Image processing device for observation and analysis

Abstract

To provide a beam separation optical system equipped with a beam separation prism, an image pickup device, etc., and in particular, a beam separation optical system excellent in color reproducibility and color rendering suitable for obtaining an infrared light image and a visible light image required by a microscope, an endoscope, a night vision camera, etc.SOLUTION: A beam separation optical system according to the present invention includes a visible light prism that acquires a visible light component of the image light condensed by a lens by reflection separation and transmits and separates the infrared light component, an infrared light prism that transmits the infrared light component separated by the visible light prism, an imaging device that converts the visible light component into a visible light video signal, and an imaging device that converts the infrared light component into an infrared light video signal, and the visible light prism is arranged closer to the incident light side of the image light than the infrared light prism.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a beam splitting optical system equipped with a beam splitting prism, an image pickup element, etc., and particularly to a beam splitting prism configuration with excellent color reproducibility and color rendering suitable for acquiring infrared light images and visible light images in microscopes, endoscopes, night vision cameras, etc., and to an image processing device using the same. [Background technology]

[0002] Advances in solid-state imaging elements used in video cameras, still cameras, and other devices have made it possible to create a wide variety of high-resolution, compact imaging devices, leading to the development of a variety of compact, broadband multispectral cameras that capture images not only in visible light (color) but also in near-infrared (NIR), short-wavelength infrared (SWIR), etc. These multispectral cameras can capture not only visible light images but also images in the wavelength characteristics of infrared light, allowing them to capture night vision images, images in fog, images under the skin, images under water, and other images, and are therefore used in a wide variety of applications, including surveillance cameras, in-vehicle cameras, medical endoscope cameras, and cameras for observing skin diseases.

[0003] In particular, medical observation and diagnostic devices such as microscopes, dermatoscopes, and endoscopes have traditionally observed lesions inside the body or on the epidermis by acquiring radiological images or near-infrared light images and spectrally analyzing the acquired images, but these images are monochromatic and color changes are difficult to see with the naked eye, so various methods have been disclosed to facilitate visual observation, such as acquiring spectral images of hemoglobin in the blood by spraying a dye, or acquiring color images from spectral images separated into R (red), G (green), and B (blue) colors (Patent Document 1, etc.). Furthermore, Patent Document 2 discloses a technology for acquiring IR (near-infrared) light images and visible light (color) images using a four-plate beam separating prism and applying them to an endoscope.

[0004] In the four-plate spectral prism in Patent Document 2, as shown in FIG. 10, the infrared (IR) component is first separated, and then the blue (B), green (G), and red (R) components, which are color images, are extracted and the infrared image is superimposed on the color image, thereby displaying the epidermal condition of the lesion as a color image.

[0005] However, the four-color separation prism used in Patent Document 2 is configured to separate the infrared light component before the three-color separation of RGB that forms visible light, and a near-infrared light separation prism is placed on the incident light side of the prism. Therefore, there is a drawback in that color reproducibility and color rendering are not improved due to the influence on the visible light component when passing through the near-infrared light separation interference film and the near-infrared light separation prism. This is thought to be because the purpose of performing near-infrared light separation before visible light separation is to prevent near-infrared light components from being mixed into the color spectral characteristics of each RGB component. However, when applied to image observation, analysis, etc., disease and pathological observation is mainly performed visually, and color rendering of visible light images is important, so there is a demand for improved image quality of visible light images. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-116353 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-178995 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a light beam separating optical system and an image processing device that mainly solve the following problems. (1) A light beam separating optical system with excellent color reproducibility and color rendering properties suitable for medical microscopes, endoscopes, dermatoscopes, etc., is provided, which is configured with a light beam separating prism that separates infrared light components and visible light components. (2) A compact light beam separating optical system and an image processing device using the same are provided, which has a light beam separating prism configuration that acquires visible light images and infrared light images and reduces shading caused by the angle dependency when separating infrared light. [Means for solving the problem]

[0008] In order to solve such problems and achieve the above-mentioned object, the light beam separating optical system of the present invention is a light beam separating optical system that includes a visible light prism that acquires the visible light components of image light focused by a lens by reflection separation and transmits and separates the infrared light components, an infrared light prism that transmits the infrared light components that have been transmitted and separated by the visible light prism, an image sensor that converts the visible light components into a visible light video signal, and an image sensor that converts the infrared light components into an infrared light video signal, and is characterized in that the visible light prism is positioned on the incident light side of the image light than the infrared light prism.

[0009] Furthermore, the light beam separation optical system of the present invention can be configured so that the visible light components are composed of color components of red light, green light, and blue light, and has three prisms and three image sensors corresponding to each of the color components.

[0010] Furthermore, the light beam separation optical system of the present invention can be configured to include a first prism that reflects and emits the red light component and a red imaging element that converts the emitted red light component into a red light video signal, a second prism that reflects and emits the green light component and a green imaging element that converts the emitted green light component into a green light video signal, a third prism that reflects and emits the blue light component and a blue imaging element that converts the emitted blue light component into a blue light video signal, and a fourth prism that receives and emits the infrared light component and an infrared imaging element that converts the emitted infrared light component into an infrared light video signal.

[0011] Furthermore, the light beam separation optical system of the present invention can be configured such that a correction filter that cuts out an infrared light band and acquires the band of each of the color components is disposed between the prism corresponding to each of the color components and the image sensor, and a correction filter that acquires a near-infrared light band is disposed between the prism corresponding to the infrared light component and the image sensor.

[0012] Furthermore, the light beam separating optical system of the present invention can be configured so that the correction filter for acquiring the near-infrared light band is a bandpass filter for extracting the absorption wavelength of the observation target substance in dye-loaded observation.

[0013] Furthermore, the light beam separation optical system of the present invention can be configured such that output signals from the red imaging element, the green imaging element, and the blue imaging element are image-processed to form a visible light image, and the output signal from the near-infrared imaging element is image-processed to form an infrared light image, and the image-processed visible light image and near-infrared light image are displayed separately or superimposed on the same screen.

[0014] The light beam separating optical system of the present invention can be configured to be applied to an image processing device for observation and analysis. [Effects of the Invention]

[0015] In the light beam separation optical system disclosed in the present invention, the prism that reflects and separates the visible light component is located closer to the incident light side of the image light than the prism that transmits and separates the infrared light component, so that the visible light component is first reflected and separated as reflected light, and the infrared light component is obtained as transmitted light. With this prism configuration, the visible light is separated first, so it is not affected by the interference film used for infrared light separation, and the angle dependency of the interference film is reduced, reducing color shading and resulting in improved color reproducibility and color rendering.

[0016] Furthermore, because infrared light is acquired as transmitted light, after adjusting the back focus of the visible light component acquired by reflection separation, the back focus on the infrared light side can be adjusted using a band-pass filter or a wedge gap, which provides various advantages, such as facilitating back-focus adjustment and replacing band-pass filters, enabling autofocus using the infrared light image alone, and furthermore, because there is flexibility in the optical path of the infrared light, shortening the infrared light prism allows for the overall size to be reduced. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is an explanatory diagram showing an example of the configuration of a light beam separating optical system according to a first embodiment of the present invention; [Figure 2] FIG. 2 is an explanatory diagram showing a modified configuration example of the first embodiment according to the present invention. [Figure 3] 1 is an explanatory diagram showing the reflection and transmission characteristics of a visible light prism according to the present invention. [Figure 4] 10A and 10B are explanatory diagrams showing the characteristics of the visible light compensation filter according to the present invention. [Figure 5] 10A and 10B are explanatory diagrams showing the characteristics of an infrared light correction filter according to the present invention. [Figure 6] FIG. 10 is an explanatory diagram showing a configuration example of a light beam separating optical system according to a second embodiment of the present invention. [Figure 7] FIG. 10 is an explanatory diagram showing a modified configuration example of the second embodiment according to the present invention. [Figure 8] 10 is a graph showing a comparison of the shading reduction effect for each RGB channel between the light beam separating optical system according to the present invention and a conventional product. [Figure 9] 1A and 1B are diagrams illustrating an example of a mounting configuration of an infrared imaging element and a correction filter according to the present invention. [Figure 10] FIG. 10 is an explanatory diagram showing a conventional four-plate type light beam separating optical system. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of a beam splitting optical system and an image processing device or imaging device equipped therewith according to the present invention will be described in detail with reference to the drawings. The present invention is intended for, but is not limited to, a beam splitting optical system used in observation and analysis of medical cameras such as medical microscopes and dermascopes, and professional cameras. Furthermore, any explanatory diagrams and drawings described in the following examples are drawn as schematic or schematic diagrams for the purpose of explaining the present invention, and actual dimensions and shapes are not particularly limited. Furthermore, the system configurations, block diagrams, dimensions, materials, shapes, relative arrangements, and use examples used in the examples are not intended to limit the technical scope of the invention to those alone, unless otherwise specified. [Example]

[0019] 1 is an explanatory diagram showing a first embodiment of a light beam separating optical system according to the present invention. Light beam separating prism 1 is disposed within a video camera device, and an image light beam captured by lens 2 enters light beam separating prism 1 via protective glass 3. When used for medical purposes, this protective glass 3 is washable and prevents dust and impurities from entering the prism optical system, and does not have wavelength characteristics in the visible light band or infrared light band.

[0020] Example 1 shows a prism configuration applied to a four-chip image sensor that separates and extracts blue (B), green (G), red (R), and infrared (IR) components for visible light. The image light beam enters the first blue separation prism 4 (P1), and the wavelength band of the blue component is reflected as reflected light by the blue component reflection / separation surface 5, while other band components are transmitted and enter the subsequent prisms.

[0021] The prism is configured so that the blue component light reflected by the reflective separation surface 5 of the blue separation prism 4 (P1) is totally reflected by the reflective surface 6 inside the prism 4, and the blue component light totally reflected by the reflective surface 6 passes through a correction filter 7 and enters a blue image sensor 8. The image sensor 8 converts the incident blue component light into an electrical signal and outputs a blue light video signal. The correction filter 7 is a filter that has the property of selectively extracting the blue light band and cutting out unnecessary bands such as infrared light, and may include a trimming filter, BPF (band pass filter), etc. depending on the purpose of use.

[0022] The transmitted light components that pass through the blue separation prism 4 (P1) are wavelength band components other than the blue band (green band, red band, infrared light band), and are incident on the green separation prism 9 (P2) that is arranged after the blue separation prism 4. Of the incident light, the green component wavelength band is reflected as reflected light on the green component reflecting / separating surface 10 of the prism 9, and the other band components are transmitted and incident on the subsequent prisms.

[0023] The prism is configured so that the green component light reflected by the reflective separation surface 10 of the green separation prism 9 (P2) is totally reflected by the inner reflective surface 11 of the prism 9, and the green component light totally reflected by the reflective surface 11 is incident on the green image sensor 13 via the correction filter 12. The image sensor 13 converts the incident green component light into an electrical signal and outputs a green light video signal. The correction filter 12 is a filter that has the characteristic of selectively extracting the green light band.

[0024] The transmitted light components that pass through the green separation prism 9 (P2) are wavelength band components (red band, infrared light band) other than the blue and green bands, and are incident on the red separation prism 14 (P3) that is arranged after the green separation prism 9. Of the incident light, the red component wavelength band is reflected as reflected light on the red component reflecting / separating surface 15 of the prism 14, and the other band components are transmitted and incident on the prisms in the next and subsequent stages.

[0025] The prism is configured so that the red component light reflected by the reflective / separating surface 15 of the red separating prism 14 (P3) is totally reflected by the reflective surface 16 inside the prism 14, and the red component light totally reflected by the reflective surface 16 is incident on the red image sensor 18 via the correction filter 17. The image sensor 18 converts the incident red component light into an electrical signal and outputs a red light video signal. The correction filter 17 is a filter that has the characteristic of selectively extracting the red light band.

[0026] The transmitted light components that pass through the red separation prism 14 are only in the infrared light band, excluding the blue, green, and red bands. These infrared light band components pass through the infrared light transmitting prism 19 (P4) and exit, and are incident on the infrared light image sensor 21 via the infrared light correction filter 20. The image sensor 21 converts the incident infrared light components into electrical signals and outputs an infrared light image signal. The infrared light correction filter 20 is a bandpass filter that extracts a desired infrared light band depending on the purpose of use, and is composed of a filter that mainly extracts a wavelength band that matches the absorbance characteristics of a specific dye (such as iodine) in, for example, a dye load test for medical analysis.

[0027] An air gap 22 is provided between the blue separation prism 4 (P1) and the green separation prism 9 (P2) to prevent mutual interference between the optical paths. Similarly, an air gap 23 is provided between the green separation prism 9 (P2) and the red separation prism 14 (P3). The gap spacing between these air gaps 22 and 23 is 5 to 10 μm. Furthermore, the red separation prism 14 (P3) and the infrared light transmission prism 19 (P4) are in close contact with each other to transmit the infrared light component, eliminating the need for an air gap. In this embodiment, the visible light components are acquired by reflection in the order of blue (B), green (G), and red (R). However, the order in which the visible light components are acquired can be any order. The important point here is that the visible light components consisting of blue (B), green (G), and red (R) are acquired before the infrared light (IR) component, and the infrared light component is acquired on the transmitted optical axis (X-X') as light transmitted through the lens and the visible light prism. In addition, each surface of the prism that makes up each air gap is coated with an anti-reflection (AR) coating to prevent reflections caused by the difference in refractive index between the prism and air, thereby preventing the reflections from affecting the image.

[0028] The blue reflective / separating surface 5 of the blue separating prism 4 (P1), the green reflective / separating surface 10 of the green separating prism 9 (P2), and the red reflective / separating surface 15 of the red separating prism 14 (P3), which are reflective films for visible light components, are formed by vapor deposition coating of a metal film or coating of a dielectric multilayer film. Aluminum coatings or gold coatings, such as aluminum (Al) or gold (Au), are used as the metal thin film, and laminated dielectric films can be used as the dielectric film. In the prism configuration of the present invention, visible light components are first captured by prism reflection, and infrared light components are captured by transmission. Therefore, any reflective material or method has a wide tolerance range, but naturally, those with low reflection loss and low angle dependency for the wavelength bands to be captured are preferred.

[0029] FIG. 3 shows an example of the reflection and transmission characteristics of each light beam splitter prism. FIG. 3(a) shows the reflection and transmission characteristics of the reflection and transmission surface 5 of the blue splitter prism 4 (P1). Here, the blue wavelength reflection component reflects wavelengths of approximately 485 nm or less, and transmits green, red, and infrared light components with wavelengths above that. FIG. 3(b) shows the reflection and transmission characteristics of the reflection and transmission surface 10 of the green splitter prism 9 (P2). Here, the green wavelength reflection component reflects wavelengths of approximately 600 nm or less, and transmits red and infrared light components with wavelengths above that. FIG. 3(c) shows the reflection and transmission characteristics of the reflection and transmission surface 15 of the red splitter prism 14 (P3). Here, the red wavelength reflection component reflects wavelengths of approximately 670 nm or less, and transmits infrared light components with wavelengths above that.

[0030] As described above, the reflection characteristics of each prism reflect and separate wavelengths in a band that includes the wavelength characteristics of each of the visible light components R, G, and B. However, due to variations in the reflecting material and coating, wavelength components outside the desired band (including infrared light components) may be mixed in. Therefore, it is desirable to provide a correction filter between the exit surface of each visible light separation prism and the image sensor. Figure 4 shows an example of the correction transmission characteristics of each of the visible light components R, G, and B. In this embodiment, the crossover point between the blue component and the green component is approximately 480 nm, and the crossover point between the green component and the red component is approximately 575 nm.

[0031] It is also desirable to provide an infrared correction filter 20 between the exit surface of the infrared light transmission prism 19 and the infrared light imaging element 21. Figure 5 shows an example of the transmission characteristics of the infrared correction filter 20. This infrared filter 20 can be applied to the near-infrared (NIR) and short-wavelength infrared (SWIR) wavelength bands, and filters with the appropriate infrared correction characteristics are used depending on the intended use. Figure 5 shows an example of the characteristics of a filter that extracts light with absorbance near 860 nm, which is used in indocyanine green (ICG) testing, etc. If the imaging device is a microscope or a dermatoscope for observing skin diseases, this filter 20 can be replaced with a bandpass filter (BPF) depending on the intended use, making it applicable to dye stress testing, which has absorbance characteristics in the infrared band of various intravascular components.

[0032] The prism configuration shown in Fig. 2 is a modified configuration of the prism for a four-chip image sensor shown in Fig. 1, and the same numbers are used for components corresponding to those in Fig. 1. In Fig. 1, the reflected red light component from the red separation prism 14 (P3) is totally reflected by the total reflection surface 16 within the prism, exits, and is captured by the red image sensor 18 via the red correction filter 17. Therefore, the red light image from the red image sensor 18 can be captured as a normal image like the other blue light, green light, and infrared light images, whereas in the embodiment shown in Fig. 2, the red reflected light component reflected by the red reflection separation surface 15 of the red separation prism 24 (P3) exits the prism directly and enters the red image sensor 18 via the red correction filter 17. Therefore, the red light image captured by the red image sensor 18 is an inverted reverse image.

[0033] With this type of prism configuration, the prism shape is simple and there are potential advantages in manufacturing, but to obtain a red light image as a normal image, it is necessary to perform image processing by inverting the image using an image inversion means (not shown). Note that with this prism configuration, the red light component is only reflected by the red separating reflecting surface 15 and is not totally reflected by the surface facing the green separating prism, so the contact surfaces between the green separating prism 9 (P2) and the red separating prism 24 (P3), and the contact surfaces between the red separating prism 24 (P3) and the infrared light transmitting prism 25 (P4) are in tight contact, and no air gap is required. [Example]

[0034] 6 and 7 are explanatory diagrams showing an example of the configuration of a light beam splitting optical system according to a second embodiment of the present invention. In the first embodiment, an example of the configuration of a light beam splitting prism using a four-chip image sensor is shown, but in the second embodiment, the present invention is applied to a two-chip image sensor. The light beam collected by the lens 2 passes through the protective glass 3 and enters the light beam splitting prism 60. This light beam splitting prism 60 is composed of a visible light splitting prism 61 (P1) and an infrared light transmitting prism 62 (P2). The visible light splitting prism 61 (P1) is positioned closer to the incident light side than the infrared light transmitting prism 62, and acquires visible light by reflection and separation.

[0035] The incident light beam first enters a visible light separation prism 61 (P1), where the visible light component is reflected by a visible light component reflecting surface 63, while the other light beam components (mainly infrared light components) are transmitted. The reflected and separated visible light components are incident on a visible light imaging element 65 via a visible light correction filter 64. When capturing color images, the visible light imaging element 65 is configured as a single-chip color imaging element, and the three primary color signals of blue (B), green (G), and red (R) obtained by filtering with a Bayer array filter or the like are sequentially extracted as video signals.

[0036] The infrared light component transmitted through the visible light separation prism 61 (P1) is incident on the infrared light imaging element 67 via the infrared light transmission prism 62 (P2) and the infrared light correction filter 66. The infrared light imaging element 67 extracts the incident infrared light as an infrared light video signal. In this second embodiment as well, the visible light component is acquired in a stage prior to acquiring the infrared light component, and the infrared light is acquired on the transmitted light axis X-X'. This makes it possible to obtain the same effects as in the first embodiment.

[0037] FIG. 7 shows a modified example of the light beam splitter prism for a two-chip image sensor shown in FIG. 6. The same components and functions as those in FIG. 6 are assigned the same numbers. The visible light image obtained in FIG. 6 is an inverted, reverse image of the infrared light image because the light beams reflected and split only by the reflecting surface 63 are directly acquired (without re-reflection). In contrast, the light beam splitter prism 70 in FIG. 7 is configured to acquire a visible light image as a normal image. The visible light components reflected by the reflecting surface 73 of the visible light splitter prism 71 (P1) are totally reflected by the total reflecting surface 74 of the prism 71, and the visible light components reflected twice are incident on the visible light image sensor 65 via the visible light correction filter 64. In other words, by reflecting the reflected visible light components twice, the visible light image acquired by the visible light image sensor 65 can be a normal image similar to the infrared light image. The infrared light component transmitted through the visible light separation prism 71 passes through the infrared light transmitting prism 72 and exits, and is incident on the infrared light imaging element 67 via the infrared light correction filter 66 .

[0038] In the above-mentioned first and second embodiments, a light beam separating prism for a four-chip image sensor and a light beam separating prism for a two-chip image sensor have been described, but the present invention can also be applied to other light beam separating optical systems for multi-chip image sensors as long as the light beam separating optical system separates visible light components and infrared light components.

[0039] By using this prism configuration, the incident light beam is first separated, so compared to conventional methods that first separate the infrared light component, the visible light component can achieve improved color saturation and color rendering without being affected by the angle dependency of the infrared light separating film. Figure 8 is a measurement comparison diagram showing the color shading reduction effect of the light beam separating optical system of the present invention compared to conventional methods. Figure 8(a) shows the shading of the conventional example shown in Figure 10, using a conventional four-plate light beam separating prism in which the infrared light separating prism is placed on the incident light side of the visible light separating prism. Figure 8(b) is a measurement diagram showing the shading of the configuration of Example 1 of the present invention, in which the visible light component is first separated and the infrared light component is obtained by transmission. In Figure 8, the horizontal axis is the vertical direction and the vertical axis is the amount of shading, with the prism transmittance for each of the R, G, B, and IR components being highest and the state with no light energy loss being 100% shading, and the graph shows the change in the amount of light energy as you move vertically from the center of the display screen (V elevation 0) toward the top and bottom edges. As can be seen from comparing Figures 8(a) and (b), when the light beam separating prism of the present invention is used, the effect of color shading is less and the color balance is superior.

[0040] Furthermore, when fine-tuning the lens back focus, if an infrared light separating prism that first separates the infrared light component is present as in the past, the infrared light separating prism affects the back focus adjustment of the visible light component, and the interference film of the infrared light separating prism affects the back focus adjustment of the visible light component. However, in the present invention, fine adjustment of the back focus of the visible light components, blue (B), green (G), and red (R), can be performed first without being affected by the infrared light separating prism.

[0041] Furthermore, since the infrared light component is acquired on the optical axis X-X' of the light beam incident on the lens, it is not affected by the back focus shift of each visible light component. Therefore, it is possible to freely replace the bandpass filter (BPF) in the infrared region. As mentioned above, this is extremely convenient for use in dye load tests, etc., by applying a bandpass filter that extracts wavelengths with absorbance in the infrared light component in medical ICS (indocyanine green) testing methods.

[0042] Figure 9 is an explanatory diagram showing an example of the mounting configuration of an infrared imaging element and correction filters in the four-plate beam splitter prism in Figure 1. The correction filter 20 provided between the infrared transmission prism 19 (P4) and the infrared imaging element 21 can be used with several interchangeable filters 90 to enable use in dye load tests with different absorbances, and multiple filters can also be replaced using a turret-like rotational system or a sliding system. Also, in Figure 9, the configuration of the present invention makes it possible to mount the infrared imaging element 21 on a rectangular prism adjustment jig 91 for the infrared transmission prism 19, allowing for easy fine adjustment of the back focus.

[0043] Furthermore, since the back focus of the infrared light component can be obtained even if the optical path precision is not strict, in the method of the present invention in which the infrared light component is obtained on the optical axis X-X', the total length of the prism from the entrance to the light beam separation prism to the infrared light imaging element can be shortened by shortening the infrared light component transmitting prism (P4).

[0044] Furthermore, because the back focus shift in the infrared region of a microscope or the like can be adjusted independently of the back focus of the visible light component, autofocusing using only infrared light is possible when acquiring an infrared component image. This infrared autofocus function can also be applied to nighttime photography using a night-vision camera, photography through clouds or fog, and the like. The beam separation optical system of the present invention can simultaneously acquire an infrared image and a visible light (color) image with excellent color rendering and reduced color shading effects. Therefore, the infrared image and the visible light image can be displayed separately on a microscope or monitor for comparison, observation, and analysis. It can also be applied to image processing devices and various multispectral cameras that can acquire subcutaneous observation, images transmitted through fog or clouds, and night-vision images using infrared images, and then superimpose the simultaneously acquired color image on the infrared image to display it on a monitor for clearer image observation, analysis, and other processing. [Industrial Applicability]

[0045] In the light beam separation optical system according to the present invention that acquires a visible light image and an infrared light image, the visible light component is acquired before infrared light separation, eliminating the influence of the infrared light prism, and infrared light is acquired on the optical axis, so that a visible light image with excellent color reproducibility and color rendering can be acquired, and a light beam separation optical system that makes it possible to reliably fine-tune the back focus of each prism can be provided, which enables a wide range of uses such as surveillance cameras, observation cameras, in-vehicle cameras, weather cameras, aircraft cameras, and microscope cameras, thereby expanding the industrial applicability to a wide range of applications such as business, consumer, industrial, and military uses. [Explanation of symbols]

[0046] 1 Beam separation optical system 2 Imaging lens 3 Protective glass 4 Blue separation prism (P1) 5 Blue reflective separation surface 6 Total reflection surface 7 Blue correction filter 8 Blue image sensor 9 Green Separator Prism (P2) 10 Green reflective separation surface 11 Total reflection surface 12 Green correction filter 13 Green image sensor 14 Red separation prism (P3) 15 Red reflective separation surface 16 Total reflection surface 17 Red Correction Filter 18 Red image sensor 19 Infrared light transmitting prism (P4) 20 Infrared light correction filter 21 Infrared imaging element 22, 23 Air gap 61, 71 Visible light separation prism (P1) 62, 72 Infrared light transmitting prism (P2)

Claims

1. a visible light prism that obtains the visible light component of the image light collected by the lens through reflection separation and transmits and separates the infrared light component; an infrared light prism that transmits the infrared light component transmitted and separated by the visible light prism; an imaging element that converts the visible light component into a visible light video signal; an imaging element that converts the infrared light component into an infrared light video signal; an infrared light adjusting unit that can adjust a distance between the infrared light prism and the imaging element, autofocus an infrared light image on the imaging element, and replace a bandpass filter in the infrared light region; 10. An image processing device for observation and analysis, wherein the visible light prism is disposed closer to the incident light side of the image light than the infrared light prism.

2. the visible light components are composed of red, green, and blue light components, 2. An image processing apparatus for observation and analysis according to claim 1, further comprising three prisms and three image pickup elements corresponding to the respective color components.

3. a first prism that reflects and emits the red light component, and a red image pickup element that converts the emitted red light component into a red light video signal; a second prism that reflects and emits the green light component, and a green image pickup element that converts the emitted green light component into a green light video signal; a third prism that reflects and emits the blue light component, and a blue image sensor that converts the emitted blue light component into a blue light video signal; 3. An image processing device for observation and analysis according to claim 2, further comprising: a fourth prism for receiving and emitting the infrared light component; and an infrared imaging element for converting the emitted infrared light component into an infrared image signal.

Images