JP7433914B2 - Imaging device and its control method - Google Patents

Description

The present invention relates to an imaging device and a control method thereof.

BACKGROUND ART Conventionally, a technique has been known that controls the depth of field by adjusting the focus position and aperture to make blur less noticeable (for example, see Patent Document 1).

JP 2017-3749 Publication

The present invention has been made in view of such problems, and an object of the present invention is to make it possible to generate a captured image with suppressed blur.

In order to solve the above-mentioned problems, an imaging device according to the present invention has the following configuration. That is, the imaging device is
an imaging optical system configured to be able to image light in the visible light region and infrared light region;
adjustment means for adjusting the focus position of the imaging optical system;
insertion/extraction means for inserting/extracting an infrared cut filter into/from the optical path of the imaging optical system;
an image processing means for converting optical images in the visible light region and infrared light region formed on the image sensor by the imaging optical system into image signals;
determining means for determining the presence or absence of blur in the image indicated by the image signal;
a control means for executing a predetermined process for suppressing blur in an image indicated by the image signal;
has
The image sensor is a color image sensor,
The imaging device has a first mode in which the infrared cut filter is inserted into the optical path of the imaging optical system and a color image signal is output from the image processing means, and a first mode in which the infrared cut filter is inserted in the optical path of the imaging optical system. a second mode in which the infrared cut filter is removed and outputs a gray scale image signal from the image processing means; and a third mode in which the infrared cut filter is inserted in the optical path of the imaging optical system and a gray scale image signal is output from the image processing means. It is configured to be able to switch between modes.
The determining means determines the presence or absence of blur based on the image signal obtained after adjusting the focus position by the adjusting means,
When the determination means determines that there is blur , the control means performs the predetermined process such that the average brightness value of the image indicated by the image signal output from the image processing means is set to a first brightness threshold value. or above and below the second brightness threshold, the imaging device is changed to the third mode, and if the average brightness value of the image exceeds the second brightness threshold, the imaging device is changed to the first mode, and when the average brightness value of the image is less than the first brightness threshold, the imaging device is changed to the second mode .
Or, the imaging device is
an imaging optical system configured to be able to image light in the visible light region and infrared light region;
illumination means for emitting infrared light in the photographing direction;
adjustment means for adjusting the focus position of the imaging optical system;
an image processing means for converting optical images in the visible light region and infrared light region formed on the image sensor by the imaging optical system into image signals;
determining means for determining the presence or absence of blur in the image indicated by the image signal;
a control means for executing a predetermined process for suppressing blur in an image indicated by the image signal;
has
The determining means determines the presence or absence of blur based on the image signal obtained after adjusting the focus position by the adjusting means,
When the determination means determines that there is blur, the control means performs the predetermined process such that one of the visible light region and the infrared light region is dominant in the subject existing in the photographing direction. Thus, the output of infrared light by the illumination means is adjusted.

FIG. 1 is a block diagram showing a functional configuration of an imaging device according to a first embodiment. It is a flowchart of blur control in a captured image. FIG. 3 is a diagram illustrating a method for determining the presence or absence of blur in a captured image. FIG. 3 is a diagram illustrating switching control of photographing modes. FIG. 3 is a diagram illustrating correspondence between shooting modes depending on the surrounding environment. It is a detailed flowchart of the blur suppression process in 2nd Embodiment. FIG. 3 is a diagram illustrating axial chromatic aberration of a lens and spectral sensitivity of an image sensor.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the claimed invention. Although a plurality of features are described in the embodiments, not all of these features are essential to the invention, and the plurality of features may be arbitrarily combined. Furthermore, in the accompanying drawings, the same or similar components are designated by the same reference numerals, and redundant description will be omitted.

(First embodiment)
When using an imaging device that uses a lens, generally visible light and infrared light have different focus positions (focal planes) (there is a shift in the optical axis direction). Therefore, when images are captured simultaneously in the visible light region and infrared light region (when images are captured in night mode), blurring occurs. Therefore, in the first embodiment, a mode will be described in which blur in a captured image is suppressed by using a shooting mode called digital night mode.

<Device configuration>
FIG. 1 is a block diagram showing the functional configuration of an imaging device according to a first embodiment. The imaging device includes an imaging optical system 101, an optical system control unit 105 that controls the imaging optical system 101, an infrared cut filter 102, an infrared control unit 106 that controls insertion and removal of the infrared cut filter 102, an imaging element 103, and image processing. 104. The imaging apparatus also includes a system controller 107 that centrally controls the above-mentioned functional units.

A subject image obtained through the imaging optical system 101 passes through a predetermined region where an infrared cut filter 102 is inserted and removed, and is formed on an image sensor 103. Note that although the imaging optical system 101 is shown as one lens in FIG. 1, it usually includes a plurality of lenses, and also includes mechanical structures for performing aperture, zoom, and focus control. The optical system control unit 105 controls the aperture, zoom, and focus of the imaging optical system 101 by controlling the operation of this mechanical structure. Further, the imaging optical system 101 is configured to be able to image light in the visible light region and infrared light region.

The infrared cut filter 102 is a filter that attenuates infrared light among the light obtained via the imaging optical system 101 and transmits visible light. The infrared cut filter 102 is configured to be inserted into and removed from a predetermined area located between the imaging optical system 101 and the image sensor 103. The infrared control unit 106 controls insertion and removal of the infrared cut filter 102 into a predetermined area. Note that here, the predetermined area is between the imaging optical system 101 and the image sensor 103, but it may be any area that crosses the optical path of the imaging optical system 101. For example, it may be placed in front of or in the middle of the imaging optical system 101.

The image sensor 103 is an image sensor (CMOS, CCD, etc.) that includes a plurality of photoelectric conversion elements for converting an image (optical image) formed on the surface (on the image sensor) of the image sensor 103 into an image signal. . As will be described in detail later, in order to be able to acquire a visible light color image, for example, an image sensor 103 having a Bayer array RGB color filter is used. Note that as the image sensor 103, it is also possible to use an image sensor in which each pixel can output RGB component values.

The image processing unit 104 performs predetermined image processing such as gamma correction on the image signal input from the image sensor 103, and then generates image data. For example, JPEG encoded image data is generated.

The system controller 107 includes a CPU that controls the system and a memory that stores signals, and sets control instructions and parameters for each of the blocks described above. The memory is used as a storage area for various purposes, such as control instructions given to each block, set parameters, focus positions, and images. Furthermore, in order to perform focus control, the system controller 107 acquires a focus evaluation value from the image processing unit 104 and sends a command to the optical system control unit 105 based on the acquired focus evaluation value. The focus evaluation value is a value used to automatically perform so-called autofocus (AF). AF includes things such as contrast AF and phase difference AF. Contrast AF is a method that creates a signal from the contrast value of an image and uses its high frequency component to perform focusing. On the other hand, phase difference AF is a method in which an image incident from a lens is divided into two, and focusing is performed based on the interval between the two images.

<Shooting mode>
As described above, the image sensor 103 is, for example, a color image sensor having RGB color filters in a Bayer array. The image processing unit 104 is configured to be able to selectively output a color image (RGB component values) and a grayscale image (Y component value) based on the image signal input from the image sensor 103.

In particular, the imaging device according to the first embodiment is configured to be able to use a shooting mode called digital night mode in addition to the day mode and night mode that are commonly used in surveillance cameras. Specifically, these three shooting modes are defined as follows.
- Day mode: A mode in which the infrared cut filter 102 is inserted between the imaging optical system 101 and the image sensor 103, and a color image signal is output from the image processing unit 104.
- Night mode: A mode in which the infrared cut filter 102 is removed from between the imaging optical system 101 and the image sensor 103, and a gray scale image signal is output from the image processing unit 104.
- Digital night mode: A mode in which the infrared cut filter 102 is inserted between the imaging optical system 101 and the image sensor 103, and a grayscale image signal is output from the image processing unit 104.

<Device operation>
FIG. 2 is a flowchart of blur control in a captured image. Specifically, this is a process for making blur less noticeable when images are captured in two wavelength regions, visible light and infrared light, at the same time. Therefore, naturally, this process is performed with the infrared cut filter removed (night mode).

In step S201, the system controller 107 controls the optical system control section 105 and the image processing section 104 to perform an AF operation. That is, control is performed to set the optimum focus position for at least one of the subject image in the visible light region or the infrared light region (generally in the visible light region). In step S202, the system controller 107 obtains, for example, the maximum value Cmax of contrast values C within the captured image (or within a predetermined area within the captured image) as the focus evaluation value.

Here, the contrast value C is given by, for example, the following equation (1) for an arbitrary region. Note that Imax is the maximum value of brightness within the area, and Imin is the minimum value of brightness within the area.
C=(Imax-Imin)/(Imax+Imin)...(1)

In step S203, the system controller 107 uses the focus evaluation value to determine the presence or absence of blur. Specifically, the focus evaluation value (Cmax) is compared with a threshold value (Th) stored in advance, and if it is less than or equal to the threshold value, it is determined that blurring has occurred, and the process proceeds to S204. On the other hand, if the focus evaluation value is larger than the threshold value, it is determined that no blurring has occurred and the process ends. In other words, the reason why the focus evaluation value is low is considered to be because a detailed pattern is lost due to blurring, and as a result, the maximum contrast value Cmax is lowered.

To simplify the explanation, we have explained an example of determining the presence or absence of blur using one threshold Th, but when using the above determination method, if the subject does not have texture (pattern, etc.) or is not clear, There is a possibility that it will be incorrectly determined. In other words, there is a possibility that the image will be determined to be out of focus even though it is in focus. Therefore, in practice, it is better to use a determination method that can deal with such problems.

For example, this can be handled by setting two thresholds (Th ₁ and Th ₂ ) and using them to determine the presence or absence of blur (here, Th ₁ <Th ₂ ). Specifically, if the contrast value at the optimal focus position set in the AF operation (S201) is greater than or equal to Th ₁ and less than or equal to Th ₂ , it is determined that blur has occurred, and blur suppression processing (S204) is performed. I decide. If the contrast value is less than Th ₁ , it is determined that the object is in a low contrast state due to no texture. Furthermore, if the contrast value is greater than Th ₂ , it is simply determined that no blurring has occurred. That is, if the contrast value is less than Th ₁ or greater than Th ₂ , it is determined not to perform the blur suppression process (S204).

Generally, the contrast value is about 0.7 when blur occurs, and about 0.3 when the subject has no texture. Therefore, Th ₁ is preferably set to a value of 0.2 to 0.4, and Th ₂ is preferably set to a value of 0.6 to 0.8.

Note that the determination of the presence or absence of blur is not limited to the above-described method; for example, contrast values for all focus positions may be obtained and the determination may be made based on the outline thereof. Specifically, a method that utilizes a change in contrast value depending on the presence or absence of blur may be used.

FIG. 3 is a diagram illustrating a method for determining the presence or absence of blur in a captured image. The graphs in FIGS. 3A to 3C each show the change in contrast value with respect to the focus position, where the horizontal axis is the focus position and the vertical axis is the contrast value. In particular, Fig. 3(a) shows the case where the subject has texture and no blur (less than a predetermined amount), and Fig. 3(b) shows the case where the subject has texture and blur (greater than the predetermined amount). 3(c) shows the case where the subject has no texture.

As can be understood from the graphs in Figures 3 (a) and (b), when there is no blur, there is a large contrast value difference between the out-of-focus state and the optimal focus position, and when there is blur, this contrast value is large. The difference becomes smaller. Further, as can be understood from the graph in FIG. 3(c), when the subject has no texture, the contrast value does not change much regardless of the focus position.

Therefore, it is possible to determine whether blurring has occurred based on the difference between the maximum and minimum focus evaluation values at each focus position during focus position adjustment in the AF operation (S201). Specifically, when the difference between the maximum value and the minimum value is greater than or equal to Th ₃ and less than or equal to Th ₄ , it is determined that blurring has occurred (Th ₃ <Th ₄ ). If it is less than Th ₃ or greater than Th ₄ , it is determined that no blurring has occurred. This determination method has the advantage that it is possible to determine the presence or absence of blur (S202-S203) at the same time as the AF operation (S201), and it is possible to determine the presence or absence of blur even when the optimal focus position is unknown. .

In step S204, the system controller 107 executes blur suppression processing. Specifically, the infrared control unit 106 is controlled to insert the infrared cut filter 102 into a predetermined area, and the operation mode is changed to digital night mode.

Compared to day mode, digital night mode reduces color noise and improves low-light performance (image quality in low-light environments). Furthermore, in the digital night mode, compared to the night mode, the amount of light incident on the image sensor 103 is reduced (the infrared light component is cut), so noise increases (S/N decreases). However, since the light incident on the image sensor 103 is limited to only the visible range, blurring of the subject image in the infrared light range does not exist (or is not noticeable).

FIG. 4 is a diagram illustrating shooting mode switching control. The switching control is executed by the system controller 107 after transition to the digital night mode by the blurring suppression process (S204).

The determination to change the operating mode is made based on changes in the amount of light in the surrounding environment. For example, when operating in the digital night mode (S401), the average brightness value B of the image indicated by the image data output from the image processing unit 104 is compared with a predetermined brightness threshold, and based on the comparison result, Change the operating mode. An image signal output from the image sensor 103 may be used instead of the image data output from the image processing unit 104.

Specifically, in S402, the average brightness value B of the image is compared with Th _H , and if the average brightness value B of the image exceeds Th _H , the mode is changed to day mode. In other words, since the surrounding environment has changed to a sufficiently bright environment, it is determined that it is suitable to output a color image.

Then, in S403, the average brightness value B of the image is compared with Th _L , and if the average brightness value B of the image is lower than Th _L , the mode is changed to night mode. In other words, since the surrounding environment has changed to a darker environment, it is determined that it is more suitable to output a captured image with less noise that allows for the blur caused by night mode, rather than an image captured with increased noise in digital night mode. . Note that Th _H >Th _L , and the values of Th _H and Th _L are preferably stored in the memory in advance.

FIG. 5 is a diagram showing correspondence between photographing modes depending on the surrounding environment. Here, an example is shown in which the contrast value C of the image is considered in addition to the average brightness value B of the image. The average brightness value B is the average brightness of a plurality of pixels included in an arbitrary area, and is calculated by the image processing unit 104. Note that in FIG. 5, "arbitrary" is written when C>Th and Th _L < B < Th _H , but the user can set it arbitrarily depending on the use case or important parameters, for example. It is shown that. Further, each threshold value may be set arbitrarily by the user.

As explained above, according to the first embodiment, if there is blur in the captured image obtained by capturing the wavelength range of visible light and infrared light, the operation shifts to the digital night mode and the blur is suppressed. Output the captured image. As a result, a captured image with slightly increased noise but suppressed blur compared to a captured image obtained in night mode can be obtained.

Note that in the above description, the amount of light in the surrounding environment is determined based on the captured image obtained when the image is captured in the night mode, and the shooting mode is changed to the optimal shooting mode. However, the determination of the surrounding environment is not limited to this form. For example, a light sensor (not shown) that measures the infrared illuminance of environmental light is separately provided, and the presence or absence of blur is determined based on the output of the light sensor and the image signal in day mode, and the mode is directly changed to the optimal mode. may be configured.

Further, since the higher the S/N or the smaller the variance value in the acquired image, the brighter it is, the determination corresponding to S402 and S403 may be made based on these values. Here, the variance value is the variance of the pixel signal value, and the S/N is the ratio of the pixel value as the signal and the variance value as the noise.

(Second embodiment)
In the second embodiment, a mode will be described in which blur in a captured image is suppressed by controlling the amount of infrared light that illuminates a subject.

<Device configuration>
The imaging device according to the second embodiment differs from the first embodiment in that the infrared control unit 106 further controls an illumination device (not shown) that irradiates infrared light in the photographing direction (that is, the subject). Specifically, the infrared control unit 106 is configured to be able to adjust the output of infrared light projected by the lighting device.

<Device operation>
The blur control in the captured image in the second embodiment is similar to that in the first embodiment (FIG. 2). However, as described above, the details of the blur suppression process (S204) differ from the first embodiment.

FIG. 6 is a detailed flowchart of the blur suppression process (S204) in the second embodiment. As described in the first embodiment, when one of the visible light region and the infrared light region is dominant, blur in the captured image in night mode is suppressed, and a clear captured image is obtained. Therefore, in the process shown in FIG. 6, the output of infrared light by the illumination device is adjusted so that one of the visible light region and the infrared light region becomes dominant.

In step S601, the system controller 107 instructs the infrared control unit 106 to maximize the output of infrared light by the lighting device. In the following steps S602 to S605, the spectral ratio of ambient light is changed by controlling the output of infrared light by the illumination device.

In step S602, the system controller 107 performs an AF operation to adjust the focus position. In step S603, the system controller 107 determines the presence or absence of blur as in S203. If it is determined that blur has occurred, the process advances to S604, and if it has been determined that blur has not occurred, the process ends.

In step S604, the system controller 107 determines whether the S/N is greater than or equal to a predetermined threshold. If it is greater than or equal to the predetermined threshold, it is considered that the image deterioration due to blurring exceeds the image deterioration due to noise, so the process proceeds to S605, weakens the infrared light output from the illumination device by a predetermined amount, and repeats the process from S602. Execute processing. On the other hand, if it is less than the threshold, it is considered that the image deterioration due to noise is greater than the image deterioration due to blur, and therefore the process is terminated. It is desirable that the above-mentioned predetermined threshold value be set in advance in accordance with an illuminance environment in which image deterioration due to noise is more noticeable than image deterioration due to blur.

In the above description, a method has been described in which the infrared light output of the illumination device is maximized and then gradually weakened. However, the present invention is not limited to this, and a method may be adopted in which the infrared light output is minimized and then gradually strengthened. In this case, it is desirable that the minimum infrared light output be an output that is at least sufficient for imaging (for example, an AF operation is possible).

Alternatively, the AF operation in S602 may be performed with the infrared light output set to a value other than the maximum output, and the illumination output may be increased or decreased if there is blur. In this case, the focus position after focus adjustment before changing the infrared light output is referred to. Then, when the difference between the focus position and the focus position of the wavelength of the illumination is less than a predetermined difference, the infrared light output is increased, and when the difference is greater than the predetermined difference, the infrared light output is adjusted to be weakened. , blur can be suppressed quickly. Note that the predetermined difference at this time may be any value, and may be, for example, the depth of focus depending on the aperture value at the time of photographing.

As described above, according to the second embodiment, by controlling the amount of infrared light that illuminates a subject, it is possible to suppress blur in a captured image in night mode. Note that this method is also effective in cases where infrared light illumination is turned on when clear imaging is desired and blurring occurs as a result.

(Third embodiment)
In the third embodiment, a mode will be described in which blur in a captured image is suppressed by adjusting the RGB combination ratio when generating a luminance (Y) signal in a grayscale image. Note that since the device configuration is the same as that of the first embodiment (FIG. 1), detailed explanation will be omitted.

<Device operation>
The blur control in the captured image in the third embodiment is similar to that in the first embodiment (FIG. 2). However, as described above, the details of the blur suppression process (S204) differ from the first embodiment.

FIG. 7 is a diagram illustrating the axial chromatic aberration of the lens and the spectral sensitivity of the image sensor 103 (RGB color image sensor). FIG. 7A exemplarily shows the characteristics of the axial chromatic aberration of the lens, and it can be understood that the larger the difference from the reference wavelength (for example, 550 nm), the larger the magnitude of the aberration (the amount of aberration). On the other hand, FIG. 7B exemplarily shows the spectral characteristics of each of the R pixel, G pixel, and B pixel of the image sensor 103. Here, the R pixel, G pixel, and B pixel mean pixels corresponding to R, G, and B color filters in the image sensor 103, for example. In addition, when using an image sensor in which each pixel can output an RGB component value, it means each RGB component in each pixel.

As can be understood from FIG. 7(b), sensitivity characteristics vary greatly depending on the pixel type (R pixel, G pixel, B pixel) in the wavelength range of visible light (for example, 350 to 750 nm). On the other hand, in the wavelength range of infrared light (for example, from 800 nm), the sensitivity characteristics depending on the pixel type are almost the same.

Since the size of aberration is related to the size of the scattering circle, it is expected that blurring will be suppressed by relatively strengthening the signal of color pixels with small aberration and relatively weakening the signal of color pixels with large aberration. can. Therefore, the signal is emphasized or suppressed by adjusting the RGB combination ratio when creating the Y signal value.

If it is determined that no blurring has occurred, a grayscale image that is a luminance image is generated using a general conversion formula (for example, Y=0.3R+0.6G+0.1B). On the other hand, if it is determined that blur has occurred, a grayscale image that is a luminance image is generated using a pre-calculated RGB ratio that can suitably suppress blur. These processes are performed by the image processing unit 104. Note that it is preferable to store the RGB ratio that can suitably suppress blur in the memory in the system controller 107 in advance. Such an RGB ratio is calculated based on aberration information of the lens and spectral characteristics of the image sensor.

For example, when using a lens and an image sensor having the characteristics shown in FIG. 7, if the amount of aberration of infrared light is used as a reference, the difference with blue light (B: around 450 nm) is small, while the difference with green light (B: around 450 nm) is small. G: around 550 nm) and the difference in aberration amount is relatively large. Therefore, as the RGB ratio that can suitably suppress blur, a ratio is set in which the signal value of the B pixel is emphasized and the signal value of the G pixel is suppressed. That is, compared to the above-mentioned general conversion formula, the degree of emphasis for the pixel signal obtained by the B pixel is set relatively larger than the degree of emphasis for the pixel signal obtained by the G pixel. Specifically, B/R and B/G are set to be 1 or more.

By the way, in a general Bayer array color filter, blocks of 2×2 pixels of R, G, G, and B are arranged in a grid pattern. That is, the resolution is higher when G pixels are used than R pixels or B pixels. When such a color filter is used, it is preferable to emphasize the G pixel regardless of the aberration characteristics if the diameter of the blur is two pixels or less.

In the above description, the RGB ratio is calculated in advance based on the aberration information of the lens and the spectral characteristics of the image sensor. However, the present invention is not limited to this method, and the RGB ratio may be determined adaptively based on the captured image. For example, three images each consisting of only R pixels, only G pixels, and only B pixels are generated (demosaic processing), and the contrast values of each are calculated. Since the contrast value corresponds to the magnitude of blur, blur can be suppressed by directly using the ratio of the contrast values of the three images as the RGB ratio for generating the Y signal. When performing this processing, there is no need to store the RGB ratio in advance, which is useful, for example, when using an imaging device with interchangeable lenses.

As described above, according to the third embodiment, by adjusting the RGB ratio when generating a grayscale image that is a luminance image, it is possible to suppress blur in a captured image in night mode.

(Other examples)
The present invention provides a system or device with a program that implements one or more of the functions of the embodiments described above via a network or a storage medium, and one or more processors in the computer of the system or device reads and executes the program. This can also be achieved by processing. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

The invention is not limited to the embodiments described above, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the following claims are hereby appended to disclose the scope of the invention.

101 Imaging optical system; 102 Infrared cut filter; 103 Imaging device; 104 Image processing section; 105 Optical system control section; 106 Infrared control section; 107 System controller

Claims (10)

An imaging device,
an imaging optical system configured to be able to image light in the visible light region and infrared light region;
adjustment means for adjusting the focus position of the imaging optical system;
insertion/extraction means for inserting/extracting an infrared cut filter into/from the optical path of the imaging optical system;
an image processing means for converting optical images in the visible light region and infrared light region formed on the image sensor by the imaging optical system into image signals;
determining means for determining the presence or absence of blur in the image indicated by the image signal;
a control means for executing a predetermined process for suppressing blur in an image indicated by the image signal;
has
The image sensor is a color image sensor,
The imaging device has a first mode in which the infrared cut filter is inserted into the optical path of the imaging optical system and a color image signal is output from the image processing means, and a first mode in which the infrared cut filter is inserted in the optical path of the imaging optical system. a second mode in which the infrared cut filter is removed and outputs a gray scale image signal from the image processing means; and a third mode in which the infrared cut filter is inserted in the optical path of the imaging optical system and a gray scale image signal is output from the image processing means. It is configured to be able to switch between modes.
The determining means determines the presence or absence of blur based on the image signal obtained after adjusting the focus position by the adjusting means,
When the determination means determines that there is blur , the control means performs the predetermined process such that the average brightness value of the image indicated by the image signal output from the image processing means is set to a first brightness threshold value. or above and below the second brightness threshold, the imaging device is changed to the third mode, and if the average brightness value of the image exceeds the second brightness threshold, the imaging device to the first mode, and if the average brightness value of the image is less than the first brightness threshold, change the imaging device to the second mode.
An imaging device characterized by: The adjustment means adjusts the focus position so that the contrast value in the image indicated by the image signal obtained by the image processing means is maximized,
The determining means determines that there is no blur if the contrast value in the image indicated by the image signal obtained after the adjustment of the focus position by the adjusting means is greater than a predetermined threshold; The imaging device according to claim 1, wherein the imaging device determines that there is blur. The adjustment means adjusts the focus position so that the contrast value in the image indicated by the image signal obtained by the image processing means is maximized,
The determining means determines that there is blur when the contrast value in the image indicated by the image signal obtained after the adjustment of the focus position by the adjusting means is greater than or equal to a first threshold value and less than or equal to a second threshold value. The imaging apparatus according to claim 1, wherein the imaging apparatus determines that there is no blur when the value is less than the first threshold value or greater than the second threshold value. 4. The determining means further determines the presence or absence of blur based on a contrast value at each focus position obtained during adjustment of the focus position by the adjusting means. imaging device. The image sensor is an RGB color image sensor,
The image processing means is configured to be able to output a grayscale image that is a luminance image obtained by combining pixel signals obtained from R pixels, G pixels, and B pixels included in the image sensor,
The control means controls the image processing means to generate a luminance image by synthesizing at a first RGB ratio when the determination means determines that there is no blur, and the determination means determines that there is blur. controlling the image processing means to generate a luminance image by synthesizing at a second RGB ratio when
Compared to the first RGB ratio, the second RGB ratio is set such that the degree of emphasis for a pixel signal obtained by a B pixel is relatively larger than the degree of emphasis for a pixel signal obtained by a G pixel. The imaging device according to any one of claims 1 to 4, characterized in that: 6. The control means determines the second RGB ratio based on a ratio of contrast values of an image made up of only R pixels, an image made only of G pixels, and an image made up of only B pixels. imaging device. an imaging optical system configured to be able to image light in the visible light region and infrared light region;
illumination means for emitting infrared light in the photographing direction;
adjustment means for adjusting the focus position of the imaging optical system;
an image processing means for converting optical images in the visible light region and infrared light region formed on the image sensor by the imaging optical system into image signals;
determining means for determining the presence or absence of blur in the image indicated by the image signal;
a control means for executing a predetermined process for suppressing blur in an image indicated by the image signal;
has
The determining means determines the presence or absence of blur based on the image signal obtained after adjusting the focus position by the adjusting means,
When the determination means determines that there is blur , the control means performs the predetermined process such that one of the visible light region and the infrared light region is dominant in the subject existing in the photographing direction. adjusting the output of infrared light by the illumination means so that
An imaging device characterized by: Each time the output of the infrared light by the illumination means is adjusted, the adjustment means adjusts the focus position, and the determination means determines whether or not there is blur in the image indicated by the image signal. 7. The imaging device according to 7 . A method for controlling an imaging device comprising an imaging optical system configured to form images of light in a visible light region and an infrared region, and an insertion/extraction means for inserting and removing an infrared cut filter into and from an optical path of the imaging optical system. hand,
an adjustment step of adjusting a focus position by the imaging optical system;
an image processing step of converting optical images in the visible light region and infrared light region formed on the image sensor by the imaging optical system into image signals;
a determination step of determining the presence or absence of blur in the image indicated by the image signal;
a control step of executing a predetermined process for suppressing blur in an image indicated by the image signal;
including;
The image sensor is a color image sensor,
The imaging device has a first mode in which an infrared cut filter is inserted into the optical path of the imaging optical system and outputs a color image signal in the image processing step, and a first mode in which the infrared cut filter is removed from the optical path of the imaging optical system. and a second mode in which a gray scale image signal is output in the image processing step, and a third mode in which the infrared cut filter is inserted in the optical path of the imaging optical system and a gray scale image signal is output in the image processing step. It is configured to be able to switch between and.
In the determination step, the presence or absence of blur is determined based on the image signal obtained after adjusting the focus position in the adjustment step,
In the control step, when it is determined that there is blur in the determination step, as the predetermined process, the average brightness value of the image indicated by the image signal output in the image processing step is set to a first brightness threshold. or above and below the second brightness threshold, the imaging device is changed to the third mode, and if the average brightness value of the image exceeds the second brightness threshold, the imaging device to the first mode, and if the average brightness value of the image is less than the first brightness threshold, change the imaging device to the second mode.
A control method characterized by: A method for controlling an imaging device including an imaging optical system configured to form an image of light in a visible light region and an infrared region , and an illumination means for irradiating infrared light in a photographing direction , the method comprising:
an adjustment step of adjusting a focus position by the imaging optical system;
an image processing step of converting optical images in the visible light region and infrared light region formed on the image sensor by the imaging optical system into image signals;
a determination step of determining the presence or absence of blur in the image indicated by the image signal;
a control step of executing a predetermined process for suppressing blur in an image indicated by the image signal;
including;
In the determination step, the presence or absence of blur is determined based on the image signal obtained after adjusting the focus position in the adjustment step,
In the control step, when it is determined that there is blur in the determination step, the predetermined process is such that one of the visible light region and the infrared light region becomes dominant in the subject existing in the photographing direction. adjusting the output of infrared light by the illumination means so that
A control method characterized by:

Images