Optical inspection method, device, and non-transitory computer-readable storage medium

Abstract

Embodiments of the present invention relate to an optical inspection method, an optical inspection apparatus, and a non-transitory computer-readable storage medium storing an optical inspection program. An optical inspection method capable of identifying the direction of light is provided. In the optical inspection method, for an image point formed by separating light rays from an object point into at least two different independent wavelength regions, a hue vector is obtained, with the intensity of the light rays from the at least two different independent wavelength regions as independent axes, and information related to the direction of the light rays from the object point is obtained from the hue vector.

Description

Technical Field

[0001] Embodiments of the present invention relate to optical inspection methods, optical inspection apparatus, and non-transitory computer-readable storage media storing optical inspection programs. Background Technology

[0002] In various industries, non-contact optical inspection of objects has become important. In optical inspection, the identification of light direction is crucial for understanding information about the object. Previously, methods used a quantity called hue to identify light direction. However, the hue used previously was a scalar quantity (that is, unlike a multidimensional vector, it only represents magnitude). This hue is specifically referred to as a hue scalar. Summary of the Invention

[0003] In the optical inspection method of the embodiment, for an image point that is imaged by separating light from an object point into at least two different independent wavelength regions, a hue vector is obtained with the intensity of light from at least two different independent wavelength regions as an independent axis, and information related to the direction of light from the object point is obtained from the hue vector.

[0004] The optical inspection apparatus of the embodiment includes: an imaging unit for imaging light from an object point; a hue vector generation unit for separating light from the object point into light of at least two different independent wavelength regions; an image acquisition unit for acquiring an image point imaged by light of at least two different independent wavelength regions passing through the hue vector generation unit; and a processing unit for acquiring a hue vector for the image point with the intensity of light of at least two different independent wavelength regions as independent axes, and acquiring information related to the direction of light from the object point from the hue vector.

[0005] The non-transitory computer-readable storage medium of the implementation method stores an optical inspection program. The optical inspection program enables a computer to perform: processing for an image point that images light from an object point by separating it into at least two different independent wavelength regions, acquiring a hue vector with the intensity of the light from at least two different independent wavelength regions as independent axes; and processing for acquiring information related to the direction of the light from the object point from the hue vector.

[0006] The optical inspection method, optical inspection apparatus, and non-transitory computer-readable storage medium storing the optical inspection program, based on the above structure, are able to identify the direction of light. Attached Figure Description

[0007] Figure 1 This is a side view showing the schematic structure of the optical inspection apparatus according to the first embodiment.

[0008] Figure 2This is a graphic illustrating an example of wavelength regions of light generated by a hue vector.

[0009] Figure 3 It is a graphic representation of the hue vector in the hue vector space.

[0010] Figure 4 This is a flowchart showing the processing of the processing unit in the optical inspection method according to the first embodiment.

[0011] Figure 5 This is a side view showing the schematic structure of the optical inspection apparatus according to the second embodiment.

[0012] Figure 6 This is a side view showing the schematic structure of the optical inspection apparatus according to the third embodiment.

[0013] Figure 7 This is a top view showing the general structure of the light direction selection unit according to the third embodiment.

[0014] Figure 8 This is a top view showing a schematic structure of a modified example of the light direction selection unit according to the third embodiment.

[0015] Figure 9 This is a perspective view showing the schematic structure of the optical inspection apparatus according to the fourth embodiment.

[0016] Symbol Explanation

[0017] 10: Optical inspection device; 20: Imaging unit; 30: Hue vector generation unit; 31, 32: Selection area; 40: Image acquisition unit; 40a: First image acquisition unit; 40b: Second image acquisition unit; 41: Pixel; 50: Processing unit; 60: Ray direction selection unit; 61: First selection area; 62: Second selection area; 63: Third selection area; 70: Two-panel camera; 80: Three-panel camera; 90: Projector illumination unit; 100: Illumination field; 101: First area; 102: Second area; 103: Third area; L1: First ray; L2: Second ray; L3: Third ray; OA: Optical axis; Lp: Line. Detailed Implementation

[0018] Hereinafter, various embodiments will be described with reference to the accompanying drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the size between parts, etc., are not necessarily limited to the same situation as in reality. In addition, even when showing the same parts, the dimensions and ratios may sometimes be shown differently depending on the drawings. In this specification and the drawings, for existing drawings, the same symbols are used for the same elements as described above, and detailed descriptions are appropriately omitted.

[0019] (First Embodiment)

[0020] Hereinafter, the first embodiment will be described in detail with reference to the accompanying drawings. A side view showing the schematic structure of the optical inspection apparatus 10 according to this embodiment will be provided. Figure 1 As shown in the image.

[0021] The optical inspection device 10 includes an imaging unit 20, a hue vector generation unit 30, an image acquisition unit 40, and a processing unit 50. In this embodiment, for convenience, two light rays in different directions are assumed. The two light rays in different directions are respectively designated as the first light ray L1 and the second light ray L2.

[0022] Ray 1 L1 and ray 2 L2 indicate the direction of light propagation. For example, light is an electromagnetic wave. That is to say, light can be any electromagnetic wave, such as X-rays, ultraviolet rays, visible light, infrared rays, millimeter waves, and microwaves. Here, we assume it to be light, specifically visible light with a wavelength of 400 nm to 800 nm.

[0023] Imaging unit 20 images the light from object point OP. Imaging the light from object point OP means moving the light emitted from object point OP to image point IP. In other words, it means imaging object point OP onto image point IP. In geometrical optics, object point OP and image point IP are conjugates. However, object point OP and image point IP are regions that can be optically considered as points. Image point IP is located in image acquisition unit 40.

[0024] The image acquisition unit 40 acquires the image formed (image) by the imaging unit 20. The image acquisition unit 40 includes at least one pixel 41. For example, the image acquisition unit 40 includes multiple pixels 41. Each pixel 41 acquires the light intensity for at least two different wavelength regions at the same time. That is, each pixel 41 can identify light in at least two different wavelength regions. Each pixel 41, for example, includes multiple light-receiving elements capable of receiving light in multiple wavelength regions. For example, the image acquisition unit 40 includes a color filter, a CCD area sensor, or a CMOS area sensor. Each pixel 41 includes multiple color regions of the color filter and multiple light-receiving elements of the area sensor. When compared with the embodiments described later, this can also be described as performing imaging based on a single-plate camera.

[0025] The hue vector generation unit 30 is capable of separating the arriving light into light in at least two different wavelength regions for transmission. Here, "transmission" means either transmission or reflection.

[0026] In this embodiment, the hue vector generation unit 30 has two selection regions 31 and 32. The two selection regions 31 and 32 separate light into two different independent wavelength regions, which then pass through separately. For example, the selection regions 31 and 32 of the hue vector generation unit 30 are each equipped with an optical filter that selectively allows light from mutually independent wavelength regions to pass through.

[0027] The two selection regions 31 and 32 are respectively designated as the first wavelength region and the second wavelength region of the transmitted light. Moreover, the first wavelength region and the second wavelength region do not substantially overlap. The substantially non-overlapping wavelength regions are called independent wavelength regions.

[0028] exist Figure 2 The diagram shows an example of two wavelength regions of light separated by selection areas 31 and 32 of the hue vector generation unit 30. The horizontal axis represents wavelength, and the vertical axis represents light intensity. The two distinct independent wavelength regions are designated B and R. For example, the two distinct independent wavelength regions B and R are designated as a first wavelength region B and a second wavelength region R, respectively. The first wavelength region B includes a wavelength of 450 nm, and the second wavelength region R includes a wavelength of 650 nm. That is, the first wavelength region B allows blue light to pass through, and the second wavelength region R allows red light to pass through. However, the first wavelength region B and the second wavelength region R are not limited to this and can be freely chosen.

[0029] In this embodiment, the light passing through the paths of the first ray L1 and the second ray L2 before reaching the hue vector generation unit 30 is assumed to be visible light with a wavelength of 400 nm to 800 nm. After passing through the hue vector generation unit 30, the light passing through the path of the first ray L1 has a wavelength of 450 nm, and the light passing through the path of the second ray L2 has a wavelength of 650 nm. That is, after passing through the hue vector generation unit 30, the light passing through the path of the first ray L1 includes blue light, and the light passing through the path of the second ray L2 includes red light.

[0030] exist Figure 3 The diagram shows a graph of the hue vector in the hue vector space. The horizontal axis represents the wavelength region B, and the vertical axis represents the wavelength region R. The hue vector space can be arranged (set) for each pixel 41 based on the signal intensity in each pixel 41. For the two independent wavelength regions B and R, the two signal intensities obtained in pixel 41 are respectively set as b and r. That is, signal intensity b represents the intensity of blue light obtained in pixel 41, and signal intensity r represents the intensity of red light obtained in pixel 41.

[0031] Furthermore, signal intensities b and r are assigned to independent coordinates. Here, signal intensities b and r are assigned to orthogonal coordinates B and R corresponding to two independent wavelength regions B and R, respectively. The coordinate positions are expressed by a vector V, where V = (b, r). That is, the hue vector space is set by orthogonal coordinates B and R, and the intensity of light imaged on pixel 41 is represented by the hue vector V = (b, r).

[0032] If the direction of the light rays imaged on pixel 41 (e.g., the unit direction in 3D space of the light emitted from object point OP) changes, the coordinates of the hue vector V = (b, r) will change accordingly. Therefore, the direction of the light rays imaged on pixel 41 can be inferred from the coordinates of the hue vector.

[0033] A key characteristic of hue vectors is that the signal intensity obtained through an independent wavelength region on one side does not affect the signal intensity obtained through an independent wavelength region on the other side. This allows for the allocation of signal intensity to mutually independent coordinate axes.

[0034] On the other hand, hue has traditionally been treated as a scalar quantity. That is, the mixing ratio of the intensities of each wavelength is used as the hue scalar. A hue scalar is a quantity that only represents magnitude, so it cannot represent a 2D hue vector with at least two constituent elements.

[0035] For example, in the overlap of two light intensities, it is impossible to obtain information about the intensities of the two light sources before the overlap from the intensity of the light after the overlap. This can be described as the overlap of light intensities being irreversible.

[0036] In contrast, for example, in the overlap of two light wavelengths, it is possible to obtain information about the intensity of the two wavelengths of light before the overlap from the intensity of the overlapped light. This can be described as the overlap of light wavelengths being reversible.

[0037] Therefore, the hue vector, which is created based on the two different wavelengths of the light that is incident on each pixel 41 through the paths of the first ray L1 and the second ray L2, has information about the direction and magnitude in the hue vector space, which means that it has more information than the previous hue scalar.

[0038] The processing unit 50 receives information about the light intensity for at least two different wavelengths from each pixel 41. Furthermore, the processing unit 50 obtains a hue vector from this information and infers the direction of the light based on the hue vector.

[0039] The processing unit 50 includes a computer. That is, the processing unit 50 includes a processor (CPU) and a storage unit (memory). The storage unit includes, for example, a main storage unit and an auxiliary storage unit. The storage unit stores programs executed by the processor. The processor performs various processes by reading the programs from the storage unit and executing them. The storage unit also stores information required for processing. For example, the processor implements the processing in the processing unit 50 of the optical inspection method according to this embodiment by reading the optical inspection program according to this embodiment from the storage unit and executing it.

[0040] The operating principle of the processing unit 50 according to this embodiment will be explained below.

[0041] For example, if the signal strength b in pixel 41 is substantially greater than 0 and the signal strength r is substantially 0, then the processing unit 50 determines that light that has passed through the path of the first ray L1 has reached pixel 41. That is, the processing unit 50 determines that light from object point OP has passed through the path of the first ray L1.

[0042] Furthermore, if the signal strength b in pixel 41 is substantially 0 and the signal strength r is substantially greater than 0, then the processing unit 50 can determine that light that has passed through the path of the second ray L2 has reached pixel 41. In other words, the processing unit 50 determines that light from object point OP has passed through the path of the second ray L2.

[0043] Alternatively, if the signal strengths b and r in pixel 41 are both substantially greater than 0, the processing unit 50 determines that the light from object point OP has passed through both the path of the first ray L1 and the path of the second ray L2.

[0044] In this way, the processing unit 50 can infer the direction of the light rays from the object point OP that are imaged on the pixel 41 from the hue vector obtained in the pixel 41 based on the signal intensity b and r in the pixel 41.

[0045] Here, we envision a situation where light intensity cannot be allocated to independent wavelength regions as in the hue vector generation unit 30 of this embodiment. In other words, we envision a situation where the wavelength regions separated by the hue vector generation unit 30 overlap and are not independent. In such a case, it is impossible to establish a hue vector space. That is, it is impossible to construct a hue vector for pixel 41.

[0046] Therefore, the signal intensity in the wavelength region where light passing through the path of the first ray L1 reaches pixel 41 increases together with the signal intensity in the wavelength region where light passing through the path of the second ray L2 reaches pixel 41. Conversely, the signal intensity in the wavelength region where light passing through the path of the second ray L2 reaches pixel 41 increases together with the signal intensity in the wavelength region where light passing through the path of the first ray L1 reaches pixel 41. Therefore, the processing unit 50 has difficulty inferring the direction of either the first ray L1 or the second ray L2 from the signal intensity of pixel 41.

[0047] Even when a hue vector cannot be constructed, a hue scalar can still be constructed. In the past, hue scalars were used to infer the direction of light, but a scalar quantity only represents magnitude, so it contains less information compared to a 2D vector.

[0048] Therefore, by using a hue vector, the information about the direction of light corresponding to the hue vector can be significantly increased compared to the information about the direction of light corresponding to the conventional hue scalar. As a result, the processing unit 50 can infer the direction of light from the object point OP that is imaged onto the pixel 41.

[0049] In the optical inspection method according to this embodiment, the hue vector generation unit 30 separates the light from the object point OP, imaged by the imaging unit 20, into at least two different independent wavelength regions. As a result, an image point IP imaged by the light from the at least two independent wavelength regions is formed in the image acquisition unit 40. In the optical inspection method, the intensity of the light from the at least two independent wavelength regions is also acquired in each pixel 41 of the image acquisition unit 40. In the optical inspection method, the direction of the light from the object point OP is also inferred in the processing unit 50 based on the light intensity of each pixel 41.

[0050] exist Figure 4 The flowchart of the process implemented in the processing unit 50 is shown.

[0051] First, the relationship between the hue vector and the light direction is preset in the processing unit 50 (S1). For example, the relationship between the hue vector and the light direction can be a lookup table obtained by recording information about the light direction based on various coordinates of the hue vector. Here, the light direction is, for example, the unit direction of light emitted from the object point OP in 3D space. For example, the relationship between the hue vector and the light direction is stored in the storage unit within the processing unit 50.

[0052] For example, in hue vector space, if the hue vector is parallel to the B-axis, the imaged light passes through the path of the first ray L1; if the hue vector is parallel to the R-axis, the imaged light passes through the path of the second ray L2.

[0053] However, the predicted direction of light can sometimes be affected by the wavelength spectrum of the light about to strike the hue vector generation unit 30, or by ambient light from the outside. In such cases, the hue vector and the direction of light can be calibrated. Alternatively, the effects of ambient light can be compensated for.

[0054] Next, the processing unit 50 acquires the hue vector of each pixel 41 based on the signal intensity in each pixel 41 of the image acquisition unit 40 for the image already captured (S2). That is, the processing unit 50 acquires the hue vector V = (b, r) of each pixel 41 based on the signal intensity b of blue light and the signal intensity r of red light in each pixel 41.

[0055] Furthermore, the processing unit 50 uses the obtained hue vector and, referring to a pre-set relationship between the hue vector and the light direction, infers the light direction of the light emitted from the object point OP that is imaged on each pixel 41 (S3). For example, as described above, the light direction is the unit direction in 3D space of the light emitted from the object point OP. Based on the above, the light direction can be inferred across all pixels 41.

[0056] Based on the optical inspection method and optical inspection apparatus described in this embodiment, the direction of light is inferred from the hue vector, thus enabling the identification of the direction of light.

[0057] (Second Implementation)

[0058] The second embodiment will now be described in detail with reference to the accompanying drawings. A side view showing the schematic structure of the optical inspection apparatus 10 according to this embodiment is provided. Figure 5 As shown in the image.

[0059] The optical inspection apparatus 10 in this embodiment is basically the same as that in the first embodiment, but it also includes a light direction selection unit 60. Furthermore, this embodiment performs imaging based on two plate cameras 70. The differences from the first embodiment will be described below.

[0060] The two-panel camera 70 includes a hue vector generation unit 30 and two image acquisition units (first image acquisition unit 40a and second image acquisition unit 40b). The first image acquisition unit 40a and the second image acquisition unit 40b can be, for example, a CCD area sensor or a CMOS area sensor. However, they are not limited to these.

[0061] The first image acquisition unit 40a has at least one first pixel 41a, and the second image acquisition unit 40b has at least one second pixel 41b. For example, the first image acquisition unit 40a has multiple first pixels 41a, and the second image acquisition unit 40b has multiple second pixels 41b. Each first pixel 41a has one first light-receiving element, and each second pixel 41b has one second light-receiving element. For example, the first light-receiving element of each first pixel 41a and the second light-receiving element of each second pixel 41b are each light-receiving elements of a region sensor.

[0062] The signals obtained from the first light-receiving element of each first pixel 41a in the first image acquisition unit 40a and the signals obtained from the second light-receiving element of each second pixel 41b in the second image acquisition unit 40b are independent signals and are assigned as signals for the same pixels 41a and 41b in the first image acquisition unit 40a and the second image acquisition unit 40b. In other words, each pixel 41a and 41b in the first image acquisition unit 40a and the second image acquisition unit 40b corresponds to each other in a one-to-one manner according to the pixel position coordinates.

[0063] In the hue vector generation unit 30 of this embodiment, selection region 31 allows light from a first wavelength region to pass through, and selection region 32 allows light from a second wavelength region to be reflected. The first wavelength region and the second wavelength region are independent of each other. For example, the first wavelength region includes a wavelength of 450 nm for blue light, and the second wavelength region includes a wavelength of 650 nm for red light.

[0064] The imaging unit 20 images (forms an image) the light emitted from the object point OP onto the first image point IPa and the second image point IPb. The first image point IPa and the second image point IPb are located in the first image acquisition unit 40a and the second image acquisition unit 40b, respectively.

[0065] The light direction selection unit 60 has at least two different selection regions. Each selection region separates arriving light into light of a specific wavelength region for transmission. Here, transmission means either transmission or reflection. The wavelength regions of the two different selection regions may not be independent. That is, the two wavelength regions may overlap. However, the two wavelength regions may also be independent.

[0066] In this embodiment, for example, the light direction selection unit 60 includes a first selection region 61 and a second selection region 62. The first selection region 61 allows light with a wavelength of 450 nm to pass through, and the second selection region 62 allows light with a wavelength of 650 nm to pass through. That is, the first selection region 61 allows blue light to pass through, and the second selection region 62 allows red light to pass through. For example, the first selection region 61 and the second selection region 62 of the light direction selection unit 60 are optical filters that allow light from different wavelength regions to pass through.

[0067] The processing unit 50 receives image data from the first image acquisition unit 40a and the second image acquisition unit 40b, and obtains a hue vector based on the image data. That is, the processing unit 50 obtains the hue vector from the light intensity information of each pixel 41a, 41b at the same position coordinates of the first image acquisition unit 40a and the second image acquisition unit 40b. Furthermore, the processing unit 50 infers the direction of the light rays from the hue vector. The processing in the processing unit 50 is the same as that described in the first embodiment.

[0068] The operation of the optical inspection apparatus 10 according to this embodiment is described.

[0069] Light emitted from object point OP and passing through the path of the first ray L1 passes through the first selection area 61 of the ray direction selection unit 60 and becomes blue light including a wavelength of 450 nm. Additionally, light emitted from object point OP and passing through the path of the second ray L2 passes through the second selection area 62 of the ray direction selection unit 60 and becomes red light including a wavelength of 650 nm.

[0070] Light passing through the path of the first ray L1 is received by the first light-receiving element of each first pixel 41a in the first image acquisition unit 40a. Light passing through the path of the second ray L2 is received by the second light-receiving element of each second pixel 41b in the second image acquisition unit 40b. The first and second light-receiving elements are assigned as constituent elements of the same pixels 41a and 41b. That is, a hue vector arranged independently on two axes can be constructed for each pixel 41a and 41b.

[0071] In the optical inspection method according to this embodiment, firstly, the light from the object point OP, imaged by the imaging unit 20, is separated into at least two different wavelength regions using the light direction selection unit 60. Then, the light is further separated into at least two different independent wavelength regions using the hue vector generation unit 30. As a result, image points IPa and IPb, imaged by the light from the at least two independent wavelength regions, are formed in the first image acquisition unit 40a and the second image acquisition unit 40b. In the optical inspection method, the intensity of the light from the at least two independent wavelength regions is also acquired in each pixel 41a and 41b of the first image acquisition unit 40a and the second image acquisition unit 40b. In the optical inspection method, the light direction from the object point OP is also inferred in the processing unit 50 based on the light intensity of each pixel 41a and 41b.

[0072] The processing unit 50 acquires the hue vectors of each pixel 41a, 41b at the same position coordinates, and infers the direction of light from the hue vectors. The processing performed by the processing unit 50 to infer the direction of light is the same as in the first embodiment.

[0073] In this embodiment, the direction of light is also inferred based on the hue vector, so the direction of light can be identified.

[0074] In the optical inspection method and optical inspection apparatus according to this embodiment, both light transmitted through the path of the first ray L1 by the hue vector generating unit 30 and light reflected through the path of the second ray L2 by the hue vector generating unit 30 are utilized. The hue vector generating unit 30 can easily make the wavelength regions of the transmitted light and the wavelength regions of the reflected light independent. Therefore, independent wavelength regions can be easily achieved.

[0075] (Third Implementation)

[0076] The third embodiment will now be described in detail with reference to the accompanying drawings. A side view showing the schematic structure of the optical inspection apparatus 10 according to this embodiment is provided. Figure 6 As shown in [the image]. Figure 6 The illustration of the processing unit 50 is omitted. Additionally, a top view showing the schematic structure of the light direction selection unit 60 according to this embodiment is provided. Figure 7 As shown in the image.

[0077] The optical inspection apparatus 10 according to this embodiment is basically the same as that in the second embodiment, but it has a light direction selection unit 60 on the focal plane FP of the imaging unit 20. Light incident on the imaging unit 20 passes through a position corresponding to its light direction on the focal plane FP of the imaging unit 20. That is, light with the same light direction passes through the same position. Figure 6 In this embodiment, light rays with the same θ direction relative to a straight line Lp parallel to the optical axis OA reach the same position on the focal plane FP. This embodiment performs imaging based on a 3-panel camera 80. The differences from the second embodiment will be described below.

[0078] In this embodiment, for convenience, three light rays in different directions are envisioned. These three light rays are designated as ray 1 L1, ray 2 L2, and ray 3 L3. For example, light passing through ray 1 L1 has a wavelength of 650 nm, light passing through ray 2 L2 has a wavelength of 450 nm, and light passing through ray 3 L3 has a wavelength of 550 nm. That is, light passing through ray 1 L1 includes red light, light passing through ray 2 L2 includes blue light, and light passing through ray 3 L3 includes green light. However, this is not a limitation, and the wavelengths can be freely chosen.

[0079] The light direction selection unit 60, for example, has multiple different selection areas arranged in concentric circles. For example, as... Figure 7As shown, the light direction selection unit 60 has a first selection region 61, a second selection region 62, and a third selection region 63, all concentrically centered at the origin O, with the point through which the optical axis OA passes. The first selection region 61 allows light with a wavelength of 650 nm to pass through, the second selection region 62 allows light with a wavelength of 450 nm to pass through, and the third selection region 63 allows light with a wavelength of 550 nm to pass through. In other words, the first selection region 61 allows red light to pass through, the second selection region 62 allows blue light to pass through, and the third selection region 63 allows green light to pass through.

[0080] For example, the first selection region 61, the second selection region 62, and the third selection region 63 of the light direction selection unit 60 are optical filters that allow light from different wavelength regions to pass through, just like in the second embodiment.

[0081] Light passing through the path of the first ray L1 passes through the innermost first selection area 61, light passing through the path of the second ray L2 passes through the middle second selection area 62, and light passing through the path of the third ray L3 passes through the outermost third selection area 63.

[0082] Here, an example is shown where the light direction selection unit 60 has concentric first selection area 61, second selection area 62, and third selection area 63. However, the first selection area 61, second selection area 62, and third selection area 63 do not necessarily need to be arranged in a concentric circle; they can be arranged in other ways. A top view showing a schematic structure of a modified example of the light direction selection unit 60 is shown below. Figure 8 As shown in the figure. The modified example of the light direction selection unit 60 has multiple strip-shaped different first selection areas 61, second selection areas 62, and third selection areas 63. The first selection area 61 is located at the center including the origin O of the coordinate system, the second selection area 62 is located above and below the first selection area 61 along the y-axis, and the third selection area 63 is located above and below the second selection area 62 along the y-axis. Figure 8 The optical characteristics of the first selection area 61, the second selection area 62, and the third selection area 63 of the light direction selection unit 60 and Figure 7 The optical characteristics of the first selection area 61, the second selection area 62, and the third selection area 63 of the light direction selection unit 60 are the same.

[0083] exist Figure 6In this embodiment, the 3-plate camera 80 is obtained by expanding the 2-plate camera 70 of the second embodiment into a 3-plate configuration. Although not shown, it can be easily imagined that the 3-plate camera 80 includes a hue vector generation unit and three image acquisition units. The hue vector generation unit separates arriving light into three different independent wavelength regions for transmission. The three image acquisition units respectively receive light from the three different wavelength regions separated by the hue vector generation unit. The imaging unit 20 images the object point OP on the surface of the object M onto three image points located in the three image acquisition units within the 3-plate camera 80.

[0084] The optical inspection apparatus 10 according to this embodiment uses a 3-plate camera 80, thus enabling the acquisition of 3D hue vectors arranged using mutually independent 3 axes. In other words, this means that when the intensity level of each axis is set to, for example, M, the hue vector can be assigned M×M×M=M. 3 The direction of the light.

[0085] The optical inspection apparatus 10 described in this embodiment uses a 3-plate camera 80 as an example, but an N-plate camera can also be used instead. Generally, an N-plate camera can acquire an N-dimensional hue vector. In this case, M... N The direction of each ray is assigned to the hue vector.

[0086] Furthermore, light incident on the imaging unit 20 passes through a position corresponding to its ray direction via a ray direction selection unit 60 disposed on the focal plane FP of the imaging unit 20. In other words, light with the same ray direction passes through the same position. Thus, in the ray direction selection unit 60, light with different wavelength regions passes through corresponding to its ray direction. Here, each wavelength region may or may not be independent. However, each wavelength region is different.

[0087] In the optical inspection method and optical inspection apparatus according to this embodiment, the hue vector can be assigned M 3 Types of levels. Therefore, as long as M is created in the light direction selection unit 60... 3 Different selection areas can be identified by the processing unit 50. 3 Different light directions. The processing of light direction recognition in the processing unit 50 is the same as in the first embodiment.

[0088] In the optical inspection method and optical inspection apparatus of this embodiment, the direction of light is inferred based on the hue vector, thus enabling the identification of the light direction. Even when the wavelength regions in the light direction selection unit 60 are not independent, since the wavelength regions are different, their differences can be identified based on the hue vector.

[0089] (Fourth implementation)

[0090] The fourth embodiment will now be described in detail with reference to the accompanying drawings. A perspective view showing the schematic structure of the optical inspection apparatus 10 according to this embodiment is provided below. Figure 9 As shown in [the image]. Figure 9 The illustration of the processing unit 50 is omitted in the text.

[0091] The optical inspection apparatus 10 according to this embodiment is basically the same as that in the second embodiment, but it also includes a projector illumination unit 90. The projector illumination unit 90 is capable of projecting light from at least two different independent wavelength regions onto an object. Through the projection of light, an illumination field 100 (the area that becomes bright due to the illumination of the projector illumination unit 90) is formed on the surface of the object. In the illumination field 100, light from at least two different independent wavelength regions is projected to different positions. The light from these different positions is imaged by a three-plate camera 80 through (that is, reflected or transmitted).

[0092] In this embodiment, the projector illumination unit 90 projects light through three paths traveling in different directions. These three paths are designated as ray 1 L1, ray 2 L2, and ray 3 L3. For example, the light traveling through ray 1 L1 has a wavelength of 450 nm, the light traveling through ray 2 L2 has a wavelength of 650 nm, and the light traveling through ray 3 L3 has a wavelength of 550 nm. That is, the light traveling through ray 1 L1 is blue light, the light traveling through ray 2 L2 is red light, and the light traveling through ray 3 L3 is green light. However, this is not a limitation, and the wavelengths can be freely selected.

[0093] An illumination field 100 is formed by the projector illumination unit 90. The illumination field 100 has three regions (region 101, region 102, and region 103). Region 101 is a blue region illuminated by blue light passing through the path of the first ray L1, region 102 is a red region illuminated by red light passing through the path of the second ray L2, and region 103 is a green region illuminated by green light passing through the path of the third ray L3.

[0094] The illumination field 100 can be considered optically equivalent to the light direction selection unit 60 in the second and third embodiments. Light from the illumination field 100 is imaged by the imaging unit 20 and the three-panel camera 80. The structure of the three-panel camera 80 is the same as that described in the third embodiment. That is, the three-panel camera 80 has three image acquisition units. The image acquisition units of the three-panel camera 80 acquire images of the illumination field 100, and the signal intensity of each pixel in the image acquisition unit is processed in the processing unit 50 in the same way as in the first embodiment to infer the light direction.

[0095] Based on the above, in the processing unit 50, it is possible to obtain the position of the light passing through the illumination field 100, i.e., the direction of the light, based on the hue vector.

[0096] In the optical inspection method and optical inspection apparatus described in this embodiment, the direction of light is also inferred based on the hue vector, so the direction of light can be identified.

[0097] The projector illumination unit 90 can also project an image onto the illumination field. In this case, the accuracy of light direction recognition can be improved.

[0098] According to the optical inspection method and optical inspection apparatus described in at least one embodiment above, the direction of light can be identified by obtaining the direction of light from the hue vector.

[0099] In the embodiments, examples of the hue vector generation unit 30 having two selection regions 31, 32 or three selection regions 31, 32, 33 are described, but the number of selection regions provided by the hue vector generation unit 30 is not limited to these. The hue vector generation unit 30 may also have four or more selection regions. For example, the hue vector generation unit 30 may also have many selection regions as long as it is able to disperse and detect the light passing through each selection region.

[0100] When the hue vector generation unit 30 has four or more selectable areas, a multidimensional hue vector space and a multidimensional hue vector with four or more independent coordinate axes can be set. By using such a multidimensional hue vector to obtain the light direction, the light direction can be identified in greater detail than in the previous embodiment.

[0101] Several embodiments of the present invention have been described, but these embodiments are given by way of example and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, and are included in the scope of the invention as set forth in the claims and their equivalents.

[0102] Furthermore, the above-described embodiments can be summarized into the following technical solutions.

[0103] Technical Solution 1

[0104] An optical inspection method, wherein,

[0105] For an image point that images light by separating light from an object point into at least two different independent wavelength regions, obtain a hue vector with the intensity of the light in the at least two different independent wavelength regions as independent axes.

[0106] Information relating to the direction of light rays from the object point is obtained from the hue vector.

[0107] Technical Solution 2

[0108] Before separating the light from the object point into light in at least two different wavelength regions.

[0109] Technical Solution 3

[0110] In technical solution 1, the imaging of the image points is performed by an N-plate camera (N is an integer greater than or equal to 2).

[0111] Technical Solution 4

[0112] In technical solution 1, the hue vector and the information are acquired for each pixel of an image formed by illuminating an object with light from at least two different wavelength regions.

[0113] Technical Solution 5

[0114] In technical solution 2, the light from the object point is separated into at least two different wavelength regions by a light direction selection unit, which has multiple concentric selection regions through which the light from the object point is separated into light with different wavelength regions.

[0115] Technical Solution 6

[0116] In technical solution 2, the light from the object point is separated into at least two different wavelength regions by a light direction selection unit, which has multiple different selection regions in the shape of strips through which the light from the object point is separated into light with different wavelength regions.

[0117] Technical Solution 7

[0118] An optical inspection device comprising:

[0119] The imaging unit performs imaging of light from the object point;

[0120] The hue vector generating unit separates the light from the object point into light in at least two different independent wavelength regions for transmission;

[0121] The image acquisition unit acquires image points formed by light passing through the at least two different independent wavelength regions of the hue vector generation unit; and

[0122] The processing unit, for the image point, acquires a hue vector with the intensity of light in the at least two different independent wavelength regions as independent axes, and obtains information related to the ray direction of the light from the image point from the hue vector.

[0123] Technical Solution 8

[0124] In technical solution 7, a light direction selection unit is also provided, which separates the light from the object point into light in at least two different wavelength regions before it reaches the hue vector generation unit.

[0125] Technical Solution 9

[0126] In technical solution 7, an N-plate camera (N is an integer greater than 2) is provided for imaging the image points. The N-plate camera includes the hue vector generation unit and the image acquisition unit.

[0127] Technical Solution 10

[0128] In technical solution 7, a projector illumination unit is included, which illuminates an object with light from at least two different wavelength regions to form an illumination field.

[0129] The image acquisition unit acquires an image of the illumination field via the imaging unit and the hue vector generation unit.

[0130] The processing unit acquires the hue vector and the information for each pixel of the image.

[0131] Technical Solution 11

[0132] In technical solution 8, the light direction selection unit has multiple concentric circular wavelength regions through which the light from the object point is separated into light with different wavelength regions.

[0133] Technical Solution 12

[0134] In technical solution 8, the light direction selection unit has multiple different wavelength regions in a strip shape that allow the light from the object point to pass through by separating the light into light with different wavelength regions.

[0135] Technical Solution 13

[0136] A non-transitory computer-readable storage medium storing an optical inspection program that enables a computer to perform:

[0137] For an image point that is imaged by separating light from an object point into at least two different independent wavelength regions, a process is performed to obtain a hue vector with the intensity of the light in the at least two different independent wavelength regions as independent axes; and

[0138] Processing of obtaining information related to the direction of light rays from the object point from the hue vector.

Claims

1. An optical inspection method, wherein, The hue vector generating unit separates the light from the object point, which is imaged by the imaging unit, into light in at least two different independent wavelength regions, and passes them through, wherein the imaging unit performs the imaging of the light from the object point; Image points formed by light imaging from at least two different independent wavelength regions from the hue vector generation unit are formed in the image acquisition unit; For the image point, the processing unit acquires a hue vector that takes the intensity of light in the at least two different independent wavelength regions as independent axes, and infers the direction of light from the object point from the acquired hue vector by referring to a pre-set relationship between the hue vector and the light direction.

2. The optical inspection method according to claim 1, wherein, The light direction selection unit separates the light from the object point into light in at least two different wavelength regions before the light is separated into at least two different independent wavelength regions by the hue vector generation unit.

3. The optical inspection method according to claim 1, wherein, The processing unit acquires the hue vector and infers the direction of light for each pixel of an image formed by illuminating an object with light from at least two different wavelength regions.

4. An optical inspection device, comprising: The imaging unit performs imaging of light from the object point; The hue vector generating unit separates the light from the object point that has passed through the imaging unit into light in at least two different independent wavelength regions. An image acquisition unit is formed in which image points imaged from light from at least two different independent wavelength regions generated by the hue vector generation unit are formed; and The processing unit, for the image point, acquires a hue vector that takes the intensity of light in the at least two different independent wavelength regions as independent axes, and infers the direction of light from the object point from the acquired hue vector by referring to a pre-set relationship between the hue vector and the light direction.

5. The optical inspection apparatus according to claim 4, wherein, It also includes a light direction selection unit that separates the light from the object point into light in at least two different wavelength regions before it reaches the hue vector generation unit.

6. The optical inspection apparatus according to claim 4, wherein, An N-plate camera is provided for imaging the image points, where N is an integer greater than or equal to 2. The N-plate camera includes the hue vector generation unit and the image acquisition unit.

7. The optical inspection apparatus according to claim 4, wherein, It includes a projector illumination unit that illuminates an object with light from at least two different wavelength regions to form an illumination field. The image acquisition unit acquires an image of the illumination field via the imaging unit and the hue vector generation unit. The processing unit acquires the hue vector and infers the direction of light for each pixel of the image.

8. The optical inspection apparatus according to claim 5, wherein, The light direction selection unit has multiple concentric circular wavelength regions through which the light from the object point is separated into light with different wavelength regions and passes.

9. The optical inspection apparatus according to claim 5, wherein, The light direction selection unit has multiple different wavelength regions in a strip shape that allow light from the object point to pass through by separating the light into light of different wavelength regions.

10. A non-transitory computer-readable storage medium storing an optical inspection program that causes a computer to perform: The hue vector generation unit separates the light from the object point, which is imaged by the imaging unit, into light in at least two different independent wavelength regions and passes them through, wherein the imaging unit performs the imaging processing of the light from the object point; The processing of forming image points in the image acquisition unit by light imaging from at least two different independent wavelength regions from the hue vector generation unit; For the image point, the processing unit acquires a hue vector that takes the intensity of light in the at least two different independent wavelength regions as independent axes, and infers the direction of light from the image point from the acquired hue vector by referring to a pre-set relationship between the hue vector and the light direction.

Images