Imaging device

Abstract

Provided is an imaging device capable of more highly accurately and efficiently inspecting the surface of an object to be inspected and the features of the shape of the object to be inspected. The imaging device includes a first optical system, a plurality of polarizers, a plurality of solid-state imaging elements, and a signal processing unit. The first optical system includes a plurality of prisms and a plurality of optical filters. The first prism, the second prism, and the third prism among the plurality of prisms are arranged adjacent to each other in this order, the first optical filter among the plurality of optical filters is disposed between the first prism and the second prism, and the second optical filter among the plurality of optical filters is disposed between the second prism and the third prism. Each of the plurality of polarizers is provided between each of the plurality of solid-state imaging elements and the light-emitting surfaces of the plurality of prisms, and transmits the emitted light emitted from the light-emitting surface in the same polarization direction to each other, generating a polarization image.

Description

Technical Field

[0001] The present invention relates to a photographing device, and particularly to a technique of a photographing device using a prism. Background Art

[0002] In recent years, research has been conducted on using a photographing device as a method for detecting the attachment of garbage, the presence or absence of foreign matter, etc. to an object to be inspected on a production line in a factory or the like. In this case, the photographing device photographs the object to be inspected on the production line, and detects the attachment of garbage and the presence or absence of foreign matter to the object to be inspected based on the photographed image.

[0003] Regarding the photographing device for photographing the object to be inspected, there are various types of photographing devices. For example, as an example of the photographing device, there is a prism camera using a prism.

[0004] Here, a prism camera has been proposed, which includes a prism unit having a multi-plate wavelength-dispersive prism and fixing plates fixedly attached to both side surfaces of the multi-plate wavelength-dispersive prism (for example, refer to Patent Document 1).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2018-93342 Summary of the Invention

[0008] Problems to be Solved by the Invention

[0009] A prism camera (photographing device) can split light with a wavelength-dispersive prism, for example, by including a wavelength-dispersive prism. However, when detecting the attachment of garbage, the presence or absence of foreign matter, etc. to an object to be inspected on a production line in a factory or the like, for example, the object to be inspected is photographed multiple times, and the attachment of garbage and the presence or absence of foreign matter to the object to be inspected are determined. In this case, conventionally, it may not be possible to inspect the object to be inspected with good accuracy and high efficiency.

[0010] Therefore, the present invention has been completed in view of such problems, and the main object is to provide a photographing device that can more accurately and efficiently inspect the surface of the object to be inspected and / or the features of the shape of the object to be inspected.

[0011] Means for Solving the Problems

[0012] The inventors of the present invention conducted intensive research to solve the above object, and as a result, successfully achieved more accurate and efficient inspection of the surface of the object to be inspected and the features of the shape of the object to be inspected, and finally completed the present invention.

[0013] That is, a photographing device includes: a first optical system;

[0014] A plurality of polarizers;

[0015] A plurality of solid-state imaging elements; and

[0016] A signal processing unit,

[0017] The first optical system includes a plurality of prisms and a plurality of optical filters,

[0018] The first prism, the second prism, and the third prism among the plurality of prisms are arranged adjacent to each other in this order,

[0019] The first optical filter among the plurality of optical filters is disposed between the first prism and the second prism, and

[0020] The second optical filter among the plurality of optical filters is disposed between the second prism and the third prism,

[0021] The first optical filter divides incident light incident on the incident prism surface of the first prism into two types: reflected light and transmitted light, reflects the first light beam of the reflected light to the incident prism surface of the first prism and emits it from the light-emitting surface of the first prism, and at the same time transmits the light beam of the transmitted light,

[0022] The second optical filter divides the transmitted light of the other party into two types: reflected light and transmitted light, reflects the second light beam of the reflected light to the incident prism surface of the second prism and emits it from the light-emitting surface of the second prism, and at the same time transmits the third light beam of the other party and emits it from the light-emitting surface of the third prism,

[0023] Each of the plurality of polarizers is disposed between each solid-state imaging element of the plurality of solid-state imaging elements and the light-emitting surface of each of the plurality of prisms, and transmits the emitted light emitted from the light-emitting surface in different polarization directions,

[0024] Each of the plurality of solid-state imaging elements converts the transmitted light transmitted in the polarization direction through each of the plurality of polarizers into an electrical signal,

[0025] The signal processing unit acquires the electrical signals converted by each of the plurality of solid-state imaging elements and generates a polarization image.

[0026] In addition, in the present invention, a photographing device is provided,

[0027] The photographing device includes: a second optical system;

[0028] At least one polarizer;

[0029] Beam splitter;

[0030] Multiple solid-state imaging elements; and

[0031] Signal processing unit,

[0032] The second optical system includes a fourth prism and a third optical filter,

[0033] The fourth prism and the beam splitter are arranged adjacent to each other in this order,

[0034] The third optical filter is disposed between the fourth prism and the beam splitter,

[0035] The third optical filter divides incident light incident on the incident prism surface of the fourth prism into two types, i.e., reflected light and transmitted light, reflects the fourth light beam of the reflected light to the incident prism surface of the fourth prism, and emits it from the light emission surface of the fourth prism,

[0036] The beam splitter divides the light beam of the other transmitted light into P-wave light and S-wave light,

[0037] The polarizer is disposed between the light emission surface of the fourth prism and one of the multiple solid-state imaging elements, and transmits the fourth light beam emitted from the light emission surface of the fourth prism in a specified polarization direction,

[0038] Each of the multiple solid-state imaging elements converts any one of the P-wave light, the S-wave light, and the transmitted light transmitted in the specified polarization direction into an electrical signal,

[0039] The signal processing unit acquires the electrical signals converted by each of the multiple solid-state imaging elements and generates a polarization image.

[0040] In addition, in the present invention, a photographing apparatus is provided,

[0041] The photographing apparatus includes: a color separation optical system;

[0042] Beam splitter;

[0043] Multiple solid-state imaging elements; and

[0044] Signal processing unit,

[0045] The color separation optical system includes multiple prisms and multiple wavelength selection filters,

[0046] The fifth prism and the sixth prism among the multiple prisms are arranged adjacent to each other in this order,

[0047] Between the fifth prism and the sixth prism, a first wavelength selection filter among the plurality of wavelength selection filters is disposed, and

[0048] Between the sixth prism and the beam splitter, a second wavelength selection filter among the plurality of wavelength selection filters is disposed,

[0049] The first wavelength selection filter divides incident light incident on the incident prism surface of the fifth prism into reflected light and transmitted light, reflects the light of the first band of the reflected light on the incident prism surface of the fifth prism and emits it from the light emission surface of the fifth prism, and at the same time transmits the light of the band of the other transmitted light,

[0050] The second wavelength selection filter divides the other transmitted light into reflected light and transmitted light, reflects the light of the second band of the reflected light on the incident prism surface of the sixth prism and emits it from the light emission surface of the sixth prism, and at the same time transmits the light of the third band of the other light,

[0051] The beam splitter divides the transmitted light of the third band into P-wave light and S-wave light,

[0052] Each of the plurality of solid-state imaging elements converts the P-wave light and the S-wave light split by the beam splitter into electrical signals, and at the same time converts the light of the first band and the light of the second band into electrical signals,

[0053] The signal processing unit acquires the electrical signals converted by each of the plurality of solid-state imaging elements and generates a polarization image.

[0054] Effects of the Invention

[0055] According to the present invention, it is possible to more accurately and efficiently inspect the surface of the object to be inspected and the features of the shape of the object to be inspected. It should be noted that the effects of the present invention are not necessarily limited to the above effects, and may also be any effects described in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 is a perspective view schematically showing the appearance of the imaging device according to the first embodiment of the present invention.

[0057] Figure 2 is a side view schematically showing the imaging device according to the first embodiment of the present invention.

[0058] Figure 3 is a front view schematically showing the sensor mounting substrate according to the first embodiment of the present invention.

[0059] Figure 4 It is a block diagram of the imaging device according to the first embodiment of the present invention.

[0060] Figure 5 It is an explanatory diagram showing an example of a polarization image captured by the imaging device according to the first embodiment of the present invention.

[0061] Figure 6 It is a block diagram of the imaging device according to the second embodiment of the present invention.

[0062] Figure 7 It is a block diagram of the imaging device according to the third embodiment of the present invention. Detailed Embodiments

[0063] Hereinafter, preferred embodiments for implementing the present invention will be described with reference to the accompanying drawings. It should be noted that the embodiments described below show an example of a representative embodiment of the present invention, and the scope of the present invention is not narrowly interpreted based thereon.

[0064] <1. First Embodiment (Example 1 of Imaging Device)>

[0065] [Overall Configuration]

[0066] Figure 1 It is a perspective view schematically showing the appearance of the imaging device (prism camera) 100 according to the first embodiment of the present invention. Figure 2 It is a side view schematically showing the imaging device (prism camera) 100 according to the first embodiment of the present invention. Figure 3 It is a front view schematically showing the sensor mounting substrate 40a according to the first embodiment of the present invention.

[0067] The imaging device (prism camera) 100 according to the first embodiment includes an optical device front panel 11 on which a lens 10 is mounted, and a prism unit 60. The prism unit 60 includes a first optical system 20, a plurality of polarizing plates (polarizing plate 31, polarizing plate 32, and polarizing plate 33), a plurality of solid-state imaging elements (solid-state imaging element (image sensor) 41, solid-state imaging element (image sensor) 42, and solid-state imaging element (image sensor) 43), and a signal processing unit 50. It should be noted that three polarizing plates are provided, and three solid-state imaging elements are also provided, but the number thereof is not limited to three. That is, two or more may be provided.

[0068] [Optical Device Front Panel]

[0069] The optical device front panel 11 is joined to the prism unit 60. On the optical device front panel 11, a lens 10 of a prism camera as an example of the imaging device is mounted.

[0070] [Prism Unit]

[0071] As Figure 1 and Figure 2 shown, the prism unit 60 of the first embodiment includes a first optical system 20, a polarizer 31, a polarizer 32, a polarizer 33, a solid-state imaging device (image sensor) 41, a solid-state imaging device (image sensor) 42, a solid-state imaging device (image sensor) 43, and a signal processing unit 50.

[0072] A sensor mounting substrate 40a, a sensor mounting substrate 40b, and a sensor mounting substrate 40c are mounted on the first optical system 20. In addition, the first optical system 20 includes a plurality of prisms and a plurality of optical filters described later.

[0073] The polarizer 31 and the solid-state imaging device (image sensor) 41 are mounted on the sensor mounting substrate 40a (see Figure 3 ). As shown in Figure 2 , the sensor mounting substrate 40a is mounted such that the side provided with the polarizer 31 is in contact with the first optical system 20 side. Similarly, the polarizer 32 and the solid-state imaging device (image sensor) 42 are mounted on the sensor mounting substrate 40b. The sensor mounting substrate 40b is mounted such that the side provided with the polarizer 32 is in contact with the first optical system 20 side. Similarly, the polarizer 33 and the solid-state imaging device (image sensor) 43 are mounted on the sensor mounting substrate 40c. The sensor mounting substrate 40c is mounted such that the side provided with the polarizer 33 is in contact with the first optical system 20 side.

[0074] The polarizer 31, the polarizer 32, and the polarizer 33 transmit light in mutually different polarization directions. For example, the polarizer 31 sets the polarization direction to 45°. For example, the polarizer 32 sets the polarization direction to 90°. For example, the polarizer 33 sets the polarization direction to 0°. It should be noted that the polarization direction is not limited to 0°, 45°, 90°, and may also be configured to include, for example, 60°, 120°, 135°, etc.

[0075] The solid-state imaging device (image sensor) 41 converts the transmitted light that has passed through the polarizer 31 into an electrical signal and sends it to the signal processing unit 50 via the wiring WR1. The solid-state imaging device (image sensor) 42 converts the transmitted light that has passed through the polarizer 32 into an electrical signal and sends it to the signal processing unit 50 via the wiring WR2. The solid-state imaging device (image sensor) 43 converts the transmitted light that has passed through the polarizer 33 into an electrical signal and sends it to the signal processing unit 50 via the wiring WR3.

[0076] The solid-state imaging elements (image sensors) 41, 42, and 43 are each constituted by, for example, a line sensor or an area sensor. Further, the solid-state imaging elements (image sensors) 41, 42, and 43 are each a CMOS image sensor (Complementary Metal Oxide Semiconductor Image Sensor), and may also be a CCD image sensor (Charge Coupled Device Image Sensor).

[0077] The signal processing unit 50 acquires the electrical signals respectively converted by the solid-state imaging elements (image sensors) 41, 42, and 43, and generates a polarization image. The signal processing unit 50 is constituted by, for example, a dedicated or general-purpose CPU (Central Processing Unit), or an application-specific integrated circuit (ASIC), a programmable logic device (e.g., a simple programmable logic device (SPLD), a complex programmable logic device (CPLD), and a field-programmable gate array (FPGA), etc.).

[0078] It should be noted that in the prism unit 60, a fixing plate 15 is provided on the side surface of the first optical system 20 (refer to Figure 1 ), and the fixing plate 15 fixes the plurality of prisms and the plurality of optical filters included in the first optical system 20. Further, the fixing plate 15 is joined to the sensor mounting substrate 40a by an adhesive. In addition, the fixing plate 15 is joined to the sensor mounting substrate 40b by an adhesive. Similarly, the fixing plate 15 is joined to the sensor mounting substrate 40c by an adhesive.

[0079] [Details of Prism Unit]

[0080] Figure 4 A detailed block diagram of the prism unit 60 is shown. Figure 4 It is a block diagram of the imaging device (prism camera) 100 according to the first embodiment of the present invention.

[0081] As shown Figure 4 As shown in FIG. Figure 4 , the prism unit 60 includes a first optical system 20 and a signal processing unit 50. The first optical system 20 of the prism unit 60 includes a plurality of prisms (a first prism 21, a second prism 22, and a third prism 23), and a plurality of optical filters (a first optical filter SF1 and a second optical filter SF2).

[0082] Regarding the first optical system 20, among the plurality of prisms, the first prism 21, the second prism 22, and the third prism 23 are arranged adjacent to each other in this order. Regarding the first optical system 20, the first optical filter SF1 among the plurality of optical filters is arranged between the first prism 21 and the second prism 22, and the second optical filter SF2 among the plurality of optical filters is arranged between the second prism 22 and the third prism 23.

[0083] The first optical filter SF1 is vapor-deposited on the prism surface 21b of the first prism 21, and the second optical filter SF is vapor-deposited on the prism surface 22b of the second prism 22. It should be noted that the first optical filter SF1 and the second optical filter SF2 are, for example, ND filters.

[0084] [Processing in the prism unit]

[0085] As shown in FIG. Figure 4 , the imaging device (prism camera) 100 of the first embodiment is arranged on the optical path L of the light emitted from the object to be inspected (not shown). Figure 4 The light emitted from the object to be inspected (not shown) via the lens 10 is incident on the incident prism surface 21a of the first prism 21 of the first optical system 20 along the optical path L.

[0086] The first optical filter SF1 divides the incident light incident on the incident prism surface 21a of the first prism 21 into two types, reflected light and transmitted light, reflects the first light beam BL1 of the reflected light to the incident prism surface 21a of the first prism 21 and emits it from the light emitting surface 21c of the first prism 21, and at the same time transmits the beam of the transmitted light.

[0087]

[0088] For example, the first optical filter SF1 emits 33% of the incident light incident on the incident prism surface 21a from the light emitting surface 21c of the first prism 21. The first optical filter SF1 transmits 66% of the incident light incident on the incident prism surface 21a of the first prism 21 and is incident on the incident prism surface 22a of the second prism 22. It should be noted that the ratio of the light emitted from the light emitting surface 21c of the first prism 21 is not limited to 33%, and can be emitted at any ratio. Similarly, the ratio of the light incident on the incident prism surface 22a of the second prism 22 is not limited to 66%, and can be emitted at any ratio.​

[0089] Here, the first optical filter SF1 makes the first light beam BL1 incident on the incident prism surface 21a of the first prism 21. The incident prism surface 21a of the first prism totally reflects the incident first light beam BL1 (refer to Figure 4 region P), and makes it exit from the light-emitting surface 21c of the first prism 21.

[0090] The incident prism surface 21a of the first prism totally reflects the incident first light beam BL1, for example, by being coated with a metal film.

[0091] Next, the second optical filter SF2 divides the other transmitted light into two types, reflected light and transmitted light. It reflects the reflected second light beam BL2 of one side to the incident prism surface 22a of the second prism 22 and makes it exit from the light-emitting surface 22c of the second prism 22. At the same time, it makes the other third light beam BL3 transmit and exit from the light-emitting surface 23c of the third prism 23.

[0092] For example, the second optical filter SF2 makes 50% of the incident light incident on the incident prism surface 22a (that is, 33% of the incident light incident on the incident prism surface 21a of the first prism 21) exit from the light-emitting surface 22c of the second prism 22. In addition, the second optical filter SF2 makes 50% of the incident light incident on the incident prism surface 22a of the second prism 22 (that is, 33% of the incident light incident on the incident prism surface 21a of the first prism 21) transmit and be incident on the incident prism surface 23a of the third prism 23. It should be noted that the ratio of the light exiting from the light-emitting surface 22c of the second prism 22 is not limited to 50% and can exit at any ratio. In addition, the ratio of the light incident on the incident prism surface 23a of the third prism 23 is not limited to 50% and can be incident at any ratio.

[0093] Here, an air gap AG1 is formed between the first optical filter SF1 and the second prism 22.

[0094] In this case, the second optical filter SF2 makes the second light beam BL2 incident on the incident prism surface 22a of the second prism 22. The incident prism surface 22a of the second prism totally reflects the incident second light beam BL2 ( Figure 4 region Q), and makes it exit from the light-emitting surface 22c of the second prism 22.

[0095] The incident prism surface 22a of the second prism totally reflects the incident second light beam BL2, for example, by being coated with a metal film.

[0096] The polarizer 31 is disposed between the light emitting surface 21c of the first prism 21 and the solid-state imaging device (image sensor) 41, and transmits the emitted light emitted from the light emitting surface 21c in the polarization direction of 45°. The polarizer 32 is disposed between the light emitting surface 22c of the second prism 22 and the solid-state imaging device (image sensor) 42, and transmits the emitted light emitted from the light emitting surface 22c in the polarization direction of 90°. The polarizer 33 is disposed between the light emitting surface 23c of the third prism 23 and the solid-state imaging device (image sensor) 43, and transmits the emitted light emitted from the light emitting surface 22c in the polarization direction of 0°. The imaging device (prism camera) 100 of the first embodiment may have three polarizers.

[0097] The solid-state imaging device (image sensor) 41 converts the transmitted light transmitted through the polarizer 31 in the polarization direction of 45° into an electrical signal. The solid-state imaging device (image sensor) 42 converts the transmitted light transmitted through the polarizer 32 in the polarization direction of 90° into an electrical signal. The solid-state imaging device (image sensor) 43 converts the transmitted light transmitted through the polarizer 33 in the polarization direction of 0° into an electrical signal.

[0098] The signal processing unit 50 acquires the electrical signals respectively converted by the solid-state imaging device (image sensor) 41, the solid-state imaging device (image sensor) 42, and the solid-state imaging device (image sensor) 43, and generates a polarization image.

[0099] Figure 5 An example of a polarization image captured by the imaging device (prism camera) 100 of the first embodiment is shown. Figure 5 It is an explanatory diagram showing an example of a polarization image captured by the imaging device (prism camera) 100 of the first embodiment.

[0100] First, Figure 5 In the column of the display image before polarization shown, a prescribed image is displayed. The image before polarization shows an example of a normal captured image captured by the imaging device (prism camera) 100.

[0101] In contrast, in the polarization display with a polarization direction of 0°, an example of a polarization image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 0° is shown. Further, in the polarization display with a polarization direction of 90°, an example of a polarization image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 90° is shown. Similarly, in the polarization display with a polarization direction of 45°, an example of a polarization image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 45° is shown.

[0102] As shown in the polarization display for each polarization direction, the polarization image obtained by transmitting light in a specified polarization direction is an image of the inspection object that is the same as the object to be inspected, but different images can also be displayed.

[0103] For example, when the polarization direction is 0°, it shows that only the components with a polarization direction of 0° can be extracted. In this example, there is no display as a polarization image. Additionally, when the polarization direction is 90°, it shows that only the components with a polarization direction of 90° can be extracted, and a polarization image of the components with a polarization direction of 90° can be displayed. Also, when the polarization direction is 45°, it shows that only the components with a polarization direction of 45° can be extracted. In this example, there is no display as a polarization image.

[0104] It should be noted that the imaging device (prism camera) 100 of the first embodiment can also display, for example, Figure 5 the polarization image shown with components having a polarization direction of 0° and components having a polarization direction of 90°. Additionally, it can also display a polarization image having components with a polarization direction of 90° and components with a polarization direction of 45°.

[0105] Thus, for example, when a certain inspection object is packaged, it is possible to see the inside by extracting a part of the reflected light from the surface of the package according to the polarization direction. Specifically, the imaging device (prism camera) 100 of the first embodiment can extract the components of a part of the polarization direction of the reflected light and display the contents placed in a transparent container in an easy-to-observe manner. Additionally, by transmitting a part of the reflected light through the front glass of the vehicle in a specified polarization direction and obtaining a polarization image, a polarization image obtained by extracting a part of the components of the reflected light from the front glass can be obtained. Thus, even in a situation where the front glass is dazzling due to reflected light, it is possible to confirm the presence or absence of people inside the vehicle.

[0106] Furthermore, the imaging device (prism camera) 100 can also inspect the shape of the package by transmitting a part of the reflected light in a specified polarization direction. The imaging device (prism camera) 100 can, for example, also inspect the shape of a transparent resin bottle by transmitting a part of the reflected light in a specified polarization direction. Additionally, the imaging device (prism camera) 100 can obtain an image of only the foreign object in the inspection for confirming whether there is a foreign object mixed in a cotton bale.

[0107] In particular, since the imaging device (prism camera) 100 of the first embodiment can obtain polarization images of multiple polarization directions in one shot, it is possible to emphasize a specific area relative to the non-polarization image. Thus, the imaging device (prism camera) 100 of the first embodiment can detect the shape, deformation, etc. of the inspection object.

[0108] Thus, even when photographing the same object to be inspected, the imaging device (prism camera) 100 of the first embodiment can obtain different images according to different polarization directions.

[0109] As described above, the imaging device (prism camera) 100 of the first embodiment includes a plurality of polarizing plates (polarizing plate 31, polarizing plate 32, and polarizing plate 33), and can transmit the specified light emitted from the light emitting surfaces (light emitting surface 21c, light emitting surface 22c, or light emitting surface 23c) of the respective prisms (first prism 21, second prism 22, and third prism 23) in a specified polarization direction.

[0110] Thereby, even when photographing the same object to be inspected, the imaging device (prism camera) 100 of the first embodiment can obtain different images according to different polarization directions, so that the surface of the object to be inspected and the features of the shape of the object to be inspected can be inspected with higher precision and efficiency.

[0111] It should be noted that in the first embodiment, regarding the imaging device (prism camera) 100, an air gap AG1 is formed between the first optical filter SF1 and the second prism 22, but it is not limited thereto. That is, regarding the imaging device (prism camera) 100 of the first embodiment, the air gap AG1 may not be formed between the first optical filter SF1 and the second prism 22. In this case, the incident prism surface 22a of the second prism, for example, is coated with a metal film to totally reflect the second light beam BL2.

[0112] In addition, the imaging device (prism camera) 100 of the first embodiment may be provided with compensation filters (trimming filters) and band-pass filters that transmit light in a specific wavelength band on the polarizing plates 31, 32, and 33.

[0113] <2. Second Embodiment (Example 2 of Imaging Device)>

[0114] The imaging device according to the second embodiment of the present invention includes a second optical system, at least one polarizer, a beam splitter, a plurality of solid-state imaging elements, and a signal processing unit. The second optical system includes a fourth prism and a third optical filter. The fourth prism and the beam splitter are arranged adjacent to each other in this order, and the third optical filter is arranged between the fourth prism and the beam splitter. The third optical filter divides the incident light incident on the incident prism surface of the fourth prism into two types of reflected light and transmitted light, reflects the fourth light beam of the reflected light to the incident prism surface of the fourth prism and emits it from the light emitting surface of the fourth prism, and the beam splitter divides the other transmitted light into P-wave light and S-wave light. The polarizer is arranged between the light emitting surface of the fourth prism and one of the plurality of solid-state imaging elements, and transmits the fourth light beam emitted from the light emitting surface of the fourth prism in a specified polarization direction. The plurality of solid-state imaging elements respectively convert any one of P-wave light, S-wave light, and transmitted light transmitted in a specified polarization direction into an electrical signal, and the signal processing unit acquires the electrical signals converted by the plurality of solid-state imaging elements respectively and generates a polarization image.

[0115] According to the imaging device of the second embodiment of the present invention, like the imaging device of the first embodiment, even when the same object to be inspected is imaged, different images can be obtained through different polarization directions, so that the surface of the object to be inspected and the features of the shape of the object to be inspected can be inspected with higher precision and efficiency.

[0116] It should be noted that the overall configuration of the second embodiment of the present invention can adopt the same configuration as that of the imaging device of the first embodiment. In addition, the beam splitter is a type of polarizer.

[0117] [Details of the prism unit]

[0118] Figure 6 It is a block diagram of the imaging device (prism camera) 101 according to the second embodiment of the present invention.

[0119] The imaging device (prism camera) 101 according to the second embodiment includes a lens 10 and a prism unit 61. The prism unit 61 includes a second optical system 20a, at least one polarizer 31, a beam splitter 70, a plurality of solid-state imaging elements (solid-state imaging element (image sensor) 41, solid-state imaging element (image sensor) 44, solid-state imaging element (image sensor) 45), and a signal processing unit 50.

[0120] The difference between the imaging device (prismatic camera) 101 of the second embodiment and the imaging device (prismatic camera) 100 of the first embodiment is that a beam splitter 70 is provided in the prism unit 61 instead of the polarizing plates 32 and 33. For the components of the imaging device (prismatic camera) 101 of the second embodiment that are the same as those of the imaging device (prismatic camera) 100 of the first embodiment, the same reference numerals are used, and the description is appropriately omitted.

[0121] The second optical system 20a includes a fourth prism P21 and a third optical filter PSF1. In the second optical system 20a, the fourth prism P21 and the beam splitter 70 are arranged adjacent to each other in this order, and the third optical filter PSF1 is arranged between the fourth prism P21 and the beam splitter 70. It should be noted that the third optical filter PSF1 is vapor-deposited on the prism surface P21b of the fourth prism P21. In addition, the first optical filter PSF1 is constituted by an ND filter, for example.

[0122] [Processing in the prism unit]

[0123] The imaging device (prismatic camera) 101 of the second embodiment is arranged on the optical path L of the light emitted from the object to be inspected (not shown), as Figure 6 shown.

[0124] The light emitted from the object to be inspected (not shown) passes through the lens 10 and travels along the optical path L, and is incident on the incident prism surface P21a of the fourth prism P21 of the second optical system 20a.

[0125] The third optical filter PSF1 divides the incident light incident on the incident prism surface P21a of the fourth prism P21 into two types, namely, reflected light and transmitted light, and reflects the reflected fourth light beam BL4 of the reflected light toward the incident prism surface P21a of the fourth prism P21 and emits it from the light emitting surface P21c of the fourth prism P21.

[0126] For example, the third optical filter PSF1 causes 50% of the incident light incident on the incident prism surface P21a to be emitted from the light emitting surface P21c of the fourth prism P21 as the fourth light beam BL4. In addition, the third optical filter PSF1 causes 50% of the incident light incident on the incident prism surface P21a of the fourth prism P21 to be transmitted.

[0127] Here, the third optical filter PSF1 makes the fourth light beam BL4 incident on the incident prism surface P21a of the first prism P21, and the incident prism surface P21a of the fourth prism P21 totally reflects the incident fourth light beam BL4 (refer to Figure 6 region R), and emits it from the light emitting surface P21c of the fourth prism P21.

[0128] The incident prism surface P21a of the fourth prism, for example, is coated with a metal film to totally reflect the incident fourth light beam BL4.

[0129] It should be noted that an air gap may also be formed between the third optical filter PSF1 and the beam splitter 70 in the imaging device (prism camera) 101 of the second embodiment. In the case where an air gap is formed, the third optical filter PSF1 can also transmit the specified incident light incident from the incident prism surface P21a of the fourth prism P21.

[0130] The beam splitter 70 includes a plate PT1, and the plate PT1 splits the other transmitted light into P-wave light (transmitted light) and S-wave light (reflected light). It should be noted that for the P-wave, the polarization direction of the light is 0° with respect to the optical axis of the incident prism surface P21a of the fourth prism P21, and for the S-wave, the polarization direction of the light is 90° with respect to the optical axis of the incident prism surface P21a of the fourth prism P21. The beam splitter 70 transmits the other transmitted light as P-wave light through the plate PT1, and at the same time reflects the other transmitted light as S-wave light through the plate PT1.

[0131] The polarizer 31 is disposed between the light emitting surface P21c of the fourth prism P21 and the solid-state imaging element (image sensor) 41, and transmits the fourth light beam BL4 emitted from the light emitting surface P21c of the fourth prism P21 in a specified polarization direction (for example, 45°).

[0132] The plurality of solid-state imaging elements (solid-state imaging element (image sensor) 41, solid-state imaging element (image sensor) 44, solid-state imaging element (image sensor) 45) respectively convert any one of P-wave (the polarization direction of the light is 0°) light, S-wave (the polarization direction of the light is 90°) light, and transmitted light transmitted in a specified polarization direction (for example, 45°) into an electrical signal.

[0133] The signal processing unit 50 acquires the electrical signals respectively converted by the plurality of solid-state imaging elements (solid-state imaging element (image sensor) 41, solid-state imaging element (image sensor) 44, solid-state imaging element (image sensor) 45), and generates a polarization image.

[0134] Utilize Figure 5 , an example of a polarization image captured by the imaging device (prism camera) 101 of the second embodiment. Figure 5 It is an explanatory diagram showing an example of a polarization image captured by the imaging device (prism camera) 101 of the second embodiment. The imaging device (prism camera) 101 of the second embodiment has the same effect as the imaging device (prism camera) 100 of the first embodiment.

[0135] First, in Figure 5In the column of the display image before polarization shown, a prescribed image is displayed. The image before polarization shows an example of a normal captured image captured by a capturing device (prism camera) 101.

[0136] In contrast, in the polarization display with a polarization direction of 0°, an example of a polarized image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 0° is shown. Further, in the polarization display with a polarization direction of 90°, an example of a polarized image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 90° is shown. Similarly, in the polarization display with a polarization direction of 45°, an example of a polarized image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 45° is shown.

[0137] As shown in the column of the polarization display in each polarization direction, the polarized image obtained by transmitting in a prescribed polarization direction is an image of the same inspection object as the object to be inspected, but different images may also be displayed.

[0138] For example, in the case where the polarization direction is 0°, it shows that only the components with a polarization direction of 0° can be extracted. In this example, there is no display as a polarized image. Further, in the case where the polarization direction is 90°, it shows that only the components with a polarization direction of 90° can be extracted, and a polarized image of the components with a polarization direction of 90° can be displayed. In addition, in the case where the polarization direction is 45°, it shows that only the components with a polarization direction of 45° can be extracted. In this example, there is no display as a polarized image.

[0139] It should be noted that the capturing device (prism camera) 101 of the second embodiment may also display, for example, Figure 5 a polarized image having components with a polarization direction of 0° and components with a polarization direction of 90° as shown, and may also display a polarized image having components with a polarization direction of 90° and components with a polarization direction of 45°.

[0140] Thus, for example, in the case where a certain inspection object is packaged, it is possible to see inside by extracting a part of the reflected light on the surface of the package according to the polarization direction. Specifically, the capturing device (prism camera) 101 of the second embodiment can extract the components of a part of the polarization direction of the reflected light and display the contents contained in the transparent container in an easy-to-observe manner. Further, by transmitting a part of the reflected light relative to the front glass of the vehicle in a prescribed polarization direction and obtaining a polarized image, a polarized image obtained by extracting a part of the components of the reflected light of the front glass can be obtained. Thus, even in a situation where the front glass is dazzling due to the reflected light, it is possible to confirm the presence or absence of a person in the vehicle.

[0141] In addition, the imaging device (prism camera) 101 can also inspect the shape of the package by transmitting a part of the reflected light in a specified polarization direction. For example, the imaging device (prism camera) 101 can also inspect the shape of a transparent resin bottle by transmitting a part of the reflected light in a specified polarization direction. In addition, the imaging device (prism camera) 101 can obtain an image of only the foreign object in the inspection for confirming whether there is a foreign object mixed in the cotton bale.

[0142] In particular, the imaging device (prism camera) 101 of the second embodiment can obtain polarization images in a plurality of polarization directions by one shot, so it can emphasize a specific area with respect to the non-polarization image. Thus, the imaging device (prism camera) 101 of the second embodiment can detect the shape, deformation, etc. of the object to be inspected.

[0143] In this way, even when the imaging device (prism camera) 101 of the second embodiment images the same object to be inspected, different images can be obtained according to different polarization directions.

[0144] As described above, the imaging device (prism camera) 101 of the second embodiment includes a beam splitter 70 and can convert the light of P wave (the polarization direction of light is 0°), the light of S wave (the polarization direction of light is 90°), and the transmitted light transmitted in a specified polarization direction (for example, 45°) into electrical signals.

[0145] Therefore, even when the imaging device (prism camera) 101 of the second embodiment images the same object to be inspected, different images can be obtained according to different polarization directions, so the surface of the object to be inspected and the characteristics of the shape of the object to be inspected can be inspected more accurately and efficiently.

[0146] <3. Third Embodiment (Example 3 of Imaging Device)>

[0147] The imaging device according to the third embodiment of the present invention includes a color separation optical system, a beam splitter, a plurality of solid-state imaging elements, and a signal processing unit. The color separation optical system includes a plurality of prisms and a plurality of wavelength selection filters. The fifth prism and the sixth prism among the plurality of prisms are arranged adjacent to each other in this order. The first wavelength selection filter among the plurality of wavelength selection filters is arranged between the fifth prism and the sixth prism, and the second wavelength selection filter among the plurality of wavelength selection filters is arranged between the sixth prism and the beam splitter. The first wavelength selection filter divides the incident light incident on the incident prism surface of the fifth prism into two types of light, i.e., reflected light and transmitted light, reflects the light of the first band of the reflected reflected light toward the incident prism surface of the fifth prism and emits it from the light emitting surface of the fifth prism, and at the same time transmits the light of the band of the other transmitted light. The second wavelength selection filter divides the other transmitted light into two types of light, i.e., reflected light and transmitted light, reflects the light of the second band of the reflected reflected light toward the incident prism surface of the sixth prism and emits it from the light emitting surface of the sixth prism, and at the same time transmits the light of the third band of the other. The beam splitter divides the transmitted light of the third band into P-wave light and S-wave light. The plurality of solid-state imaging elements respectively convert the P-wave light and S-wave light divided by the beam splitter into electrical signals, and convert the light of the first band and the light of the second band into electrical signals. The signal processing unit acquires the electrical signals respectively converted by the plurality of solid-state imaging elements and generates a polarization image.

[0148] The imaging device according to the third embodiment of the present invention, like the imaging device according to the first embodiment and the imaging device according to the second embodiment, can obtain different images through different polarization directions even when photographing the same object to be inspected. Therefore, it is possible to more accurately and efficiently inspect the surface of the object to be inspected and the characteristics of the shape of the object to be inspected.

[0149] It should be noted that the overall configuration of the third embodiment of the present invention can adopt the same configuration as the imaging device according to the first embodiment. In addition, the beam splitter is a type of polarizing plate. In the following description, as an example, the light of the first band is short-wavelength light including blue light, the light of the second band is long-wavelength light including red light, and the light of the third band is described as green light excluding the long wavelength of red light, but it is not limited thereto. For example, the light of the first band may also be green light excluding the long wavelength of red light, the light of the second band may also be short-wavelength light including blue light, and the light of the third band may also be long-wavelength light including red light.

[0150] [Details of the prism unit]

[0151] Figure 7 is a block diagram of the imaging device (prism camera) 102 according to the third embodiment of the present invention.

[0152] The imaging device (prismatic camera) 102 of the third embodiment includes a lens 10 and a prism unit 62. The prism unit 62 includes a color separation optical system 20b, a beam splitter 71, a plurality of solid-state imaging elements (solid-state imaging element (image sensor) 46, solid-state imaging element (image sensor) 47, solid-state imaging element (image sensor) 48, solid-state imaging element (image sensor) 49), and a signal processing unit 51.

[0153] The difference between the imaging device (prismatic camera) 102 of the third embodiment and the imaging device (prismatic camera) 100 of the first embodiment is that in the prism unit 62, the color separation optical system 20b is provided instead of the first optical system 20, and the beam splitter 71 is further provided. For the components that are the same as those of the imaging device (prismatic camera) 100 of the first embodiment in the imaging device (prismatic camera) 102 of the third embodiment, the same reference numerals are used, and the description is appropriately omitted.

[0154] The color separation optical system 20b includes a plurality of prisms (fifth prism 24, sixth prism 25), and a plurality of wavelength selection filters (first wavelength selection filter CS1, second wavelength selection filter CS2).

[0155] Regarding the color separation optical system 20b, the fifth prism 24 and the sixth prism 25 among the plurality of prisms (fifth prism 24, sixth prism 25) are arranged adjacent to each other in this order, the first wavelength selection filter CS1 among the plurality of wavelength selection filters (first wavelength selection filter CS1, second wavelength selection filter CS2) is arranged between the fifth prism 24 and the sixth prism 25, and the second wavelength selection filter CS2 among the plurality of wavelength selection filters (first wavelength selection filter CS1, second wavelength selection filter CS2) is arranged between the sixth prism 25 and the beam splitter 71.

[0156] It should be noted that the first wavelength selection filter CS1 is vapor-deposited on the prism surface 24b of the fifth prism 24, and the second wavelength selection filter CS2 is vapor-deposited on the prism surface 25b of the sixth prism 25. It should be noted that the first wavelength selection filter CS1 and the second wavelength selection filter CS2 are formed of a dichroic film, for example.

[0157] [Processing in the prism unit]

[0158] The imaging device (prismatic camera) 102 of the third embodiment is arranged on the optical path L of the light emitted from the object to be inspected (not shown) as Figure 7 shown.

[0159] The light emitted from the object to be inspected (not shown) passes through the lens 10 and travels along the optical path L and is incident on the incident prism surface 24a of the fifth prism 24 of the color separation optical system 20b.

[0160] The first wavelength selection filter CS1 divides the incident light incident on the incident prism surface 24a of the fifth prism 24 into two types, reflected light and transmitted light, reflects the light of the first wavelength band (light in the short wavelength band including blue light) B of the reflected light to the incident prism surface 24a of the fifth prism 24 and emits it from the light emitting surface 24c of the fifth prism 24, and at the same time transmits the light of the wavelength band of the other transmitted light (light in the intermediate wavelength band including green light).

[0161] For example, the first wavelength selection filter CS1 makes the light B in the short wavelength band including blue light incident on the incident prism surface 24a of the fifth prism 24, and the incident prism surface 24a of the fifth prism 24 totally reflects the light B in the short wavelength band including this blue light (refer to Figure 7 region S), and emits it from the light emitting surface 24c of the fifth prism 24.

[0162] The incident prism surface 24a of the fifth prism totally reflects the incident light B in the short wavelength band including blue light, for example, by being coated with a metal film.

[0163] The second wavelength selection filter CS2 divides the other transmitted light (light in the intermediate wavelength band including green light) into two types, reflected light and transmitted light, reflects the light of the second wavelength band (light in the long wavelength band including red light) R of the reflected light to the incident prism surface 25a of the sixth prism 25 and emits it from the light emitting surface 25c of the sixth prism 25, and at the same time transmits the light of the third wavelength band (green light other than the long wavelength band of red light) G of the other.

[0164] Here, an air gap AG2 is formed between the first wavelength selection filter CS1 and the sixth prism 25.

[0165] In this case, the second wavelength selection filter CS2 makes the light R of the second wavelength band (light in the long wavelength band including red light) incident on the incident prism surface 25a of the sixth prism 25, and the incident prism surface 25a of the sixth prism 25 totally reflects the light R of the second wavelength band (light in the long wavelength band including red light) (refer to Figure 7 region T), and emits it from the light emitting surface 25c of the sixth prism 25.

[0166] The incident prism surface 25a of the sixth prism totally reflects the incident light R in the long wavelength band including red light, for example, by being coated with a metal film.

[0167] The beam splitter 71 includes a plate PT2, and divides the transmitted light G of the third wavelength band (green light other than the long wavelength band of red light) into P-wave light and S-wave light with the plate PT2.

[0168] Multiple solid-state imaging elements (solid-state imaging elements (image sensors) 46, solid-state imaging elements (image sensors) 47, solid-state imaging elements (image sensors) 48, solid-state imaging elements (image sensors) 49) respectively convert the light of the P wave and the light of the S wave split by the beam splitter 71 into electrical signals, and also convert the light of the first band (short-wavelength light including blue light) B and the light of the second band (long-wavelength light including red light) R into electrical signals.

[0169] The signal processing unit 51 acquires the electrical signals respectively converted by the multiple solid-state imaging elements (solid-state imaging elements (image sensors) 46, solid-state imaging elements (image sensors) 47, solid-state imaging elements (image sensors) 48, solid-state imaging elements (image sensors) 49) and generates a polarization image.

[0170] Use Figure 5 An example of a polarization image captured by the imaging device (prism camera) 102 of the third embodiment will be described. The imaging device (prism camera) 102 of the third embodiment has the same effect as the imaging device (prism camera) 100 of the first embodiment.

[0171] Figure 5 In the column of the display image before polarization shown, a specified image is displayed. This image before polarization shows an example of a normal captured image captured by the imaging device (prism camera) 102.

[0172] In contrast, in the polarization display with a polarization direction of 0°, an example of a polarization image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 0° (P wave) is shown. Additionally, in the polarization display with a polarization direction of 90°, an example of a polarization image obtained by transmitting the captured light of the normal captured image before polarization in the polarization direction of 90° (S wave) is shown.

[0173] As shown in the column of the polarization display in each polarization direction, the polarization image obtained by transmitting in a specified polarization direction is an image of the same object to be inspected as the object to be inspected, but different images can also be displayed.

[0174] For example, in the case where the polarization direction is 0°, it shows that only the components with a polarization direction of 0° can be extracted, and in this example, nothing is displayed as the polarization image. Additionally, in the case where the polarization direction is 90°, it shows that only the components with a polarization direction of 90° can be extracted, and a polarization image of the components with a polarization direction of 90° can be displayed.

[0175] It should be noted that the imaging device (prism camera) 102 of the third embodiment can also display simultaneously, for example. Figure 5A polarization image having a component with a polarization direction of 0° and a component with a polarization direction of 90°.

[0176] For example, when an inspection object is packaged, it is possible to see inside by extracting a part of the reflected light from the surface of the package according to the polarization direction. Specifically, the imaging device (prism camera) 102 of the third embodiment can extract the component of a part of the polarization direction of the reflected light, and display the contents contained in a transparent container in an easy-to-observe manner. In addition, by transmitting a part of the reflected light through the front glass of the vehicle in a specified polarization direction and obtaining a polarization image, it is possible to obtain a polarization image obtained by extracting a part of the component of the reflected light from the front glass. Thus, even in a situation where the front glass is dazzled by the reflected light, it is possible to confirm the presence or absence of a person in the vehicle.

[0177] In addition, the imaging device (prism camera) 102 can also inspect the shape of the package by transmitting a part of the reflected light in a specified polarization direction. The imaging device (prism camera) 102 can also inspect the shape of a transparent resin bottle, for example, by transmitting a part of the reflected light in a specified polarization direction. In addition, the imaging device (prism camera) 102 can obtain an image of only the foreign object in an inspection for confirming whether there is a foreign object mixed in a cotton bale.

[0178] In particular, the imaging device (prism camera) 102 of the third embodiment can obtain polarization images in multiple polarization directions by one shot, so it is possible to emphasize a specific area with respect to a non-polarization image. Thus, the imaging device (prism camera) 102 of the third embodiment can detect the shape, deformation, etc. of the object to be inspected.

[0179] In this way, the imaging device (prism camera) 102 of the third embodiment can obtain different images according to different polarization directions even when photographing the same object to be inspected.

[0180] As described above, the imaging device (prism camera) 102 of the third embodiment includes a color separation optical system 20b and a beam splitter 71, and can perform color separation on the light of the object to be inspected, and obtain polarization images of P-wave (polarization direction of 0°) light and S-wave (polarization direction of 90°) light.

[0181] Thus, the imaging device (prism camera) 102 of the third embodiment can obtain polarization images and color images of P-wave light and S-wave light of the object to be inspected, so it can display different images further, and can inspect the surface of the object to be inspected and the characteristics of the shape of the object to be inspected more accurately and efficiently.

[0182] In the third embodiment, an air gap AG2 is formed between the first wavelength selection filter CS1 and the sixth prism 25 in the imaging device (prism camera) 102, but it is not limited thereto. That is, in the imaging device (prism camera) 102 of the third embodiment, an air gap AG2 may not be formed between the first wavelength selection filter CS1 and the sixth prism 25. In this case, the incident prism surface 25a of the sixth prism is, for example, coated with a metal film to totally reflect the light of the second wavelength band (light in the long wavelength band including red light) R.

[0183] It should be noted that the first to third embodiments of the present invention are not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present invention. For example, the first to third embodiments can be implemented in combination. Specifically, the first embodiment can be applied to the second embodiment, and alternatively, the first embodiment can be applied to the third embodiment.

[0184] In addition, the effects described in this specification are merely illustrative and not restrictive, and there are other effects.

[0185] In addition, the present invention can be configured as follows.

[0186] (1) An imaging device, comprising: a first optical system;

[0187] a plurality of polarizing plates;

[0188] a plurality of solid-state imaging elements; and

[0189] a signal processing unit,

[0190] The first optical system includes a plurality of prisms and a plurality of optical filters,

[0191] The first prism, the second prism, and the third prism among the plurality of prisms are arranged adjacent to each other in this order,

[0192] The first optical filter among the plurality of optical filters is disposed between the first prism and the second prism, and

[0193] The second optical filter among the plurality of optical filters is disposed between the second prism and the third prism,

[0194] The first optical filter divides the incident light incident from the incident prism surface of the first prism into two types, i.e., reflected light and transmitted light, reflects the first light beam of the reflected light on the incident prism surface of the first prism and emits it from the light emitting surface of the first prism, and at the same time transmits the light beam of the transmitted light.

[0195] The second optical filter divides the transmitted light of the other party into reflected light and transmitted light. The second light beam of the reflected light of the reflected party is reflected toward the incident prism surface of the second prism and exits from the light emitting surface of the second prism. At the same time, the third light beam of the other party is transmitted and exits from the light emitting surface of the third prism.

[0196] Each of the plurality of polarizers is disposed between each of the plurality of solid-state imaging elements and the light emitting surfaces of the plurality of prisms, and transmits the emitted light exiting from the light emitting surface in different polarization directions.

[0197] Each of the plurality of solid-state imaging elements converts the transmitted light transmitted in the specified polarization direction through each of the plurality of polarizers into an electrical signal.

[0198] The signal processing unit acquires the electrical signals converted by each of the plurality of solid-state imaging elements and generates a polarization image.

[0199] (2) According to the imaging device described in (1) above, the different polarization directions include 0°, 45°, and 90°.

[0200] (3) According to the imaging device described in (1) or (2) above, the number of polarizers is three.

[0201] (4) According to the imaging device described in any one of (1) to (3) above, an air gap is formed between the first optical filter and the second prism.

[0202] (5) According to the imaging device described in (4) above, the second optical filter makes the second light beam incident on the incident prism surface of the second prism.

[0203] The incident prism surface of the second prism totally reflects the incident second light beam so that it exits from the light emitting surface of the second prism.

[0204] (6) According to the imaging device described in any one of (1) to (3) above, no air gap is formed between the first optical filter and the second prism.

[0205] (7) According to the imaging device described in any one of (1) to (6) above, the first optical filter makes the first light beam incident on the incident prism surface of the first prism.

[0206] The incident prism surface of the first prism totally reflects the incident first light beam so that it exits from the light emitting surface of the first prism.

[0207] (8) According to the imaging device described in any one of (1) to (7) above, the first optical filter is vapor-deposited on the prism surface of the first prism,

[0208] The second optical filter is vapor-deposited on the prism surface of the second prism.

[0209] (9) An imaging device, comprising: a second optical system;

[0210] At least one polarizing plate;

[0211] A beam splitter;

[0212] A plurality of solid-state imaging elements; and

[0213] A signal processing unit,

[0214] The second optical system includes a fourth prism and a third optical filter,

[0215] The fourth prism and the beam splitter are arranged adjacent to each other in this order,

[0216] The third optical filter is disposed between the fourth prism and the beam splitter,

[0217] The third optical filter divides the incident light incident from the incident prism surface of the fourth prism into two types of reflected light and transmitted light, and reflects the fourth light beam of the reflected light to the incident prism surface of the fourth prism and emits it from the light emitting surface of the fourth prism,

[0218] The beam splitter divides the light beam of the other transmitted light into P-wave light and S-wave light,

[0219] The polarizing plate is disposed between the light emitting surface of the fourth prism and one of the plurality of solid-state imaging devices, and transmits the fourth light beam emitted from the light emitting surface of the fourth prism in a specified polarization direction,

[0220] Each of the plurality of solid-state imaging elements converts any one of the P-wave light, the S-wave light, and the transmitted light transmitted in the specified polarization direction into an electrical signal,

[0221] The signal processing unit acquires the electrical signals converted by each of the plurality of solid-state imaging elements and generates a polarization image.

[0222] (10) According to the imaging device described in (9) above, the third optical filter reflects the fourth light beam to the incident prism surface of the fourth prism,

[0223] The incident prism face of the fourth prism totally reflects the incident fourth light beam, causing it to exit from the light emission face of the fourth prism.

[0224] (11) In the imaging device according to (9) or (10) above, the polarization direction of the light of the P wave is 0° with respect to the incident prism face of the fourth prism.

[0225] The polarization direction of the light of the S wave is 90° with respect to the incident prism face of the fourth prism.

[0226] (12) An imaging device including: a color separation optical system;

[0227] a beam splitter;

[0228] a plurality of solid-state imaging elements; and

[0229] a signal processing unit,

[0230] The color separation optical system includes a plurality of prisms and a plurality of wavelength selection filters.

[0231] The fifth prism and the sixth prism among the plurality of prisms are arranged adjacent to each other in this order.

[0232] The first wavelength selection filter among the plurality of wavelength selection filters is disposed between the fifth prism and the sixth prism, and

[0233] The second wavelength selection filter among the plurality of wavelength selection filters is disposed between the sixth prism and the beam splitter.

[0234] The first wavelength selection filter divides the incident light incident from the incident prism face of the fifth prism into two types, i.e., reflected light and transmitted light, reflects the light of the first band of the reflected light to the incident prism face of the fifth prism and causes it to exit from the light emission face of the fifth prism, and at the same time transmits the light of the other transmitted light band.

[0235] The second wavelength selection filter divides the other transmitted light into two types, i.e., reflected light and transmitted light, reflects the light of the second band of the reflected light to the incident prism face of the sixth prism and causes it to exit from the light emission face of the sixth prism, and at the same time transmits the light of the other third band.

[0236] The beam splitter divides the transmitted light of the third band into light of the P wave and light of the S wave.

[0237] Each of the plurality of solid-state imaging elements converts the light of the P wave and the light of the S wave split by the beam splitter into electrical signals, and at the same time converts the light of the first band and the light of the second band into electrical signals.

[0238] The signal processing unit acquires the electrical signals converted by the plurality of solid-state imaging elements respectively, and generates a polarization image.

[0239] (13) According to the imaging device described in (12) above, the first wavelength selection filter makes the light of the first band incident on the incident prism surface of the fifth prism.

[0240] The incident prism surface of the fifth prism totally reflects the light of the first band, and makes it exit from the light emitting surface of the fifth prism.

[0241] (14) According to the imaging device described in (12) or (13) above, the second wavelength selection filter makes the light of the second band incident on the incident prism surface of the sixth prism.

[0242] The incident prism surface of the sixth prism totally reflects the light of the second band, and makes it exit from the light emitting surface of the sixth prism.

[0243] (15) According to the imaging device described in any one of (12) to (14) above, an air gap is formed between the first wavelength selection filter and the sixth prism.

[0244] (16) According to the imaging device described in any one of (12) to (15) above, the first wavelength selection filter is vapor-deposited on the prism surface of the fifth prism, and the second wavelength selection filter is vapor-deposited on the prism surface of the sixth prism.

[0245] (17) According to the imaging device described in any one of (12) to (16) above, the light of the first band is short-wavelength light including blue light.

[0246] The light of the second band is long-wavelength light including red light.

[0247] The light of the third band is green light other than the long wavelength band of the red light.

[0248] (18) According to the imaging device described in any one of (12) to (17) above, the solid-state imaging element is composed of a line sensor or an area sensor.

[0249] Description of Reference Numerals

[0250] 10 Lens

[0251] 20, 20a First optical system

[0252] 21 First prism

[0253] 22 Second prism

[0254] 23 Third prism

[0255] P21 Fourth prism

[0256] 24 Fifth prism

[0257] 25 Sixth prism

[0258] 22, 23, 24, 25 First prism

[0259] 31, 32, 33 Polarizing plate

[0260] 41, 42, 43 Solid-state imaging device (image sensor)

[0261] 44, 45, 46 Solid-state imaging device (image sensor)

[0262] 50 Signal processing unit

[0263] 60, 60a, 60b Prism unit

[0264] 70, 71 Beam splitter

[0265] B Light including short wavelength band of blue light

[0266] R Light including long wavelength band of red light

[0267] G Green light except long wavelength band of red light

[0268] BL1 First light beam

[0269] BL2 Second light beam

[0270] BL3 Third light beam

[0271] BL4 Fourth light beam

[0272] SF1, SF1a First optical filter

[0273] SF2 Second optical filter

[0274] PSF1 Third optical filter

[0275] PT1, PT2 Disk

[0276] CS1 First wavelength selection filter

[0277] CS2 Second wavelength selection filter

Claims

1. A photographing apparatus, comprising: a first optical system; a plurality of polarizers; a plurality of solid-state imaging elements; and a signal processing unit, wherein the first optical system includes a plurality of prisms and a plurality of optical filters, a first prism, a second prism, and a third prism among the plurality of prisms are arranged adjacent to each other in this order, a first optical filter among the plurality of optical filters is disposed between the first prism and the second prism, and a second optical filter among the plurality of optical filters is disposed between the second prism and the third prism, the first optical filter divides incident light incident on an incident prism surface of the first prism into two types, i.e., reflected light and transmitted light, reflects a first light beam of the reflected light to the incident prism surface of the first prism and emits it from a light-emitting surface of the first prism, and at the same time transmits a light beam of the transmitted light, the second optical filter divides the transmitted light of the other party into two types, i.e., reflected light and transmitted light, reflects a second light beam of the reflected light to the incident prism surface of the second prism and emits it from a light-emitting surface of the second prism, and at the same time transmits a third light beam of the other party and emits it from a light-emitting surface of the third prism, an optical element including the plurality of prisms and the plurality of optical filters divides incident light incident on the incident prism surface of the first prism into three directions with equal light intensity, and the three directions are a direction of emitting from the light-emitting surface of the first prism, a direction of emitting from the light-emitting surface of the second prism, and a direction of incident on the incident prism surface of the third prism, each of the plurality of polarizers is disposed between each of the plurality of solid-state imaging elements and a light-emitting surface of each of the plurality of prisms, and transmits the emitted light emitted from the light-emitting surface in mutually different polarization directions, each of the plurality of solid-state imaging elements converts the transmitted light transmitted in the polarization direction through each of the plurality of polarizers into an electrical signal, the signal processing unit acquires the electrical signals converted by each of the plurality of solid-state imaging elements and generates a polarization image.

2. The photographing apparatus according to claim 1, wherein the mutually different polarization directions include 0°, 45°, and 90°.

3. The photographing apparatus according to claim 1 or 2, wherein the number of the polarizers is 3.

4. The photographing apparatus according to claim 1 or 2, wherein an air gap is formed between the first optical filter and the second prism.

5. The photographing apparatus according to claim 4, wherein the second optical filter makes the second light beam incident on the incident prism surface of the second prism, and the incident prism surface of the second prism totally reflects the incident second light beam and emits it from the light-emitting surface of the second prism.

6. The photographing apparatus according to claim 1 or 2, wherein no air gap is formed between the first optical filter and the second prism.

7. The photographing apparatus according to claim 1 or 2, wherein The first optical filter makes the first light beam incident on the incident prism surface of the first prism. The incident prism surface of the first prism totally reflects the incident first light beam and causes it to exit from the light-emitting surface of the first prism.

8. The imaging device according to claim 1 or 2, wherein the first optical filter is vapor-deposited on the prism surface of the first prism, and the second optical filter is vapor-deposited on the prism surface of the second prism.

9. The imaging device according to claim 1 or 2, wherein the solid-state imaging element is composed of a line sensor or an area sensor.

10. An imaging device, comprising: a second optical system; at least one polarizing plate; a beam splitter; a plurality of solid-state imaging elements; and a signal processing unit, wherein the second optical system includes a fourth prism and a third optical filter, the fourth prism and the beam splitter are arranged adjacent to each other in this order, the third optical filter is disposed between the fourth prism and the beam splitter, the third optical filter divides the incident light incident on the incident prism surface of the fourth prism into two types, i.e., reflected light and transmitted light, reflects the fourth light beam of the reflected light to the incident prism surface of the fourth prism, and causes it to exit from the light-emitting surface of the fourth prism, the beam splitter divides the beam of the other transmitted light into transmitted light with a polarization direction of 0° with respect to the optical axis of the incident prism surface of the fourth prism and reflected light with a polarization direction of 90° with respect to the optical axis of the incident prism surface of the fourth prism, the optical elements including the fourth prism, the beam splitter, and the third optical filter divide the incident light incident on the incident prism surface of the fourth prism into two directions with equal light intensity, and the two directions are the direction of exiting from the light-emitting surface of the fourth prism and the direction of incident on the beam splitter, the polarizing plate is disposed between the light-emitting surface of the fourth prism and one of the plurality of solid-state imaging devices, and causes the fourth light beam exiting from the light-emitting surface of the fourth prism to transmit in a specified polarization direction, each of the plurality of solid-state imaging elements converts any one of the transmitted light with a polarization direction of 0° with respect to the optical axis of the incident prism surface of the fourth prism, the reflected light with a polarization direction of 90° with respect to the optical axis of the incident prism surface of the fourth prism, and the transmitted light transmitted in the specified polarization direction into an electrical signal, the signal processing unit acquires the electrical signals converted by each of the plurality of solid-state imaging elements and generates a polarization image.

11. The imaging device according to claim 10, wherein the third optical filter makes the fourth light beam incident on the incident prism surface of the fourth prism, and the incident prism surface of the fourth prism totally reflects the incident fourth light beam and causes it to exit from the light-emitting surface of the fourth prism.

12. The imaging device according to claim 10 or 11, wherein the solid-state imaging element is composed of a line sensor or an area sensor.

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