Method for photographing evaluation image for vehicular glass

Abstract

To evaluate the characteristics of a vehicular glass by photographing light transmitted through the vehicular glass by a camera arranged close to the glass.SOLUTION: In a method for photographing an evaluation image for a vehicular glass, the vehicular glass has: a window area in which an on-vehicle sensor observes the outside of a vehicle from the inside of the vehicle, when mounted on the vehicle; and a shielding part which surrounds the window area and does not transmit the light. The method includes: a first procedure in which the vehicular glass is arranged so that the window area is located on an optical axis of an imaging apparatus for photographing a target on which a predetermined pattern is drawn; a second procedure in which the imaging apparatus vertically photographs the target in a direction where the optical axis of the imaging apparatus passes through a central area of the window area; and a third procedure in which the imaging apparatus photographs the target so as to include a boundary between the window area and the shielding part.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present disclosure relates to a method for measuring perspective distortion in vehicle glass. [Background technology]

[0002] Conventionally, the characteristics of vehicle glass were evaluated by the light transmitted through the glass using a camera installed at a distance. Recently, with the introduction of advanced driver assistance systems (ADAS) and autonomous driving systems (AD), on-board sensors that monitor the outside of the vehicle from the window area of ​​the vehicle glass are installed close to the vehicle glass.

[0003] Patent Document 1 discloses a stereo camera having two cameras arranged at a predetermined base line length apart, a grid chart arranged in front of the stereo camera and having center markers arranged at grid points corresponding to the cameras, a protective hood that can be freely interposed between the stereo camera and the grid chart, a characteristic detection unit that images the grid chart with the cameras and determines the coordinates of each grid point of the grid chart, and a geometry table that stores geometric distortion correction data for each grid point based on the difference between the coordinates of each grid point determined by the characteristic detection unit and the corresponding ideal coordinates, the protective hood being interposed between the stereo camera and the grid chart. a geometric table creating unit that creates geometric tables for a state in which no protective hood is present and a state in which different types of protective hoods are present, respectively; a data storage unit that stores the geometric tables created by the geometric table creating unit; and a calibration calculation unit that combines a plurality of the geometric tables stored in the data storage unit and removes geometric distortion between the stereo camera and each of the protective hoods or reproduces geometric distortion of different protective hoods using the geometric distortion correction data stored in each of the geometric tables.

[0004] Patent Document 2 discloses a method for inspecting a windshield glass for a vehicle, which includes setting a target recognition rate for an in-vehicle imaging device to be mounted at a predetermined position inside the vehicle, setting a contrast ratio threshold value associated with the target recognition rate, arranging the windshield glass and the imaging device having the same performance as the in-vehicle imaging device so that the relative positional relationship between the windshield glass and the imaging device matches the relative positional relationship between the windshield glass and the in-vehicle imaging device when the vehicle is completed, imaging a black-and-white chart positioned at a predetermined distance from the imaging device using the imaging device through the windshield glass, and the black-and-white chart has a reference black area from which a reference value for black luminance can be calculated and a reference white area from which a reference value for white luminance can be calculated. the contrast ratio is calculated as a value obtained by normalizing a difference between a maximum luminance and a minimum luminance of the striped pattern region on a virtual line segment extending so as to cross the black and white regions of the striped pattern region in the black and white chart included in an image captured by the imaging device, between the luminance of the reference black region and the luminance of the reference white region; and if a contrast ratio condition is satisfied that the calculated contrast ratio is greater than the contrast threshold, the windshield glass is determined to be a non-defective product. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2017-62198 A [Patent Document 2] Patent Publication No. 2022-15847 Summary of the Invention [Problem to be solved by the invention]

[0006] The characteristics of vehicle glass are measured using parallel light, which means that the characteristics measured are different from those of an on-board sensor. In addition, since the on-board sensor has a wider angle than the measurement camera, if the camera is placed at the same position as the sensor, it is difficult to measure the entire wide-angle area captured by the sensor. If an image of the entire window area is captured using a lens with a wide angle of view, the influence of lens distortion is small in the center of the window area, but the influence of lens distortion is large at the edge of the window area. In this way, it is difficult to accurately evaluate the characteristics of vehicle glass in an image with large lens distortion. In particular, cameras for ADAS / AD are expected to have a wide angle of view and high resolution, and it is necessary to guarantee the quality of the glass to accurately control the vehicle based on high-resolution images captured by high-resolution cameras.

[0007] For this reason, it is necessary to evaluate the characteristics of vehicle glass by capturing images of light passing through the vehicle glass using a camera placed close to the glass. [Means for solving the problem]

[0008] Disclosure (1) of the present specification is a method for capturing an evaluation image of vehicle glass, the vehicle glass having a window area for an on-board sensor to observe the outside of the vehicle from inside the vehicle when installed in the vehicle, and a light-opaque shielding portion surrounding the window area, the method including a first step of positioning the vehicle glass so that the window area is positioned on the optical axis of an imaging device that captures an image of a target having a predetermined pattern drawn thereon, a second step of the imaging device capturing an image of the target from a vertical direction such that the position of the principal point of the lens of the on-board sensor when the on-board sensor is installed and the optical axis of the imaging device pass through a central area of ​​the window area, and a third step of the imaging device capturing an image of the target from another direction that passes through the position of the principal point and the window area.

[0009] Disclosure (2) of the present specification is a method according to disclosure (1), characterized in that the different direction in the third step is at least one of a rightward direction and a leftward direction in a horizontal plane.

[0010] Disclosure (3) of the present specification is a method according to Disclosure (1), wherein the different direction in the third step is at least one of an upward direction and a downward direction in a vertical plane.

[0011] Disclosure (4) of the present specification is a method according to disclosure (2) or (3), characterized in that in the third step, when the imaging device photographs the target from the right direction, it photographs the target to include a range of 30 mm inward from the window area and the left boundary of the shielding part, when the imaging device photographs the target from the left direction, it photographs the target to include a range of 30 mm inward from the window area and the right boundary of the shielding part, when the imaging device photographs the target from the top direction, it photographs the target to include a range of 30 mm inward from the window area and the lower boundary of the shielding part, and when the imaging device photographs the target from the bottom direction, it photographs the target to include a range of 30 mm inward from the window area and the upper boundary of the shielding part.

[0012] Disclosure (5) of the present specification is a method according to disclosure (1), characterized in that the order of execution of the second step and the third step is either that the third step is performed after the second step, or that the second step is performed after the third step.

[0013] Disclosure (6) of the present specification is a method according to disclosure (1), characterized in that in the first step, the target is arranged perpendicular to the optical axis of the vehicle-mounted sensor, and in an area including a point where the target intersects with the optical axis of the vehicle-mounted sensor, the pitch of an evaluation pattern constituting a drawn pattern is 0.1 mm or less.

[0014] Disclosure (7) of the present specification is a method according to disclosure (1), wherein the angle of view of the imaging device is smaller than the angle of view of the vehicle-mounted sensor.

[0015] Disclosure (8) of the present specification is a method according to disclosure (1), characterized in that the target is photographed in the second step and the third step in each area into which the vehicle glass is divided. Effect of the Invention

[0016] According to one aspect of the present disclosure, the quality of a window area of ​​glass can be accurately evaluated even if an on-board sensor captures images using a lens with a wide angle of view. [Brief description of the drawings]

[0017] [Figure 1A] FIG. 2 is a plan view illustrating a method for measuring perspective distortion of the glass of embodiment 1. [Figure 1B] FIG. 2 is a side view illustrating a method for measuring a perspective distortion of the glass of the first embodiment. [Figure 2A] FIG. 2 is a diagram showing a method for measuring perspective distortion of the glass of the first embodiment. [Figure 2B] FIG. 2 is a diagram showing a method for measuring perspective distortion of the glass of the first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of a target according to the first embodiment. [Figure 4] FIG. 2 is a diagram showing an example of a target according to the first embodiment. [Diagram 5] FIG. 1 is a diagram showing a configuration of a glass transmission distortion measuring system according to a first embodiment. [Figure 6A] FIG. 11 is a plan view illustrating a method for measuring perspective distortion of the glass of embodiment 2. [Figure 6B] FIG. 11 is a side view illustrating a method for measuring a perspective distortion of a glass according to a second embodiment. [Figure 7] FIG. 11 is a diagram showing a method for measuring perspective distortion of the glass of embodiment 3. [Figure 8] FIG. 11 is a diagram showing a method for measuring perspective distortion of the glass of embodiment 3. [Figure 9] FIG. 11 is a plan view illustrating a method for measuring perspective distortion of the glass of embodiment 3. [Figure 10] FIG. 11 is a side view illustrating a method for measuring perspective distortion of a glass according to a third embodiment. [Figure 11]13A to 13C are diagrams showing specific examples of shooting directions of a shooting area in the third embodiment. [Figure 12] 13A to 13C are diagrams showing specific examples of shooting directions of a shooting area in the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] <Embodiment 1> The glass perspective distortion measuring method of this embodiment includes a first step of arranging the glass 1 so that the window area 1A of the glass 1 is located on the optical axis of the imaging device 22 that captures the target 3 on which a predetermined pattern is drawn, a second step of the imaging device 22 vertically capturing the target 3 from the position of the optical axis when the vehicle-mounted sensor 5 is installed, with the optical axis of the imaging device 22 oriented to pass through the central area of ​​the window area 1A, and a third step of the imaging devices 21 and 23 capturing the target 3 from an oblique direction on a horizontal plane so as to include the boundary between the window area 1A and the shielding part 1B. The captured image is image-processed by the glass perspective distortion measuring system 100 described later, and the perspective distortion (e.g., blur, distortion, perspective double image) of the window area 1A is evaluated.

[0019] Figures 1A, 1B, 2A and 2B are figures showing a method for measuring perspective distortion of glass of embodiment 1, in which Figure 1A is a plan view seen from above, Figure 1B is a side view seen from the side, and Figures 2A and 2B are views of the periphery of a window region 1A in the upper central part of the glass 1 as seen from inside the vehicle.

[0020] As shown in FIG. 2A, the glass 1 to be measured in this embodiment has a light-transmitting window area 1A in the upper center, and a light-opaque shielding portion 1B surrounding the window area 1A. When the glass 1 is installed in a vehicle, the window area 1A becomes a window for acquiring external information, and an on-board sensor 5 for monitoring the outside of the vehicle is installed on the inside of the window area 1A. When measuring the perspective distortion of the glass 1, the on-board sensor 5 is not installed on the glass 1, but the virtual position where the on-board sensor 5 is installed in an actual vehicle is shown by a dashed line in FIG. 1A. The shielding portion 1B is a colored (usually black) layer formed by printing and baking an insulating ceramic paste made by mixing low-melting point glass powder and pigment into a paste on the glass 1.

[0021] The area 30 mm inside from the boundary between the window area 1A and the shielding portion 1B is called the central area of ​​the window area 1A, and in the second step, the imaging device 22 photographs the target 3 from the vertical direction so that its optical axis passes through the central area of ​​the window area 1A and the position of the principal point 5A of the lens of the on-board sensor 5 at the virtual position where the on-board sensor 5 is attached. The principal point of the lens is a reference point on the optical axis of the lens that optically defines the focal length. Note that the imaging device 22 may photograph the target 3 from the vertical direction so that its optical axis passes through the central area of ​​the window area 1A and the center point of the lens of the on-board sensor 5 at the virtual position where the on-board sensor 5 is attached.

[0022] In addition, the glass distortion is large in a range of 30 mm inward from the boundary between the window region 1A and the shielding portion 1B, and this range is called the side region of the window region 1A. In the third step, the target 3 is photographed from an oblique direction so as to include a range of 30 mm inward from the boundary between the window region 1A and the shielding portion 1B. Depending on the type of glass and the manufacturing method, the boundary between the central region and the side region may be 20 mm or 10 mm from the boundary between the window region 1A and the shielding portion 1B instead of 30 mm. The closer the glass 1 is to the boundary between the window region 1A and the shielding portion 1B, the larger the angle of incidence of the light path from the position of the vehicle-mounted sensor 5 to the glass 1 and the longer the passing length of the glass, resulting in larger distortion. Therefore, it is desirable to change the boundary between the central region and the side region depending on the amount of allowable distortion.

[0023] In the first embodiment, a plurality of imaging devices 21, 22, 23, 24, 25 that capture images of the window area 1A from different directions are provided on a first surface side of the glass 1. A target 3 that is captured by the imaging devices 21, 22, 23, 24, 25 through the glass 1 is provided on a second surface side opposite to the first surface side of the glass 1. As shown in FIG. 1B, the glass 1 is disposed between the imaging devices 21, 22, 23, 24, 25 and the target 3 at approximately the same inclination as when the glass 1 is mounted on the vehicle. The distance between the glass 1 and the imaging devices 22 is several meters, and the distance between the glass 1 and the target 3 is also several meters.

[0024] Preferably, the imaging device 22 is disposed at a position and angle where its optical axis 22A passes through the center of the window region 1A perpendicular to the glass 1 in the horizontal plane, and images the target 3 through the center of the window region 1A and the position of the principal point 5A of the lens of the on-board sensor 5 at the virtual position where the on-board sensor 5 is attached. That is, the optical axis 22A of the imaging device 22 and the optical axis of the on-board sensor 5 are the same. The imaging device 21 is disposed at a position and angle where its optical axis 21A enters the glass 1 at a shallow angle from the right direction in the horizontal plane and passes near the boundary with the shielding part 1B on the left side of the window region 1A from the right direction of the glass 1, and images the target 3 through the left region of the window region 1A to include a range of 30 mm inward from the left boundary. The imaging device 23 is disposed at a position and angle such that its optical axis 23A enters the glass 1 from the left at a shallow angle on the horizontal plane, passes from the left of the glass 1 near the boundary with the shielding portion 1B at the right side of the window area 1A, and images the target 3 through the right side of the window area 1A to include a range of 30 mm inward from the right side boundary. The imaging device 24 is disposed at a position and angle such that its optical axis 24A enters the glass 1 from the bottom at a shallow angle on the vertical plane, passes from the bottom of the glass 1 near the boundary with the shielding portion 1B at the upper side of the window area 1A, and images the target 3 through the upper area of ​​the window area 1A to include a range of 30 mm inward from the upper boundary. The imaging device 25 is positioned at a position and angle such that its optical axis 25A enters the glass 1 at a shallow angle from above in the vertical plane and passes from above the glass 1 near the boundary with the shielding portion 1B of the lower part of the window area 1A, and captures an image of the target 3 through the lower area of ​​the window area 1A to include a range of 30 mm inward from the lower boundary.

[0025] The imaging devices 21, 22, 23, 24, and 25 are arranged such that the optical axes 21A, 22A, 23A, 24A, and 25A of the imaging devices 21, 22, 23, 24, and 25 intersect at the position of the principal point 5A of the lens of the vehicle-mounted sensor 5.

[0026] Imaging devices 21, 22, 23, 24, and 25 are arranged so that the optical axes of the imaging devices are positioned on a single horizontal plane, and perspective distortion caused by differences in horizontal position is measured. For example, in the case of a front window glass (windshield) for an automobile, it is necessary to reduce perspective distortion in the left-right direction rather than the up-down direction, so imaging devices 21, 22, 23, 24, and 25 are arranged in the left-right direction on a horizontal plane. If it is necessary to reduce perspective distortion in the up-down direction, imaging devices 21, 22, 23, 24, and 25 should be arranged in the up-down direction on a vertical plane.

[0027] The angle of view of each of the imaging devices 21, 22, 23, 24, and 25 may be smaller than the angle of view of the on-board sensor 5, and at least the angle of view of the imaging device 22 is smaller than the angle of view of the on-board sensor 5. By making the angle of view of the imaging devices smaller than the angle of view of the on-board sensor 5, a lens with less optical distortion can be used to accurately measure the perspective distortion of the glass.

[0028] Although the glass 1 is illustrated in which the shielding portion 1B is provided so as to surround the window region 1A, the present invention can also be applied to glass in which the shielding portion 1B is not provided around the window region 1A. In this case, since there is no explicit boundary of the window region 1A, the imaging devices 21, 23, 24, 25 are disposed at positions and angles such that their optical axes 21A, 23A, 24A, 25A pass near the practical boundary of the window region 1A.

[0029] As shown in Fig. 2B, the glass 1 is photographed for perspective distortion in five regions. In each region adjacent to the shielding portion 1B, the target 3 is photographed from an oblique direction so as to include a range of 30 mm inward from the side boundary included in the region.

[0030] As described above, the imaging of the target 3 by the imaging devices 21, 22, 23, 24, and 25 should be performed by the imaging device 22 in order to observe the representative characteristics of the glass 1 in the central portion, but the imaging of the target 3 may be performed by the other imaging devices 21, 23, 24, and 25 depending on the region that needs to be measured. Also, instead of photographing the target 3 in the central region by the imaging device 22, the imaging of the target 3 through the side regions by the imaging devices 21, 23, 24, and 25 depending on the region that needs to be measured may be performed to observe the characteristics of the peripheral portion of the glass 1.

[0031] The order of photographing the target 3 by the imaging devices 21, 22, 23, 24, and 25 described above may be such that photographing by the imaging device 22 is performed after photographing by the imaging devices 21, 23, 24, and 25, or photographing by the imaging device 22 is performed after photographing by the imaging devices 21, 23, 24, and 25. Also, photographing by the imaging devices 21, 22, 23, 24, and 25 may be performed simultaneously.

[0032] In the description of this specification, the left and right directions are those seen from the imaging device 22 side.

[0033] 1A and 1B, the imaging devices 21, 22, 23, 24, and 25 are fixedly installed, and in the first step of placing the glass 1, the glass 1 may be moved on a conveyor. Alternatively, the glass 1 may be carried to the photographing position by an arm having a chuck at the tip thereof capable of adsorbing the glass 1.

[0034] 1 illustrates multiple fixedly installed imaging devices 21, 22, 23, 24, and 25, but a single imaging device 22 attached to a moving device (e.g., an arm) may be moved to capture images at the five locations illustrated. That is, multiple cameras may capture images of a target at approximately the same time, or one camera may be moved to capture images from different positions.

[0035] 3 and 4 are diagrams showing examples of the target 3 according to the first embodiment.

[0036] The target 3 has a predetermined geometric pattern drawn on it. For example, the target 3 shown in Fig. 3 is configured with black and white stripes extending in an oblique direction. Moreover, the target 3 shown in Fig. 4 is configured with a black and white checkered pattern. The stripe and checkered patterns of the target 3 do not have to be black and white as long as they are of colors that provide high contrast.

[0037] At the point where the target 3 intersects with the optical axis of the imaging device 22 (that is, the optical axis of the vehicle-mounted sensor 5), the pitch of the evaluation pattern constituting the drawn design is preferably 0.1 mm or less.

[0038] FIG. 5 is a block diagram showing the configuration of a glass transmission distortion measuring system 100 of this embodiment.

[0039] The glass perspective distortion measurement system 100 of this embodiment is configured by a computer having a processor (CPU) 101, a memory 102, an auxiliary storage device 103, and a communication interface 104. The glass perspective distortion measurement system 100 may have an input interface 105 and an output interface 108.

[0040] The processor 101 is a calculation device that executes programs stored in the memory 102. The functions of the glass transparency distortion measurement system 100 are realized by the processor 101 executing various programs. Note that a part of the processing performed by the processor 101 by executing the programs may be executed by another calculation device (for example, hardware such as ASIC or FPGA).

[0041] The memory 102 includes a ROM, which is a non-volatile storage element, and a RAM, which is a volatile storage element. The ROM stores unchanging programs (e.g., BIOS) and the like. The RAM is a high-speed, volatile storage element such as a DRAM (Dynamic Random Access Memory), and temporarily stores programs executed by the processor 101 and data used when the programs are executed.

[0042] The auxiliary storage device 103 is, for example, a large-capacity non-volatile storage device such as a magnetic storage device (HDD) or a flash memory (SSD). The auxiliary storage device 103 also stores data used by the processor 101 when the processor 101 executes a program, and the program executed by the processor 101. That is, the program is read from the auxiliary storage device 103, loaded into the memory 102, and executed by the processor 101 to realize each function of the glass perspective distortion measurement system 100.

[0043] The communication interface 104 is a network interface device that controls communications with other devices in accordance with a predetermined protocol.

[0044] The input interface 105 is an interface to which the imaging devices 21, 22, 23, 24, and 25 are connected and which receives input of images. The input interface 105 is also an interface to which input devices such as a keyboard 106 and a mouse 107 are connected and which receives input from an operator. The output interface 108 is an interface to which output devices such as a display device 109 and a printer (not shown) are connected and which outputs the execution result of a program in a format that is visible to a user. Note that a user terminal connected to the glass perspective distortion measurement system 100 via a network may provide the input device and the output device. In this case, the glass perspective distortion measurement system 100 may have a function of a web server, and the user terminal may access the glass perspective distortion measurement system 100 using a predetermined protocol (e.g., http).

[0045] The program executed by the processor 101 is provided to the glass perspective distortion measurement system 100 via a removable medium (CD-ROM, flash memory, etc.) or a network, and is stored in a non-volatile auxiliary storage device 103, which is a non-transitory storage medium. For this reason, the glass perspective distortion measurement system 100 may have an interface for reading data from the removable medium.

[0046] The glass transparency distortion measurement system 100 is a computer system configured on one physical computer, or on multiple logically or physically configured computers, and may operate on a virtual computer constructed on multiple physical computer resources.

[0047] The glass perspective distortion measurement system 100 evaluates the influence caused by the manufacture of the glass 1, for example, by subtracting theoretical data of the evaluation pattern of the target 3 transmitted through the glass 1 from data obtained by photographing the evaluation pattern of the target 3. Evaluation items include, for example, blur, distortion, and perspective double images.

[0048] As described above, according to the first embodiment of the present invention, the angle of the optical axis of the imaging device is changed and images are captured multiple times for the vehicle glass to be evaluated. Therefore, even when images are captured with an imaging device with a narrow angle of view, the effects of lens distortion are reduced and the quality of the glass can be accurately evaluated.

[0049] <Embodiment 2> In the above-described embodiment 1, the imaging devices 21, 22, 23, 24, and 25 each capture an image of one target 3. Therefore, since the target 3 is flat, the imaging devices 21, 23, 24, and 25 capture images of the target 3 from an oblique direction. In embodiment 2, targets 31, 32, 33, 34, and 35 are provided for each of the imaging devices 21, 22, 23, 24, and 25, and the imaging devices 21, 22, 23, 24, and 25 capture images of the targets 31, 32, 33, 34, and 35 from a vertical direction. Note that in embodiment 2, differences from embodiment 1 will be mainly described, and the same components as those in embodiment 1 will be denoted by the same reference numerals, and description thereof will be omitted.

[0050] 6A and 6B are diagrams showing a method for measuring perspective distortion of a glass of embodiment 2, where FIG. 6A is a plan view seen from above and FIG. 6B is a side view seen from the side.

[0051] In the second embodiment, a plurality of imaging devices 21, 22, 23, 24, 25 for photographing the window area 1A from different directions are provided on the first surface side of the glass 1. In addition, a target 31 photographed by the imaging device 21 through the glass 1, a target 32 ​​photographed by the imaging device 22 through the glass 1, a target 33 photographed by the imaging device 23 through the glass 1, a target 34 photographed by the imaging device 24 through the glass 1, and a target 35 photographed by the imaging device 25 through the glass 1 are provided on the second surface side opposite to the first surface side of the glass 1.

[0052] Preferably, the imaging device 22 is disposed at a position and angle such that its optical axis 22A passes perpendicularly to the glass 1 through the center of the window area 1A and the position of the principal point 5A of the lens of the on-board sensor 5 at the virtual position where the on-board sensor 5 is attached, in the horizontal plane, and images the target 32 ​​through the center of the window area 1A. The imaging device 21 is disposed at a position and angle such that its optical axis 21A enters the glass 1 at a shallow angle from the right direction in the horizontal plane and passes near the boundary with the shielding part 1B of the left side of the window area 1A from the right direction of the glass 1, and images the target 31 through the left side area of ​​the window area 1A to include a range of 30 mm inward from the left side boundary. Moreover, imaging device 23 is disposed at a position and angle such that its optical axis 23A enters glass 1 from the left direction on the horizontal plane at a shallow angle, passes from the left direction of glass 1 near the boundary with shielding portion 1B at the right side of window area 1A, and images target 33 through the right side area of ​​window area 1A to include a range of 30 mm inward from the right side boundary. Moreover, imaging device 24 is disposed at a position and angle such that its optical axis 24A enters glass 1 from the bottom direction on the vertical plane at a shallow angle, passes from the bottom direction of glass 1 near the boundary with shielding portion 1B at the upper side of window area 1A, and images target 34 through the upper area of ​​window area 1A to include a range of 30 mm inward from the upper boundary. The imaging device 25 is positioned at a position and angle such that its optical axis 25A enters the glass 1 at a shallow angle from above in the vertical plane and passes from above the glass 1 near the boundary with the shielding portion 1B of the lower part of the window area 1A, and captures an image of the target 35 through the lower area of ​​the window area 1A to include a range of 30 mm inward from the lower boundary.

[0053] 6A and 6B show multiple imaging devices 21, 22, 23, 24, and 25 that are fixedly installed, but a single imaging device 22 attached to a moving device (for example, an arm) may be moved to the five locations shown to capture images.

[0054] As described above, according to the second embodiment of the present invention, the optical axes 21A, 23A, 24A, and 25A of the imaging devices 21, 23, 24, and 25 are perpendicular to the targets 31, 33, 34, and 35, so that the targets 31, 33, 34, and 35 can be photographed without geometric distortion and can be accurately evaluated.

[0055] <Embodiment 3> In the above-described first and second embodiments, the window area 1A is entirely photographed including both sides thereof by a plurality of imaging devices, but in the third embodiment, the window area 1A is divided into a plurality of photographing areas, and each divided photographing area is photographed by an imaging device. Note that in the third embodiment, differences from the second embodiment will be mainly described, and the same reference numerals will be used to designate the same components as those in the first and second embodiments, and the description thereof will be omitted.

[0056] 7 and 8 are diagrams showing a method for measuring perspective distortion of the glass according to the third embodiment.

[0057] In the third embodiment, the window area 1A is divided into a plurality of areas. The divided imaging areas are arranged on the upper, lower, left and right sides of the window area 1A, but are not arranged in the center of the window area 1A.

[0058] In the third embodiment, a plurality of imaging devices 21, 22 that capture images of the window area 1A from different directions are provided on the first surface side of the glass 1. A target 31 that the imaging device 21 captures an image of through the glass 1 is provided on the second surface side opposite to the first surface side of the glass 1, and a target 32 ​​that the imaging device 22 captures an image of through the glass 1 is provided. In the third embodiment, the plurality of imaging devices 21, 22 may capture an image of one target 3, as in the first embodiment.

[0059] Preferably, the imaging device 22 is disposed at a position and angle such that its optical axis 22A passes perpendicularly to the glass 1 through the center of the window area 1A and the position of the principal point 5A of the lens of the on-board sensor 5 at the virtual position where the on-board sensor 5 is attached, in the horizontal plane, and images the target 32 ​​through the center of the window area 1A. The imaging device 21 is disposed at a position and angle such that its optical axis 21A enters the glass 1 at a shallow angle from the right direction in the horizontal plane and passes near the boundary between the left side of the window area 1A and the shielding part 1B from the right direction of the glass 1, and images the target 31 through the left side area of ​​the window area 1A to include a range of 30 mm inward from the left side boundary, and includes the left boundary between the window area 1A and the shielding part 1B. Furthermore, imaging device 23 is disposed at a position and angle such that its optical axis 23A enters glass 1 from the left direction on the horizontal plane at a shallow angle, passes from the left direction of glass 1 near the boundary with shielding portion 1B at the right side of window area 1A, and photographs target 31 including the right boundary of window area 1A and shielding portion 1B through the right side area of ​​window area 1A to include a range of 30 mm inward from the right side boundary. Imaging device 24 is disposed at a position and angle such that its optical axis 24A enters glass 1 from the bottom direction on the vertical plane at a shallow angle, passes from the bottom direction of glass 1 near the boundary with shielding portion 1B at the upper side of window area 1A, and photographs target 34 through the upper area of ​​window area 1A to include a range of 30 mm inward from the upper boundary. The imaging device 25 is positioned at a position and angle such that its optical axis 25A enters the glass 1 at a shallow angle from above in the vertical plane and passes from above the glass 1 near the boundary with the shielding portion 1B of the lower part of the window area 1A, and captures an image of the target 35 through the lower area of ​​the window area 1A to include a range of 30 mm inward from the lower boundary.

[0060] 8, imaging devices 21, 22, 23, 24, and 25 are fixedly installed, and in the first step of positioning the glass 1, the glass 1 may be placed on a stage and moved on a conveyor. The horizontal shooting position of the glass 1 can be changed by moving it on the conveyor. The height of the stage is adjustable, and changing the height of the stage can change the shooting position of the glass 1 in the vertical direction. Also, the glass 1 may be carried to the shooting position by an arm having a chuck at the tip that can suction the glass 1.

[0061] FIG. 8 illustrates a plurality of fixedly installed imaging devices 21, 22, 23, 24, and 25, but a single imaging device 22 attached to a moving device (for example, an arm) may be moved among the three locations illustrated to capture images.

[0062] 9 and 10 are diagrams illustrating a method for measuring perspective distortion of the glass of the third embodiment.

[0063] Each of the divided shooting areas of the window area 1A is provided on one or two of the upper side, lower side, right side, and left side of the window area 1A. Therefore, the shooting direction of each shooting area is not only the vertical direction, but also the opposite side to the side where one or two sides exist.

[0064] 9, the imaging device 22 is disposed at a position and angle such that its optical axis 22A passes vertically through the center of the window area 1A on the horizontal plane of the glass 1 and the position of the principal point 5A of the lens of the vehicle-mounted sensor 5 at the virtual position where the vehicle-mounted sensor 5 is attached, and captures a vertical image of the target 32 ​​through the center of the window area 1A. The imaging device 21 is disposed at a position and angle such that its optical axis 21A enters the glass 1 at a shallow angle from the right direction on the horizontal plane, passes from the right direction of the area to the left side of the window area 1A (from the inside of the window area 1A to the outside of the window area 1A) near the boundary with the shielding part 1B, and captures an image of the target 31 through the left area of ​​the window area 1A to include a range of 30 mm inward from the left boundary, and includes the left boundary of the window area 1A and the shielding part 1B.

[0065] 10, the imaging device 22 is disposed at a position and angle such that its optical axis 22A passes vertically through the center of the window area 1A on the horizontal plane of the glass 1 and the position of the principal point 5A of the lens of the vehicle-mounted sensor 5 at the virtual position where the vehicle-mounted sensor 5 is attached, and vertically photographs the target 32 ​​through the center of the window area 1A. The imaging device 24 is disposed at a position and angle such that its optical axis 24A enters the glass 1 at a shallow angle from below on the horizontal plane, passes from below the area to the upper part of the window area 1A (from the inside of the window area 1A to the outside of the window area 1A) near the boundary with the shielding part 1B, and photographs the target 34 through the upper area of ​​the window area 1A to include a range of 30 mm inward from the left boundary, and includes the upper boundary of the window area 1A and the shielding part 1B.

[0066] 11 and 12 are diagrams showing specific examples of shooting directions of a shooting area in the third embodiment.

[0067] 11 is provided on the upper and left sides of the window region 1A, the imaging device 22 is disposed at a position and angle where its optical axis 22A passes through the center of the window region 1A perpendicular to the glass 1, and images the target 32 ​​through the center of the window region 1A. The imaging device 21 is disposed at a position and angle where its optical axis 21A enters the glass 1 from the right at a shallow angle and passes near the boundary with the shielding portion 1B of the left side of the window region 1A from the right of the glass 1, and images the target 31 through the left region of the window region 1A. The imaging device 24 is disposed at a position and angle where its optical axis 24A enters the glass 1 from below at a shallow angle and passes near the boundary with the shielding portion 1B of the upper part of the window region 1A from below the glass 1, and images the target 34 through the upper region of the window region 1A.

[0068] 12 is provided on the upper side of the window region 1A, the imaging device 22 is disposed at a position and angle where its optical axis 22A passes through the center of the window region 1A perpendicular to the glass 1, and images the target 32 ​​through the center of the window region 1A. The imaging device 24 is disposed at a position and angle where its optical axis 24A enters the glass 1 from below at a shallow angle and passes near the boundary with the shielding part 1B at the upper part of the window region 1A from below the glass 1, and images the target 34 through the upper region of the window region 1A.

[0069] As described above, according to the third embodiment of the present invention, the angle at which the optical axis of the imaging device enters the glass becomes smaller (the angle it makes with the glass surface becomes larger), and even when shooting with a lens with a wide angle of view, the effect of lens distortion is reduced, enabling the quality of the glass to be evaluated more accurately.

[0070] Although the present invention has been described in detail above with reference to the accompanying drawings, the present invention is not limited to such specific configurations, and includes various modifications and equivalent configurations within the spirit of the appended claims. [Explanation of symbols]

[0071] 1. Glass 1A shielding part 1B Window Region 21, 22, 23, 24, 25 Imaging device 21A, 22A, 23A, 24A, 25A Optical axis of imaging device 3, 31, 32, 33, 34, 35 Target 5. Vehicle sensors 100 Glass Transparency Distortion Measurement System

Claims

1. A method for taking an image for evaluation of a vehicle glass, comprising: The vehicle glass has a window area through which an on-board sensor observes the outside of the vehicle from inside the vehicle when the vehicle glass is installed in the vehicle, and a light-blocking portion surrounding the window area, A first step of arranging the vehicle glass so that the window area is positioned on an optical axis of an imaging device that captures an image of a target on which a predetermined pattern is drawn; a second step of imaging the target from a vertical direction by the imaging device, with the position of the principal point of the lens of the vehicle-mounted sensor when the vehicle-mounted sensor is installed and the optical axis of the imaging device passing through a central area of ​​the window area; and a third step of the imaging device photographing the target from another direction passing through the location of the principal point and the window area.

2. 2. The method of claim 1 , The method according to claim 3, wherein the other direction in the third step is at least one of a rightward direction and a leftward direction in a horizontal plane.

3. 2. The method of claim 1 , The method of claim 3, wherein the other direction in the third step is at least one of an upward direction and a downward direction in a vertical plane.

4. 4. The method according to claim 2 or 3, In the third step, the imaging device When photographing the target from the right direction, the target is photographed so as to include a range of 30 mm inward from the left boundary of the window region and the shielding portion, When photographing the target from the left direction, the target is photographed so as to include a range of 30 mm inward from the right boundary of the window region and the shielding portion, When photographing the target from the above direction, the target is photographed so as to include a range of 30 mm inward from the window region and the lower boundary of the shielding portion; A method for capturing an image of the target from the downward direction, the method comprising: capturing an image of the target so as to include a range of 30 mm inward from the window region and an upper boundary of the shielding portion.

5. 2. The method of claim 1 , A method according to claim 1, wherein the order of execution of the second step and the third step is either performing the third step after the second step, or performing the second step after the third step.

6. 2. The method of claim 1 , In the first step, the target is disposed perpendicular to an optical axis of the vehicle-mounted sensor; The method is characterized in that the pitch of the evaluation pattern constituting the drawn pattern in the region including the point where the target intersects with the optical axis of the vehicle-mounted sensor is 0.1 mm or less.

7. 2. The method of claim 1 , The method, wherein the angle of view of the imaging device is smaller than the angle of view of the vehicle-mounted sensor.

8. 2. The method of claim 1 , The method comprises photographing the target in the second and third steps in each area into which the vehicle glass is divided.

Images