one or more fasteners that are not shown.
    [00125] Equipment 1 also includes a source of electromagnetic radiation 50, shown on an enlarged scale in figure 3, and a light sensor 51. The equipment also comprises a movement device to put source 50, light sensor 51 and tire P in relative motion so as to position the light sensor and the source at the desired position and distance with respect to one of the radially internal or external surfaces 5a, 5b of the tire P.
    [00126] Preferably, the movement device is such that the light sensor and the source move as a unit.
    [00127] In the example of figure 1, the movement device includes a robotic arm 41, to which the light sensor and the source are attached, and which can move away from and / or approach the tire P, which remains stationary on the base 40. Preferably, the robotic arm 41 is an anthropomorphic robotic arm with at least three axes. In another representative anthropomorphic, the P tire is put in rotation and / or translation on the base 40 by other rotation and / or translation devices (not shown), while the light sensor and / or the source are fixed. In addition, both the P tire and the source and / or light sensor can be mobile; for example, tire P can also be moved to simplify the movement of the robotic arm 41, or in such a way that the latter can be positioned in proximity to any point on the surface of the tire.
    [00128] In the preferred example of figure 1, light sensor 51 and source 50 are moved as a unit.
    [00129] The source 50 is moved by the means of movement in order to illuminate a portion of the tire surface P at a predetermined angle. In a preferred example, the source is positioned so as to illuminate the tire surface with an essentially striking light.
    [00130] The radiation source 50 emits electromagnetic radiation in the visible spectrum, and more precisely within a range of about 380 to about 760 nm. Preferably, the source 50 includes a light-emitting diode (LED) 58, and even more preferably it includes a plurality of LEDs 58. In a preferred embodiment, the LEDs are arranged in a linear group, one after the other, as shown in figure 3. Preferably, the LEDs are positioned at the shortest distance possible from light sensor 51, for example about 5 cm from light sensor 51. For example, they can be high brightness LEDs with a half irradiation angle of 15 degrees, supplied with electrical power. Additionally, source 50 is preferably almost telecentric.
    [00131] In an exemplary embodiment, the electromagnetic radiation emitted by the source 50 is green.
    [00132] Preferably, the radiation source emits electromagnetic radiation along a main direction, which can be selected. Alternatively, there may be a plurality of radiation sources, each used to radiate a portion of the tire along a different main direction.
    [00133] The light sensor 51 includes, for example, a video camera, more preferably a linear scan color video camera, to acquire an image of a surface portion of the tire P, particularly the portion of the tire that is illuminated by source 50. Preferably, the video camera is capable of acquiring an image at an essentially constant viewing angle and with an essentially constant angle of incidence of electromagnetic radiation.
    [00134] With reference to figure 11, the light sensor 51 is associated for operation with a memory 52, which can be inside or outside the light sensor itself, for the purpose of storing the data related to the acquired images of the tire. The images, in other words the data, acquired in this way are also processed by a processor 53, for example part of an external unit such as a personal computer or other device known in the art.
    [00135] The minimum defect size that can be detected by means of the invention depends on the resolution of the light sensor 51. In particular, in the case of a linear scanning video camera, it depends primarily on the number of pixels of the sensor used. In the case of the aforementioned drawings, the scale is equal to 1/10 mm per pixel, as an example. In the preferred example, the minimum defect size and / or feature 70 that can be detected is about 0.5 mm. On the other hand, the sweep frequency is preferably related to the tire's rotation speed, and it is specified in order to obtain the resolution, for example the aforementioned 1/10 mm resolution.
    [00136] Equipment 1 may include other devices and other radiation sources and / or light sensors, in order to illuminate a portion of the tire surface P alternatively with different radiation spectra or in combination with these spectra in order to perform different types of inspection and analysis. In addition, the image acquired using light sensor 51 can be processed separately by separate processors or by the same processor 53, using separate algorithms, in order to identify different relevant characteristics of the P tire, each characteristic preferably being detectable by a separate method. .
    [00137] Equipment 1 also preferably includes input devices 54, electrically connected to processor 53, through which an operator can send commands to the processor, for example to select the type of characteristic or defect to be identified, to obtain information regarding the type of tire placed on equipment 1, and for other purposes. Input devices 54 can also operate automatically without any action by the operator; for example, the equipment may include a reader for an identification code such as a bar code (not shown in the drawings), this reader being able to read a code printed on the tire P that carries information about the structural characteristics of the tire. This code reader can be activated by the operator.
    [00138] The operation of equipment 1 and the method of the invention are described below.
    [00139] Depending on the type of feature or defect to be detected on the radially external and / or radially internal surface 5a, 5b of the tire P, it may be preferable not to examine the entire internal and / or external surface using the method or equipment of the invention , but only part of the surface. Therefore, a first optional action is to identify the radially internal and / or external surface area 5b, 5a of the tire P to be segmented.
    [00140] Optionally, therefore, according to the method of the invention, this part, which can be either continuous, in other words a single area of the inner and / or outer surface of the tire, or separated into unconnected areas, is divided into portions 100, each of which is illuminated as described below. The size of the portion 100 depends on the characteristics of the source 50, the light sensor 51 and the type of characteristic or defect to be examined: for example, whether it is desired to obtain a condition in which the electromagnetic radiation is essentially scratchy with respect to the portion examined , the rqt> «q fgxg ugt uwhkeigpVgogpVg" pgc] iignc “rctc cuugiwtct swg c ewtxcVwtc fq tire does not excessively affect the analysis Clearly, the size of this portion therefore depends on the radius of the tire, and more generally on the type, the width of the shoulder, etc.
    [00141] In figure 4, a portion 100 of the outer surface 5a of tire P is identified with the help of a rectangle to make it visible. The portion 100 includes the groove 4 and a top surface portion 17. A single portion 100 is shown, but numerous portions 100 may be present on the tire surface P.
    [00142] Preferably, this portion 100 is located on the tread 3 of the tire, and more preferably on a shoulder of the tire P.
    [00143] Consequently, when the P tire was positioned on the base 40 of equipment 1, the method of the invention optionally provides for automatic commands or appropriate operator commands to be sent to processor 53 in order to move the light sensor and / or the source and / or the tire in relation to each other, in order to orient the tire with respect to the source and light sensor in the most favorable way in order to obtain an image with the desired illumination of the portion 100. Clearly, the tire and / or the light sensor and / or the source are preferably moved again to each different portion 100, to enable the light sensor, source and tire to be optimally repositioned with respect to the new portion. The use of the robotic arm 41 and a fixed coupling between the light sensor 51 and the source 50, using for example a U-shaped upright 42 on whose opposite arms 42a, 42b the source and the light sensor are fixed, ensures that access is essentially possible to any part of the P tire.
    [00144] With reference to the portion 100 shown in figure 4, in the present preferred example the tire is positioned so that the source 50 illuminates the bottom wall 18 of the groove 4 in an essentially flat manner, so that only one groove is present within portion 100, and so that the main longitudinal direction of the groove is essentially parallel to the scan axis of the linear video camera.
    [00145] All these data can be present in the code of kfgpVkfíec> «q fq rpgw swg“ kphotoc ”q rtqeguucfqt 75 fqu fcfqu fg construction of the P tire, so that the correct positioning and the correct inclination are automatically calculated.
    [00146] After the optional positioning according to the reading of the tire identification code P, the predetermined portion 100 of the area to be analyzed is illuminated by means of the radiation source 50. An image 100a of the illuminated portion 100 is acquired by means of of light sensor 51. Examples of the acquired image 100a are shown in figures 6a, 7a and 8a. The image 100a is then saved in memory 52, and is then processed by processor 53. Processing can take place simultaneously with image acquisition; in other words, in the case of a linear video camera for example, each acquisition of a line of pixels of the image in place simultaneously with the processing of the line of pixels. Alternatively, it can take place sequentially; in other words, the entire image is acquired and stored initially, and is subsequently processed.
    [00147] Image 100a is processed in order to segment it into regions 101 that belong to the groove and regions 102 that do not belong to the groove. In other words, the image 100a is segmented into areas, or regions, where the groove is present and in areas where no groove is present, regardless of any other element, other than groove 4, that may be present.
    [00148] At the end of the segmentation operation of image 100a, described below, a groove region inqdcn "323Ó" fi "fghkpkfc." eqoq "woc" combination of all groove regions, and a non-global groove region 324Ó guVá Vcodfio rtgugpVgo Eqo tgfetêpekc fg pqxq §u fiiwtcu 8c. 9c g: d. c inqdcn groove region 323Ó g c non-groove region 324Ó u «q knwuvtcfcu0
    [00149] Region 101 or 102 of image 100a can be, for example, a column of pixels: as shown in figures 6a, 7a, 8a, the column shown as a broken line represents the region for which the goal is to determine whether it belongs to groove 101 regions or non-groove 102 regions (in other words, whether the pixel column is located inside or outside groove 4). The pixel columns represent the scan lines of the linear video camera. However, regions having different sizes and geometries can also be considered in the present invention.
    [00150] In order to determine whether a region 101, 102 is a groove region or not, it is processed as follows. Initially, a variable, in other words a physical quantity, is calculated for each region, this variable being related to the irradiation of this area. For example, it may be related to the luminous intensity of the surface region. For example, the luminance of each pixel is calculated on a pixel by pixel basis for each region 101, 102. For example, figure 6b shows a histogram in which, for each pixel in the pixel column identified by 102 in figure 6a, which has a base of 3 pixels and a height of 600 pixels (corresponding to an area of 0.3 cm by 6 cm), the luminance of the pixel is shown, as detected from the image 100a. Therefore, the graph in Fig. 6b is a visual representation of the luminance of each pixel across the entire column of pixels (which constitutes region 102), including 1800 pixels in this case. Preferably, the column has a base of more than one, for example three, as illustrated above: the video camera 50 follows lines with an amplitude of one pixel and calculates the statistical parameter taking into account the current pixel column of unit width , as well as the previous and subsequent columns (the calculation can actually be performed one column later).
    [00151] Similarly, the graphs of figures 7b and 8b represent in histograms the luminance values, pixel by pixel, of the column of pixels shown in broken lines in figures 7a and 8a respectively.
    [00152] From this plurality of values, a single statistical quantity is calculated, for example by means of a calculator 55 that is part of processor 53, for the entire region 101, 102, this quantity being a single quantity associated with the region , whereby it is possible to determine whether the region under examination belongs to the groove or not.
    [00153] Preferably, this statistical quantity of the region is a statistical quantity identifying the dispersion of data from the irradiation-related variable. Even more preferably, this amount guVcVíuVkec fi q fguxkq rcft «qj fqu fcfqu fc swcpVkfcfg fíukec ecnewncfc = go particular, the standard deviation of the luminance values for the pixel column is obtained, in other words:

    [00154] qpfg x fi c ofifkc fqu xcnqtgu fc xctkáxgL
    [00155] With reference again to the graphs 6b, 7b, 8b, as it was said they correspond to the luminance values for each pixel of the column of pixels shown in figures 6a, 7a, 8a respectively. As can be seen, the first column of pixels, in figure 6a, is completely out of the groove, fgxg rqrtcpVq ugt ecVgiqtkzcfc eqoq woc “tgii« qp «q rgrtgpegpfq to the groove”, in other words, the 102 region. column of pixels, in figure 7a, is completely inside groove 4, and should therefore be categorized as “tgiião belonging to the groove” woc, qw ugjc c tgik «q 323o Pc fíiwtc: c. c third pixel column gutá “pc atgc fg ttcpui>« q ”gpttg the groove and the outside, and therefore it may or may not be defined as a groove region, depending on predetermined initialization settings. In the case in question, it is considered to be a non-furrow region.
    [00156] As can be clearly seen from a comparison between the histograms in figures 6b and 7b, the dispersion of data in a region outside the groove is much greater than the dispersion of data in a region within the groove, and this This fact is demonstrated by the two standard deviation values, which are, in particular, equal to 101.31 outside the groove and 58.26 inside it. When the region examined is located in a transition region (as in the case of the third column of pixels shown in figure 8a), the value of the standard deviation hiec “c ogiq ecoipjq” gpttg qu uwrtcogpeiqpcfqu fqiu xcnqtgu. ugpfq iiwcn c 99.01.
    [00157] Repeating the calculation of the standard deviation, or of another statistical quantity, for all the regions that constitute the image 100a, a graph is obtained as the one of the figure 9: the horizontal axis shows the pixel number of each position in the column of pixels in image 100a, and the vertical axis shows the corresponding value of the standard deviation of the luminance of the column of pixels at this position. As the graph shows, there is a clear differentiation between the groove regions and the non-groove regions, the regions belonging to the groove providing a standard deviation value that is much less than the corresponding value for the non-groove regions.
    [00158] In particular, for example, in order to determine whether two regions (such as the first and second pixel columns of figures 6a and 7a) both belong to groove 4 or both do not belong to groove 4, or whether a column is one groove region while the other column is not a groove region, it is possible to calculate the ratio between the two values of the statistical quantity calculated for the two regions. In the present case, the calculation of the ratio between the standard deviation of the luminance of the first column and the standard deviation of the second column gives a value of 1.73. Preferably, if the ratio value is greater than 1.25 or less than 0.8, the two regions belong to two separate groups; in other words, one is a groove region and the other is a non-groove region, as in the present case. However, if this ratio is in the range of 0.8 to 1.25, both regions belong to the same group, which can be the groove group or the non-groove group.
    [00159] In this case, the threshold value of the standard deviation is taken to be 80, for a region to be considered as belonging to the groove.
    [00160] It follows from the above that the calculation of a statistical quantity such as standard deviation can be used to determine, for each region of the image 100a, whether or not it belongs to groove 4, and therefore to segment the image 100a into regions 101 and 102, in other words to select each region, using a selector 56, placing it in the group to which it belongs and thus forming the groove region inqdcn "323Ó" g "c" tgik «q" p «Q" fg "groove 124Ó0
    [00161] The operation described above is repeated for all relevant regions 100 of the P tire, forming the area that must be segmented, as stated above.
    [00162] After segmentation, according to the method of the invention, provision is made optionally to detect defects 70 in the portion 100 of tire P that has been segmented into groove 101 regions and non-groove 102 regions. This detection includes the processing of only one of two groups of regions, in other words processing only groove 101 regions or just non-groove 102 regions. Preferably, only groove 101 regions are considered.
    [00163] Figure 10a shows a detail of the groove region inqdcn "323Ó derived from the segmentation of image 100a of figures 6a, 7a, 8a.
    [00164] A possible defect 70 detectable in the detail of the groove region inqdcn "323Ó" fi. "Rqt" gzgornq. "Wo" eqtfqpgn "exposed inside groove 4, which is identified in figures 5a to 8a by an oval in lines interrupted.
    [00165] This groove region inqdcn "323Ó" fi "rqtvcpvq" rtqeguucfc "rqt" appropriate algorithms known in the technical field of image processing, for example by means of processor 53 or another additional processor (not shown). In the illustrated example, the groove region inqdcn "323Ó of figure 10a is processed by means of a swctvc small wave transform" qtfgo. "Qdvgpfq" cuuko "c" tgik «q" inqdcn "rtqeguucfc" 323ÓÓ "fc" hkiwtc " 32d "Using another optional processing operation, for example by setting a threshold over the gray values of the image, the global region doubly procguucfc 323ÓÓÓ fc fíiwtc 32e fi qdvkfc. Qpfg cu" qpfwnc> õgu "which are a sign of the presence of a exposed cordon 70 are clearly visible.
    [00166] Of course, the type of algorithm used depends on the type of defect to be identified or displayed, and therefore numerous other processing operations can be performed using the method and equipment of the invention. In addition, a plurality of processing operations can be performed simultaneously or successively in order to identify different types of defects in the same region.
    权利要求:
    Claims (14)
    [0001]
    1. Method for segmenting the surface (5a, 5b) of a tire (P) including at least one groove (4), said method comprising: irradiating a portion (100) of said surface (5a, 5b) of said tire (P ) with electromagnetic radiation having a wavelength in the visible spectrum; acquiring an image (100a) of said portion (100) of the irradiated surface; processing said image (100a) in order to segment it into regions (101, 102) corresponding to regions of the tire that belong or not to said at least one groove (4); where to process said image (100a) in order to segment it includes: calculating a statistical quantity associated with irradiation by said electromagnetic radiation for each region (101, 102) of said image (100a); determine whether said region (101, 102) of said image belongs or not to said at least one groove (4) according to the value of said statistical quantity, characterized by the fact that calculating said statistical quantity for each region (101, 102 ) of said image (100a) includes calculating the value of the data dispersion in relation to a variable related to a luminous intensity of each region (101, 102) of the image (100a) of said portion (100) of the irradiated surface (5a, 5b) acquired, and in which to determine whether said region (101, 102) of said image (100a) belongs or not to said groove (4) also includes calculating the ratio between two values of said statistical quantity of two separate regions (101, 102); wherein one of the two regions belongs to said groove and the other does not belong to said groove when said ratio has a value outside a predetermined range.
    [0002]
    2. Method according to claim 1, characterized by the fact that radiating a portion (100) of said surface (5a, 5b) includes the fact that said electromagnetic radiation is essentially scratching with respect to a lower surface (18) of at least one groove (4) is said.
    [0003]
    3. Method according to claim 1, characterized by the fact that two regions (101, 102) both belong to said groove (4) or both do not belong to said groove when said ratio has a value within said predetermined range.
    [0004]
    4. Method according to claim 1, characterized by the fact that calculating this statistical quantity for each region (101, 102) of said image (100a) includes calculating the standard deviation (o) of the data in relation to a variable related to a luminous intensity of each region of the image of the portion of the acquired irradiated surface.
    [0005]
    5. Method according to any one of the preceding claims, characterized by the fact that calculating a statistical quantity associated with irradiation for each region (101, 102) of said image (100a) includes: calculating said statistical quantity for a region (101 , 102) of said image (100a) including a column of pixels having a width of at least one pixel.
    [0006]
    Method according to any one of the preceding claims, characterized by the fact that said at least one groove (4) is present in a shoulder area of a tread (3) of said tire (P).
    [0007]
    7. Method for detecting defects (70) on a surface (5a, 5b) of a tire (P), characterized by the fact that it includes the method for segmenting the surface of a tire (P), as defined in any of the claims 1 to 6, and in which said method includes: processing at least one of said regions (101) of said image (100a) belonging to said at least one groove, for the detection of defects (70) within it.
    [0008]
    8. Equipment (1) for segmenting a surface (5a, 5b) according to the method as defined in any one of claims 1 to 7, said equipment (1) comprising: a source of electromagnetic radiation (50) capable of radiating a portion (100) of said surface of said tire with electromagnetic radiation having a wavelength in the visible spectrum; a light sensor (51) capable of acquiring an image (100a) of said portion (100) of the radiated surface of said tire; a processor (53) capable of processing said image by dividing it into regions (101, 102) that belong or not to said at least one groove (4), said processor (53) including: a calculator (55) capable of calculating a statistical quantity associated with irradiation by said electromagnetic radiation for each region (101, 102) of said image (100a); a selector (56) capable of determining whether said region (101, 102) of said image (100a) belongs to said at least one groove (4) according to the value of said statistical quantity, characterized by the fact that said When calculating said statistical quantity for each region (101, 102) of said image (100a), it calculates a value of the data dispersion in relation to a variable related to the luminous intensity of each region (101, 102) of the image ( 100a) of said portion (100) of the acquired irradiated surface (5a, 5b), and in which said calculator still calculates the ratio between two values of said statistical quantity of two separate regions (101, 102), and the selector determines that one of the two regions belongs to said groove and the other does not belong to said groove when said ratio has a value outside a predetermined range.
    [0009]
    9.Equipment (1) according to claim 8, characterized by the fact that said source of electromagnetic radiation (50) is almost telecentric.
    [0010]
    10. Equipment (1) according to claim 8 or 9, characterized by the fact that said electromagnetic radiation is essentially scratching with respect to a lower surface (18) of said at least one groove (4).
    [0011]
    11. Equipment (1) according to any one of claims 8 to 10, characterized in that said radiation source (50) includes an LED (58).
    [0012]
    Equipment (1) according to any one of claims 8 to 11, characterized by the fact that it includes another processor capable of processing at least one of said regions (101,102) belonging to said groove (4), for the detection of defects (70) within it.
    [0013]
    13. Equipment (1) according to any one of claims 8 to 12, characterized by the fact that at least one of said light sensor (51) and said source (50) is moved by a robotic arm (41).
    [0014]
    14. Equipment (1) according to claim 13, characterized by the fact that said light sensor (51) and said source (50) are fixed together and moved by the same robotic arm (41).
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    同族专利:
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    RU2017126754A|2019-01-31|
    US20150226644A1|2015-08-13|
    BR112015001413A2|2017-08-01|
    EP2880415B1|2020-11-18|
    MX348775B|2017-06-27|
    WO2014020485A1|2014-02-06|
    RU2017126754A3|2020-12-03|
    MX2015000927A|2015-04-10|
    RU2742316C2|2021-02-04|
    CN104541145B|2019-03-12|
    US9835524B2|2017-12-05|
    CN104541145A|2015-04-22|
    EP2880415A1|2015-06-10|
    RU2015105804A|2016-09-20|
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    FR2925706B1|2007-12-19|2010-01-15|Soc Tech Michelin|DEVICE FOR EVALUATING THE SURFACE OF A TIRE.|
    ES2366110T3|2008-04-14|2011-10-17|Snap-On Equipment Srl A Unico Socio|DEVICE TO DETERMINE THE STATE OF A WHEEL ASSEMBLY.|
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    FR3038111B1|2015-06-29|2017-08-11|Michelin & Cie|IMAGE SEGMENTATION METHOD|
    EP3391015B1|2015-12-16|2020-10-14|Pirelli Tyre S.p.A.|Device and method for the analysis of tyres|
    WO2017103809A1|2015-12-16|2017-06-22|Pirelli Tyre S.P.A.|Apparatus and method for the analysis of tyres|
    US10605698B2|2015-12-16|2020-03-31|Pirelli Tyre S.P.A.|Method and apparatus for checking tyres|
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    CN108474720B|2015-12-22|2020-08-07|倍耐力轮胎股份公司|Apparatus and method for inspecting tyres|
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    CN108463705B|2015-12-28|2020-08-07|倍耐力轮胎股份公司|Method and setting device for setting a tire inspection apparatus|
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    BR112019001466A2|2016-07-26|2019-05-07|Pirelli Tyre S.P.A.|method for checking a tire and checking station|
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    IT201800020395A1|2018-12-20|2020-06-20|Pirelli|Method of controlling a molding and vulcanization process of a tire and tire obtained through a manufacturing process that implements this method|
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    法律状态:
    2018-12-04| B06F| Objections, documents and/or translations needed after an examination request according art. 34 industrial property law|
    2020-03-31| B06U| Preliminary requirement: requests with searches performed by other patent offices: suspension of the patent application procedure|
    2020-10-13| B09A| Decision: intention to grant|
    2020-12-15| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 23/07/2013, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    ITPD2012A000234|2012-07-31|
    ITPD20120234|2012-07-31|
    US201261678709P| true| 2012-08-02|2012-08-02|
    US61/678,709|2012-08-02|
    PCT/IB2013/056023|WO2014020485A1|2012-07-31|2013-07-23|Method for segmenting the surface of a tyre and apparatus operating according to said method|
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