JP6886026B2 - Imaging device - Google Patents

Description

The present invention relates to an image pickup device, and more particularly to a color image pickup device that obtains a wide dynamic range image by synthesizing images captured by a plurality of image pickup elements whose light receiving amount is changed by spectroscopic or exposure control.

In recent years, with the spread of organic light emitting diode (OLED) technology, display devices such as HDR (High Dynamic Range) compatible with a contrast ratio closer to that of human eyes have been attracting attention.

Along with this, there is a strong demand for expanding the dynamic range so that the imaging device that captures the image to be displayed can also support HDR. However, the amount of light that can be photoelectrically converted by the image sensor is limited, and when the amount of light is large, a predetermined level or more is saturated. That is, the dynamic range of the image sensor is limited, and is actually much narrower than that of human vision. In addition, as the number of pixels of the image sensor increases (higher density), the individual pixel sizes tend to become smaller, and the dynamic range tends to become even narrower.

Therefore, as a technique for obtaining an image with an expanded dynamic range, the dynamic range is expanded by continuously capturing two images with different exposures of a single image sensor and synthesizing the two images. (See, for example, Patent Document 1).

In addition, the incident light is separated to form the same subject image on the two image sensors, the exposures of the two image sensors are different, and the two images are simultaneously imaged to expand the dynac range by synthesizing the two images. (See, for example, Patent Document 2).

Further, in an image pickup device having a configuration in which incident light is color-separated and each color component is received by each image sensor, the exposure of a color component having a small saturation amount is reduced to increase a substantial saturation amount, and the saturation amount of each color component is increased. The dynamic range is expanded by matching with the color component having the largest saturation amount (see, for example, Patent Document 3).

The dynamic range of the image pickup apparatus described here indicates the ratio of the amount of light at which the output of the image pickup apparatus is saturated when the amount of light at which the output of the image pickup apparatus becomes the reference level is 1.

Japanese Unexamined Patent Publication No. 1-204579 Japanese Unexamined Patent Publication No. 9-149314 Japanese Unexamined Patent Publication No. 7-250332

However, when the exposure of a single image sensor is different with a time lag and continuous images are taken, if the subject moves during continuous imaging, the combined image will cause subject blur. It ends up. This is not suitable for shooting an image in which the subject is constantly moving, that is, a moving image.

Further, the image pickup device having a configuration in which the incident light is separated and received by two image pickup elements is mainly used for broadcasting applications, and has a configuration in which the incident light is color-separated and each color component is received by three image pickup elements. Compared with a plate-type image sensor, the image quality such as signal-to-noise ratio (hereinafter, S / N ratio), color reproducibility, and frequency band is inferior. However, even if an attempt is made to form a similar configuration with a three-panel image pickup device, an image pickup element is added to each color component, which makes physical arrangement difficult. Even if it can be realized, the cost of the image pickup device will increase significantly because the number of image pickup elements will be doubled.

Further, when the exposure of the image sensor of the color component having a small saturation amount is reduced, the S / N ratio of the color component with the reduced exposure is deteriorated. Further, since the difference in the saturation amount of each color component is at most about 3 times, the dynamic range cannot be dramatically expanded.

An object of the present invention is that subject blur does not occur, a color image in a low-luminance region can obtain a good S / N ratio, a high gradation, and a wide frequency band, and a color image in a high-luminance region has a wide dynamic range. An object of the present invention is to provide an image pickup apparatus capable of obtaining good color reproducibility.

Another object of the present invention is to provide an image pickup apparatus capable of obtaining an image having a wide dynamic range by synthesizing images captured by a plurality of image pickup elements whose light receiving amounts are changed by spectroscopy or exposure control.

Other challenges and novel features will become apparent from the description and accompanying drawings herein.

A brief description of a typical example of the present invention is as follows.

That is, the imaging device decomposes the luminous flux incident from the lens into a first luminous flux having a relatively small amount of light and a second luminous flux having a relatively large amount of light, and decomposes the second luminous flux into each color component of red light, green light, and blue light. A color separation optical system, a mosaic color filter image pickup element that receives the first luminous flux, three monochrome image pickup elements that receive each of red light, green light, and blue light, and an electric signal obtained from each image pickup element is converted. It has a signal processing unit that produces a color image. The signal processing unit mainly generates a color image in a high-luminance region from the electric signal obtained from the mosaic color filter imaging element, and mainly generates a color image in the low-luminance region from the electric signal obtained from the three monochrome imaging elements. , A color image in the high-luminance region and a color image in the low-luminance region are combined to generate one color image.

Further, in the above-mentioned image pickup apparatus, when an exposure control unit for controlling the exposure of the image pickup element is provided and it is desired to capture an image having a wider dynamic range, the exposure control unit lowers the exposure of the mosaic color filter image pickup element.

Further, in the above image pickup apparatus, when a gain correction unit for controlling the gain of the image is provided and the S / N ratio of the low-luminance region color image is desired to be improved, the gain correction unit is used to display the color image in the low-luminance region. Lower the gain.

According to the present invention, subject blur does not occur, a color image in a low-luminance region can obtain a good S / N, a high gradation, and a wide frequency band, and a color image in a high-luminance region has a wide dynamic range and good quality. Color reproducibility can be obtained.

Further, according to the present invention, it is possible to obtain an image having a wide dynamic range by synthesizing images captured by a plurality of image pickup elements whose light receiving amounts are changed by spectroscopy or exposure control.

It is a block diagram which shows the structural example of the image pickup apparatus which concerns on embodiment. It is a block diagram of the video signal processing unit which concerns on embodiment. It is a relationship diagram of the amount of light incident on the image pickup device and the signal output of the image pickup device according to the first embodiment. It is a relationship diagram of the amount of light incident on the image pickup device and the signal output of an image pickup apparatus which concerns on Example 1. FIG. It is a relationship diagram of the amount of light incident on the image pickup device and the signal output of the image pickup device according to the second embodiment. It is a relationship diagram of the amount of light incident on the image pickup device and the signal output of an image pickup apparatus which concerns on Example 2. FIG. It is a relationship diagram of the amount of light incident on the image pickup device and the signal output of the image pickup device according to the third embodiment. It is a relationship diagram of the amount of light incident on the image pickup device and the signal output of an image pickup apparatus which concerns on Example 3. FIG.

Hereinafter, embodiments and examples will be described with reference to the drawings. However, in the following description, the same components may be designated by the same reference numerals and repeated description may be omitted. In addition, in order to clarify the explanation, the drawings may schematically represent the width, thickness, shape, etc. of each part as compared with the actual embodiment, but this is just an example, and the interpretation of the present invention is used. It is not limited.
(Embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing a configuration example of an imaging device according to an embodiment of the present invention.

In FIG. 1, the image pickup device 1 includes a color separation optical system 11, a mosaic color filter (C, Color) image sensor 12C, a monochrome image sensor 12R for red (R, Red), and a monochrome image sensor 12G for green (G, Green). , Blue (B, Blue) monochrome image sensor 12B, video signal processing unit 13, exposure control unit 14, and central processing unit (CPU) unit 15.

The mosaic color filter image sensor 12C has a configuration in which minute color filters arranged in a mosaic pattern are provided on the image sensor, and a color image or a color image can be obtained with one image sensor. As the mosaic color filter, for example, a color filter arranged by a buyer can be adopted.

The red (R, Red) monochrome image sensor 12R has a configuration in which a red monochromatic filter is provided on the image sensor. The green (G, Green) monochrome image sensor 12G has a configuration in which a green monochromatic filter is provided on the image sensor. The blue (B, Blue) monochrome image sensor 12B has a configuration in which a blue monochromatic filter is provided on the image sensor.

Further, as the image sensor (12C, 12R, 12G, 12B), a solid-state image sensor such as a CCD (Charge-Coupled Device) image sensor or a CMOS image sensor can be adopted.

The CPU unit 15 controls each unit of the image pickup apparatus 1. Further, the exposure control unit 14 controls the exposure of the mosaic color filter image sensor 12C and the monochrome image sensors 12R, 12G, and 12B, respectively, according to the control from the CPU unit 15. As the circuit or means for controlling the exposure, for example, an electronic shutter or the like can be adopted, but the circuit or means is not limited thereto.

The incident light from the subject is imaged by the lens 2 and decomposed by the color separation optical system 11 into a first luminous flux BE1 having a relatively small amount of light and a second luminous flux BE2 having a relatively large amount of light. The second luminous flux BE2 is further decomposed into red light, green light and blue light. The decomposed first luminous flux BE1 is photoelectrically converted into a first electric signal as a color signal (C signal) by the mosaic color filter image sensor 12C. The second light beam BE2 color-separated into red light, green light, and blue light is the R signal, G signal, and B signal of the R signal, G signal, and B signal of the monochrome image sensors 12R, 12G, and 12B, respectively. It is photoelectrically converted into a fourth electric signal. The C signal, R signal, G signal, and B signal are input to the video signal processing unit 13, and various signal processing is performed by the video signal processing unit 13, for example, an HD-SDI (High Definition Serial Digital Interface) signal. Is output as.

The video signal output from the image pickup apparatus 1 of the present invention is not limited to the HD-SDI signal, and various video signals can be adopted. Further, the video signal processing unit 13 may include a compression processing circuit, an encryption processing circuit, or the like, and may be subjected to processing such as compression or encryption to output the video signal from the image pickup apparatus 1.

FIG. 2 is a block diagram of a video signal processing unit according to an embodiment of the present invention.

In FIG. 2, the video signal processing unit 13 includes a gain correction unit 131, a pixel interpolation unit 132, a delay unit 133, a synthesis unit 134, a gamma correction unit 135, and a video signal output unit 136. Each unit of the video signal processing unit 13 is controlled by the CPU unit 15.

In the video signal processing unit 13, gain correction is applied to the C signal, R signal, G signal, and B signal by the gain correction unit 131, and the C signal is subjected to the pixel interpolation processing of the bayer-arrangement by the pixel interpolation unit 132 to perform R'. After being separated into a signal, a G'signal, and a B'signal, the compositing unit 134 synthesizes them into an R signal, a G signal, and a B signal, respectively. After that, various video signal processing such as color correction, gamma correction, knee correction, etc. is performed by the gamma correction unit 135, and the video signal output unit 136 is used from the R video signal, the G video signal, and the B video signal, for example, an HD-SDI signal. Is generated and output.

The delay unit 133 is a delay process performed to match the timing of the R signal, the G signal, and the B signal with the timing of the R'signal, the G'signal, and the B'signal.

The delay unit 133 may be an LPF (Low Pass Filter). Further, the delay unit 133 may be unnecessary when the signal can be read with a delay of a predetermined time by the driving method of the monochrome image pickup devices 12R, 12G, and 12B.

Next, Examples 1, 2, and 3 of the present invention will be described with reference to FIGS. 3 to 8.

FIG. 3 is a diagram showing the relationship between the amount of incident light on the image sensor and the signal output of the image sensor according to the first embodiment. FIG. 4 is a diagram showing the relationship between the amount of light incident on the image sensor according to the first embodiment and the signal output of the image sensor.

FIG. 5 is a diagram showing the relationship between the amount of light incident on the image sensor and the signal output of the image sensor according to the second embodiment. FIG. 6 is a diagram showing the relationship between the amount of light incident on the image sensor according to the second embodiment and the signal output of the image sensor.

FIG. 7 is a diagram showing the relationship between the amount of light incident on the image sensor and the signal output of the image sensor according to the third embodiment. FIG. 8 is a diagram showing the relationship between the amount of light incident on the image sensor according to the third embodiment and the signal output of the image sensor.

In FIGS. 3, 5 and 7, the horizontal axis indicates the amount of incident light LQ on the image sensor (12C, 12R, 12G, 12B), and the vertical axis indicates the signal output LO of the image sensor (12C, 12R, 12G, 12B). Is shown. The saturation level SL shown on the vertical axis indicates the saturation amount of the mosaic color filter image sensor 12C that receives the first luminous flux BE1 and the monochrome image sensors 12R, 12G, 12B that receive the second luminous flux BE2. The first luminous flux saturated light amount SLBE1 shown on the horizontal axis indicates the saturated light amount of the first luminous flux BE1 when the mosaic color filter image sensor 12C is at the saturation level SL. The second luminous flux saturated light amount SLBE2 shown on the horizontal axis indicates the saturated light amount of the second luminous flux BE2 when the monochrome image sensors 12R, 12G, and 12B are at the saturation level SL.

In FIGS. 4, 6 and 8, the horizontal axis represents the amount of incident light LQ on the image sensor (12C, 12R, 12G, 12B), and the vertical axis represents the signal output VO of the image sensor 1. The saturation level SLVO shown on the vertical axis indicates the saturation level of the signal output VO of the image pickup apparatus 1, and the saturated light amount SLLQ shown on the horizontal axis indicates the saturated light amount of the incident light amount LQ at the saturation level SLVO. There is. The second luminous flux use region UARBE2 shown on the horizontal axis is a region in which each color component of the second luminous flux BE2 is not saturated, and can be regarded as a low-luminance region. The first luminous flux use region UARBE1 shown on the horizontal axis is a region in which each color component of the second luminous flux BE2 is saturated, and is a region in which each color component of the first luminous flux BE1 is not saturated, and is regarded as a high-luminance region. It can be considered. Further, the color image CVBE1 shows a color image in a high-luminance region, and the color image CVBE2 shows a color image in a low-luminance region. Note that FIGS. 4, 6 and 8 also show a reference level RFVO of the signal output VO of the image pickup apparatus 1 in the reference light amount RFLQ of the incident light amount LG.

Next, the operation of the image pickup apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 3 and 4.

As shown in FIG. 3, the color separation optical system 11 decomposes incident light so that the ratio of the amount of light (spectral ratio SR) of the first luminous flux BE1 and the second luminous flux BE2 is 1 / N: 1. N is a positive number (including a decimal number) of 1 or more. If the saturation amount (saturation level SL) of the mosaic color filter imaging element 12C that receives the first luminous flux BE1 and the monochrome imaging elements 12R, 12G, 12B that receive the second luminous flux BE2 are the same, the saturated light amount of the first luminous flux BE1. (First luminous flux saturated light amount SLBE1) is N times larger than the saturated light amount of the second luminous flux BE2 (second luminous flux saturated light amount SLBE2) (SLBE1 = N × SLBE2).

As shown in FIG. 4, the video signal processing unit 13 sets the second luminous flux BE2 as red light, green light, and blue light in the region where each color component of the second luminous flux BE2 is not saturated (the second luminous flux use region UARBE2). A color image CVBE2 is generated from the R signal, G signal, and B signal photoelectrically converted by the respective monochrome imaging elements 12R, 12G, and 12B.

The video signal processing unit 13 also N times the C signal obtained by photoelectrically converting the first luminous flux BE1 by the mosaic color filter imaging element 12C in the region where each color component of the second luminous flux BE2 is saturated (the first luminous flux use region UARBE1). The color image CVBE1 is generated by correcting the gain.

A color image CVBE2 in the low-luminance region and a color image CVBE1 in the high-luminance region are combined to generate one color image. After that, various video signal processes are applied to the synthesized color video to generate, for example, an HD-SDI signal and output it.

In the first embodiment, since the mosaic color filter image sensor 12C and the monochrome image sensors 12R, 12G, and 12B are exposed at the same time, when the exposures of a single image sensor are different by a time difference and continuously imaged and combined. The subject blur that occurs does not occur.

Further, when compared with the three-plate image pickup device, the configuration in which the second luminous flux BE2 is color-separated and then photoelectrically converted by the three monochrome image pickup elements 12R, 12G, and 12B to generate a color image is the same as that of the three-plate image pickup device. Therefore, the color image generated from the second luminous flux BE2 can obtain the same image quality as that of the three-plate image pickup device. The amount of light of the second luminous flux BE2 is 1-1 / N times that of the total incident light, but if N is large, it does not significantly affect the deterioration of the S / N ratio and gradation.

Further, since the saturation amount of the first luminous flux BE1 received by the mosaic color filter imaging element 12C is N times that of the second luminous flux BE2, the color image in which the first luminous flux BE1 and the second luminous flux BE2 are combined has a wide dynamic range. Good color reproducibility can be obtained even in a high brightness region.

Since the color video signal in the high-luminance region generated from the mosaic color filter image pickup element 12C is a mosaic color filter as compared with the color video signal in the low-luminance region generated from the monochrome image pickup elements 12R, 12G, and 12B. Since the degree of modulation in the high frequency band is inferior and the gain of the subject image of the first light beam BE1 having a small amount of light is increased by the image signal processing unit 13, the S / N ratio and the gradation are inferior. However, due to human visual characteristics, the S / N ratio, the gradation of brightness, and the degree of modulation in the high frequency band are high in the high brightness region where the display device such as a display using OLED or the monitor feels dazzling. It doesn't stand out, so it doesn't matter.

As described above, according to the first embodiment, the wide dynamic range and good color reproducibility of the color image in the high-luminance region can be obtained without causing blurring of the subject and impairing the image quality of the color image in the low-luminance region. It is possible to obtain.

Next, the operation of the image pickup apparatus according to the second embodiment of the present invention will be described with reference to FIGS. 5 and 6.

As shown in FIG. 5, the exposure control unit 14 controls the exposure of the mosaic color filter image sensor 12C that receives the first luminous flux BE1 to 1 / M times. M is a positive number (including a decimal number) of 1 or more. As a result, the saturation amount of the first luminous flux BE1 becomes M times as much as that in the case of the first embodiment.

As shown in FIG. 6, the video signal processing unit 13 sets the second luminous flux BE2 as red light, green light, and blue light in the region where each color component of the second luminous flux BE2 is not saturated (the second luminous flux use region UARBE2). A color image VCBE2 is generated from the R signal, the G signal, and the B signal, which are decomposed into the above and photoelectrically converted by the respective monochrome imaging elements 12R, 12G, and 12B.

The video signal processing unit 13 also N × N × the C signal obtained by photoelectrically converting the first luminous flux BE1 with the mosaic color filter imaging element 12C in the region where each color component of the second luminous flux BE2 is saturated (the first luminous flux use region UARBE1). The color image VCBE1 is generated by correcting the gain by M times.

A color image CVBE2 in the low-luminance region and a color image CVBE1 in the high-luminance region are combined to generate one color image. After that, various video signal processes are applied to the synthesized color video to generate, for example, an HD-SDI signal and output it.

In the second embodiment, the exposure and gain of the respective monochrome image sensors 12R, 12G, and 12B that receive the second luminous flux BE2 are the same as those in the first embodiment, so that the image quality of the color image CVBE2 in the low luminance region is the same. Is not impaired. Further, since the saturation amount of the first luminous flux BE1 is M times, the dynamic range of the entire image pickup apparatus 1 is M times. The dynamic range of the color image CVBE2 in the high-luminance region can be widened.

The video signal (color video CVBE1) in the high-luminance region generated from the mosaic color filter image sensor 12C is a video signal processing unit in which the amount of light of the first luminous flux BE1 is reduced as compared with the case of the first embodiment. Since the gain is increased at 13, the image becomes inferior in S / N ratio and gradation. However, as described above, the S / N ratio and the gradation of the brightness are not conspicuous in the high brightness region, so that there is no particular problem.

On the other hand, when trying to widen the dynamic range by reducing the exposure of the image sensor in a three-panel image pickup device, the exposure in the low-luminance region also decreases, and the gain must be increased by that amount. The image quality is also impaired. At this time, if the amount of light is increased by M times by opening the lens diaphragm without increasing the gain by 1 / M times the exposure, the image quality can be maintained. However, as a result, the amount of light received by the image sensor does not change, and the output of the image sensor is saturated, so that the dynamic range does not widen.

As described above, according to the second embodiment, it is possible to obtain a wider dynamic range of the color image in the high-luminance region without impairing the image quality of the color image in the low-luminance region.

Next, the operation of the image pickup apparatus according to the third embodiment of the present invention will be described with reference to FIGS. 7 and 8.

As shown in FIG. 7, the exposure control unit 14 controls the exposure of the mosaic color filter image sensor 12C that receives the first luminous flux BE1 to 1 / L times. L is a positive number (including a decimal number) of 1 or more. As a result, the saturation amount of the first luminous flux BE1 becomes L times that of the case of the first embodiment.

As shown in FIG. 8, the video signal processing unit 13 sets the second luminous flux BE2 as red light, green light, and blue light in the region where each color component of the second luminous flux BE2 is not saturated (the second luminous flux use region UARBE2). The R signal, G signal, and B signal, which are decomposed into light and photoelectrically converted by the respective monochrome image pickup elements 12R, 12G, and 12B, are gain-corrected 1 / L times to generate a color image CVBE2.

The video signal processing unit 13 also N times the C signal obtained by photoelectrically converting the first luminous flux BE1 by the mosaic color filter imaging element 12C in the region where each color component of the second luminous flux BE2 is saturated (the first luminous flux use region UARBE1). The color image CVBE1 is generated by correcting the gain.

A color image CVBE2 in the low-luminance region and a color image CVBE1 in the high-luminance region are combined to generate one color image. After that, various video signal processes are applied to the synthesized color video to generate, for example, an HD-SDI signal and output it.

In Example 3, the first luminous flux BE1 has an exposure of 1 / L times, and the second luminous flux BE2 has a gain of 1 / L times. Therefore, the video signal level of the combined color image is 1 / L times, but the video signal level can be interpolated by increasing the amount of light to L times by opening the lens diaphragm or the like. Even if the amount of light is L times, the saturation amount of the first luminous flux BE1 is L times, so that the dynamic range of the entire image pickup apparatus 1 is not narrowed. By setting the gain of the second luminous flux BE2 to 1 / L, the S / N ratio and the gradation of the color image in the low-luminance region are improved to L times.

In the second luminous flux BE2, the saturation amount of the color image in the low-luminance region generated from the second luminous flux BE2 is reduced by the amount of lowering the gain, but the saturation amount of the high-luminance region generated from the first luminous flux BE1 is reduced by that amount. It can be interpolated with color images. The color image generated from the first luminous flux BE1 is inferior in image quality to the color image generated from the second luminous flux BE2. However, unless the gain of the second luminous flux BE2 is lowered too much, the second luminous flux BE2 will not be saturated in the low-luminance region, and in the high-luminance region interpolated by the color image generated from the first luminous flux BE1, S / Since the N ratio, the gradation of brightness, and the degree of modulation in the high frequency band are not conspicuous, there is no particular problem.

On the other hand, when the gain is lowered and the S / N ratio is increased in the three-plate image sensor, the saturation amount of the image sensor itself does not change, so that the saturation amount of the entire three-plate image sensor is lowered by the gain. , The dynamic range is narrowed.

As described above, according to the third embodiment, it is possible to obtain a better S / N ratio and high gradation in a color image in a low-luminance region while maintaining a wide dynamic range.

The invention made by the present inventor has been specifically described above based on the embodiments and examples, but the present invention is not limited to the above embodiments and examples, and can be variously modified. Not to mention.

1: Image sensor 2: Lens 11: Color separation optical system 12C: Mosaic color filter Image sensor 12R, 12G, 12B: Monochrome image sensor 13: Video signal processing unit 14: Exposure control unit 15: CPU unit 131: Gain correction unit 132 : Pixel interpolation unit 133: Delay unit 134: Synthesis unit 135: Gamma correction unit 136: Video signal output unit

Claims (3)

A color-resolving optical system that decomposes the luminous flux incident from the lens into a first luminous flux and a second luminous flux, and decomposes the second luminous flux into red light, green light, and blue light.
A first image sensor provided with a color filter that receives the first luminous flux and generates a first electric signal.
A second image sensor for red that receives the red light and generates a second electric signal,
A third image sensor for green that receives the green light and generates a third electric signal,
A fourth image sensor for blue that receives the blue light and generates a fourth electric signal,
A signal processing unit that converts the first to fourth electric signals to generate a color image, and
Have,
The signal processing unit
A gain correction unit that can control the gain of the first to fourth electric signals, and
It has a compositing unit which is connected to the output of the gain correction unit and synthesizes a first output signal corresponding to the first electric signal and a second output signal corresponding to the second to fourth electric signals. And
The color separation optical system decomposes the light flux so that the ratio of the light flux of the first light beam to the second light beam is 1 / N: 1 (N is a positive number of 1 or more).
When the saturation amount of the first electric signal and the saturation amount of the second to fourth electric signals are the same, the signal processing unit may perform the signal processing unit.
In a region where the second to fourth electric signals are not saturated, a color image in a low brightness region is generated based on the second output signal corresponding to the second to fourth electric signals.
In the region where the second to fourth electric signals are saturated, a color image in a high-luminance region is generated based on the first output signal obtained by gain-correcting the first electric signal N times by the gain correction unit.
The compositing unit synthesizes the color image in the low-luminance region and the color image in the high-luminance region.
Imaging device. A color-resolving optical system that decomposes the luminous flux incident from the lens into a first luminous flux and a second luminous flux, and decomposes the second luminous flux into red light, green light, and blue light.
A first image sensor provided with a color filter that receives the first luminous flux and generates a first electric signal.
A second image sensor for red that receives the red light and generates a second electric signal,
A third image sensor for green that receives the green light and generates a third electric signal,
A fourth image sensor for blue that receives the blue light and generates a fourth electric signal,
A signal processing unit that converts the first to fourth electric signals to generate a color image, and
An exposure control unit that can control the exposure of the first to fourth image sensors,
Have,
The signal processing unit
A gain correction unit that can control the gain of the first to fourth electric signals, and
It has a compositing unit which is connected to the output of the gain correction unit and synthesizes a first output signal corresponding to the first electric signal and a second output signal corresponding to the second to fourth electric signals. And
The color separation optical system decomposes the light flux so that the ratio of the light flux of the first light beam to the second light beam is 1 / N: 1 (N is a positive number of 1 or more).
The exposure control unit controls the exposure of the first image sensor to be 1 / M times (M is a positive number of 1 or more).
When the saturation amount of the first electric signal and the saturation amount of the second to fourth electric signals are the same, the signal processing unit may perform the signal processing unit.
In a region where the second to fourth electric signals are not saturated, a color image in a low brightness region is generated based on the second output signal corresponding to the second to fourth electric signals.
In the region where the second to fourth electric signals are saturated, a color image in a high-luminance region is generated based on the first output signal obtained by gain-correcting the first electric signal by N × M times by the gain correction unit. ,
The compositing unit synthesizes the color image in the low-luminance region and the color image in the high-luminance region.
Imaging device. A color-resolving optical system that decomposes the luminous flux incident from the lens into a first luminous flux and a second luminous flux, and decomposes the second luminous flux into red light, green light, and blue light.
A first image sensor provided with a color filter that receives the first luminous flux and generates a first electric signal.
A second image sensor for red that receives the red light and generates a second electric signal,
A third image sensor for green that receives the green light and generates a third electric signal,
A fourth image sensor for blue that receives the blue light and generates a fourth electric signal,
A signal processing unit that converts the first to fourth electric signals to generate a color image, and
An exposure control unit that can control the exposure of the first to fourth image sensors,
Have,
The signal processing unit
A gain correction unit that can control the gain of the first to fourth electric signals, and
It has a compositing unit which is connected to the output of the gain correction unit and synthesizes a first output signal corresponding to the first electric signal and a second output signal corresponding to the second to fourth electric signals. And
The color separation optical system decomposes the light flux so that the ratio of the light flux of the first light beam to the second light beam is 1 / N: 1 (N is a positive number of 1 or more).
The exposure control unit controls the exposure of the first image sensor to be 1 / L times (L is a positive number of 1 or more).
When the saturation amount of the first electric signal and the saturation amount of the second to fourth electric signals are the same, the signal processing unit may perform the signal processing unit.
In a region where the second to fourth electric signals are not saturated, a low-luminance region based on the second output signal obtained by gain-correcting the second to fourth electric signals by a factor of 1 / L by the gain correction unit. Generate a color image,
In the region where the second to fourth electric signals are saturated, a color image in a high-luminance region is generated based on the first output signal obtained by gain-correcting the first electric signal N times by the gain correction unit.
The compositing unit synthesizes the color image in the low-luminance region and the color image in the high-luminance region.
Imaging device.

Images