Method for image capturing of a marking on an object
By dividing the surface of the object into multiple sub-regions, illuminating and collecting images one by one, combining image processing and automated recognition technology, the problem of high-contrast acquisition of markers is solved, and efficient image acquisition and automatic recognition of vehicle component markers is achieved.
Patent Information
- Application Number
- CN202510177970.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-02-26
- Filing Date
- 2025-02-18
- Publication Date
- 2025-08-26
AI Technical Summary
The prior art is difficult to achieve high contrast image acquisition of marks formed by surface structures of objects, especially when the lighting conditions change, it is difficult to effectively collect authentication text marks on vehicle components.
By dividing the object into multiple sub-regions, lighting equipment illuminates each sub-region one by one in different time ranges, and using an image acquisition device to acquire a single image, and finally combine it into an overall image, combining image processing methods and automated optical character recognition technology to achieve high-contrast acquisition of marks.
High-contrast image acquisition of markers is realized, and the authentication text on vehicle components can be automatically recognized and digitized, improving the effect and efficiency of image acquisition.
Smart Images
Figure CN120544207A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for capturing an image of a marking on an object. The object may be a plastic body. Preferably, the object is a vehicle component requiring approval. For example, the object is a transparent portion of a vehicle light. Other object configurations are also conceivable. Importantly, the object has a marking. For vehicle components requiring approval, the marking may include a certification text with corresponding inspection characters (e.g., ECE or CCC inspection characters). Background Art
[0002] In the sense of the present invention, such a marking is formed by a structure on a surface section of the object.
[0003] After manufacturing such objects, the markings must be visually inspected. In this case, automated visual inspection systems are typically used, in which the markings are captured using an image acquisition device (e.g., a camera). Since the markings are formed by structures on the surface sections of the object and their capture by the image acquisition device can be highly dependent on the ambient light incidence, it is difficult to capture high-contrast images of the markings. Therefore, the object of the present invention is to achieve improved image capture of such markings. Summary of the Invention
[0004] This problem is solved by a method of the type mentioned at the outset, wherein the method comprises the following steps:
[0005] a) providing an object and receiving and holding the object in a device, wherein the object has a marking formed by a structure at a surface section of the object;
[0006] b) providing a lighting device, which is designed to illuminate predefinable subregions of the surface segment within a predefinable time range, wherein each subregion is assigned a time range, and wherein the surface segment with the marking is combined from m subregions, so that the m subregions can be illuminated within the m time ranges;
[0007] c) providing an image acquisition device, which is configured to acquire at least a subregion of the surface segment as a single image in each time range, wherein each time range is assigned a single image, so that m single images can be acquired in m time ranges;
[0008] d) illuminating an nth subregion (24) of the surface segment (23) with a lighting device (40) within an nth time range (Tn), wherein n is a natural number and is initially equal to 1;
[0009] e) acquiring an nth subregion of the surface segment within an nth time range using an image acquisition device, and storing the resulting nth single image in a memory;
[0010] f) continuing to repeat steps d) and e), wherein n is increased by 1 before each repetition, and the repetition is terminated after the m-1th repetition;
[0011] g) Creating an overall image by combining individual images.
[0012] m is a natural number.
[0013] Advantageously, provision can be made for the surface segment to be divided into at least 2, preferably at least 10, particularly preferably at least 50 subregions, whereby m is at least equal to 2, preferably at least equal to 10, particularly preferably at least equal to 50.
[0014] To simplify the combination of the individual images, it can advantageously be provided that the subregions partially overlap, so that in each step d) a partial structure of the surface segment is illuminated which is or has already been illuminated in at least one other step d).
[0015] Another advantage is that the marking has at least partially printable characters and that after step g) the marking is at least partially digitized from the overall image by automated optical character recognition.
[0016] Flexible use of the method is achieved in that the lighting device is accommodated on the apparatus so as to be movable relative to the object, so that with each repetition of step d), a different sub-area is illuminated due to a change in the position of the lighting device than during the previous execution of step d).
[0017] Alternatively or additionally thereto, the lighting device may be configured to radiate segmented light, so that during each repetition of step d), a different subregion than during the previous execution of step d) is illuminated by a suitable segment of the light radiated by the lighting device. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention is illustrated below with the aid of the accompanying drawings which are exemplary and non-limiting.
[0019] Figure 1 Display objects with markers,
[0020] Figure 2 showing the device with the contained object,
[0021] Figure 3 An exemplary flow chart showing a method,
[0022] FIG4 shows an exemplary single image, and
[0023] Figure 5 An exemplary overall image is shown. DETAILED DESCRIPTION
[0024] Figure 1 An object 20 is shown with a marking 10 . The marking 10 is formed by a structure 21 at a surface section 23 of the object 20 .
[0025] Such an object 20 can be designed as a plastic body. Preferably, the object 20 is a component of a vehicle that requires approval.
[0026] For example, object 20 is a transparent part of a vehicle lamp. Other configurations of object 20 are also conceivable. Importantly, object 20 bears marking 10. For vehicle components requiring approval, marking 10 may include certification text with corresponding inspection characters (e.g., ECE or CCC inspection characters).
[0027] Such a marking 10 within the meaning of the present invention is formed by a structure 21 on a surface section 23 of an object. Such a structure 21 can be designed as a molding, a roughening, or a depression on the surface 22 of the object 20. In the example of the present application, the structure 21 in the form of a depression is introduced into the surface 22 of the object 20 by material removal using a laser. The section of the surface 22 of the object 20 that has the structure 21 can be referred to as a surface section 23. If an object 20 has a plurality of markings 10, then the object 20 has a plurality of surface sections 23.
[0028] For example, such a structure 21 can also be produced as a roughened portion on the surface 22 of the object 20 by known engraving methods. Furthermore, such a structure 21 can also be produced as a molded portion by appropriately designed tools using a forming method (e.g., injection molding) as early as during the production process of the object 20. Many other approaches are known for producing such a structure 21. As shown, the structure 21 is an integral part of a surface section 23 of the object 20 itself and, in this case, forms the marking 10 in its entirety, which is a readable sequence and printable characters for an observer.
[0029] Alternately refer to Figure 3 The flowchart and Figures 4a to 4c A single image in Figure 2 .
[0030] Figure 2 A device 30 is shown which is configured to receive and hold an object 20. In step a) of the method, the object 20 is provided, received, and held in the device 30. For this purpose, the device 30 may have suitable receiving means 31. Providing the object 20 means that the object 20 is arranged in the device 30, for example, via a conveyor belt (not shown) or a robot arm (not shown).
[0031] In step b) of the method, a lighting device 40 is provided. For this purpose, the apparatus 30 may include a first holding device 32. The first holding device 32 in turn has a rod 33, which is configured to carry the lighting device 40. Although only the first holding device 32 connected to the rod 33 is shown, alternative holding devices are also conceivable, for example, a movable robotic arm (not shown) may be provided for this purpose.
[0032] The lighting device 40 is configured to illuminate a predeterminable partial area 24 of the surface segment 23 in a targeted manner within a predeterminable time range Tn. The duration of the time range Tn can vary, but is preferably approximately the same. For example, the duration of each time range Tn is less than one second. In this case, a time range Tn is assigned to each sub-area 24. The targeted illumination of the predeterminable sub-area 24 can preferably be carried out in a largely closed environment, so that relatively little or no external light appears on the surface segment 23. The final illuminance at the predeterminable sub-area 24 within each time range Tn should be selected so that there is a significant illuminance difference at least in the vicinity of each illuminated sub-area 24. Figures 4a to 4c As shown, the sharpest possible transition from the illuminated subregion 24 to the surrounding area, ie a steep gradient, is advantageous.
[0033] Surface segment 23 with marking 10 is composed of m subregions 24. m is a natural number. Each subregion 23 is assigned a time range Tn, so m subregions 24 can be illuminated within m time ranges Tn. The number of subregions 24, i.e., the natural number m, can be related to the length of marking 10 and predetermined. However, m is at least 2, preferably at least 10, and particularly preferably at least 50. As will be described later, subregions 24 may also partially overlap.
[0034] In step c) of the method, an image acquisition device 50, preferably a camera, is provided. For this purpose, the apparatus 30 may include a second holding device 34. The second holding device 34 is configured to carry the image acquisition device 50. Similar to the first holding device 32, alternative holding devices are also conceivable.
[0035] The image acquisition device 50 is configured to acquire at least one sub-region 24, preferably all sub-regions 24, and thus the entire surface section 23 within each time range Tn as a single image 60. Thus, each time range Tn can be assigned a single image 60, so that m single images 60 can be acquired within m time ranges Tn.
[0036] In step d) of the method, the nth sub-region 24 of the surface segment 23 is illuminated in a targeted manner by the lighting device 40 in the nth time range Tn. In this case, n is a natural number, the initial value of which is 1. That is, when step d) is first performed, n is equal to 1. Therefore, the first sub-region 24 of the surface segment 23 is illuminated in a targeted manner in the first time range Tn. By way of example, Figure 4a An illuminated area is shown in FIG. , which corresponds to the first sub-area 24 .
[0037] If, as shown, the lighting device 40 is accommodated on the apparatus 30 so as to be movable relative to the object 20 , selected subregions 24 of the surface section 23 can be illuminated in a targeted manner by changing the position of the lighting device 40 .
[0038] Alternatively or additionally, the lighting device 40 can be configured to emit segmented light. Thus, a subregion 24 of the surface segment 23 can be selected at any time without movable parts to be specifically illuminated by the lighting device 40. For this purpose, such a lighting device 40 can have, for example, a plurality of individually controllable light sources arranged in an array.
[0039] In step e) of the method, the n-th sub-region 24 is captured by the image acquisition device 50 within the n-th time range Tn. If step e) of the method is carried out for the first time, n is equal to 1, so that the first sub-region 24 is captured by the image acquisition device 50 within the first time range Tn. It should be noted that in step e), the entire surface section 23 can be captured by the image acquisition device 50. It is important that in step e), at least the n-th sub-region is captured. The image captured in this step is stored in the memory as the n-th single image 60. If n is equal to 1, the first single image 60 is captured in step e). This first single image 60 can correspond to Figure 4a The image displayed in .
[0040] In step f) following step d) and step e), the number n is increased by 1. Furthermore, steps d) and e) are repeated, whereby n equals 2. Thus, in the first repetition of step d), the second sub-region 24 of the surface segment 23 is illuminated in a targeted manner by the lighting device 40 within the second time range Tn. For example, the second sub-region 24 may correspond to Figure 4b In the first repetition of step e), the second sub-region 24 is captured by the image capture device 50 in the same second time range Tn. The image captured in the first repetition of step e) is stored in the memory as a second single image 60. The second single image 60 may correspond to Figure 4b The image displayed in .
[0041] Subsequently, before steps d) and e) are repeated in a second repetition, the number n is again increased by 1. So n is equal to 3. For example, the third single image 60 thus obtained may correspond to Figure 4c The image displayed in .
[0042] Steps d) and e) are repeated continuously until all predetermined sub-regions 24 of the surface segment 23 are illuminated in a targeted manner by the lighting device 40 and captured by the image capture device 50. The repetition of steps d) and e) ends after m minus the first repetition. In other words, the repetition ends after the last repetition in which n equals m.
[0043] In step g) of the method, a plurality of images 60 stored in the memory are combined. Figures 4a to 4c As can be seen from the exemplary individual images 60 of FIG, each individual image 60 covers the entire surface section 23. Known image processing methods can be used to combine the individual images 60 into an image 70. Such image processing methods can identify, based on a significant illumination difference with the surroundings, subregions 24 that are illuminated, for example, in a targeted manner, in each individual image 60, cut out, and accordingly combine with the other individual images 60. Thus, at least one section of an individual image 60 is combined with at least one section of each of the other individual images 60 to form the overall image 70, wherein the respective section in the individual images 60 includes the subregion 24 that was illuminated in step d) and captured in step e). Figure 5 The resulting overall image 70 is shown in FIG. In this context, it should be noted that step g) does not necessarily have to be performed upon completion of the repetition according to step f). Variants are also conceivable in which step g) is partially integrated into the repetition according to step f). For example, a first number of individual images 60 may be combined first, and then the repetition according to step f) may be continued to combine a second number of individual images according to step g) with the combined first number of individual images 60.
[0044] Figure 4a An exemplary first individual image 60 is shown, which was captured in a first time range Tn by the image capture device 50. In this case, as described, the first sub-region 24 is illuminated in a targeted manner by the lighting device 40.
[0045] Figure 4b An exemplary second individual image 60 is shown, which was captured in a second time range Tn by the image capture device 50. In this case, as described, the second sub-region 24 is illuminated in a targeted manner by the lighting device 40.
[0046] Figure 4cAn exemplary third individual image 60 is shown, which was captured in the second time range Tn by the image capture device 50. In this case, as described, the third sub-region 24 is illuminated in a targeted manner by the lighting device 40.
[0047] It can be seen that the subregions 24 partially overlap, so that in each step d), a portion of a structure 21 is illuminated, which was or has already been illuminated in at least one other step d). In other words, the subregions 24 specifically illuminated in each time range Tn partially overlap. As a result, at least portions of structures 21 of the surface segment 23 are captured in each individual image 60 that were or have already been captured in at least one other individual image 60. This simplifies the combination described in connection with step g) using image processing methods. Preferably, the individual subregions 24 overlap by at least 20%.
[0048] Figure 5 The resulting overall image 70 is shown in FIG. The entire indicium 10 is recognizable with sufficiently high contrast, allowing, for example, automated testing. If the indicium 10 has at least partially printable characters, automated optical character recognition (OCR) can be applied after step g) to digitize and, if necessary, correct the printable characters. For example, the printable characters can be based on a character encoding such as ASCII.
[0049] Finally, it should be noted that the described method process appears to be abstract, and therefore, in practice, the illumination and acquisition of marker 10 does not necessarily correlate with an increase in the value of the variable. As shown, sub-regions 24 do not necessarily correlate directly with the continuous time range Tn. The present invention is not limited to the illustrated embodiments. Moreover, various aspects of the present invention or embodiments may be employed and combined with one another. Any reference numerals in the claims are exemplary and serve only to make the claims easier to read and do not limit the claims.
Claims
1. A method for capturing an image of a marker (10) on an object (20), wherein: The method comprises the following steps: a) providing an object (20) and accommodating and holding the object (20) in a device (30), wherein the object (20) has a marking (10) formed by a structure (21) at a surface section (23) of the object (20); b) providing a lighting device (40), said lighting device (40) being configured to illuminate predefinable subregions (24) of said surface segment (23) within predefinable time ranges (Tn), wherein each said subregion is assigned a time range (Tn), and wherein said surface segment (23) having said marking (10) consists of m said subregions (24), such that m said subregions (24) can be illuminated within m said time ranges (Tn); c) providing an image acquisition device (50), which is configured to acquire at least one of the subregions (24) of the surface segment (23) as a single image (60) within each of the time ranges (Tn), wherein each of the time ranges (Tn) is assigned one of the single images (60), such that m of the single images (60) can be acquired within m of the time ranges (Tn); d) illuminating the nth subregion (24) of the surface segment (23) with the lighting device (40) within the nth time range (Tn), wherein n is a natural number and is initially equal to 1; e) acquiring the nth sub-region (24) within the nth time range (Tn) using the image acquisition device (50), and storing the nth single image (60) obtained thereby in a memory; f) continuing to repeat steps d) and e), wherein n is increased by 1 before each repetition, and the repetition is terminated after the m-1th repetition; g) Creating an overall image (70) by combining said individual images (60).
2. The method according to claim 1, wherein The surface section (23) is divided into at least two sub-areas (23), whereby m is at least equal to 2.
3. The method according to claim 1, wherein The surface section (23) is divided into at least 10 sub-regions (23), whereby m is at least equal to 10.
4. The method according to claim 1, wherein The surface section (23) is divided into at least 50 sub-regions (23), whereby m is at least equal to 50.
5. A method according to any one of the preceding claims, wherein The sub-regions (24) partially overlap, so that in each step d) a partial structure (21) of the surface section (23) is illuminated, which structure (21) is illuminated or has been illuminated at least once in another step d).
6. The method according to any one of claims 1 to 4, wherein The indicia (10) has at least partially printable characters, and wherein, after step g), the indicia (10) is digitized from the overall image (70) at least in part by automated optical character recognition.
7. The method according to any one of claims 1 to 4, wherein The lighting device (40) is movably accommodated at the apparatus (30) relative to the object (20), so that each time step d) is repeated, a different sub-area (24) is illuminated due to a change in position of the lighting device (40) compared to the previous execution of step d).
8. The method according to any one of claims 1 to 4, wherein The lighting device (40) is configured to radiate segmented light so that each time step d) is repeated, a different sub-region (24) than the previous time step d) is performed is illuminated by an appropriate segment of the light radiated by the lighting device (40).