JP2024002255A - Imaging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging device capable of achieving both multidirectional focusing state detection and high-quality image acquisition with reduced missing information due to phase difference detection pixels, by a simple method.

SOLUTION: A multiplate imaging system imaging device comprises: a first image sensor that has a phase difference detection pixel having such a first structure that a light-receiving part of a pixel is divided into two in one direction and shielding a half region; a second image sensor that has a phase difference detection pixel having such a second structure that the light-receiving part of the pixel is divided into two in a direction orthogonal to the one direction and shielding a half region; a phase difference information reading circuit that reads out a signal of the phase difference detection pixel of the first image sensor and a signal of the phase difference detection pixel of the second image sensor, and outputs the signals as two types of phase difference images; and a phase difference detection circuit that detects a relative position vector between the two kinds of phase difference images and calculates a focusing state from the relative position vector.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to an imaging device, and more particularly to an imaging device that detects a focus state according to a difference between a lens focus distance and a subject distance when photographing an image.

In recent years, there has been an increasing need to add an autofocus function and a function to acquire depth information at the same time as an image to imaging devices. To realize these functions, a technique for detecting the in-focus state of a photographed image, which changes depending on the positional relationship between the lens focus distance and the subject distance, is effective. BACKGROUND ART Conventionally, an image plane phase difference detection method is well known as a method for simultaneously acquiring an image and detecting a focus state. The image plane phase difference detection method uses an image sensor equipped with multiple pairs of pixels (phase difference detection pixels) each having a sensitivity corresponding to exit pupils of different shapes, and detects the relative position on the image plane. This method detects the in-focus state from a vector (phase difference information) (for example, Patent Document 1).

Patent Document 1 discloses an imaging device in which multiple types of phase difference detection pixels are arranged with different opening areas of photodiodes (photoelectric conversion units) and positions in the X direction and Y direction, and The in-focus state in two orthogonal array directions is detected from the outputs of a plurality of types of phase difference detection pixel pairs. Patent Document 1 is an example of a focus state detection method in a so-called single-chip imaging method in which a color image is acquired from a single image sensor having a color filter array.

In addition, a device has been proposed that acquires ranging information based on a sum value obtained by adding up the outputs of multiple phase difference detection pixels supplied from an image sensor in which multiple phase difference detection pixels with different phase difference characteristics are arranged. (Patent Document 2). This device has an optimal exit pupil distance according to the lens by arranging phase difference detection pixels that perform multiple types of pupil division on different lines of the sensor in the image plane phase difference sensor of an interchangeable lens camera. A phase difference detection pixel is selected and outputted, or a plurality of them are added and outputted. Patent Document 2 describes an imaging device that splits incident light into a dedicated phase difference AF sensor and an image plane phase difference sensor via a semi-transmissive mirror, in which the dedicated phase difference AF sensor detects a horizontal line, and the image plane phase difference sensor detects a horizontal line. also describes a technique for performing cross distance measurement by detecting vertical lines individually.

On the other hand, cameras that require high image quality such as high sensitivity and excellent color reproducibility, such as broadcast cameras, use multiple image sensors and a dichroic prism (spectroscopic prism) to separate incident light, typically using a three-sensor imaging system. A multi-chip imaging method is often used to acquire color images using Here, in the three-chip imaging system, a spectroscopic prism is used to mainly separate light into three components: Rch (channel), Gch, and Bch.

However, an optimal method for detecting the image plane phase difference in such a three-plate imaging system has not been established. If a method similar to Patent Document 1 is used and each image sensor of a three-chip imaging system is equipped with multiple types of phase difference detection pixels, the phase difference detection pixels will be treated as pixel defects during image acquisition, so the image A problem arises in that the image quality deteriorates in a wide area within the camera, and the advantage of the three-chip imaging system, which aims to obtain high-quality images, is lost. Furthermore, as in Cited Document 2, adding a special optical system such as a semi-transmissive mirror or a dedicated phase difference AF sensor complicates the optical system, making it unrealistic to apply it to a three-panel imaging system. isn't it.

The present inventors have been working on the development of technology for detecting the in-focus state in imaging devices using multi-chip imaging methods, including three-chip imaging methods, and have proposed various imaging devices so far ( For example, Patent Document 3).

The imaging device of Patent Document 3 includes a first image sensor having a phase difference detection pixel in which one half (right half) of the pixel is shielded from light, and a first image sensor having a phase difference detection pixel in which one half (the left half) of the pixel is shielded from light. A second image sensor is provided with a second image sensor having phase difference detection pixels, which detects a relative position vector between two types of phase difference images obtained from these phase difference detection pixels, and determines the in-focus state from this relative position vector. It is something to seek. According to this imaging device, it is possible to achieve both high-precision focusing state detection and high-quality image acquisition using a simple method.

JP2016-99416A International Publication No. 2019/031000 JP 2021-175052 Publication

However, since the imaging device of Patent Document 3 uses a phase difference detection pixel in which one half of the pixel is shielded from light and a phase difference detection pixel in which the other half of the pixel is shielded from light, the in-focus state is The detection target was limited to a specific direction, and there was room for improvement.

Therefore, an object of the present invention, which has been made in view of the above-mentioned problems, is to provide an imaging device using a multi-chip imaging system, such as a three-chip imaging system, which is capable of detecting focus states in multiple directions using a simple method. It is an object of the present invention to provide an imaging device capable of achieving both high-quality image acquisition with little information loss due to phase difference detection pixels.

In order to solve the above problems, an imaging device according to the present invention includes:
(1) A multi-sensor imaging device including a plurality of image sensors, including a first image sensor having phase difference detection pixels of a first structure, and a second image sensor having phase difference detection pixels of a second structure. phase difference information that reads signals from the image sensor, the phase difference detection pixel of the first image sensor, and the phase difference detection pixel of the second image sensor, and outputs them as two types of phase difference images. a readout circuit; and a phase difference detection circuit that detects a relative position vector between the two types of phase difference images and determines a focused state from the relative position vector, and the phase difference detection pixel of the first structure has a pixel. The light-receiving part of the pixel is divided into two in one direction so that half of the area is shielded from light. The region is light-shielded, and the phase difference detection pixels of the first structure and the phase difference detection pixels of the second structure are located at the same position on the two-dimensional imaging planes of the first and second image sensors. This is an imaging device.

(2) In the imaging device of (1) above, it is further preferable that the phase difference detection pixels have the same pitch in the horizontal direction and the vertical direction on the two-dimensional imaging planes of the first and second image sensors. .

(3) In the imaging device of (1) or (2) above, it is preferable that the phase difference detection circuit further detects the relative position vector using a block matching method.

(4) In the imaging device according to any one of (1) to (3) above, it is further preferable that the phase difference detection circuit shifts in units of subpixels during a search using a block matching method.

(5) The imaging device according to any one of (1) to (4) above further sets a region of interest for the two types of phase difference images, cuts out and outputs the phase difference image included in the region of interest. It is preferable to further include a region of interest extraction circuit.

(6) Preferably, the imaging device according to any one of (1) to (5) above further includes a sensitivity correction circuit that corrects a sensitivity difference between the two types of phase difference images.

(7) In the imaging device according to any one of (1) to (6) above, a signal of a pixel other than the phase difference detection pixel of the plurality of image sensors is further inputted from the phase difference information readout circuit; The signal at the position of the phase difference detection pixel is combined with the signal of the peripheral pixels of the phase difference detection pixel, and the signal at the same position on the two-dimensional imaging plane as the phase difference detection pixel of an image sensor other than the first and second image sensors. It is preferable to further include a pixel interpolation circuit that performs interpolation or estimation processing from at least one of a pixel signal and signals of surrounding pixels.

According to the imaging device of the present invention, in an optical system of a multi-chip imaging system such as a three-chip imaging system, it is possible to detect the in-focus state in multiple directions using a simple method, and to detect high-speed images with little information loss due to phase difference detection pixels. It is possible to obtain both high-quality images.

1 is an example of a block diagram of an imaging device according to an embodiment of the present invention. FIG. 3 is a diagram showing an example of an imaging surface of an image sensor with phase difference detection pixels. It is a figure which shows another example of the imaging surface of the image sensor with a phase difference detection pixel. It is a figure which shows the example of the shape of the exit pupil seen from a phase difference detection pixel and a normal pixel. It is an example of the relative position vector on the imaging plane of two image sensors with phase difference detection pixels.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is an example of a block diagram of an imaging device according to an embodiment of the present invention. The imaging device 1 in FIG. 1 is a three-chip imaging device 1, including a lens 10, a spectroscopic prism 20, an image sensor group 30 (31 to 33), a phase difference information readout circuit 40, a region of interest extraction circuit 41, and a sensitivity It includes a correction circuit 42, a phase difference detection circuit 43, a pixel interpolation circuit 50, and an image processing circuit 60. Each component circuit will be explained below.

The lens 10 is a general camera lens, has a predetermined focal length, and forms an image (image of an object) on the imaging plane of each image sensor (imaging device) 31 to 33. For example, a broadcasting zoom lens consists of lens groups such as a focus group, a zoom group, a relay group, and an extender group, and some have as many as 30 to 40 lenses. The lens 10 may be configured to be separable from the imaging device 1. Further, the lens 10 includes a lens driver (not shown) and is capable of focus control.

The spectroscopic prism 20 performs color separation of incident light. For example, the spectroscopic prism 20 uses selective reflection by a dichroic mirror to separate incident light into three colors: R (red), G (green), and B (blue).

The image sensor group 30 includes a first image sensor 31 and a second image sensor 32 with phase difference detection pixels. The other image sensor 33 may be a normal image sensor (without phase difference detection pixels). For example, the B component (Bch) image sensor 31 can be a first image sensor with phase difference detection pixels, and the R component (Rch) image sensor 32 can be a second image sensor with phase difference detection pixels. It is not limited to. It is possible to set as appropriate which color channel the image sensor with phase difference detection pixels (sometimes simply referred to as "phase difference detection image sensor") and the normal image sensor are used.

Note that Bch images have a low contribution to brightness information in human vision, so even if some missing pixels (phase difference detection pixels) are included, there is little effect on the deterioration of the image quality perceived by humans, and Bch It is advantageous in terms of image quality to use an image sensor with phase difference detection pixels as the image sensor 31. The image sensor group 30 acquires an image including phase difference information for each of the incident lights separated by the spectroscopic prism 20, and outputs the captured image to the phase difference information reading circuit 40.

FIGS. 2A and 2B show examples of imaging surfaces of image sensors with phase difference detection pixels. In the present invention, the phase difference detection pixel of one phase difference detection image sensor has the first structure, and the light receiving part of the pixel is divided into two in one direction (for example, horizontal direction), and half the area is shaded. pixel. In addition, the phase difference detection pixel of the other phase difference detection image sensor has a second structure, in which the light receiving part of the pixel is divided into two in a direction perpendicular to one direction (e.g., vertical direction), resulting in a half area. is the shaded pixel. That is, the arrangement directions (light-shielding directions) of the light-shielding regions of the phase difference detection pixels are different between the two image sensors. However, the phase difference detection pixels are arranged at the same position on the two-dimensional imaging plane of each image sensor.

Here, FIG. 2A is an example of the imaging surface of the Bch image sensor 31, and the phase difference detection pixel 312 uses a pixel whose right half in the horizontal direction is shielded from light. FIG. 2B is an example of the imaging surface of the Rch image sensor 32, and the phase difference detection pixel 322 uses a pixel whose lower half in the vertical direction is shielded from light. Note that since Gch is a normal image sensor (without phase difference detection pixels), illustration thereof is omitted.

In this embodiment, the Bch image sensor 31 includes a normal pixel 311 and a phase difference detection pixel 312. In the Bch phase difference detection pixel 312, as shown in FIG. 2A, the right half of the pixel opening is shielded from light by, for example, a metal layer. The image formed by the output of the phase difference detection pixel 312 is sometimes referred to as a horizontal phase difference image H because it shifts in the horizontal direction depending on the focusing state, as described later. The arrangement of the phase difference detection pixels 312 has, for example, a pitch of 4 pixels in the horizontal and vertical directions of the screen. The more phase difference detection pixels 312 there are, the more accurate phase difference detection is possible, but since the phase difference detection pixels 312 become pixel defects during imaging, the more phase difference detection pixels 312, the more the image quality deteriorates. Therefore, the horizontal and vertical pitches of the phase difference detection pixels 312 can be set as appropriate, taking into consideration the balance between the phase difference detection sensitivity and the image quality of the captured image. Note that the pitches in the horizontal and vertical directions can be independently set as desired, but it is more preferable to make both pitches the same because the phase difference detection sensitivity in the horizontal and vertical directions will be the same. .

The Rch image sensor 32 includes a normal pixel 321 and a phase difference detection pixel 322. As shown in FIG. 2B, the Rch phase difference detection pixel 322 shields the lower half of the pixel opening from light with, for example, a metal layer, and the direction of light shielding is orthogonal to the Bch phase difference detection pixel 312 ( (rotated 90 degrees). The image formed by the output of the phase difference detection pixel 322 is sometimes referred to as a vertical phase difference image V because it shifts in the vertical direction depending on the focusing state, as will be described later. Regarding the arrangement of the phase difference detection pixels 322, for example, the pitch in the horizontal and vertical directions of the screen is 4 pixels. The horizontal and vertical pitches of the phase difference detection pixels 322 can be set as appropriate in the same way as for Bch, but the position of the phase difference detection pixels 322 on the two-dimensional imaging plane is different from that of the Bch phase difference detection pixels 312. configured to match.

Returning to FIG. 1, the phase difference information readout circuit 40 acquires captured images from the image sensor group 30, and among the acquired images, the phase difference information readout circuit 40 acquires captured images from the image sensors with phase difference detection pixels (Bch image sensor 31, Rch image sensor 32). The signal of the phase difference detection pixel is read out and outputted to the attention area cutting circuit 41 as two types of phase difference images (H, V). In this embodiment, a signal from the phase difference detection pixel 312 of the Bch image sensor 31 is read out to form a horizontal phase difference image H, and a signal from the phase difference detection pixel 322 of the Rch image sensor 32 is read out to form a vertical phase difference image V. Note that the phase difference image is an image composed of output signals of phase difference detection pixels, and is an image for acquiring a relative position vector for detecting a phase difference (in-focus state).

At the same time, the phase difference information readout circuit 40 outputs signals of other normal pixels (normal images) to the pixel interpolation circuit 50. In this embodiment, images of pixels 311 other than the phase difference detection pixels of the Bch image sensor 31, images of pixels 321 other than the phase difference detection pixels of the Rch image sensor 32, and images of all pixels of the Gch image sensor 33 are Output as a normal image.

The attention area extraction circuit 41 sets the attention area based on the coordinate information of the attention area inputted from the outside or object information in the image recognized in advance from the input image from the image sensor, and extracts phase difference information. Regions of interest are each cut out from the phase difference images H and V input from the readout circuit 40. For example, the following methods can be used to determine the region of interest.
・Determine manually from the output image.
・Determine using a model that has been machine learned from the output image.
- Set to a fixed value (for example, a preset area in the center of the image) regardless of the output image.

When cutting out a region of interest, it is desirable to set a region that includes an edge as the region of interest. Note that in the present invention, the direction of the edge is not limited, and the edge may be in any direction. In the conventional technology (Patent Document 3), it was necessary to select a region including an edge in a direction that can be detected by phase difference detection pixels as a region of interest, but in the present invention, a region including an edge in an arbitrary direction is selected. This has the effect of increasing the degree of freedom in setting the region of interest. The attention area cutting circuit 41 outputs the cut out phase difference image (H', V') of the attention area to the sensitivity correction circuit 42.

Note that in FIG. 1, the region of interest extraction circuit 41 is described as a circuit independent of the phase difference information readout circuit 40, but it may be configured as an internal circuit of the phase difference information readout circuit 40. In this case, the attention area cutting out circuit 41 cuts out an image area to be the attention area from the input image from the image sensor, and then converts the signal of the phase difference detection pixel included in the cut out attention area into the phase difference image (H' , V').

The sensitivity correction circuit 42 uses the image average and histogram information between the phase difference images (H', V') to correct the sensitivity difference (brightness difference, contrast difference) between the two images. For example, it is desirable to correct the images so that the histograms of both images match.

Phase difference images use information from phase difference detection pixels generated from different wavelengths (and different apertures) on each phase difference detection image sensor, so brightness, contrast, object edge shape, etc. do not match between phase difference images. There are cases. In such a state, there is a risk that the accuracy of phase difference detection (block matching) in the subsequent stage may be reduced. Therefore, it is desirable that the sensitivity correction circuit 42 performs matching of brightness, contrast, and edge shape. For brightness and contrast matching, correction using known techniques as exemplified below can be applied.
・Multiplication by fixed coefficient determined from shading rate and pixel sensitivity ・Matching of peak values (maximum value, minimum value) ・Normalization ・Histogram matching

The sensitivity correction circuit 42 outputs the phase difference image (H", V") whose sensitivity has been corrected to the phase difference detection circuit 43. Note that when the sensitivities of the horizontal phase difference image H' and the vertical phase difference image V' are almost the same, the sensitivity correction may be omitted.

The phase difference detection circuit 43 detects the relative position (relative position vector) between the sensitivity-corrected phase difference images (H'', V'') using, for example, a block matching method, and detects the sign and magnitude of the obtained relative position vector. The in-focus state (phase difference) is calculated and output.

In the present invention, suitable phase difference detection methods (block matching methods) include methods that are robust against sensitivity differences between phase difference images, such as ZSAD (zero-mean SAD), NCC (Normalized Cross-Correlation), and ZNCC ( Zero-means Normalized Cross-Correlation) is preferred. More preferably, matching is performed using an evaluation formula in which ZNCC is squared, and the shift amount that takes the maximum value (the shift amount that takes the value closest to 1) is output as a phase difference. By squaring the ZNCC cross-correlation coefficient, square root calculations that are difficult to calculate on hardware can be excluded, and matching can be determined even for images with negative correlation. Therefore, the evaluation formula in which ZNCC is squared is effective for correctly determining focus, especially when there is a possibility that the brightness and dark regions of edge brightness may be reversed between phase contrast images.

In this embodiment, the search direction for block matching is two-dimensional in both the horizontal and vertical directions. Further, during the search, a shift in sub-pixel units, which is finer than in pixel units, may be used. By performing matching using minute shifts, it is possible to detect phase differences with even finer precision than the pixel unit of the original image sensor.

The pixel interpolation circuit 50 receives a normal image (an image in which a phase difference detection pixel is a missing pixel) from the phase difference information readout circuit 40, and generates an image (signal) at the position of the phase difference detection pixel that is a missing image. is determined by interpolation processing. This interpolation process can be performed using any known means, and for example, the average of pixel values of adjacent surrounding pixels may be calculated and used as an interpolated value. Furthermore, surrounding pixels (including surrounding pixels) of the missing pixel (phase difference detection pixel), pixels at the same position on the two-dimensional imaging plane as the missing pixel of other image sensors (image sensors other than the phase difference detection image sensor), and their Known interpolation or estimation processing may be performed from at least one piece of information about surrounding pixels. There is a strong correlation between an image at the position of a missing pixel (phase difference detection pixel) and an image at the same position as the missing pixel of another image sensor. Further, the correlation between an image at the same position as the missing pixel of another image sensor and an image of its surrounding pixels can be used when estimating an image at the position of the missing pixel from images of surrounding pixels of the missing pixel. The pixel interpolation circuit 50 outputs a complete image in which the missing image is restored by interpolation or estimation processing to the image processing circuit 60.

In this embodiment, since only one type of phase difference detection pixel (right shaded pixel or bottom shaded pixel) is provided in one image sensor, the phase difference can be detected with the same accuracy as conventional methods (Patent Documents 1 and 2). For example, the number of phase difference detection pixels can be halved. Therefore, since there are fewer missing images per image sensor, more accurate interpolation processing is possible, and the quality of the restored image is higher than before.

The image processing circuit 60 performs various types of image processing that are generally performed within an imaging device. For example, the image processing circuit 60 performs white balance adjustment, gain adjustment, gamma correction, edge enhancement processing, etc. of the RGB signals, and outputs the processed image as an output image of the imaging device 1.

Next, acquisition of the relative position vector (phase difference information) will be explained. FIG. 3 is an example of the shape of the exit pupil seen from the phase difference detection pixels and normal pixels in FIGS. 2A and 2B. In FIG. 3, incident light from a subject is separated into each color by a spectroscopic prism 20, and is incident on each image sensor. A Bch phase difference detection pixel (light-shielded pixel), a Gch normal pixel, and an Rch phase difference detection pixel (light-shielded pixel) are assumed to be RGB pixels at the same position in a three-plate optical system. Here, since the normal pixel for Gch has the aperture at the center, the center of gravity of the exit pupil is also formed at the center. The Bch phase difference detection pixel 312 has an exit pupil that is eccentrically shifted in the horizontal direction. The Rch phase difference detection pixel 322 has an exit pupil that is eccentrically shifted in the vertical direction.

In the image sensor group 30 having the above configuration, when performing phase difference detection on a subject having edges only in the vertical direction (such as a vertical striped pattern), the phase difference image formed from the Bch phase difference detection pixels is While the image center shifts in the horizontal direction depending on the state, the image center of the phase difference image formed from the Rch phase difference detection pixels does not shift. Therefore, it is possible to obtain a relative position vector (to which the shift of Bch contributes) from this pair of phase difference images of Bch and Rch, and from the sign of the vector, the focus shift direction (front focus/rear focus) and the size of the vector can be determined. Focus judgment such as the amount of deviation from the side can be realized.

In addition, when performing phase difference detection on a subject that has edges only in the horizontal direction (such as a horizontal striped pattern), the image center of the phase difference image from Bch does not shift, and the image center of the phase difference image from Rch is vertical. Shift in the direction. Therefore, it is possible to obtain a relative position vector (to which the Rch shift contributes) from this Bch and Rch phase difference image pair, and the sign of the vector determines the direction of the focus shift, and the magnitude of the vector determines the amount of shift. Judgment can be realized.

When performing phase difference detection on a subject with edges in a diagonal direction, the image center of the phase difference image from Bch shifts horizontally, and the image center of the phase difference image from Rch shifts vertically. It can be obtained as a two-dimensional relative position vector. In the example of FIG. 3, the relative position vector is a direction that connects the aperture eccentricity of Bch and Rch, and is projected onto the first or third quadrant. Focus determination can be achieved.

FIG. 4 is an example of relative position vectors on the imaging plane of two image sensors. a is an example of a relative position vector when a subject with edges in the vertical direction (such as a vertical striped pattern) is out of focus. b is an example of a relative position vector when a subject with edges in the horizontal direction (horizontal striped pattern, etc.) is out of focus. c is an example of a relative position vector when a focus shift of a subject having an edge in a diagonal direction occurs. As described above, according to the present invention, it is possible to detect a focus state in multiple directions.

Further, according to the present invention, it is possible to determine focus on an image having edge information in multiple directions only from the phase difference detection pixel pair of the first structure and the second structure at the same position in the multi-sensor imaging system. Therefore, compared to the conventional method of arranging a plurality of phase difference detection pixel pairs, it is possible to simultaneously obtain high-quality images with less information missing due to detection pixels.

In the above embodiment, the configuration and operation of the imaging device 1 have been described, but the present invention is not limited to this, and may be configured as a method for detecting a focus state (phase difference) in the imaging device 1. That is, the focus state detection method includes the steps of reading phase difference information from an image sensor including phase difference detection pixels of a first structure and a second structure, correcting sensitivity, and detecting the phase difference. It may be configured as

Further, in the above embodiment, as shown in FIGS. 2A and 2B, the image sensor including the phase difference detection pixels of the first structure and the second structure each has one type of phase difference detection pixel. However, a single image sensor may have multiple types of phase difference detection pixels. In that case, the light-shielding regions of the phase difference pixels at the same position on the two-dimensional imaging plane between the two types of image sensors are arranged in orthogonal directions.

Although the embodiments described above have been described as representative examples, it will be apparent to those skilled in the art that many modifications and substitutions can be made within the spirit and scope of the invention. Therefore, the present invention should not be construed as being limited to the above-described embodiments, and various modifications and changes can be made without departing from the scope of the claims. For example, it is possible to combine a plurality of configuration blocks described in the embodiments into one, or to divide one configuration block.

10 Lens 20 Spectroscopic prism 30 Image sensor group 31 to 33 Image sensor 40 Phase difference information readout circuit 41 Attention area extraction circuit 42 Sensitivity correction circuit 43 Phase difference detection circuit 50 Pixel interpolation circuit 60 Image processing circuit 311 Normal pixel 312 Phase difference detection pixel 321 Normal pixel 322 Phase difference detection pixel

Claims (7)

An imaging device using a multi-sensor imaging system equipped with a plurality of image sensors,
a first image sensor having a phase difference detection pixel having a first structure;
a second image sensor having a second structure of phase difference detection pixels;
a phase difference information readout circuit that reads out the signal of the phase difference detection pixel of the first image sensor and the signal of the phase difference detection pixel of the second image sensor, and outputs it as two types of phase difference images;
a phase difference detection circuit that detects a relative position vector between the two types of phase difference images and determines a focused state from the relative position vector,
In the phase difference detection pixel having the first structure, the light receiving part of the pixel is divided into two parts in one direction so that half of the area is shielded from light. It is divided into two parts in the direction perpendicular to the direction, and half the area is blocked from light.
An imaging device, wherein the phase difference detection pixel of the first structure and the phase difference detection pixel of the second structure are located at the same position on two-dimensional imaging planes of the first and second image sensors. The imaging device according to claim 1,
The imaging device is characterized in that the phase difference detection pixels have the same pitch in the horizontal direction and the vertical direction on the two-dimensional imaging planes of the first and second image sensors. The imaging device according to claim 2,
An imaging device, wherein the phase difference detection circuit detects the relative position vector using a block matching method. The imaging device according to claim 3,
An imaging device, wherein the phase difference detection circuit shifts in subpixel units during a search using a block matching method. The imaging device according to claim 4,
An imaging device further comprising: an attention area cutting circuit that sets an attention area for the two types of phase difference images, and cuts out and outputs a phase difference image included in the attention area. The imaging device according to claim 5,
An imaging device further comprising a sensitivity correction circuit that corrects a sensitivity difference between the two types of phase difference images. The imaging device according to any one of claims 1 to 6,
Signals of pixels other than the phase difference detection pixel of the plurality of image sensors are inputted from the phase difference information readout circuit, and the signal of the position of the phase difference detection pixel is inputted to the signal of the peripheral pixels of the phase difference detection pixel, Interpolation or estimation processing is performed from at least one of a signal of a pixel at the same position on a two-dimensional imaging plane as the phase difference detection pixel of an image sensor other than the first and second image sensors, and a signal of a peripheral pixel thereof. An imaging device further comprising a pixel interpolation circuit that calculates the pixel value using the pixel interpolation circuit.

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