Imaging apparatus, imaging system, control method, program, and storage medium

Abstract

To provide an imaging apparatus that can execute appropriate exposure control.SOLUTION: An imaging apparatus has an imaging unit that picks up a photographed image, and a control unit that controls the exposure of the photographed image. When the control unit does not acquire first information indicating that the photographed image is distributed next, it controls the exposure of the photographed image in a first mode. When the control unit acquires the first information, it controls the exposure of the photographed image in a second mode for controlling at least one of parameters used in the first mode with a fixed value.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an imaging apparatus, an imaging system, a control method, a program, and a storage medium. [Background technology]

[0002] In recent years, imaging devices that automatically control various shooting parameters are used in systems that output (distribute) one image selected from images captured by multiple imaging devices. A program selection signal indicating that the output image is being distributed and a preview selection signal indicating that the output image will be distributed next are sent to the imaging device as signals indicating the selection state of the image being output (output image). Patent Document 1 discloses a configuration that limits the upper limit of the drive speed of a pan-tilt mechanism when a program selection signal and a preview selection signal are received. Patent Document 2 discloses a configuration that controls the execution of image blur correction when a program selection signal and a preview selection signal are received. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-34824 A [Patent Document 2] JP 2020-17796 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the configuration of Patent Document 1 cannot handle the case where a flicker phenomenon occurs due to, for example, a change in the shutter in exposure control. Also, the configuration of Patent Document 2 cannot follow the exposure when the brightness of the subject changes, so it is necessary to change the control of the execution of image blur correction according to each exposure parameter.

[0005] An object of the present invention is to provide an imaging apparatus capable of performing appropriate exposure control. [Means for solving the problem]

[0006] An imaging device according to one aspect of the present invention has an imaging unit that captures a captured image and a control unit that controls the exposure of the captured image, and the control unit controls the exposure of the captured image in a first mode when first information indicating that the captured image will be distributed next has not been acquired, and when the first information has been acquired, controls the exposure of the captured image in a second mode in which at least one of the parameters used in the first mode is controlled to a fixed value. Effect of the Invention

[0007] According to the present invention, it is possible to provide an imaging apparatus capable of performing appropriate exposure control. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing an example of a configuration diagram of an imaging system including an imaging device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing the internal configuration of the imaging apparatus. [Diagram 3] 13 is a flowchart showing an exposure control process. [Figure 4] FIG. 11 is a diagram showing an example of a control sequence of exposure parameters. [Diagram 5] 3A and 3B are diagrams illustrating various states of a switcher and an imaging device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals are used to refer to the same components, and duplicated descriptions will be omitted.

[0010] 1 is a diagram showing an example of the configuration of an imaging system including an imaging device according to an embodiment of the present invention. The imaging system includes imaging devices 100 and 110, a switcher (selection device) 120, and a monitor .

[0011] The imaging device 100 includes a video output terminal 101 and a control communication terminal 102. The video output terminal 101 outputs a video captured by the imaging device 100. A terminal conforming to standards such as SDI or HDMI (registered trademark) may be used as the video output terminal 101, or an Ethernet (registered trademark) terminal may be used by packetizing the video using IP (Internet Protocol). The control communication terminal 102 is used when communicating with a device such as an external control device (the switcher 120 in this embodiment). For example, a terminal such as RS-232C or Ethernet (registered trademark) may be used as the control communication terminal 102.

[0012] Like the imaging device 100, the imaging device 110 includes a video output terminal and a control communication terminal.

[0013] The switcher 120 includes a video input terminal 121, a control signal terminal 122, a program selection button 123, a preview selection button 124, a monitor video output terminal 125, a video output terminal 126, and a video switching lever 127. The video input terminal 121 includes a plurality of terminals each used to acquire a video (output video) output from a corresponding one of the plurality of imaging devices. The control signal terminal 122 includes a plurality of terminals each used to transmit a control signal to a corresponding one of the plurality of imaging devices. The control signal includes a selection signal by the program selection button 123 and the preview selection button 124, etc. The program selection button 123 is used to select a program video to be output (distributed) from the imaging system among the videos input to the plurality of video input terminals. At this time, a program selection signal (second information) indicating that the output video is being distributed (selected as a program video) is transmitted to the control communication terminal connected to the imaging device that outputs the program video. The preview selection button 124 is used to select a preview video to be output (distributed) next from the imaging system among the videos input to the plurality of video input terminals. At this time, a preview selection signal (first information) indicating that the output video will be distributed next (selected as the preview video) is transmitted to the control communication terminal of the imaging device that outputs the preview video. The monitor video output terminal 125 outputs a video in which the video input to the video input terminal 121, the program video, and the preview video are arranged to the monitor 130. The video output terminal 126 outputs the program video to a live distribution device, a program recording device, etc. The video switching lever 127 switches the preview video to the program video.

[0014] In this embodiment, the switcher 120 is operated by a user, but may be configured to perform automatic control.

[0015] 2 is a block diagram showing the internal configuration of the imaging device 100. Note that the imaging device 110 also has the same internal configuration as the imaging device 100.

[0016] The imaging device 100 includes an imaging lens 201, an aperture 202, an ND filter 203, an imaging unit 204, an A / D converter 205, an image processing unit 206, a system control unit (control unit) 207, a video output unit 208, a communication unit 209, and a storage unit 210. The imaging lens 201 is a lens group including a zoom lens, a focus lens, and a shift lens, and forms a subject image. The aperture 202 adjusts the amount of light. The ND filter 203 is used when reducing light. The imaging unit 204 includes an imaging element including a CCD or CMOS element that converts an optical image into an electrical signal. The imaging unit 204 also has functions such as controlling accumulation by an electronic shutter, changing analog gain, and changing readout speed. The A / D converter 205 converts an analog signal output from the imaging unit 204 into a digital signal. The image processing unit 206 performs resizing such as pixel complementation and reduction, detection of luminance information, color information, and characteristic objects, color conversion, gamma correction, and digital gain addition on the signal from the A / D converter 205. The image processing unit 206 also performs a predetermined calculation process using the captured image (image data) and sends the calculation result to the system control unit 207. The system control unit 207 performs exposure control, focus detection control, white balance control, and the like based on the calculation result sent from the image processing unit 206. This allows TTL-type AF (autofocus) processing, AE (automatic exposure) processing, AWB (auto white balance) processing, and the like to be performed. The video output unit 208 converts the video data generated by the system control unit 207 into a predetermined video format and outputs it to the switcher 120 via the video output terminal 101. The communication unit 209 communicates with devices such as an external control device (the switcher 120 in this embodiment). Specifically, the communication unit 209 transmits communication data received at the control communication terminal 102 to the system control unit 207, and transmits communication data instructed by the system control unit 207 via the control communication terminal 102. The storage unit 210 is an electrically erasable and recordable memory, such as an EEPROM. The storage unit 210 stores constants and programs for the operation of the system control unit 207. The program referred to here is a program for executing a flowchart described later.

[0017] The system control unit 207 controls the entire image capturing apparatus 100. The system control unit 207 also executes programs stored in a storage unit 210 to perform various processes of this embodiment, which will be described later.

[0018] FIG. 3 is a flowchart showing the exposure control process performed by the system control unit 207.

[0019] In step S301, the system control unit 207 acquires, from the communication unit 209, a signal transmitted from the control signal terminal 122 to the imaging device 100.

[0020] In step S302, the system control unit 207 determines whether the signal acquired in step S301 is a program selection signal. If the system control unit 207 determines that a program selection signal has been acquired, it executes the process of step S313, and if it determines that a program selection signal has not been acquired, it executes the process of step S303.

[0021] In step S303, the system control unit 207 determines whether the signal acquired in step S301 is a preview selection signal. If the system control unit 207 determines that a preview selection signal has been acquired, it executes the process of step S307, and if it determines that a preview selection signal has not been acquired, it executes the process of step S304.

[0022] The processes in steps S304 to S306 are exposure control (exposure control in the first mode) in a state (unselected state) in which the system control unit 207 has not acquired either the program selection signal or the preview selection signal. In the unselected state, the monitor video output terminal 125 outputs the video of the imaging device 100, and in order to make it easier for a user who switches the shooting angle of view or the subject to recognize, priority is given to outputting a video with appropriate brightness rather than the quality or image quality of the video.

[0023] In step S304, the system control unit 207 performs exposure control with exposure parameters including the ND filter 203 as shown in FIG. 4(a). The sensitivity and shutter speed are suitable for changing the exposure at a high speed, rather than the ND filter 203 and the aperture 202, which take a long time to drive. Therefore, in the exposure control, it is considered that the sensitivity and shutter speed are controlled with priority, and the aperture 202 and the ND filter 203 are controlled after reaching the upper or lower limit. Note that, in this embodiment, the exposure control is performed in the above-mentioned control order, but the control order is not limited to this. In addition, other exposure parameters may be controlled with intermediate values. The intermediate value may be, for example, a shutter speed value that does not cause a flicker phenomenon, or a shutter speed value that intentionally causes a flicker phenomenon so that it is easy to detect by the system control unit 207. In addition, when the image capturing device 100 is in an unselected state, since the image of the image capturing device 100 is not output, there is no problem even if the movement of the ND filter 203 is reflected in the image, so the ND filter 203 may be automatically changed according to the change in brightness.

[0024] In step S305, the system control unit 207 narrows the range in which exposure control is not performed (proper exposure range) based on the appropriate brightness information. The system control unit 207 determines whether the brightness of the captured image transmitted from the image processing unit 206 is within the appropriate exposure range. If the system control unit 207 determines that the brightness of the captured image is within the appropriate exposure range, it determines that there is no need to change the exposure. That is, by narrowing the appropriate exposure range in the unselected state, the frequency of exposure control due to changes in brightness increases, and a more appropriate brightness can be maintained.

[0025] In step S306, the system control unit 207 sets the exposure control speed to be faster. This makes it possible to reduce the time required for transition to an image with appropriate brightness. Note that the exposure control speed set in this step (the exposure control speed in the exposure control in the first mode) is set to be faster than the exposure control speed in the second mode described later.

[0026] The processes in steps S305 and S306 may or may not be executed.

[0027] The processes of steps S307 to S312 are exposure control (exposure control in the second mode) when the system control unit 207 has acquired a preview selection signal. The program selection signal is notified to the imaging device 100 when or after switching of the program video output by the video output terminal 126. Therefore, as shown in FIG. 5, a video output by the imaging device 100 as a preview video may be output from the video output terminal 126 as a part of the program video at the time of switching. In consideration of such a case, it is desirable for the imaging device 100 that has acquired the preview selection signal to set the preview video to a stable video so that it may be switched to the program video at any time. Specifically, exposure control is performed to control at least one of the exposure parameters used in the first mode to a fixed value (to limit the change in at least one).

[0028] In step S307, the system control unit 207 controls the ND filter 203 and the shutter speed to fixed values, as shown in Fig. 4(b). This makes it possible to limit the operation of the ND filter 203, which causes movement to be captured in the image, and the shutter, which causes a flicker phenomenon due to the frequency of the light source. In other words, the system control unit 207 performs exposure control using only the aperture 202 and the sensitivity.

[0029] The operation of the ND filter 203 is limited when the system control unit 207 has acquired a preview selection signal (preview selection state), but may operate when switching from an unselected state. That is, the fixed value may be a value set in the unselected state (a value at the time of receiving the preview selection signal; in other words, a parameter value determined by exposure control in the first mode executed immediately before receiving the preview selection signal), or may be a different value. By using the value set in the unselected state, the movement of the ND filter 203 does not affect the program video even if the video is selected as a program video immediately after switching to the preview selection state. On the other hand, since it is generally considered that there is a margin of time for the ND filter 203 to drive between switching to the preview selection state and selection as a program video, a value different from the value set in the unselected state may be used as the fixed value. When a different value is set as the fixed value, a value calculated from each exposure parameter in the unselected state may be set as the fixed value. For example, when the value of the aperture 202 in the immediately preceding unselected state is Av1, the shutter speed value is Tv1, the sensitivity value is Sv1, and the value of the ND filter 203 is Nv1, the brightness Bv1 is calculated by the following formula (1).

[0030] Bv1 = Av1 + Tv1 - Sv1 + Nv1 (1) Moreover, the upper limit Bv2max and the lower limit Bv2min of the brightness are calculated by the following formulas (2) and (3), respectively.

[0031] Bv2max=Av2max+Tv2-Sv2min+Nv2 (2) Bv2min=Av2min+Tv2-Sv2max+Nv2 (3) Here, Av2max and Av2min are the upper and lower limit values ​​of the aperture 202 in the preview selection state. Sv2max and Sv2min are the upper and lower limit values ​​of the sensitivity in the preview selection state. Tv2 is the shutter speed value in the preview selection state. Nv2 is the ND filter value in the preview selection state.

[0032] The value Nv2 can be set so that the brightness Bv1 is within the range between the upper limit Bv2max and the lower limit Bv2min, and the value ||Bv2max-Bv1|-|Bv1-Bv2min|| is the smallest. This allows the brightness to be brought closer to the center of the range of brightness that can be controlled in the preview selection state, based on the brightness in the previous unselected state.

[0033] In step S308, the system control unit 207 sets the appropriate exposure range to be wider than the range set in step S305. That is, by setting the appropriate exposure range wider in the preview selected state than in the unselected state, the frequency of exposure control due to changes in brightness can be reduced compared to the unselected state, and a stable image can be output.

[0034] In step S309, the system control unit 207 determines whether the current brightness is appropriate exposure. If the system control unit 207 determines that the current brightness is appropriate exposure, it executes the process of step S312, and if it determines that the current brightness is not appropriate exposure, it executes the process of step S310.

[0035] In step S310, the system control unit 207 determines whether a certain time has passed since acquiring the preview selection signal. If the system control unit 207 determines that the certain time has passed, it executes the process of step S312, and if it determines that the certain time has not passed, it executes the process of step S311.

[0036] In step S311, system control unit 207 sets the exposure control speed to be faster for a predetermined time. When processing this step, the exposure is not correct when the preview selection signal is acquired, that is, the state is not ready to switch to the program video at any time. Therefore, in this step, the exposure control speed is increased for a predetermined time, and the correct exposure is quickly reached. Normally, when switching the preview video to the program video, time is required for the user to operate program selection button 123 or video switching lever 127. Increasing the exposure control speed in the preview selection state reduces the quality of the video, but does not affect the program video as long as it is within the above-mentioned user operation time (predetermined time).

[0037] In step S312, the system control unit 207 sets the exposure control speed to be slower than in steps S306 and S311, thereby making it possible to output a stable image in which exposure changes are not noticeable.

[0038] It should be noted that each process from step S308 to step S312 may or may not be executed.

[0039] The process of step S313 is exposure control when the system control unit 207 receives a program selection signal. It is desirable for the imaging device 100 that has acquired the program selection signal to output an image with a certain exposure and image quality so as not to give a sense of discomfort to the user.

[0040] In step S313, the system control unit 207 fixes the exposure parameters, that is, the system control unit 207 does not perform exposure tracking even if the brightness changes depending on the subject.

[0041] In this embodiment, the control in step S313 fixes all the exposure parameters, but exposure control may be performed so that at least one of the exposure parameters used in the first mode is a fixed value, similar to the exposure control in the second mode. Also, exposure control in a third mode may be performed in which the exposure control speed is slower, the appropriate exposure range is wider, or the control order is different, compared to the exposure control in the second mode.

[0042] As described above, according to the configuration of this embodiment, the exposure control is changed in response to the signal acquired by the imaging device, making it possible to execute appropriate exposure control.

[0043] In this embodiment, an example in which the image capture device 100 performs AE control has been described, but even when a user manually operates the image capture device, the exposure control operation may be changed according to a signal acquired by the image capture device. This allows the user to change the exposure parameters without being aware of factors other than brightness, such as flicker phenomena.

[0044] In addition, in the present embodiment, the limitation of the operation of the ND filter and the shutter is taken as an example, but when an ND filter capable of continuously changing the density of liquid crystal or the like is used, the image obtained is less unnatural even if the parameter value of the ND filter is changed. Therefore, the operation of the ND filter does not need to be limited. Similarly, in an environment where no flicker occurs, the operation of the shutter does not need to be limited. In this case, even if none of the exposure parameters are fixed, a stable image can be output as a preview image by performing at least one of steps S308 and S312. Therefore, instead of setting the exposure control in the second mode to a mode in which at least one of the parameters is controlled with a fixed value, it may be set to a mode in which the appropriate exposure range is set wide, or a mode in which the exposure control speed is set slow.

[0045] In addition, although the present embodiment uses examples of limiting the operation of the ND filter and the shutter, the operation of exposure parameters such as sensitivity and aperture may be limited and controlled at fixed values ​​in order to avoid an increase in noise due to increased sensitivity or diffraction due to narrowing the aperture. [Other Examples] The present invention can also be realized by a process in which a program for implementing one or more of the functions of the above-mentioned embodiments is supplied to a system or device via a network or a storage medium, and one or more processors in a computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0046] The disclosure of this embodiment includes the following configurations and methods.

[0047] (Configuration 1) An imaging unit that captures a photographed image; A control unit that controls exposure of the captured image, The control unit controls the exposure of the captured image in a first mode when first information indicating that the captured image will be distributed next has not been obtained, and when the first information has been obtained, controls the exposure of the captured image in a second mode in which at least one of the parameters used in the first mode is controlled to a fixed value. (Configuration 2) The imaging device according to configuration 1, characterized in that, when the control unit acquires second information indicating that the captured image is being distributed, the control unit controls the exposure of the captured image in the second mode. (Configuration 3) 3. The imaging apparatus according to configuration 1 or 2, wherein an exposure control speed in the second mode is slower than an exposure control speed in the first mode. (Configuration 4) The imaging device described in any one of configurations 1 to 3, characterized in that a range in which the control unit does not control the exposure of the captured image based on a predetermined brightness set in advance in the second mode is wider than the range in the first mode. (Configuration 5) 5. The imaging apparatus according to any one of configurations 1 to 4, wherein a control sequence of exposure parameters is different between the first mode and the second mode. (Configuration 6) The imaging device described in configuration 1, characterized in that when the control unit acquires second information indicating that the captured image is being distributed, it controls the exposure of the captured image in a third mode in which at least one of the exposure parameters in the second mode is controlled to a fixed value. (Configuration 7) 7. The imaging apparatus according to configuration 6, wherein an exposure control speed in the third mode is slower than an exposure control speed in the second mode. (Configuration 8) The imaging device according to configuration 6 or 7, characterized in that a range in which the control unit does not control the exposure of the captured image based on a predetermined brightness set in advance in the third mode is wider than the range in the second mode. (Configuration 9) 9. The imaging apparatus according to any one of configurations 6 to 8, wherein a control sequence of exposure parameters is different between the second mode and the third mode. (Configuration 10) The imaging device according to any one of configurations 1 to 9, wherein the control unit, in the second mode, increases an exposure control speed for a predetermined period of time if the exposure is not appropriate. (Configuration 11) 11. The imaging device according to any one of configurations 1 to 10, wherein in the second mode, a filter that reduces light to an imaging section is controlled to a fixed value. (Configuration 12) 12. The imaging device according to claim 11, wherein the fixed value is obtained using the value of each parameter obtained in the first mode. (Configuration 13) 13. The imaging apparatus according to any one of configurations 1 to 12, wherein in the second mode, the shutter speed is controlled to a fixed value. (Configuration 14) 14. The imaging device according to configuration 13, wherein the fixed value is a value determined based on a frequency of a light source. (Configuration 15) An imaging device according to any one of configurations 1 to 14; a selection device for acquiring an image from the imaging device and selecting an image to be distributed or an image to be distributed next, said selection device comprising: (Method 1) An imaging step of capturing a photographed image; A control step of controlling the exposure of the captured image, A control method for an imaging device, characterized in that in the control step, if first information indicating that the captured image will be distributed next is not obtained, the exposure of the captured image is controlled in a first mode, and if the first information is obtained, the exposure of the captured image is controlled in a second mode in which at least one of the parameters used in the first mode is controlled by a predetermined value. (Configuration 16) A program for causing a computer to execute the control method according to method 1. (Configuration 17) A computer-readable storage medium storing the program according to configuration 16.

[0048] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0049] 100 Imaging device 204 Imaging unit 207 System Control Unit (Control Unit)

Claims

1. The imaging unit captures the image, It has a control unit that controls the exposure of the captured image, The imaging device is characterized in that, if the control unit has not acquired first information indicating that the captured image will be distributed next, it controls the exposure of the captured image in a first exposure mode, and if the control unit has acquired the first information, it controls the exposure of the captured image in a second exposure mode in which at least one of the exposure parameters that can be changed in the first exposure mode is controlled in a state that cannot be changed until the state in which the captured image will be distributed next is released.

2. The imaging device according to claim 1, characterized in that when the control unit acquires second information indicating that the captured image is being distributed, it controls the exposure of the captured image in the second exposure mode.

3. The imaging device according to claim 1, characterized in that the exposure control speed in the second exposure mode is slower than the exposure control speed in the first exposure mode.

4. The imaging device according to claim 1, characterized in that the range in which the control unit does not control the exposure of the captured image based on a predetermined brightness set in advance in the second exposure mode is wider than the range in the first exposure mode.

5. The imaging device according to claim 1, characterized in that the control order of the exposure parameters is different in the first exposure mode and the second exposure mode.

6. The imaging apparatus according to claim 1, characterized in that when the control unit acquires second information indicating that the captured image is being distributed, it controls the exposure of the captured image in a third exposure mode in which at least one of the exposure parameters in the second exposure mode is controlled by a fixed value.

7. The imaging device according to claim 6, characterized in that the exposure control speed in the third exposure mode is slower than the exposure control speed in the second exposure mode.

8. The imaging device according to claim 6, characterized in that the range in which the control unit does not control the exposure of the captured image based on a predetermined brightness set in advance in the third exposure mode is wider than the range in the second exposure mode.

9. The imaging device according to claim 6, characterized in that the control order of the exposure parameters is different in the second exposure mode and the third exposure mode.

10. The imaging apparatus according to claim 1, characterized in that the control unit increases the exposure control speed for a predetermined time if the exposure is not appropriate in the second exposure mode.

11. The imaging apparatus according to claim 1, characterized in that the second exposure mode controls an optical filter that reduces the amount of light reaching the image sensor by a fixed value.

12. The imaging device according to claim 11, characterized in that the fixed value is determined based on the value of each exposure parameter used in the first exposure mode.

13. The imaging apparatus according to claim 1, characterized in that the second exposure mode controls the shutter speed by a fixed value.

14. The imaging apparatus according to claim 13, characterized in that the fixed value is a value determined based on the frequency of the light source.

15. An imaging device according to any one of claims 1 to 14, A shooting system characterized by having a selection device that acquires video from the aforementioned imaging device and selects the video to be distributed or the next video to be distributed.

16. The imaging step involves capturing an image, The system includes a control step for controlling the exposure of the captured image, A control method for an imaging device, characterized in that, in the control step, if first information indicating that the captured image will be distributed next has not been acquired, the exposure of the captured image is controlled in a first exposure mode; and if the first information has been acquired, the exposure of the captured image is controlled in a second exposure mode in which at least one of the exposure parameters that can be changed in the first exposure mode is controlled in a state that cannot be changed until the state in which the captured image will be distributed next is released.

17. A program characterized by causing a computer to execute the control method described in claim 16.

18. A storage medium readable by a computer that stores the program described in claim 17.

Images