JP6432315B2 - Imaging apparatus and imaging method - Google Patents

Description

  The present invention relates to an imaging apparatus and an imaging method.

  In a three-plate type imaging device that uses dedicated imaging elements for R (red), G (green), and B (blue), the R / B pixel array is ½ pixel at a time relative to the G pixel array. A method using a pixel shifting method in which the pixels are shifted in the x and y directions to improve the resolution, and a method using a normal method in which the R / B pixel array is aligned with the G pixel array without shifting. There is.

  For example, in Patent Document 1, a glass plate that is periodically tilted is provided between a lens that forms an image and a dichroic prism, and an image pickup device (imager) is provided using this glass plate. The image signal with improved resolution is obtained by shifting the ½ pixel optical axis of the image and processing the image signal when the ½ pixel is shifted and the image signal when the ½ pixel is not shifted in time series. An imaging device for creating the image is described.

  Further, in Patent Document 2, the spatial position is calculated by adding the centroid of the output of the R image sensor so that the centroid of the output of the B image sensor is alternately present in the horizontal and vertical directions. An imaging device is described that increases the number of sample points and reduces resolution degradation.

Japanese Patent Laid-Open No. 06-261236 JP 2006-033129 A

  As described above, according to the pixel shifting method, the horizontal and vertical resolutions can be improved. However, since the G pixel and the R / B pixel are arranged in a two-dimensional manner, a color false signal is generated. Further, according to a normal method for two-dimensionally matching the G pixel and the R / B pixel, no color false signal is generated, but the resolution cannot be improved.

  At present, in an 8K4K (for example, 7680 × 4320 dots) camera for high-resolution super high-definition, a 4K2K (for example, 3840 × 2160 dots) black and white sensor is used, and an 8K4K pixel shift method using G pixels and R / B pixels is used. The image of is taken. However, the playback environment for video content is still 4K2K. Therefore, it is desirable that a Super Hi-Vision camera can capture 8K4K and can capture 4K2K.

  It is also possible to capture an 8K4K image and down-convert it to create a 4K2K image. However, in this case, a color false signal is generated, and the color false signal cannot be completely removed, so that the imaging quality is impaired. It is.

  The present invention has been made to solve such a problem, and is compatible with both high-resolution imaging and high-quality low-resolution imaging, and high-resolution imaging and low-resolution imaging. It is an object of the present invention to provide an imaging apparatus and an imaging method that can be switched with a simple and easy-to-adjust configuration.

  Therefore, the present invention provides a color separation prism that separates an optical image of a subject into a blue image, a red image, and a green image, and a translucent plate that is displaceable on the optical path of the color-separated green image, An image sensor that converts each color image into an image signal; and an image processing circuit that processes the image signal to obtain a video signal; and the optical path of the green image is obtained by displacing the translucent plate in units of at least one frame. An imaging device for obtaining the video signals having different resolutions is provided.

  The present invention also provides a color separation prism that separates an optical image of a subject into a blue image, a red image, and a green image, and a translucent plate that is displaceable on the optical path of the color-separated green image, An imaging method of an imaging apparatus comprising: an imaging device that converts each color image into an image signal; and an image processing circuit that processes the image signal to obtain a video signal, wherein the translucent plate is in units of at least one frame. The imaging method for obtaining the video signals having different resolutions by changing the optical path of the green image by displacing the green image is provided.

  According to the present invention, an imaging apparatus capable of switching between high-resolution imaging and low-resolution imaging with a simple and easy-to-adjust configuration that achieves both high-resolution imaging and high-quality low-resolution imaging. And an imaging method, for example, an imaging apparatus that can be used as both an 8K4K camera and a 4K2K camera can be provided.

It is a block diagram which shows schematic structure of the imaging device 1 which concerns on this Embodiment. It is a figure which shows the optical paths 102 and 103 before and behind inclining the translucent board 30 of the imaging device 1 which concerns on this Embodiment. It is a figure which shows the change of an optical path when the translucent board 31 is inserted / removed between the prisms 23. FIG.

Hereinafter, an imaging apparatus and an imaging method according to the present embodiment will be described with reference to the drawings.
The imaging apparatus and imaging method according to the present embodiment obtains a high-resolution image or a low-resolution image by switching the presence or absence of pixel shift of a three-plate camera in units of at least one frame.

First, the configuration of the imaging apparatus according to the present embodiment will be described.
FIG. 1 is a block diagram illustrating a schematic configuration of an imaging apparatus 1 according to the present embodiment.
The imaging device 1 is, for example, a television camera, and includes a lens 10, a dichroic prism (color separation prism) 20, a translucent plate 30, imaging elements 41, 42, 43, an image processing circuit 50, and a control unit 60. And.

  In FIG. 1, lines with arrows that enter the lens 10 and enter the imaging elements 41, 42, and 43 through the dichroic prism 20 indicate optical paths. Further, lines connecting the image pickup devices 41, 42, 43 and the image processing circuit 50 and lines output from the image processing circuit 50 indicate wiring in the image pickup apparatus 1.

The lens 10 that forms an image of a subject may be generally used in an imaging apparatus, and detailed description thereof is omitted here.
The dichroic prism 20 color-separates the image formed by the lens 10 and separates the image into three primary color images (spectral components) of R (red), G (green), and B (blue). A prism of a type having an air gap (also called a Philips type) is used. The dichroic prism 20 includes a blue band imaging prism 21 that emits a blue image, a red band imaging prism 22 that emits a red image, and a green band imaging prism 23 that emits a green image. And have.

  The translucent plate 30 is a parallel flat glass plate, and can be displaced between two prisms formed by dividing the green band imaging prism 23 substantially perpendicular to its optical axis. Is provided so as to be rotatable about a predetermined axis. That is, the translucent plate 30 can be tilted with respect to the optical axis so that it can be tilted with respect to the optical axis of the green band imaging prism 23. .

The image pickup devices 41, 42, and 43 receive the blue image, the red image, and the green image separated by the dichroic prism 20, respectively, convert them into electric signals, and output them. Alternatively, a CMOS (Complementary Metal Oxide Semiconductor) sensor may be used. In addition, the image pickup devices 41, 42, and 43 output a 4K2K image signal in the above-described normal method without shifting the pixels using the three-plate method.
The image processing circuit 50 processes electric signals from the image sensors 41, 42, and 43 and outputs video signals such as luminance signals and color difference signals.
The control unit 60 controls each operation of the imaging apparatus 1.

The translucent plate 30 may be provided at any position on the optical path from when the green image is separated in the dichroic prism 20 until it enters the image sensor 43.
That is, even after the red image is reflected by the red reflecting dichroic film (not shown) provided between the red band imaging prism 22 and the green band imaging prism 23 and the green image is separated. For example, a space may be provided next to the red reflecting dichroic film, and the light transmitting plate 30 may be provided in the space, or the light transmitting light may be provided between the green band imaging prism 23 and the image sensor 43. A plate 30 may be provided.

  In consideration of manufacturing restrictions, the translucent plate is between two prisms formed by dividing the green band imaging prism 23 as in the translucent plate 30 according to the present embodiment. It is good to provide in.

FIG. 2 is a diagram illustrating the optical paths 102 and 103 before and after the light transmitting plate 30 of the imaging apparatus 1 according to the present embodiment is tilted.
When the light transmitting plate 30 is orthogonal to the optical path 101 of the green image emitted from the green band imaging prism 23 (FIG. 2 left), the green image incident on the light transmitting plate 30 passes through the light transmitting plate 30. The light travels straight and exits vertically from the translucent plate 30, and the optical path 102 of the emitted green image is on the extension of the optical path 101.

  On the other hand, when the translucent plate 30 is inclined by a predetermined angle Θ with respect to the optical path 101 of the green image (right side in FIG. 2), the green image emitted by refraction when passing through the translucent plate 30. The optical path 103 is shifted from the optical path 102 by the image movement amount ΔS. As a result, the green image incident on the image sensor 43 is also shifted by the image movement amount ΔS. Therefore, when the image movement amount ΔS is the same as the size of 1/2 pixel of the pixels constituting the image sensor 43, the green image Can be shifted by 1/2 pixel with respect to the blue image and the red image.

As described above, the pixel shift position can be adjusted by the rotation around the optical axis of the light transmitting plate 30 and the tilt angle. This adjustment can be realized, for example, by using the configuration (spring, pressing plate, etc.) described in Patent Document 1 and Japanese Patent Application Laid-Open No. 09-009115, and detailed description thereof is omitted here.
The image movement amount ΔS is expressed by the following equation, where t is the thickness of the light transmitting plate 30, n is the refractive index, and Θ is the inclination angle with respect to the optical axis.

ΔS = 1 / n · t · cosΘ

  When the translucent plate 30 is orthogonal to the optical path 101 of the green image emitted from the green band imaging prism 23, the blue image, red image, and green image received by the image sensors 41, 42, and 43 are 1 /. It is not shifted by two pixels. For this reason, the image processing circuit 50 outputs a low-resolution 4K2K video signal.

  On the other hand, when the light transmitting plate 30 is tilted with respect to the optical path 101 of the green image emitted from the green band imaging prism 23, the green image received by the image sensor 43 and the image sensors 41 and 42 receive the light. The blue image and the red image are shifted by 1/2 pixel. Therefore, the image processing circuit 50 outputs a high-resolution 8K4K video signal.

  The displacement of the translucent plate 30 is at least one frame. Normally, the translucent plate 30 is displaced in units of video content to output high-resolution or low-resolution video content (video signal). However, the translucent plate 30 is displaced every frame to obtain high resolution. Alternatively, it is technically possible to alternately output a low-resolution video signal for each frame.

  The light transmitting plate 30 does not necessarily need to be orthogonal to the optical path 101 of the green image emitted from the green band imaging prism 23 before tilting. That is, as long as the optical path of the green image is shifted by 1/2 pixel before and after changing the inclination angle, the angle before and after changing the inclination angle of the translucent plate 30 may be any.

Next, the imaging method according to the present embodiment will be briefly described.
As described above, the imaging apparatus 1 selects the inclination of the light transmitting plate 30 and outputs a low resolution video signal or a high resolution video signal from the image processing circuit 50.
Therefore, when an 8K4K video signal is required, the tilt of the light-transmitting plate 30 is adjusted to output an image signal shifted by 1/2 pixel from the image sensor, and an 8K4K video signal is obtained from the image processing circuit 50. Like that.

  When a 4K2K video signal is required, the tilt of the light-transmitting plate 30 is adjusted to output an image signal that is not shifted by 1/2 pixel from the image sensor, and the image processing circuit 50 outputs the 4K2K video signal. To get.

  The imaging apparatus and imaging method according to the present embodiment have been described above. However, in the imaging apparatus and imaging method of the present invention, the dichroic prism may be a prism having no air gap. Even in the case of a prism of a type without an air gap, a light transmitting plate may be provided at some position after the green image is separated and before entering the image sensor.

  In the imaging apparatus and imaging method of the present invention, the translucent plate can be inserted into and removed from the green image optical path, that is, the translucent plate can be inserted into and removed from the green image optical path. The optical path of the green image may be changed by displacing.

FIG. 3 is a diagram showing changes in the optical path when the translucent plate 31 is inserted and removed between the prisms 23.
As shown in FIG. 3, a light transmitting plate that is inclined with respect to the optical axis in advance from between the divided green band imaging prisms 23 or that is inclined in advance with respect to the optical axis, such as a parallelogram shape. When 31 is removed, the green image goes straight. As shown in the lower part of FIG. 3, when the light-transmitting plate 31 is inserted between the prisms 23, the green image is refracted by the light-transmitting plate 31 and proceeds away from the original optical path. With such a configuration, it is possible to realize pixel shifting more easily than inclining the translucent plate.

  As described above, the imaging apparatus 1 according to the present embodiment includes the color separation prism 20 that separates an optical image of a subject into a blue image, a red image, and a green image, and the optical path 101 for the color-separated green image. A translucent plate 30 provided so as to be displaceable, imaging elements 41, 42, and 43 that convert each color image into an image signal, and an image processing circuit 50 that processes the image signal to obtain a video signal, and the translucent plate 30 is displaced in units of at least one frame to change the optical path of the green image to obtain video signals having different resolutions. With such a configuration, both high-resolution imaging and low-quality imaging with good quality can be achieved, and high-resolution imaging and low-resolution imaging can be switched with a simple and easily adjustable configuration.

  In the imaging apparatus 1 according to the present embodiment, the color separation prism 20 includes a blue band imaging prism 21, a red band imaging prism 22, and a green band imaging prism 23. The translucent plate 30 is preferably provided between two prisms obtained by dividing the green band imaging prism 23.

In the imaging apparatus 1 according to the present embodiment, it is preferable to displace the light transmitting plate 30 by rotating or tilting the light transmitting plate 30 around the optical axis.
In addition, the imaging apparatus 1 according to the present embodiment preferably displaces the light transmissive plate 31 by inserting and removing the light transmissive plate 31 having an inclination with respect to the optical path 101 of the green image.
In the imaging apparatus 1 according to the present embodiment, the color separation prism is preferably a prism having an air gap, but may be a prism having no air gap.

  In addition, the imaging method according to the present embodiment is provided so as to be displaceable on a color separation prism 20 that separates an optical image of a subject into a blue image, a red image, and a green image, and an optical path 101 of the color-separated green image. The imaging method of the imaging apparatus 1 includes the translucent plate 30, imaging elements 41, 42, 43 that convert each color image into an image signal, and an image processing circuit 50 that processes the image signal to obtain a video signal. In this imaging method, the light transmitting plate 30 is displaced in units of at least one frame to change the optical path of the green image to obtain video signals having different resolutions. With such a configuration, both high-resolution imaging and low-quality imaging with good quality can be achieved, and high-resolution imaging and low-resolution imaging can be switched with a simple and easily adjustable configuration.

DESCRIPTION OF SYMBOLS 1 Imaging device 20 Dichroic prism 23 Green band imaging prisms 30 and 31 Light transmitting plates 41, 42, and 43

Claims (6)

A color separation prism having a blue band imaging prism, a red band imaging prism, and a green band imaging prism, which separates an optical image of a subject into a blue image, a red image, and a green image When,
A translucent plate provided displaceably on an optical path of the color- separated green image between two prisms obtained by dividing the green band imaging prism ;
An image sensor for converting each color image into an image signal;
An image processing circuit for processing the image signal to obtain a video signal,
An imaging apparatus that obtains the video signals having different resolutions by changing the light path of the green image by displacing the translucent plate in units of at least one frame. The imaging device according to claim 1, wherein the translucent plate is displaced by inclining the translucent plate with respect to an optical axis. The imaging apparatus according to claim 1, wherein the translucent plate is inclined by inserting and removing the translucent plate having an inclination with respect to the optical path of the green image into the optical path. The imaging apparatus according to any one of claims 1 to 3 , wherein the color separation prism is a prism having an air gap. The imaging apparatus according to any one of claims 1 to 3 , wherein the color separation prism is a prism without an air gap. A color separation prism having a blue band imaging prism, a red band imaging prism, and a green band imaging prism, which separates an optical image of a subject into a blue image, a red image, and a green image And a translucent plate disposed on the optical path of the color- separated green image between two prisms obtained by dividing the green band imaging prism, and converting each color image into an image signal. An imaging method for an imaging apparatus comprising: an imaging element; and an image processing circuit that processes the image signal to obtain a video signal,
An imaging method for obtaining the video signals having different resolutions by changing the optical path of the green image by displacing the translucent plate in units of at least one frame.

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