Inspection equipment

Abstract

Even when projecting light and dark patterns onto the object being examined using multiple adjacent displays, the light and dark patterns are captured sufficiently. [Solution] The inspection device 1 comprises a display 2a, a display 2b, a camera 3a1, and a camera 3b1. The displays 2a and 2b are arranged adjacent to each other on the same plane so that their display surfaces are oriented in the same direction, and they display a light and dark pattern and project the light and dark pattern onto the inspection target K by irradiating the display light onto the inspection target K. Camera 3a1 is positioned to capture images of the dead zone portion B2, which is caused by the edges 23a and 23b and is not captured by the camera 3b1. Camera 3b1 is positioned to capture images of the dead zone portion B1, which is caused by the edges 23a and 23b and is not captured by the camera 3a1.

Description

Technical Field

[0001] The present disclosure relates to an inspection apparatus.

Background Art

[0002] There is a technique of projecting a light and dark pattern onto an inspection object having specular reflectivity (for example, a painted surface of an automobile), imaging the inspection object onto which the light and dark pattern is projected with a camera, and inspecting the inspection object based on the captured image. For example, Patent Document 1 discloses a technique of projecting a light and dark pattern onto an inspection object (inspected surface), imaging it, and inspecting the smoothness of the inspected surface according to the degree of variation in the width of the light and dark boundary region in a binarized image obtained by binarizing the obtained captured image (received light image).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is conceivable to employ a display as a device for projecting a light and dark pattern, display the light and dark pattern on the display surface of the display, and project the light and dark pattern onto the inspection object by irradiating the inspection object with the display light emitted from the display surface. Further, in order to expand the projection range, it is conceivable to arrange a plurality of displays adjacent to each other and project the light and dark pattern with the plurality of displays.

[0005] On the other hand, the camera captures a light and dark pattern by receiving reflected light from the object being inspected. In particular, when the object being inspected has a specular surface, the reflected light received by the camera is mainly specular reflection. However, since a display has an edge outside the display surface, even if multiple displays are placed adjacent to each other, there will be areas between the display surfaces of the multiple displays that do not emit light due to the edges. If there are areas that do not emit light, depending on the positional relationship between the camera, the edge, and the object being inspected, it may not be possible to receive specular reflection from the object being inspected. Therefore, if there are areas that do not emit light due to the edges, there is a risk that a dead zone will be created on the object being inspected in which the light and dark pattern cannot be captured. Consequently, when projecting a light and dark pattern onto an object being inspected using multiple displays placed adjacent to each other, there is a risk that the light and dark pattern may not be captured sufficiently.

[0006] The purpose of this disclosure is, in view of the above circumstances, to provide an inspection device that can sufficiently capture a light and dark pattern even when projecting the light and dark pattern onto an inspection target using multiple adjacently arranged displays. [Means for solving the problem]

[0007] To achieve the above objectives, the inspection apparatus relating to the perspective of this disclosure is An inspection device that projects a light and dark pattern onto an object to be inspected, and detects defects occurring in the object to be inspected based on an image obtained by capturing the light and dark pattern projected onto the object to be inspected, It comprises a first display, a second display, a first camera, and a second camera. The first display and the second display are arranged adjacent to each other on the same plane such that their display surfaces are oriented in the same direction. The first display and the second display project the light and dark pattern onto the object to be inspected by displaying the light and dark pattern and irradiating the object to be inspected with the display light. The first camera is positioned to capture a second dead zone, which is a dead zone created by a first edge of the first display adjacent to the second display and a second edge of the second display adjacent to the first display, and in which the second camera cannot capture the light and dark pattern. The second camera is positioned to capture the first dead zone, which is a dead zone created by the first edge and the second edge, and in which the first camera cannot capture the light and dark pattern. [Effects of the Invention]

[0008] According to this disclosure, even when projecting a light and dark pattern onto an object to be inspected using multiple adjacent displays, the light and dark pattern can be sufficiently captured. [Brief explanation of the drawing]

[0009] [Figure 1] This is a front view showing the overall configuration of the inspection device according to the embodiment of the present disclosure. [Figure 2] This is a right side view showing the overall configuration of the inspection device according to the embodiment of this disclosure. [Figure 3] This figure shows an example of a shift in the brightness pattern in the projection section according to an embodiment of the present disclosure. [Figure 4] This figure shows an example of a dead zone in an inspection device according to an embodiment of the present disclosure. [Figure 5] This is a front view illustrating a method for determining the dead zone in an inspection device according to an embodiment of the present disclosure. [Figure 6] This is a right side view illustrating a method for determining the dead zone in an inspection device according to an embodiment of the present disclosure. [Figure 7] This is a front view showing the overall configuration of an inspection device according to a modified embodiment of the present disclosure. [Modes for carrying out the invention]

[0010] The inspection apparatus according to the embodiments of this disclosure will be described below with reference to the drawings. In each drawing, the same or equivalent parts are denoted by the same reference numerals.

[0011] (Embodiment) An inspection apparatus 1 according to an embodiment will be described with reference to the front view shown in Figure 1 and the right side view shown in Figure 2. The inspection apparatus 1 comprises a display 2a and a display 2b (these displays may be collectively referred to as display 2), cameras 3a1, 3a2, 3b1, and 3b2 (these cameras may be collectively referred to as camera 3), a fixing member 4, and a control unit 10. The control unit 10 is not shown in Figure 1. In Figure 2, each display 2 and each camera 3 are shown together. The control unit 10 is communicateably connected to each display 2 and each camera 3. The inspection apparatus 1 projects a light / dark pattern onto the inspection target K using each display 2, captures the light / dark pattern projected onto the inspection target K using each camera 3, and the control unit 10 detects defects such as dirt and dents on the inspection target K based on the captured image of the light / dark pattern. The inspection apparatus 1 is an example of an inspection apparatus according to this disclosure.

[0012] In the front view of Figure 1, the X-axis is defined as running from right to left, the Y-axis as running from bottom to top, and the Z-axis as running from front to back. With the axes defined in this way, in the right side view of Figure 2, the X-axis is defined as running from front to back, the Y-axis as running from the bottom right to the top left and parallel to the long side of display 2b, and the Z-axis as the Y-axis rotated 90° clockwise.

[0013] In Figure 2, display 2 more precisely includes display 2b located on the near side (negative X-axis direction) and display 2a located behind display 2b (positive X-axis direction) and hidden by display 2b. Similarly, in Figure 2, camera 3 more precisely includes camera 3b2 located at the very front, and cameras 3b1, 3a1, and 3a2 located behind camera 3b2 and hidden by camera 3b2.

[0014] The inspection target K is assumed to have specular reflectivity under normal conditions where no defects are present, such as the painted surface of an automobile.

[0015] Each display 2 displays a light and dark pattern including slit-shaped light portions 21 and dark portions 22 arranged alternately, based on the control by the control unit 10. Each display 2 projects the light and dark pattern onto the inspection target K by irradiating the inspection target K with display light L1. The display light L1 is reflected by the inspection target K to become reflected light L2. The displays 2a and 2b are arranged adjacent to each other on the same plane such that the orientations of their display surfaces are the same. In FIG. 1, the display 2a is arranged adjacent to the left side (positive X-axis direction) of the display 2b. Each display 2 is fixed on the same plane by a fixing member 4. In FIG. 1, although the displays 2a and 2b have the same shape, the length in the lateral direction (X-axis direction) of the display 2a and the length in the lateral direction (X-axis direction) of the display 2b do not have to be the same. The inspection apparatus 1 can project a light and dark pattern over a wide range by including a plurality of displays 2. The display 2a is an example of the first display according to the present disclosure, and the display 2b is an example of the second display according to the present disclosure.

[0016] Based on the control of the control unit 10, the display 2, for example, as shown in FIG. 3, shifts the light and dark pattern displayed on the display 2 by d / 2, which is half of the slit width d, at regular intervals (for example, every 0.1 second). As a result, as shown in FIG. 3, the light and dark pattern displayed on the display 2 changes periodically as (A), (B), (C), (D), (A), (B), (C), (D), ···. Thereby, the light and dark pattern projected onto the inspection target K also changes periodically.

[0017] Each camera 3 is an optical camera, and by receiving the reflected light L2, it images the light and dark pattern projected onto the inspection target K. Each camera 3 can image the periodically changing light and dark pattern by periodically imaging the light and dark pattern based on the control of the control unit 10. Since the inspection target K has specular properties under normal conditions, most of the reflected light L2 received by the camera 3 is due to regular reflection (regular reflection light), and there is little due to diffuse reflection. In FIG. 1, the cameras 3a1 and 3a2 are arranged above the display 2a (in the positive Y-axis direction) and to the left of the display 2b (in the positive X-axis direction). The camera 3a2 is arranged outside (in the positive X-axis direction) of the camera 3a1. In FIG. 1, the cameras 3b1 and 3b2 are arranged above the display 2b (in the positive Y-axis direction) and to the right of the display 2a (in the negative X-axis direction). The camera 3b2 is arranged outside (in the negative X-axis direction) of the camera 3b1. Each camera 3 is arranged on the same plane. As shown in FIG. 2, each camera 3 is arranged such that the angle formed by the imaging direction on the YZ plane and the display surface of the display 2 is an acute angle (for example, 30°). Each camera 3 is fixed by a fixing member 4. The camera 3a1 is an example of the first camera according to the present disclosure, the camera 3b1 is an example of the second camera according to the present disclosure, and the cameras 3a2 and 3b2 are examples of the third camera according to the present disclosure.

[0018] The fixing member 4 is a member that fixes each display 2 and each camera 3. The fixing member 4 fixes each display 2 on the same plane. The fixing member 4 fixes each camera 3 on the same plane. The fixing member 4 fixes each display 2 and each camera 3 by, for example, bolts and nuts not shown in the figure.

[0019] The arrangement of each camera 3 will be described in more detail with reference to Figure 4. However, while Figure 4 is based on the front view shown in Figure 1, the description of the fixing member 4 and the description of the brightness and darkness patterns displayed on each display 2 are omitted. Hereinafter, as shown in the shaded area of ​​Figure 4, the edge of display 2a adjacent to display 2b will be referred to as edge 23a, and the edge of display 2b adjacent to display 2a will be referred to as edge 23b. Edges 23a and 23b will be collectively referred to as edge 23. In Figure 4, the side closer to edge 23 may be referred to as the inside, and the side further from edge 23 may be referred to as the outside. Edge 23a is an example of a first edge according to this disclosure, and edge 23b is an example of a second edge according to this disclosure.

[0020] With respect to edges 23a and 23b, the arrangement of each camera 3 can be rephrased as follows: Cameras 3a1 and 3a2 are arranged such that edge 23a is closer to edge 23b than edge 23b. Cameras 3a1 and 3a2 are arranged such that the distance from camera 3a2 to edge 23a is greater than the distance from camera 3a1 to edge 23a. Cameras 3b1 and 3b2 are arranged such that edge 23b is closer to edge 23a than edge 23a. Cameras 3b1 and 3b2 are arranged such that the distance from camera 3b2 to edge 23b is greater than the distance from camera 3b1 to edge 23b.

[0021] As shown in Figure 4, each camera 3 is positioned such that its imaging direction on the XY plane is inward from the longitudinal direction (Y-axis direction) of the edge 23. Furthermore, with respect to the edge 23, camera 3a2 is positioned further out than camera 3a1, and camera 3b2 is positioned further out than camera 3b1.

[0022] As described above, each display 2 projects a light / dark pattern onto the inspection target K, and each camera 3 captures the projected light / dark pattern. On the other hand, each display 2 has adjacent edges 23a and 23b, and these edges 23a and 23b have areas that do not emit light. As will be described in detail later, the edges 23 create a dead zone B1 that cannot be captured by camera 3a1 and a dead zone B2 that cannot be captured by camera 3b1 on the inspection target K. However, all portions of the light / dark pattern projected by display 2a that are projected outside the field of view of camera 3a1 are assumed to be within the field of view of camera 3a2. Similarly, all portions of the light / dark pattern projected by display 2b that are projected outside the field of view of camera 3b1 are assumed to be within the field of view of camera 3b2. Dead zone B1 is an example of the first dead zone portion related to this disclosure, and dead zone B2 is an example of the second dead zone portion related to this disclosure.

[0023] Therefore, by setting the installation positions and imaging directions of cameras 3a1 and 3b1 so that camera 3b1 can image the dead zone B1 that camera 3a1 cannot image, and camera 3a1 can image the dead zone B2 that camera 3b1 cannot image, the light and dark pattern projected onto the inspection target K can be captured without omission. For example, by orienting the imaging direction of camera 3a1 toward the direction of the edge 23 so that the dead zone B2 can be imaged, and orienting the imaging direction of camera 3b1 toward the direction of the edge 23 so that the dead zone B1 can be imaged, camera 3b1 can image the dead zone B1 that camera 3a1 cannot image, and camera 3a1 can image the dead zone B2 that camera 3b1 cannot image, thus capturing the light and dark pattern projected onto the inspection target K without omission. Therefore, by arranging cameras 3a1 and 3b1 in this manner, the inspection device 1 can sufficiently capture the light and dark pattern projected onto the inspection target K.

[0024] The dead zones B1 and B2 that occur in the inspection target K due to the edge portion 23 will be explained below. To facilitate understanding, the entrance pupil of each camera 3 will be assumed to be small and will be approximated as a point for discussion below. Furthermore, below we will focus on camera 3a1 and the dead zone portion B1, which is the dead zone portion that cannot be imaged by camera 3a1, and the same will apply to camera 3b1 and the dead zone portion B2.

[0025] Assuming that illumination light is emitted from the edge 23, we consider the specularly reflected light at each point of the object K being inspected, which is the illumination light from the edge 23 that is specularly reflected at that point. Among the points of the object K being inspected, the points at which this specularly reflected light reaches the entrance pupil of the camera 3a1 are the points that constitute the dead zone B1 (hereinafter referred to as "dead spots"). In reality, no light is emitted from the edge 23, so there is no specularly reflected light that enters the entrance pupil of the camera 3a1 from the dead spots, and therefore the camera 3a1 cannot receive light from the dead spots.

[0026] How to determine such a dead zone will be explained with reference to the front view shown in Figure 5 and the right side view shown in Figure 6. Figure 5 is the same as Figure 4, but with the camera 3a1, edge 23, and inspection target K omitted, and the necessary information for explaining the dead zone added. Similarly, Figure 6 is the same as Figure 2, but with the camera 3a1, edge 23, and inspection target K omitted, and the necessary information for explaining the dead zone added.

[0027] First, consider camera 3x, which is obtained by reflecting camera 3 symmetrically with respect to the surface (reflective surface) of the object K being inspected. Next, consider a straight line connecting the entrance pupil of camera 3x and a point on the edge 23. The intersection of this line and the surface of the object K being inspected becomes the dead zone P. By determining the dead zone P in this way at each point on the edge 23, the dead zone B1 that camera 3a1 cannot image can be identified. Therefore, the dead zone B1 is determined based on the position of the entrance pupil of camera 3a1, the position of the object K being inspected, and the position of the edge 23 (the positions of edge 23a and edge 23b).

[0028] In addition to identifying the dead zone B1 as described above, the dead zone B1 may also be identified based on the captured image. For example, the dead zone B1 can be identified by periodically capturing a periodically changing light and dark pattern projected onto the object K for inspection using camera 3a1, scanning each point of the periodically obtained captured image, and determining the points where the pixels do not change as dead zones.

[0029] The inspection apparatus 1 according to the embodiment has been described above. While the inspection apparatus 1 can project a light and dark pattern over a wide area using displays 2a and 2b, the edges 23a and 23b create dead zones B1 and B2 that cannot be captured by camera 3a1 and camera 3b1, respectively. However, by positioning camera 3a1 to capture dead zone B2 and camera 3b1 to capture dead zone B1, the light and dark pattern projected onto the inspection target K can be captured without omission. Therefore, the inspection apparatus 1 can adequately capture the light and dark pattern projected onto the inspection target K.

[0030] (modified version) In this embodiment, the inspection device 1 includes only two displays 2. However, the inspection device 1 may include three or more displays 2. For example, as shown in Figure 7, a display 2c may be located to the right of display 2b. However, Figure 7 omits the description of the brightness and darkness patterns displayed on each display 2. In this case, cameras 3c1 and 3c2 are further included, and unlike the embodiment shown in Figure 1, it is necessary to change the orientation of camera 3b2 in order to image the dead zone portion of camera 3c1.

[0031] In this embodiment, each camera 3 was arranged on the same plane. However, each camera 3 does not necessarily have to be arranged on the same plane. It is sufficient that each camera 3 is arranged so that the light and dark pattern projected onto the inspection target K is captured without any omissions, including the dead zones B1 and B2. In particular, cameras 3a2 and 3b2 should be arranged so that they can capture the parts of the projected light and dark pattern that cannot be captured by either camera 3a1 or camera 3b1.

[0032] Furthermore, if the light and dark patterns can be captured without omission using only cameras 3a1 and 3b1, the inspection device 1 does not need to be equipped with cameras 3a2 and 3b2. [Explanation of Symbols]

[0033] 1. Inspection device 2,2a,2b,2c displays 3,3a1,3a2,3b1,3b2,3c1,3c2,3x Camera 4 Fixing members 10 Control Unit 21 Akabe 22 Dark part 23,23a,23b Edge B1, B2 dead zone P blind point K Test Subject L1 display light L2 reflected light

Claims

1. An inspection device that projects a light and dark pattern onto an object to be inspected, and detects defects occurring in the object to be inspected based on an image obtained by capturing the light and dark pattern projected onto the object to be inspected, It comprises a first display, a second display, a first camera, and a second camera. The first display and the second display are arranged adjacent to each other on the same plane such that their display surfaces are oriented in the same direction. The first display and the second display project the light and dark pattern onto the object to be inspected by displaying the light and dark pattern and irradiating the object to be inspected with the display light. The first camera is positioned to capture a second dead zone, which is a dead zone created by a first edge of the first display adjacent to the second display and a second edge of the second display adjacent to the first display, and in which the second camera cannot capture the light and dark pattern. The second camera is positioned to capture the first dead zone, which is a dead zone created by the first edge and the second edge and in which the first camera cannot capture the light and dark pattern. Inspection device.

2. The first dead zone portion is determined based on the position of the entrance pupil of the first camera, the position of the object to be inspected, the position of the first edge, and the position of the second edge. The second dead zone is determined based on the position of the entrance pupil of the second camera, the position of the object to be inspected, the position of the first edge, and the position of the second edge. The inspection apparatus according to claim 1.

3. The first camera is positioned such that the first edge is closer to the second edge than the first edge, and the second camera is positioned such that the second edge is closer to the first edge than the first edge. The inspection apparatus according to claim 1 or 2.

4. The system further includes a third camera that captures the portion of the light and dark pattern projected onto the object to be inspected that cannot be captured by either the first camera or the second camera. The inspection apparatus according to claim 1 or 2.

Images