Optical detection device and method for making marking features

Abstract

The invention discloses an optical detection device and a related method for making a two-mark feature. The optical detection device is used for detecting whether a target object has different surface treatment features or not. The optical detection device comprises an image sensor and an arithmetic processor. The image sensor is used for obtaining a detection image covering the target object. The arithmetic processor is electrically connected with the image sensor. The arithmetic processor calculates the change of the image brightness parameter of the detection image, and determines whether the image sensor detects the boundary of the surface treatment features according to the change of the image brightness parameter. According to the optical detection device, the marking features with stable quality can be manufactured at low cost, and the marking features can be quickly and accurately identified under the condition that the automatic exposure mode is started.

Description

Technical Field

[0001] The present invention relates to an optical detection device, and in particular to an optical detection device for detecting whether a target object has different surface treatment features and a method for making a plurality of marking features. Background Art

[0002] When a traditional optical detection device wants to detect the relative movement of a target object, it will make a marking feature on the surface of the target object and turn off the automatic exposure mechanism of the optical detection device to use the interference fringes generated by the marking feature to identify the movement change of the target object relative to the optical detection device. Common marking features may be coated with black matte paint on the surface of the target object, but the black matte paint is easy to fall off after long-term use, and the optical detection device loses its detection ability; another common marking feature is to use laser engraving technology to carve burn marks on the surface of the target object, but the engraving stability of laser engraving technology is not good, and the sizes of multiple burn marks may be inconsistent with each other, which will reduce the detection accuracy of the optical detection device; another common marking feature is to use computer numerical control technology to process the surface of the target object. The size of the marking feature produced by this technology is stable, but the processing cost is expensive. Therefore, how to design an optical detection device that does not need to turn off the automatic exposure mechanism and can accurately detect marking features with low production cost and stable production quality is one of the development goals of the relevant optical detection industry. Summary of the invention

[0003] The invention relates to an optical detection device for detecting whether a target object has different surface treatment features and a method for making a plurality of marking features.

[0004] The present invention further discloses an optical detection device for detecting whether a target object has different surface treatment features. The optical detection device includes an image sensor and a computing processor. The image sensor is used to obtain a detection image covering the target object. The computing processor is electrically connected to the image sensor. The computing processor calculates the change of the image brightness parameter of the detection image, and determines whether the image sensor detects the boundary of the surface treatment features according to the change of the image brightness parameter.

[0005] The invention also discloses that the image brightness parameter is the image contrast or spot size of the detection image. The operation processor calculates the change of the image brightness parameter of the detection image when the image sensor starts the automatic exposure mode.

[0006] The present invention also discloses that the operation processor further compares the image brightness parameter with a predetermined threshold, and determines that the image sensor detects the intersection when the image brightness parameter crosses the predetermined threshold. The operation processor further calculates the time length of the image brightness parameter crossing the predetermined threshold, and uses the time length to obtain the size of one of the surface treatment features. The operation processor further calculates the number of times the image brightness parameter crosses the predetermined threshold, and uses the number to obtain the number of the intersections detected by the image sensor. The operation processor further calculates the time length of the image brightness parameter crossing the predetermined threshold, and uses the time length and the number to obtain the barcode or coding information represented by the arrangement of the surface treatment features.

[0007] The invention also discloses that the computing processor further detects the structural feature points of the target object to calculate the relative position change between the image sensor and the target object. The computing processor further analyzes and obtains the spacing of multiple boundaries of the surface treatment features, and uses the spacing to correct the relative position change.

[0008] The present invention also discloses that the operation processor calculates the difference between the first pixel with the maximum pixel intensity and the second pixel with the minimum pixel intensity of the detection image as the image brightness parameter. The operation processor divides all pixels of the detection image into a first pixel group and a second pixel group according to their pixel intensity, and calculates the difference between the first average intensity of the first pixel group and the second average intensity of the second pixel group as the image brightness parameter. The operation processor calculates the intensity mean of all pixels, and classifies several pixels with the pixel intensity greater than or equal to the intensity mean among the multiple pixels as the first pixel group, and classifies other pixels with the pixel intensity less than the intensity mean among the multiple pixels as the second pixel group.

[0009] The present invention also discloses that the image sensor does not have a lens element. The optical detection device further includes a laser light source for projecting an illumination beam onto the target object. The size of the surface treatment feature is greater than or equal to the illumination range of the illumination beam projected onto the target object. The optical detection device is suitable for detecting whether the target object made of metal material has different surface treatment features.

[0010] The present invention also discloses a method for making two marking features, including selecting a surface on a target object, and using a surface treatment technology to form the two marking features in two areas of the surface. The surface treatment technology includes metal brush treatment or paint treatment, and the surface treatment features of the two areas are different from the surface treatment features of the surface outside the two areas. The two marking features are spaced apart from each other to form a barcode or coded information.

[0011] The optical detection device of the present invention does not need to turn off the automatic exposure mode. It can analyze the spot pattern of the detection image to obtain its image contrast when the automatic exposure mode is turned on, and use the image contrast to analyze and find the barcode or coding information represented by the existence, size, quantity or arrangement of the marking features in the detection image. Compared with the prior art, the optical detection device of the present invention can manufacture the marking features with stable quality at a low cost, and can quickly and accurately identify the marking features when the automatic exposure mode is turned on. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 FIG. 4 is a functional block diagram of an optical detection device according to an embodiment of the present invention.

[0013] Figure 2 FIG. 4 is a schematic diagram of an application of an optical detection device and a target object according to an embodiment of the present invention.

[0014] Figures 3 to 5 It is a schematic diagram of detection images obtained by photographing different target objects or different ranges of the same target object by an optical detection device according to an embodiment of the present invention.

[0015] Figure 6 for Figure 3 and Figure 5 Pixel intensity distribution diagram of the detection image shown.

[0016] Figure 7 FIG. 4 is a schematic diagram for comparing the image contrast of the detection image according to an embodiment of the present invention.

[0017] Figure 8 The figure is a flow chart of a method for making marking features according to an embodiment of the present invention.

[0018] The reference numerals are described as follows:

[0019] 10Optical detection device

[0020] 12 Image Sensor

[0021] 14Laser light source

[0022] 16-processor

[0023] OTarget object

[0024] R Region

[0025] M,M' marking feature

[0026] ALighting Range

[0027] B Illumination beam

[0028] S surface

[0029] D Direction

[0030] I1, I2, I3 detection images

[0031] G1 Pixel Group 1

[0032] G2 Second pixel group

[0033] C1, C2, C3 curves

[0034] Steps S100 and S102 DETAILED DESCRIPTION

[0035] See also Figure 1 and Figure 2 , Figure 1 is a functional block diagram of an optical detection device 10 according to an embodiment of the present invention. Figure 2 1 is an application diagram of an optical detection device 10 and a target object O according to an embodiment of the present invention. The optical detection device 10 can be used to detect whether the target object O has different surface treatment features; generally speaking, the target object O is preferably made of a metal material, and a portion R of the metal surface of the target object O may be subjected to special surface treatment, such as wool wheel polishing to make the region R have a smooth surface treatment feature, or sandblasting to make the region R have a rough surface treatment feature, thereby forming a marking feature M using the smooth surface treatment feature or the rough surface treatment feature.

[0036] The area outside the area R of the metal surface of the target object O is not subjected to special surface treatment, that is, the area R and the area outside the area R of the target object O can have different surface treatment characteristics respectively; the present invention can preferably define the surface treatment characteristics of the area R as a marking feature M, and the marking feature M may be but is not limited to the above-mentioned smooth surface treatment characteristics or rough surface treatment characteristics, which can be determined according to design requirements. The target object O is not limited to being made of metal materials, as long as the material can provide a relatively different surface treatment characteristic after surface treatment, it meets the design purpose of the target object O and can be applied to the optical detection device 10 of the present invention.

[0037] The optical inspection device 10 may include an image sensor 12, a laser light source 14, and a processor 16. The laser light source 14 may be used to project an illumination beam B onto the target object O. The laser light source 14 may have high directivity; therefore, the illumination range A of the illumination beam B projected onto the target object O may be calculated based on the light-emitting angle of the laser light source 14 and the distance of the laser light source 14 relative to the target object O, and the size of the surface treatment feature (i.e., the marking feature M) is preferably greater than or equal to the size of the illumination range A. During the relative movement of the optical inspection device 10 and the target object O, the illumination range A of the laser light source 14 may completely enter the range of the surface treatment feature, thereby providing a preferred detection accuracy.

[0038] In the present invention, the image sensor 12 of the optical detection device 10 usually does not have a lens element, and the detection image obtained by the image sensor 12 covering the target object O may not show a clear image, but there will be spot light and dark changes due to the different characteristics of the surface treatment features (i.e., smooth surface and / or rough surface). The present invention electrically connects the computing processor 16 to the image sensor 12 in a wired or wireless manner, and uses the computing processor 16 to analyze and calculate the changes in the image brightness parameters of the detection image, and judge whether the image sensor 12 detects the intersection of the surface treatment features according to the changes in the image brightness parameters. In an embodiment of the present invention, the image brightness parameter can be the image contrast or spot pattern size of the detection image, but the actual application is not limited to the above-mentioned implementation. Image contrast is the degree of distinction between black and white blocks of objects in the detection image at a specific resolution. Spot size refers to the size of the color block composed of pixels of the same or similar color in the detection image.

[0039] It is worth mentioning that, in the case of conventional optical detection technology, when lens elements are not used and a clear image cannot be seen, the automatic exposure mechanism of the optical detection device must be turned off to limit the exposure time in order to produce sufficient pixel brightness changes for identification. However, the optical detection device 10 of the present invention can observe that the area R with special surface treatment on the metal surface of the target object O has characteristics that can be accurately identified without turning off the automatic exposure mode (i.e., changes in image brightness parameters, or image contrast or spot size). Therefore, when the image sensor 12 starts or turns off the automatic exposure mode, the computing processor 16 can analyze and calculate the changes in the image brightness parameters of the detection image, thereby finding the boundaries of the surface treatment features and obtaining the existence, quantity, size and distribution of the surface treatment features.

[0040] See also Figures 3 to 6 , Figures 3 to 5 Schematic diagram of detection images I1, I2 and I3 obtained by photographing different target objects O or different ranges of the same target object O by the optical detection device 10 according to an embodiment of the present invention, Figure 6 for Figure 3 and Figure 5 The pixel intensity distribution diagram of the detection images I1, I2 and I3 shown in FIG. 1 is a graph showing the pixel intensity distribution of the detection images I1, I2 and I3. The optical detection device 10 can obtain the image of the target object O outside the region R. Figure 3 The detection image I1 shown in the figure is taken by shooting the area R of the target object O to obtain Figure 4 The detection image I2 shown or Figure 5 The detection image I3 is shown; the detection image I2 can be obtained by performing special surface treatment on the area R by polishing with a wool wheel, and the detection image I3 can be obtained by performing special surface treatment on the area R by sandblasting.

[0041] Figure 6 The curve C1 is the pixel intensity distribution of the detection image I1, the curve C2 is the pixel intensity distribution of the detection image I2, and the curve C3 is the pixel intensity distribution of the detection image I3. Figure 6 As shown, the pixel intensity distribution of the range of the target object O that has not undergone special surface treatment (i.e., curve C1) is approximately between 60 and 160, the pixel intensity distribution of the area R of the target object O that has undergone special surface treatment by wool wheel polishing (i.e., curve C2) is approximately between 20 and 220, and the pixel intensity distribution of the area R of the target object O that has undergone special surface treatment by sandblasting (i.e., curve C3) is approximately between 80 and 130.

[0042] The image brightness parameter calculated by the optical detection device 10 can preferably be used as the image contrast of the detection image I1 (or the detection image I2 or the detection image I3), for example, the difference between the first pixel with the maximum pixel intensity and the second pixel with the minimum pixel intensity of the detection image I1 (or the detection image I2 or the detection image I3) is calculated as the image brightness parameter. Figure 7 , Figure 7 Schematic diagram for comparing the image contrast of the detection images I1, I2 and I3 according to an embodiment of the present invention. Number 1 represents the intensity difference between the brightest pixel (i.e., the first pixel with the maximum pixel intensity) and the darkest pixel (i.e., the second pixel with the minimum pixel intensity) of curve C1. Number 2 represents the intensity difference between the brightest pixel and the darkest pixel of curve C2. Number 3 represents the intensity difference between the brightest pixel and the darkest pixel of curve C3.

[0043] Alternatively, the optical detection device 10 may also divide all pixels of the detection image I1 (or the detection image I2 or the detection image I3) into a first pixel group G1 and a second pixel group G2 according to their pixel intensities. Figure 6The first average intensity of the first pixel group G1 is greater than the second average intensity of the second pixel group G2. The optical detection device 10 can calculate the difference between the first pixel group G1 and the second pixel group G2 (eg, the difference between the first average intensity and the second average intensity) as the image brightness parameter.

[0044] The present invention provides a variety of ways to set the first pixel group G1 and the second pixel group G2. For example, the intensity mean of all pixels can be calculated first, and then several pixels whose pixel intensities are greater than or equal to the intensity mean are classified as the first pixel group G1, and the other pixels whose pixel intensities are less than the intensity mean are classified as the second pixel group G2. Alternatively, all pixels can be arranged according to their pixel intensity distribution, and the first pixel group G1 and the second pixel group G2 can be divided according to the overall number of pixels by taking the middle value. The setting method of the pixel group is not limited to the above-mentioned implementation mode, and it depends on the design requirements.

[0045] like Figure 7 As shown, the image brightness parameters (such as the intensity difference value of number 1) of the detection image I1 of the original metal material surface of the target object O (i.e., the range outside the area R) are significantly greater than the image brightness parameters (such as the intensity difference value of number 3) of the detection image I3 of the area R of the target object O that is specially surface treated by sandblasting; and the image brightness parameters (such as the intensity difference value of number 2) of the detection image I2 of the area R of the target object O that is specially surface treated by wool wheel polishing are significantly greater than the image brightness parameters (such as the intensity difference value of number 1) of the detection image I1.

[0046] Thus, the present invention can be used Figure 7 The predetermined threshold is set based on the information provided, for example, the predetermined threshold is set to 150 or 75; then, when the optical inspection device 10 obtains any inspection image, the image brightness parameter of the inspection image can be calculated and compared with the predetermined threshold. When the image sensor 12 is aligned with or facing the original metal material surface of the target object O, the image brightness parameter will be roughly maintained at around 100. If the image brightness parameter crosses the predetermined threshold, for example, exceeds 150 or is lower than 75, it means that the image sensor 12 detects the boundary of different surface treatment features on the target object O, which means that the image sensor 12 is aligned with or facing the area R to capture the marking feature M.

[0047] As described above, the optical detection device 10 of the present invention can determine the presence of the marker feature M based on the comparison result between the image brightness parameter and the predetermined threshold. Figure 2As shown, if the target object O moves along the direction D, the optical detection device 10 will first detect that the image brightness parameter crosses the predetermined threshold, indicating that the illumination range A begins to overlap with the marking feature M; then, the image brightness parameter will fall back to the predetermined threshold to return to the initial value, indicating that the illumination range A is away from the marking feature M, and at this time it can be regarded that the optical detection device 10 has read the existence of a marking feature M. In other possible embodiments of the present invention, the optical detection device 10 can further determine the number of times the image brightness parameter crosses the predetermined threshold, for example, if the image brightness parameter first crosses and then falls back to the predetermined threshold, and then crosses again and then falls back to the predetermined threshold, it can be said that the optical detection device 10 detects four intersections and reads two marking features M.

[0048] In another possible embodiment of the present invention, the optical detection device 10 can also calculate the time length that the image brightness parameter crosses a predetermined threshold. Figure 2 As shown, when the target object O moves along the direction D, the length of time that the illumination range A overlaps with the marking feature M is shorter than the length of time that the illumination range A overlaps with the marking feature M'. The optical detection device 10 can use the difference in the above-mentioned time lengths to determine the size ratio or relative size relationship between the marking feature M and the marking feature M'. According to various possible embodiments of the present invention, the optical detection device 10 can calculate the number of times the image brightness parameter crosses a predetermined threshold during the detection process, and the length of time each time it crosses and falls back to the predetermined threshold, to determine the number and size of the marking feature M and / or the marking feature M', thereby converting and calculating the barcode or coding information represented by the arrangement of the marking features M and M'.

[0049] In addition, the optical detection device 10 can also detect and analyze the structural feature points of the target object O (e.g., any identifiable reference points formed on the metal surface) to calculate the position change of the target object O relative to the image sensor 12 along the direction D. In this case, if the number and spacing of the marking features M on the surface of the target object O are known information, the optical detection device 10 can analyze the detection image to obtain the spacing of the marking features M, and then use these spacings to correct the relative position change of the target object O and the image sensor 12, so as to obtain correct optical tracking data.

[0050] See also Figure 2 and Figure 8 , Figure 8Flow chart of the method for making a marking feature M according to an embodiment of the present invention. Regarding the method for making a marking feature M, first, step S100 may be executed to select a surface S on the target object O; the surface S should be the end surface of the target object O facing the optical detection device 10, and the marking feature M formed on the surface S can be read by the optical detection device 10. Next, step S102 is executed to form a plurality of marking features M in a plurality of regions R of the surface S by using a surface treatment technology. The surface treatment technology may be a metal brush treatment, a spray paint treatment, or a wool wheel polishing treatment, which is used to form a marking feature M with a rough surface or a smooth surface; the rough surface or the smooth surface here refers to the range outside the region R of the surface S. For example, performing a metal brush treatment or a spray paint treatment on the region R will obtain a marking feature M that is rougher than the range outside the region R of the surface S; if a wool wheel polishing treatment is performed on the region R, a marking feature M that is smoother than the range outside the region R of the surface S is obtained. Furthermore, the plurality of marking features M are spaced apart from each other to form barcodes or coded information, which can be read by the optical detection device 10 using the above description.

[0051] In summary, the optical detection device of the present invention does not need to turn off the automatic exposure mode. It can analyze the spot pattern of the detection image to obtain its image contrast when the automatic exposure mode is turned on, and use the image contrast to analyze and find the barcode or coding information represented by the existence, size, quantity or arrangement of the marking features in the detection image. Compared with the prior art, the optical detection device of the present invention can manufacture the marking features with stable quality at a low cost, and can quickly and accurately identify the marking features when the automatic exposure mode is turned on.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An optical detection device for detecting whether a target object has different surface treatment characteristics, characterized in that: The optical detection device comprises: An image sensor for obtaining a detection image covering the target object; and The computing processor is electrically connected to the image sensor, and the computing processor calculates the change of the image brightness parameter of the detection image, and determines whether the image sensor detects the boundary of the surface treatment features according to the change of the image brightness parameter.

2. The optical detection device according to claim 1, characterized in that: The image brightness parameter is the image contrast or spot size of the detection image.

3. The optical detection device according to claim 1, characterized in that: The operation processor calculates the change of the image brightness parameter of the detection image when the image sensor starts the automatic exposure mode.

4. The optical detection device according to claim 1, characterized in that: The operation processor further compares the image brightness parameter with a predetermined threshold, and determines that the image sensor detects the boundary when the image brightness parameter crosses the predetermined threshold.

5. The optical detection device according to claim 4, characterized in that: The computing processor further calculates the time length that the image brightness parameter crosses the predetermined threshold, and uses the time length to obtain the size of one of the surface treatment features.

6. The optical detection device according to claim 4, characterized in that: The operation processor further calculates the number of times that the image brightness parameter crosses the predetermined threshold, and uses the number to obtain the number of the boundaries detected by the image sensor.

7. The optical detection device according to claim 6, characterized in that: The operation processor further calculates the time length that the image brightness parameter crosses the predetermined threshold, and uses the time length and the number of times to obtain the barcode or coding information represented by the arrangement of the surface treatment features.

8. The optical detection device according to claim 1, characterized in that: The operation processor further detects the structural feature points of the target object to calculate the relative position change between the image sensor and the target object.

9. The optical detection device according to claim 8, characterized in that: The computing processor further analyzes and obtains the spacings of a plurality of boundaries of the surface treatment features, and uses the spacings to correct the relative position change.

10. The optical detection device according to claim 1, characterized in that: The operation processor calculates a difference value between a first pixel with a maximum pixel intensity and a second pixel with a minimum pixel intensity of the detection image as the image brightness parameter.

11. The optical detection device according to claim 1, characterized in that: The operation processor divides all pixels of the detection image into a first pixel group and a second pixel group according to their pixel intensities, and calculates a difference between a first average intensity of the first pixel group and a second average intensity of the second pixel group as the image brightness parameter.

12. The optical detection device according to claim 11, characterized in that: The operation processor calculates the intensity mean of all the pixels, and classifies several pixels among the multiple pixels having pixel intensities greater than or equal to the intensity mean as the first pixel group, and classifies other pixels among the multiple pixels having pixel intensities less than the intensity mean as the second pixel group.

13. The optical detection device according to claim 1, characterized in that: The image sensor has no lens elements.

14. The optical detection device according to claim 1, characterized in that: The optical detection device further includes a laser light source for projecting an illumination beam onto the target object.

15. The optical detection device according to claim 14, characterized in that: The size of the surface treatment feature is greater than or equal to the illumination range of the illumination light beam projected on the target object.

16. The optical detection device according to claim 1, characterized in that: The optical detection device is suitable for detecting whether the target object made of metal material has different surface treatment features.

17. A method for making a two-mark feature, characterized in that, The method includes: Selecting a surface on the target object; and forming the two marking features in two regions of the surface by using a surface treatment technique; The surface treatment technology includes metal brush treatment or paint treatment, and the surface treatment characteristics of the two areas are different from the surface treatment characteristics of the surface outside the two areas.

18. The method of claim 17, wherein the two marking features are spaced apart from each other to form a barcode or coded information.

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