JP6409472B2 - Imaging device provided with image display device - Google Patents

Description

  The present invention relates to an imaging device that captures still images and moving images, and particularly includes an image display device capable of displaying an image for confirming an imaging screen at the time of shooting, a so-called live view image (also referred to as a through image). The present invention relates to an imaging device.

  An imaging device such as a digital camera or a video camera is provided with an image display device capable of displaying a live view image in order to confirm an image captured at the time of shooting. Such an image display device is also referred to as a monitor device, and is hereinafter referred to as a monitor device. In recent years, an increase in the size of a monitor device has been achieved in this type of imaging device, which is particularly preferable in checking the focus state of a subject image using a live view image. However, it cannot be denied that the power consumption increases with the increase in the size of the monitor device, and the number of images and the imaging time in an imaging device using a battery as a power source are limited.

  In order to suppress such an increase in power consumption in the monitor device, a technology for lowering the brightness of the backlight by shifting to a low power consumption after a lapse of a certain time from the start of image display on the monitor device, or in the monitor device A technique for reducing the frame rate (number of frames / time) of image display, and a technique for thinning display pixels to display at a low resolution are conceivable. However, if the light intensity of the backlight is lowered, it is difficult to check the image outdoors, and if the frame rate is lowered, the followability to moving objects is deteriorated. Such a problem does not occur when the pixels are thinned out to reduce the resolution, but the image quality of the live view image is lowered, and it is difficult to check the in-focus state of the subject at the time of shooting.

  Japanese Patent Application Laid-Open No. 2005-228867 discloses a configuration in which display is performed on an image display device by switching between a first display mode for displaying at high resolution and a second display mode for displaying at low resolution. A technique for suppressing power consumption in image display in the second display mode has been proposed. That is, the technique of Patent Document 1 is based on the type of power source whether the power source is an AC power source or a battery, the remaining battery level, the change in ambient temperature, and the bit rate value of a recorded image or a reproduced image. And the second display mode. Also, the first and second display modes are switched based on the difference between live image display and playback image display, the difference between a still image and a moving image, the motion component and frequency characteristics of the display image. Furthermore, the first and second display modes are switched by a switch operation by the photographer.

JP 2009-118159 A

  The technique of Patent Document 1 suppresses power consumption by switching the display mode to the low-resolution second display mode when a predetermined condition is satisfied. When this happens, the monitor device is automatically switched to a low resolution image. For this reason, when shooting while viewing the live view image of the monitor device, it may be switched to a low-resolution image, it becomes impossible to check the focus state of the subject, a suitable shooting obstacle become.

  An object of the present invention is to provide an imaging device including an image display device that secures a high-resolution display image at the time of shooting while reducing power consumption when the necessity for confirmation of the display image is low. .

The present invention relates to an image display apparatus that displays at least a live view image based on an image signal output from an image sensor and a lens that is detachably mounted, and is based on lens information obtained from the lens. first state and an imaging and thereby determining the second state by the object image, the first state or the high-resolution or low-resolution the image by a second state in which the state determination means determines the image capturing device And a resolution switching means for switching display.

Subject as a preferred form of the present invention, the imaging device includes a camera body, and this to the camera body wearing detachably mounted lenses, camera body, which is imaged by the image display device and the lens An image sensor that captures an image is provided, and an image captured by the image sensor is displayed on an image display device.

  In addition, as a first state that is preferably displayed at a high resolution, the state determination unit has a lens resolving power when a manual focus operation is performed or when AF focusing (automatic focusing) is performed. When the value is equal to or greater than a certain value, it is determined that the digital filter is in an invalid state. Further, as a second state that is preferable to display at a high resolution, it is determined that the display image gain is in any state when the display image gain is equal to or less than a certain value and the spatial frequency of the subject is equal to or greater than a certain value. In this case, it is preferable that the state determination unit waits for a predetermined time between the determination of the first state and the determination of the second state.

  According to the present invention, when the first state or the second state in which it is necessary to check an image such as a live view image at a high resolution on the image display device is determined, the image is displayed at a high resolution. Therefore, the image is displayed with high quality, the in-focus state of the subject as the photographing target can be confirmed with high resolution, and suitable photographing can be performed. On the other hand, when it is less necessary to display an image at a high resolution, the image is displayed at a low resolution, so that power consumption in the imaging apparatus is reduced.

1 is an external perspective view of an embodiment in which the present invention is applied to a digital single lens reflex camera. The block block diagram which shows the internal structure of the camera of embodiment. The schematic diagram explaining the high resolution display mode and the low resolution display mode. The flowchart explaining switching of a display mode. The flowchart which shows only a part of flow of a modification.

  Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external perspective view of an embodiment in which the image display device of the present invention is applied to an interchangeable lens type digital single lens reflex camera. A detachable lens (interchangeable lens) L is attached to the front surface of the camera body B, and a subject image formed by the lens L is imaged by the imaging element 2 provided in the camera body B. In FIG. 1, the image sensor 2 is indicated by a broken line. Also, on the rear surface of the camera body B, a monitor device 1 comprising an LCD (liquid crystal display device) having a configuration in which a large number of display pixels are arranged in a matrix is disposed. The subject image captured by the image sensor 2 is subjected to predetermined electrical image processing and displayed on the monitor device 1 as a live view image. The photographer takes a picture by performing a release operation while viewing the live view image displayed on the monitor device.

  FIG. 2 is a block diagram showing the internal configuration of the camera, and shows only the configuration related to the present invention. The lens L includes a lens group 3 and a lens mechanism 4 for driving the lens group 3, and the lens mechanism 4 is driven by manually operating a focus ring FR provided on the outer periphery of the lens L, or FIG. When the lens mechanism 4 is driven by a motor that does not appear in the above, the position of the lens group 3 in the optical axis direction is set and focusing (focusing) is performed. That is, with this lens L, it is possible to perform MF (manual focus) in which the photographer manually operates the focus ring FR and AF (auto focus) in which the motor performs focusing.

  The lens L is provided with a lens communication unit 5 for transmitting and receiving lens information to and from the camera body B. This lens information is two pieces of information here, that the lens L is AF controllable and the resolving power of the lens L. These lens information are stored in a lens memory (not shown) built in the lens communication unit 5. Is remembered. Further, the lens information includes driving information of the focus ring FR, that is, information on whether or not focusing is driven manually. The lens communication unit 5 reads out the former two pieces of lens information from the lens memory, detects the latter lens information in the lens mechanism 5, and then directs the lens information to the camera body B. Send.

  The camera body B includes an image sensor module 20 configured to include the image sensor 2. The camera body B captures a subject image formed by the lens L, and A / D converts the image signal to obtain a desired image. Output as an image signal. This image signal is input to the image processing block 10 where required image processing is performed. An image obtained by this image processing, that is, a live view image is displayed on the monitor device 1.

  The image processing block 10 includes an image capturing unit 11, an output image memory 12, an image processing unit 13, and an image display control unit 14. The image capturing unit 11 captures an image signal output from the image sensor module 20 and outputs it as Bayer data. The output image memory 12 stores the Bayer data output from the image capturing unit 11. The image processing unit 13 converts the Bayer data YUV data stored in the output image memory 12, performs a scaling process, and outputs the image signal. The image display control unit 14 processes the image signal output from the image processing unit 13 and displays it as an image suitable for the monitor device 1.

  The image capturing unit 11 can capture the image signal output from the image sensor module 20 by thinning out the image signal. As will be described later, when this thinning is not performed, the live view image can be displayed on the monitor device 1 in the high resolution display mode, and when the thinning is performed, the live view image is displayed on the monitor device 1 in the low resolution display mode. It will be.

  The image processing unit 13 performs digital filter processing. That is, in the digital filter processing, noise included in the image is removed. When this digital filter is effective, the components of the fine image are removed together with the noise, so that it is difficult to identify the deterioration of the image quality.

  The image display control unit 14 performs display image gain adjustment. That is, the magnification correction is performed on the luminance value of the input image. For example, in the case of a dark image, since a bright image is displayed by increasing the gain value, it is difficult to identify deterioration in image quality. The image display control unit 14 can also perform so-called scaling processing, and adjusts the image to an appropriate size for display on the monitor device 1.

  On the other hand, the camera body B includes an overall control unit 15 and communicates with the lens communication unit 5 of the lens L to receive the lens information. In addition, it controls imaging in the imaging element module 20 and controls the image capturing unit 11, the image processing unit 13, and the image display control unit 14 of the image processing block 10. The overall control unit 15 is configured as state determination means in the present invention and as resolution switching means in the present invention.

  That is, the overall control unit 15 determines whether or not the lens L is a lens capable of AF control based on lens information from the lens communication unit 5 as a state determination unit according to the present invention. When it is determined that the lens L is a lens capable of AF control, it is further determined whether or not AF is in focus from the image captured by the image sensor module 20. Further, it is determined whether or not the focus ring FR of the lens L is rotated, that is, whether or not a manual focus operation is being performed.

  Further, the overall control unit 15 acquires the resolving power of the lens L based on the lens information from the lens communication unit 5, and the resolving power is equal to or greater than a predetermined value set in advance. Determine whether. This fixed value of the resolving power substantially matches the resolution when the live view image is displayed in the high resolution display mode on the monitor device 1. Further, it is determined whether the digital filter provided in the image processing unit 13 is in an invalid state or in a valid state. These determinations are determinations based on camera settings at the time of shooting, and are the determinations of the first state in the present invention.

  Further, the overall control unit 15 determines whether the display image gain in the image display control unit 14 is equal to or less than a predetermined value set in advance. Further, it is determined from the captured image whether the spatial frequency of the subject, that is, the fineness of the light and dark pattern existing in the subject is equal to or greater than a predetermined value. This constant value of the spatial frequency substantially matches the frequency of the bright and dark pattern that can be resolved when the live view image is displayed in the high resolution display mode on the monitor device 1. In particular, when the spatial frequency of the subject is equal to or higher than a certain value, degradation in image quality can be identified when displayed on the monitor device 1, but when the spatial frequency of the subject is less than a certain value, it is difficult to identify degradation in image quality. These determinations are determinations based on the captured image, and are determinations of the second state in the present invention.

  Further, in this embodiment, the overall control unit 15 determines whether the image display of the monitor device 1 is a live view image display or other display, for example, an image reproduction display. Judgment from the state of. That is, it is determined whether or not the live view image display is continued in the monitor device 1.

  On the other hand, the overall control unit sets and changes the image thinning rate in the image sensor module 20 for the image capturing unit 11 as the resolution switching unit according to the present invention. This image thinning will be described later. Further, the setting and change of the scaling process are executed for the image processing unit 13. Further, the image display control unit 14 sets and changes the image display size.

  The resolution of the display image in the camera having the above configuration will be described with reference to FIG. Here, as an example, the number of pixels of the picked-up image A1 picked up by the image pickup device 2 is 4000 × 3000 in the vertical and horizontal directions, and this is displayed on the monitor device 1 with a display pixel number of 720 × 480. When capturing a still image, the overall control unit 15 receives the release operation and sets the image capturing unit 11 and the image sensor module 20 to the all-pixel mode. Therefore, an image having a pixel number of 4000 × 3000 is captured by the image capturing unit 11 and stored in the output image memory 12 as a storage image A2.

  On the other hand, when a live view image is displayed on the monitor device 1 when the release operation is not performed, the image processing block 10 performs image processing on the display image so as to be 30 to 60 frames per second. Is required. For this reason, the pixels of the image picked up by the image pickup device 2 are thinned out and scaled for display on the monitor device 1.

  By thinning out images, the number of A / D conversion processes inside the image sensor module 20 is reduced to save power, and the number of pixel processes when the thinned image is scaled in the image processing block 10 is reduced. As a result, power consumption is reduced. However, since the number of image information captured by thinning is reduced, the image quality of the image displayed on the monitor device 1 is deteriorated and the resolution is lowered. That is, the power consumption and the image quality (resolution) associated with the thinning rate are in a trade-off relationship.

  Therefore, when the thinning rate is increased to reduce the power consumption, the image quality of the display image of the monitor device 1 is deteriorated, and the image is displayed in the low resolution display mode. This low resolution display mode can be referred to as a “low power consumption display mode”. On the contrary, if the thinning rate is lowered to avoid the deterioration of the image quality of the display image of the monitor device 1 and the image display is performed in the high resolution display mode, the power consumption increases. This high resolution display mode can also be referred to as a “high power consumption display mode”.

  Here, as shown in FIG. 3, in the high-resolution display mode, the number of pixels of the thinned image A3 is set to 1332 × 1000, and the image processing unit 13 scales it to a display image A4 of 720 × 480. As a result, the live view image displayed on the monitor device 1 is displayed at a high resolution. On the other hand, in the low-resolution display mode, the number of pixels of the thinned image A5 is set to 1332 × 332, and the image processing unit 13 scales it to a display image A6 of 720 × 480. As a result, the live view image displayed on the monitor device 1 is displayed at a low resolution. Therefore, in the low resolution display mode, the resolution of the display image is lowered as compared with the high resolution display mode, but the effect of reducing the power consumption is high.

  A flow of live view display on the monitor device 1 based on the above configuration will be described with reference to FIG. When the camera is turned on or the lens is replaced (S11), the overall control unit 15 controls the image sensor module 20 and the image processing block 10, and the live view display on the monitor device 1 is a high resolution display. The mode is set (S12). At this time, the thinning rate in the image sensor module 20 is small, and the live view image displayed on the monitor device 1 is displayed with high resolution, so that the photographer can visually recognize the subject with high resolution.

  Next, the overall control unit 15 reads lens information of the lens L that is currently used from the lens communication unit 5, and determines whether or not the lens L is a lens that can be AF controlled (S13). When it is determined that the lens is not capable of AF control, since the photographer is highly likely to perform a manual focus operation while checking the live view image, the overall control unit 15 maintains the high resolution display mode.

  On the other hand, when it is determined that the lens is AF-controllable, it is subsequently determined whether a manual focus operation by the photographer has been performed and whether or not the AF is in focus (S14). When the manual focus operation is not performed or when the AF is not in focus, the overall control unit 15 switches to the low resolution display mode because the photographer is less likely to perform the release operation while checking the live view image. (S15). Thereby, power consumption is reduced. In this low-resolution display mode, when a manual focus operation is subsequently performed, or when AF is in focus, the photographer may check the live view image and perform a release operation. Therefore, the overall control unit switches to the high resolution display mode (S16).

  Subsequently, the overall control unit 15 determines whether or not the resolving power of the lens L is greater than or equal to a certain value from the lens information from the lens communication unit 5 while maintaining the high resolution display mode (S17). When the resolving power of the lens L is a certain value or more, the deterioration of the live view image is conspicuous when the low resolution display mode is set. When the resolving power of the lens is less than a certain value, even in the high resolution display mode, the live view image cannot be displayed at a high resolution, and power consumption is wasted, so the mode is switched to the low resolution display mode (S18).

  Next, the overall control unit 15 determines whether or not the digital filter processing is performed in the image processing unit 13 of the image processing block 10, that is, whether or not the digital filter is valid (S19). When the digital filter is disabled, the high resolution display mode is maintained because the deterioration of the live view image is noticeable when the low resolution display mode is set. When the digital filter is effective, the fine image components are removed together with the image noise, so that it is difficult to identify the deterioration of the image quality. Therefore, even if the live view image is displayed at a high resolution, the live view image cannot be displayed at a high resolution, so the mode is switched to the low resolution display mode (S18).

  As described above, when switching to the low resolution display mode is performed based on the determination result of the resolving power of the lens L and the determination of the validity / invalidity of the digital filter, it is determined whether or not the live view image display of the camera is released (S20). When the live view image display is canceled, the flow ends. When the live view display is continued, the low resolution display mode is maintained, and the process returns to step S17.

  Next, the overall control unit 15 determines whether or not the display image gain in the image display control unit 14 of the image processing block 10 is equal to or less than a certain value (S21). When the display image gain is higher than a certain value, it is difficult to identify the deterioration of the image quality even if the live view image is displayed at a low resolution, so the mode is switched to the low resolution display mode (S22). When the display image gain is equal to or smaller than a certain value, the process proceeds to the next step S23.

  In step S23, the overall control unit 15 determines whether or not the spatial frequency of the subject detected by the image sensor module 20 is greater than or equal to a certain value. When the spatial frequency is less than a certain value, it is difficult to identify the collapse of the light / dark pattern even if the live view image is displayed at a low resolution, so the mode is switched to the low resolution display mode (S24). When the spatial frequency is greater than or equal to a certain value, the low-resolution display mode is switched to the high-resolution display mode because the bright / dark pattern of the subject in the live view image may be crushed (S25).

  When the above-described flow is completed and the high-resolution display mode is maintained, it is determined whether the live view image display of the camera has been canceled (S26). When the live view image display is canceled, the flow ends. When the live view image display is continued, the process returns to step S21.

  As described above, when it is necessary for the photographer to check the live view image at a high resolution, the live view image is displayed in the high resolution display mode on the monitor device 1, so that the object to be photographed is matched. The in-focus state can be confirmed with high resolution, and suitable photographing can be performed. On the other hand, when the necessity for displaying the live view image at high resolution is low, the monitor device 1 switches to the low resolution display mode for displaying the live view image at low resolution. In this low-resolution display mode, as described above, by increasing the thinning rate in the image sensor, the number of A / D conversion processes inside the image sensor module 20 is reduced, and power saving is achieved. This reduces the number of pixel processes when image processing such as scaling is performed on the image in the image processing block 10, thereby reducing power consumption.

  Here, FIG. 5 shows a part of a modification of the flow. In FIG. 5, the same steps as those in FIG. 4 are denoted by the same reference numerals. In this modified example, as shown in FIG. 4, the monitoring device 1 is between the determination of the first state consisting of steps S13, S14, S17 and S19 and the determination of the second state consisting of steps S21 and S23. The resolution of the live view image displayed on the screen is appropriately controlled to further reduce the power consumption.

  That is, as shown in FIG. 5, step S30 for waiting is inserted between step S19 and step S21. In step S30, when the mode is switched to the high resolution display mode, a process for holding the high resolution display mode for a predetermined waiting time, for example, about 10 seconds is performed. In other words, this standby time is usually a time for the photographer to perform a release operation and perform photographing. When a release operation is performed during the standby in step S30, a prescribed release flow is executed, but the description thereof is omitted here.

  On the other hand, when the release operation is not performed during the standby, the orientation of the camera is usually changed, or the subject is changed by zooming or the like, and accordingly, the possibility that the live view image is also changed is increased. Therefore, steps S21 and S23 are executed after waiting time has elapsed. That is, a change in display image gain is determined, and then a change in the spatial frequency of the subject is determined. As a result, the high resolution display mode is maintained or the mode is switched to the low resolution display mode. In step S30, it is preferable to periodically perform the above-described waiting time every time.

  According to this modification, when the mode is switched to the low resolution display mode in steps S22 and S24, the state of the low resolution display mode is maintained during the standby time in step S30. Electric power can be reduced. In particular, the waiting time is about 10 seconds as described above, and the time ratio in the entire flow is large. Therefore, the effect of reducing the power consumption becomes remarkable.

  In the present embodiment, the first state and the second state are determined as a state in which the image display device of the imaging device according to the present invention determines that it is preferable to display an image with high resolution, As described above, the first state is a determination based on camera settings at the time of shooting, and the second state is a determination based on image processing on a captured image. Accordingly, the first state in the present invention can be applied to any state that is closely related to the state in which the photographer confirms the monitor device in the camera. In addition, any image processing that affects the resolution of a captured image can be applied as the second state in the present invention. For example, the first state is not limited to the manual focus, and a zooming operation, an exposure correction operation, and the like performed by the photographer at the time of shooting may be determined, and the display mode is switched based on this determination. It may be.

  In the above embodiment, the image display on the monitor device 1 has been shown as an alternative example of low resolution display and high resolution display. However, in the present invention, the low resolution display is divided into two or more levels of resolution display. At the same time, the state determination in the overall control unit 15 may be determined more finely and switched to one of two or more levels of low resolution display according to the determination result. For example, the first low resolution display, the second low resolution display, and the third low resolution display are divided from the higher resolution side, and these are selected and displayed. Thereby, the power consumption of the third resolution display can be reduced as compared with the first low resolution display by switching from the first to the third low resolution display while ensuring the image resolution required by the monitor device 1. Is possible.

  In the above embodiment, the present invention is applied to an interchangeable lens type digital single lens reflex camera. However, the present invention can also be applied to a camera including a monitor device in which a lens and a camera body are integrated, a so-called compact digital camera. Alternatively, it can be applied to a video camera. In the case of these cameras, the lens information may be stored in a memory in the camera body, and the overall control unit may be read from this memory as necessary. Further, in such a camera, the AF-capable lens determination step S13 and the lens resolving power determination step S17 in the flow shown in FIG. 4 may be omitted.

  The image display device of the present invention is not limited to a monitor device disposed on the back of the body of a camera or a video camera, but is applied as an EVF (electronic viewfinder) that can be viewed through an eyepiece system. It is also possible to do. Furthermore, the present invention can be applied as an independent image display device connected to the camera body by wire or wirelessly. Further, it can be applied as a camera function of a mobile terminal such as a smartphone.

  The present invention is effective when employed in an imaging apparatus including a digital image display device that displays an image as a pixel.

B Camera body L Lens 1 Monitor device (image display device)
2 Image sensor 3 Lens group 4 Lens mechanism 5 Lens communication unit 10 Image processing block 11 Image capture unit 12 Output image memory 13 Image processing unit 14 Image display control unit 15 Overall control unit (state determination unit, resolution switching unit)
20 Image sensor module

Claims (9)

An image display apparatus that displays at least a live view image based on an image signal output from an image sensor, and a lens that is detachably mounted. The image pickup apparatus uses lens information obtained from the lens. a first state, the display thereby determining the second state by the taken subject image, the image by the first state or the second state in which the state determination means determines a high resolution or low resolution An imaging apparatus comprising resolution switching means for performing switching. The imaging apparatus according to claim 1, wherein the lens information is a resolution of the lens . The imaging apparatus according to claim 1, wherein the state determination unit determines the first state including setting of a digital filter of the imaging apparatus. The imaging device, the display of the image at low resolution in the image display apparatus, in any one of claims 1 to 3, characterized in that the display power consumption small compared to the display of the image at high resolution The imaging device described. The imaging device includes a camera body, a camera lens that is worn detachably mounted to the body, said camera body captures and the image display device, an image of an object, which is imaged by the lens an imaging device, the imaging device according to any one of 4 to claims 1 and displaying an image taken by the image pickup element to the image display device. The state determination means is a second state that is preferably displayed at a high resolution, and is in any state when the display image gain is less than a certain value or when the spatial frequency of the subject is more than a certain value. The imaging apparatus according to claim 1 , wherein the imaging apparatus is determined.   The imaging apparatus according to claim 6, wherein the state determination unit waits for a predetermined time between the determination of the first state and the determination of the second state.   8. The image pickup apparatus according to claim 1, further comprising an image pickup device for picking up the image, wherein the resolution switching unit thins out pixels picked up by the image pickup device and switches to a low resolution. The imaging device according to any one of the above.   The imaging apparatus according to claim 8, wherein the image display apparatus is a liquid crystal display apparatus having a large number of display pixels.

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