JP2016225760A - Imaging apparatus, control method of the same, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus capable of reducing consumption power of the imaging apparatus when using an imaging element capable of controlling a radius of curvature of a bendable imaging surface.SOLUTION: An imaging apparatus includes: imaging means so configured that an imaging surface is bendable; drive means for bending the imaging surface of the imaging means; and control means for controlling a radius of curvature of the imaging surface by driving the drive means in accordance with an imaging condition.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus, a control method thereof, and a program.

  2. Description of the Related Art Conventionally, there has been known an imaging device (hereinafter simply referred to as a variable curvature sensor) in which a photoelectric conversion element is disposed on the concave curved surface side of a curved imaging surface and the curvature of the concave curved surface can be controlled. In addition, the digital camera equipped with such a variable curvature sensor and optical zoom improves the focus of the entire imaging surface by controlling the curvature of the variable curvature sensor according to the focal length that changes with the optical zoom. What is to be known is known.

  In such a digital camera, when the lens is close to the imaging surface with a wide-angle lens, the radius of curvature of the concave surface of the sensor is reduced (the curvature radius is the reciprocal of the curvature), while the lens is far from the imaging surface with a telephoto lens. In this case, the radius of curvature of the concave surface of the sensor is increased. In this way, since the curvature of the concave curved surface can be controlled so that the curvature of field aberration of the lens is minimized, an image in which the entire imaging surface is in focus can be generated regardless of the lens position. . Patent Document 1 proposes a technique for changing the curvature of a sensor using a change in magnetic force by an electromagnet, a volumetric shrinkage due to heat, or a degree of vacuum due to an attractive force.

JP 2012-182194 A

  On the other hand, digital cameras and video cameras are becoming more common that have a live view display function and a moving image shooting function in addition to a still image shooting function. In particular, in moving image shooting, the processing is enormous and complicated compared to still image shooting, and thus power consumption may increase. On the other hand, with the demand for miniaturization of these cameras, reduction of the maximum amount of power is desired from the viewpoint of heat generation and the like.

  In a digital camera using the above-described variable curvature sensor, additional power is required to change the curvature according to the magnification (focal length) of the optical zoom and to maintain the changed curvature. In particular, in live view display and moving image shooting, it is necessary to maintain the curvature according to the set optical zoom magnification over the shooting period, and therefore a measure to reduce power consumption is desired.

  The present invention has been made in view of the above-described problems of the prior art, and an imaging apparatus capable of reducing power consumption when using an imaging element capable of controlling the curvature of a curved imaging surface, and the imaging apparatus It is an object to provide a control method and a program.

  In order to solve this problem, for example, an imaging apparatus of the present invention has the following configuration. That is, an image pickup unit configured to be able to bend the image pickup surface, a drive unit that curves the image pickup surface of the image pickup unit, a control unit that drives the drive unit and controls the curvature of the image pickup surface according to shooting conditions, It is characterized by having.

  ADVANTAGE OF THE INVENTION According to this invention, when using the image pick-up element which can control the curvature of the imaging surface curved, it becomes possible to reduce the power consumption of an imaging device.

1 is a block diagram illustrating an example of a functional configuration of a digital camera as an example of an imaging apparatus according to an embodiment of the present invention. 7 is a flowchart showing a series of operations of curvature control processing according to the first embodiment. FIG. 3 is a block diagram illustrating an example of a functional configuration of a digital camera according to a second embodiment 7 is a flowchart showing a series of operations of curvature control processing according to the second embodiment. 7 is a flowchart showing a series of operations of curvature control processing according to the third embodiment. The figure explaining the outline of the curvature control processing in each embodiment

(Embodiment 1)
Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In the following, an example in which the present invention is applied to an arbitrary digital camera including an imaging device capable of controlling the curvature of the imaging surface will be described as an example of the imaging apparatus. However, the present invention is not limited to a digital camera and can be applied to any electronic device that can control the curvature of the imaging surface of the imaging device. These devices may include information terminals (for example, mobile phones, game machines, tablet terminals, personal computers, watch-type or glasses-type terminals), in-vehicle devices, monitoring devices, robots, and the like.

(Configuration of digital camera 100)
FIG. 1 is a block diagram illustrating a functional configuration example of a digital camera 100 as an example of an imaging apparatus according to the present embodiment. One or more of the functional blocks shown in FIG. 1 may be realized by hardware such as an ASIC or a programmable logic array (PLA), or may be realized by a programmable processor such as a CPU or MPU executing software. May be. Further, it may be realized by a combination of software and hardware. Therefore, in the following description, even when different functional blocks are described as the operation subject, the same hardware can be realized as the subject.

  The imaging optical system 101 includes a lens group including a focus lens and a zoom lens, and a diaphragm. In accordance with an instruction from the imaging optical system driving unit 106, the zoom lens is moved in the optical axis direction to zoom magnification (or focal length). ) Can be changed. Further, the aperture diameter of the diaphragm can be changed in accordance with an instruction from the imaging optical system driving unit 106.

  The imaging element 102 is an imaging element whose imaging surface can be curved, and a photoelectric conversion element is arranged on the concave curved surface side so that the curvature of the imaging surface having a concave curved surface can be controlled. The image sensor 102 has a configuration in which a plurality of pixels having photoelectric conversion elements are two-dimensionally arranged on the concave surface side. The imaging element 102 may be an imaging element such as a CCD (Charge-Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. The subject optical image formed by the imaging optical system 101 is photoelectrically converted by each pixel, and further analog / digital converted by an A / D conversion circuit (not shown) to output a digital signal (image data) in units of pixels. Also, for example, image data in which one frame is 1920 horizontal pixels × 1080 vertical pixels can be output at a predetermined frame rate (for example, 30 frames per second). Note that a plurality of independent photoelectric conversion elements may be provided for each pixel of the image sensor, and a plurality of image data having a phase difference may be output.

  In addition, the image sensor 102 is an image sensor (also referred to as a variable curvature sensor) having a drive unit for changing and maintaining the curvature of the imaging surface, and also for changing the curvature of the imaging surface and maintaining the curvature. Power or control signal. In the present embodiment, for example, the curvature control unit 107 supplies power to control the curvature of the imaging surface.

  The imaging system signal processing unit 103 performs image signal processing such as various correction processes on the image data or video data (hereinafter also simply referred to as image data) output from the imaging element 102, and outputs the processed image data. The data is output to the recording / reproduction system signal processing unit 104. The recording / playback signal processing unit 104 encodes the input image data in accordance with, for example, a predetermined encoding method, compresses the amount of information, and converts the data into data suitable for recording. Data processed by the recording / reproducing system signal processing unit 104 is recorded on the recording medium 109. The recording medium 109 is a recording medium such as a memory card for recording the image data output from the recording / reproducing system signal processing unit 104, and includes a semiconductor memory, a magnetic disk, and the like.

  The display unit 105 includes a monitor such as a touch panel, for example, and includes image data output from the recording / playback signal processing unit 104, video data for live view display, or an operation screen (menu screen for operating the digital camera 100). ) Etc. are displayed. The display unit 105 may be any display device such as a liquid crystal display, an organic EL display, and electronic paper.

  The imaging optical system driving unit 106 includes a driving device that drives the imaging optical system 101 to a predetermined position, and operates according to an instruction from the control unit 113, for example.

  The curvature control unit 107 includes a control circuit or a control module, and includes imaging conditions (for example, subject brightness, F value, subject motion amount) detected by the detection unit 108 and imaging optics from the imaging optical system driving unit 106. The curvature of the imaging surface of the image sensor 102 is controlled based on information indicating the state of the system (focal length information and diaphragm information) (curvature control processing).

  The detection unit 108 receives the image data output from the imaging system signal processing unit 103 or acquires information on the aperture set from the imaging optical system driving unit 106 to detect the imaging conditions of the digital camera 100. .

  The changeover switch 110 includes, for example, a mechanical switch for selecting a moving image shooting mode and a still image shooting mode. The zoom switch 111 is a switch for setting an optical zoom magnification, and the trigger switch 112 operates to start and stop moving image recording.

  The control unit 113 is, for example, a CPU or MPU, and is a control unit that controls the entire digital camera 100 by developing and executing a program stored in the ROM in a RAM work area. Signals from the selector switch 110, the zoom switch 111, and the trigger switch 112 are received, and each unit is controlled according to each operation content. In the present embodiment, the curvature control unit 107 and the detection unit 108 are described as independent from the control unit 113, but the control unit 113 may realize these functions.

(Outline of curvature control processing according to the present invention)
When the control information or the control command corresponding to the state of the zoom switch 111 is input from the control unit 113, the imaging optical system driving unit 106 drives and controls the zoom lens of the imaging optical system 101 to the wide angle side or the telephoto side. Further, the imaging optical system driving unit 106 supplies focal length information of the zoom lens of the imaging optical system 101 to the curvature control unit 107. The imaging optical system driving unit 106 controls opening and closing of the aperture of the imaging optical system 101 according to the luminance of the subject and the depth of field desired by the user, and drives the focus lens of the imaging optical system 101 to subject the subject. The imaging position in the optical axis direction of the optical image is controlled.

  When focusing on the entire imaging surface, the curvature control unit 107 minimizes or reduces the field curvature aberration based on the focal length information of the lens supplied from the imaging optical system driving unit 106 (that is, depending on the angle of view). The curvature of the imaging surface of the image sensor 102 is controlled so as to reduce the difference in the condensing position. The optimal curvature of the imaging surface corresponding to the focal length is stored, for example, in a memory of the control unit 113 as a predetermined curvature value as a table, and the curvature control unit 107 selects all of the curvature values in this table or A part is acquired at a predetermined timing (via the control unit 113).

  When the image sensor 102 has a drive unit that controls the radius of curvature by, for example, stress, the image sensor 102 is controlled so that the radius of curvature is reduced by applying stress to the image sensor. At this time, the image sensor 102 consumes power for generating stress (that is, power for controlling curvature). Further, when the curvature of the imaging surface is, for example, an optimal curvature (that is, a state in which stress is applied), the imaging element 102 consumes electric power for maintaining the curvature. This optimal curvature is maintained until, for example, the position of the zoom lens of the image pickup optical system 101 is changed or until the moving image shooting is completed. Therefore, the longer the time required for this maintenance, the more power is consumed.

  If the stress is controlled as described above, the distance between the center of the imaging surface and the imaging optical system 101 varies, and the focus position is shifted. However, normally, when the focus is constantly monitored by contrast AF or the like during moving image shooting, the focus shift due to the change in the curvature of the imaging surface can be absorbed by this normal AF operation.

  On the other hand, when the imaging element 102 does not apply stress, for example, the imaging surface changes from a concave shape to a shape close to flat. In this state, power for controlling the curvature of the imaging surface is not consumed or the power consumption is lower than a predetermined value (hereinafter, this imaging surface state is referred to as an initial state or a non-energized state). That is, when the image sensor 102 is in the initial state, the power supplied to the image sensor 102 is not required or can be reduced, so that power consumption by the image sensor 102 can be reduced.

  In the present embodiment, attention is paid to the fact that even when the image sensor 102 is in an initial state and is out of focus, the out-of-focus state may be allowed depending on shooting conditions. For example, in a scene where the brightness of the detected subject is low and the field curvature aberration is inconspicuous, priority is given to reducing power consumption by setting the image sensor 102 to the initial state described above.

  More specifically, the subject luminance of the image data output from the imaging system signal processing unit 103 is detected, and the curvature is controlled according to the detected subject luminance (that is, the imaging condition) and the focal length of the imaging optical system 101. In the present embodiment, as shown in FIG. 6A, when the luminance value is smaller than a predetermined luminance value, the curvature of the image sensor 102 is set to an initial state (or a state where the curvature is small), while the luminance is set in advance. When the value is equal to or greater than the predetermined value, the curvature is controlled according to the focal length of the imaging optical system 101. By doing so, it is possible to effectively reduce the power consumption of the image pickup device and thus the power consumption of the image pickup device within the range where the influence of the field curvature aberration is not noticeable.

  In the digital camera 100 of the present embodiment, for example, the detection unit 108 detects the luminance of the subject based on the image data output from the imaging system signal processing unit 103. The detection unit 108 supplies a detection signal for the luminance to the curvature control unit 107 when the detected luminance value is smaller than a predetermined luminance value. That is, the detection unit 108 detects the case where the luminance of the subject is low and notifies the curvature control unit 107, and the curvature control unit 107 receives the detection signal from the detection unit 108 and receives the detection signal from the image sensor 102. The power supplied to maintain the curvature is stopped or lowered (hereinafter also referred to as releasing the curvature control). Then, the imaging surface of the imaging element 102 is in an initial state.

  On the other hand, the detection unit 108 does not supply a detection signal when the luminance of the detected subject is equal to or higher than a predetermined value. For this reason, the curvature control unit 107 performs power supply for changing or maintaining the curvature of the image sensor 102, whereby the image sensor 102 changes the curvature of the imaging surface or minimizes the field curvature aberration. maintain.

(A series of operations related to the curvature control processing of the imaging surface)
Next, a series of operations related to the curvature control processing of the imaging surface will be described with reference to FIG. Note that this processing is started when the digital camera 100 is in a standby state for moving image shooting, for example, when a user operation is performed on a switch such as the zoom switch 111 or the changeover switch 110. This is realized by the control unit 113 expanding and executing the program stored in the ROM in the work area of the RAM. Further, each step described below is executed by the control unit 113 unless otherwise described.

  In step S201, the control unit 113 determines whether to perform a zoom operation. Specifically, the control unit 113 determines whether or not there is an input signal from the zoom switch 111. If it is determined that there is an input signal, the control unit 113 proceeds to S202 to determine the zoom position. On the other hand, if the control unit 113 determines that there is no input signal from the zoom switch 111, the control unit 113 advances the process to S203.

  In S203, the control unit 113 determines an optimal curvature of the imaging surface according to the zoom position. When the zoom operation is not performed in S201, the control unit 113 determines the optimal curvature of the imaging surface corresponding to the initial position of the lens. For example, if a table indicating a set of the zoom position, the focal length, and the optimal curvature of the imaging surface is stored in a memory or the like in advance, the optimal curvature of the imaging surface can be obtained from the obtained zoom position (or focal length). it can. The control unit 113 stores the obtained optimal curvature value in the memory area.

  In step S204, the control unit 113 determines whether to start moving image recording. For example, when the control unit 113 detects that the user has operated the trigger switch 112, the control unit 113 determines that moving image recording is to be started, and advances the processing to S205. At this time, the control unit 113 starts moving image recording separately. Otherwise, the process returns to S204.

  In S205, the detection unit 108 detects subject brightness. As described above, the detection unit 108 acquires the image data output from the imaging system signal processing unit 103, calculates the luminance value of the entire image or a part of the image (such as the peripheral part of the image), for example, Detects subject brightness.

  In step S206, the control unit 113 determines whether moving image recording is continuing. If the recording is being continued, the control unit 113 proceeds to step S207, and if not, ends the series of processing.

  In step S207, the detection unit 108 determines whether the subject brightness is equal to or higher than a predetermined value. When the detection unit 108 determines that the subject brightness is smaller than the predetermined value, the control unit 113 returns the process to S205 again and repeats the processes of S205 to S207. If the detection unit 108 determines that the subject brightness is equal to or higher than the predetermined value, the control unit 113 advances the process to S208. In S208, the curvature control unit 107 acquires the curvature value obtained in S203 from the control unit 113, and controls the curvature of the imaging surface of the imaging element 102.

  In step S209, the detection unit 108 detects subject brightness. In S210, the control unit 113 determines whether or not the moving image recording is continuing. If the moving image recording is continuing, the process proceeds to S211. If not, the process proceeds to S213 to cancel the curvature control of the image sensor 102. Then, the series of operations is completed.

  In step S211, the detection unit 108 determines whether the subject brightness is equal to or higher than a predetermined value. When the detection unit 108 determines that the subject brightness is equal to or higher than the predetermined value, the control unit 113 returns the process to S209, and when the subject brightness is lower than the predetermined value, the process proceeds to S212. In S212, the control unit 113 cancels the curvature control of the image sensor 102 (that is, sets the initial state). Note that when the curvature of the imaging surface is changed by canceling the curvature control as described above, the distance between the center of the imaging surface and the lens is changed and a focus shift occurs. However, in this embodiment, since this control is performed when the brightness of the captured image is low, the movement and shift of the focus are less noticeable than in the case of a normal bright image. For this reason, power consumption can be effectively reduced within a range in which the influence of the field curvature aberration is not noticeable during use.

  In step S214, the control unit 113 determines whether moving image recording is continuing. If it is determined that recording is continuing, the control unit 113 returns the processing to step S205 again and repeats subject luminance detection. On the other hand, if it is determined that the moving image recording is not continuing, the series of operations of this process is terminated.

  In this embodiment, in the case of canceling the curvature control, the example in which the imaging surface is set to the initial state and the curvature is controlled so that the power consumption is lower than a predetermined value has been described. However, it is obvious that the effect of the present invention can be obtained at an arbitrary curvature as long as the power consumption is reduced from the power consumption required for the optimum curvature, even if the imaging surface is not in the initial state.

  In the present embodiment, the image pickup device having a structure that controls the curvature of the image pickup surface by applying stress has been described as an example. However, the curvature of the image pickup surface may be controlled and power consumption may be involved in the control. It is not limited to this. For example, power may be supplied and the curvature of the imaging surface may be controlled by a change in magnetic force by an electromagnet, a volume contraction rate by heat, or an attractive force.

  In this embodiment, the curvature control unit 107 controls the curvature of the imaging surface by controlling the supply of power to the imaging element 102. However, the curvature control unit 107 may output a control signal to the image sensor 102, and the image sensor 102 may control the imaging surface in accordance with the control signal. Even if it does in this way, power consumption can be reduced as a result of control of an imaging surface.

  As described above, in the present embodiment, the curvature of the imaging surface is controlled in accordance with the detected brightness in the imaging device configured to reduce the field curvature aberration based on the state of the imaging optical system. . In particular, when the luminance of the detected image data is smaller than a predetermined luminance value, the power consumption for changing or maintaining the curvature is suppressed by setting the curvature of the image sensor 102 to the initial state. That is, in the case of a dark screen, it is possible to effectively reduce power consumption by utilizing the case where the influence of field curvature aberration is not noticeable. In addition, when the detected subject brightness is equal to or higher than a predetermined brightness value, the optimum curvature is maintained, so that the merit of the variable curvature sensor can be utilized in a scene where the influence of field curvature aberration is conspicuous. .

(Embodiment 2)
Next, Embodiment 2 will be described. In the first embodiment, the subject luminance is detected as the photographing condition. In the second embodiment, the curvature of the imaging surface is controlled based on the state of the diaphragm of the imaging optical system 101. In the configuration of the digital camera 100 according to the present embodiment, the imaging optical system driving unit 106 supplies the state of the aperture of the imaging optical system 101 to the detection unit 108, and the detection unit 108 and the curvature control unit 107 have a curvature according to the state of the aperture. The point of controlling is different. Since other configurations are the same as those of the first embodiment, the same components are denoted by the same reference numerals, and redundant description will be omitted, and differences will be mainly described.

  FIG. 3 shows a functional configuration example showing the digital camera 100 according to the present embodiment. The difference from the first embodiment is that the imaging optical system drive unit 106 and the detection unit 108 are connected, and information indicating the aperture state (for example, F value) of the imaging optical system 101 is transmitted from the imaging optical system drive unit 106 to the detection unit 108. This is the output point.

  More specifically, as shown in FIG. 6B, the curvature of the imaging surface is controlled to the curvature according to the initial state or the focal length of the imaging optical system 101 according to the F value. The

  The detection unit 108 detects the aperture state (F value) of the imaging optical system 101 supplied from the imaging optical system driving unit 106. The detection unit 108 supplies a detection signal to the curvature control unit 107 when the detected F value is smaller than a predetermined value.

  In response to receiving the detection signal from the detection unit 108, the power supplied to maintain the curvature of the image sensor 102 is stopped or reduced (that is, the curvature of the image sensor 102 is set to the initial state). ). In other words, when the F value is small, the depth of field becomes shallow, so that a photograph with a blurred periphery of the subject can be taken like a portrait photograph, and the periphery of the subject is blurred, so there is a curvature of field aberration. It may be difficult to stand out.

  On the other hand, when the F value detected by the detection unit 108 is equal to or larger than a predetermined value, the detection signal is not supplied as in the first embodiment. For this reason, the curvature control unit 107 continues to supply power for maintaining the curvature of the imaging surface of the imaging element 102, whereby the imaging element 102 adjusts the curvature of the imaging surface so that the field curvature aberration is minimized. Change or maintain.

  Next, a series of operations of curvature control processing according to the present embodiment will be described with reference to the flowchart shown in FIG. In the present embodiment, as in the first embodiment, when the digital camera 100 is in a moving image shooting standby state, for example, when a user operation is performed on a switch such as the zoom switch 111 or the changeover switch 110, this processing is started. This is realized by the control unit 113 expanding and executing the program stored in the ROM in the work area of the RAM. Further, each step described below is executed by the control unit 113 unless otherwise described.

  The control unit 113 performs each process of S201 to S204.

  In step S <b> 401, the detection unit 108 detects the F value of the imaging optical system 101. If the control unit 113 determines in S206 that the moving image recording has not ended, the detection unit 108 determines in S402 whether the F value of the imaging optical system 101 is greater than or equal to a predetermined value. If the F value is greater than or equal to the predetermined value, the control unit 113 advances the process to S403, and if the F value is lower than the predetermined value, returns the process to S401.

  In S403, the curvature control unit 107 controls the curvature curvature of the image sensor 102 to the value obtained in S203 because the F value is equal to or greater than a predetermined value. When the F value is large, the depth of field becomes deep, so that a focused image can be taken at every corner of the screen regardless of the distance to the subject. When the F value is large in this way, the influence of the field curvature aberration is conspicuous, so the curvature of the imaging surface is controlled according to the field curvature aberration.

  In S404, the detection unit 108 detects the F value of the imaging optical system 101 again. If it is determined in S210 that the moving image recording has not ended, then in S405, the detection unit 108 determines whether the F value of the imaging optical system 101 is equal to or greater than a predetermined value. When the detection unit 108 determines that the F value of the imaging optical system 101 is smaller than the predetermined value, the control unit 113 advances the process to S212 and cancels the curvature control of the imaging element 102. When the curvature control of the image sensor 102 is canceled, the imaging surface of the image sensor 102 is in an initial state.

  When the detection unit 108 determines in step S405 that the F value of the imaging optical system 101 is greater than or equal to a predetermined value, the control unit 113 returns the process to step S404 and continues to detect the F value of the imaging optical system 101. When the control unit 113 determines in S210 that the moving image recording has ended, the curvature control of the image sensor 102 is canceled in S213.

  As described above, according to the present embodiment, the curvature of the imaging surface is controlled according to the detected diaphragm state in the imaging device configured to reduce the field curvature aberration based on the state of the imaging optical system. I tried to do it. In particular, when the detected F value is smaller than a predetermined aperture value, power consumption for changing or maintaining the curvature is suppressed by setting the curvature of the image sensor 102 to the initial state. That is, it is possible to effectively reduce the power consumption by utilizing the fact that the influence of the field curvature aberration is not noticeable when the depth of field is shallow. In addition, when the detected aperture value is equal to or greater than a predetermined aperture value, the optimum curvature is maintained, so that the merit of the variable curvature sensor can be utilized in a scene where the influence of field curvature aberration is conspicuous.

(Embodiment 3)
Furthermore, Embodiment 3 will be described. In the first embodiment, the subject luminance is detected as the shooting condition. In the third embodiment, the detection unit 108 detects the amount of movement of the subject, and the curvature control unit 107 controls the curvature of the imaging surface based on the detection result. Since the configuration of the digital camera 100 of the present embodiment is the same as that of the functional configuration example shown in FIG. 1, the same components are denoted by the same reference numerals and redundant description is omitted, and the differences are emphasized. explain.

  The difference from the first embodiment is that, as described above, the detection unit 108 obtains a motion amount of the subject from a plurality of image data (video data) output from the imaging system signal processing unit 103, and performs imaging according to the motion amount. The point is to control the curvature of the element. More specifically, as shown in FIG. 6C, the curvature of the image sensor 102 is controlled to an initial state or a curvature corresponding to the focal length of the imaging optical system 101 according to the detected amount of motion.

  In the present embodiment, the detection unit 108 detects the amount of motion of the subject based on the video data output from the imaging system signal processing unit 103, and if the detected amount of motion is greater than a predetermined value, the detection unit 108 notifies the curvature control unit 107. Supply detection signal. In response to receiving the detection signal from the detection unit 108, the curvature control unit 107 stops or reduces the power supplied to maintain the curvature of the image sensor 102 (that is, the image sensor 102). The curvature is the initial state). In general, since the user pays attention to the movement of the subject when it is moving, it is harder to notice the effect of field curvature aberration compared to a still image, and the image plane is also shaken when the entire screen is shaking like camera shake. Difficult to notice the effects of curvature aberrations. That is, when there is a movement of the subject, it can be difficult to recognize the influence of the field curvature aberration due to the movement of the subject or the screen.

  On the other hand, when the amount of motion detected by the detection unit 108 is equal to or less than a predetermined value, no detection signal is supplied as in the first embodiment. For this reason, the curvature control unit 107 continues to supply power for maintaining the curvature of the imaging surface of the imaging element 102, whereby the imaging element 102 adjusts the curvature of the imaging surface so that the field curvature aberration is minimized. Change or maintain.

  Next, a series of operations of curvature control processing according to the present embodiment will be described with reference to the flowchart shown in FIG. In the present embodiment, as in the first embodiment, when the digital camera 100 is in a moving image shooting standby state, for example, when a user operation is performed on a switch such as the zoom switch 111 or the changeover switch 110, this processing is started. This is realized by the control unit 113 expanding and executing the program stored in the ROM in the work area of the RAM. Further, each step described below is executed by the control unit 113 unless otherwise described.

  The control unit 113 performs each process of S201 to S204.

  In step S501, the detection unit 108 detects the movement of the subject in the video data. Note that the motion of the subject can be detected using, for example, a known motion vector detection method. If the control unit 113 determines in S206 that moving image recording is continuing, in S502, the detection unit 108 determines whether the detected amount of motion of the subject is greater than or equal to a predetermined value. If the amount of motion is less than or equal to the predetermined value, the control unit 113 advances the process to S503, and if the amount of motion is greater than the predetermined value, returns the process to S501 and continues moving image shooting.

  In step S503, the curvature control unit 107 controls the curvature curvature of the image sensor 102 to the value obtained in step S203. When the amount of motion is small, there is little blur due to motion and the influence of field curvature aberration is conspicuous, so the curvature of the imaging surface is controlled in accordance with field curvature aberration.

  In step S504, the detection unit 108 detects the amount of movement of the subject. Next, when it is determined in S210 that moving image recording is continuing, in S505, the detection unit 108 determines whether the detected amount of movement of the subject is equal to or less than a predetermined value. If the detection unit 108 determines that the amount of movement of the subject is greater than the predetermined value, the control unit 113 advances the processing to S212 and cancels the curvature control of the image sensor 102. When the curvature control of the image sensor 102 is canceled, the imaging surface of the image sensor 102 is in an initial state.

  In S505, if the detection unit 108 determines that the amount of movement of the subject is equal to or less than the predetermined value, the control unit 113 returns the process to S504 and continues to detect the amount of movement of the subject. When the control unit 113 determines in S210 that the moving image recording has ended, the curvature control of the image sensor 102 is canceled in S213.

  As described above, according to the present embodiment, in the imaging device configured to reduce the field curvature aberration based on the state of the imaging optical system, the curvature of the imaging surface is set according to the detected amount of movement of the subject. I tried to control it. In particular, when the detected amount of motion of the subject is larger than a predetermined amount of motion, the power consumption for changing or maintaining the curvature is suppressed by setting the curvature of the image sensor 102 to the initial state. That is, it is possible to effectively reduce power consumption by using the fact that it becomes difficult to recognize the influence of field curvature aberration due to the movement of the subject and the screen. In addition, when the detected amount of motion of the subject is less than or equal to a predetermined amount of motion, to maintain the optimal curvature, the advantages of the variable curvature sensor can be used in scenes where the influence of field curvature aberration is conspicuous. Can do.

  In the above-described embodiment, the curvature control of the image sensor during moving image recording has been described, but the power reduction effect can be similarly obtained even when applied during shooting standby in the still image mode. In particular, when live view display is performed, the image sensor 102 generates image data at any time as in the case of moving image recording, so that the same effect as that during moving image recording can be obtained.

  In addition, in order to prevent destruction of the image sensor, a means for detecting the amount of curvature of the image sensor may be provided to limit the curvature control so that the curvature does not exceed a predetermined value.

(Other embodiments)
The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

DESCRIPTION OF SYMBOLS 101 ... Imaging optical system, 102 ... Imaging element, 106 ... Imaging optical system drive part, 107 ... Curvature control part, 108 ... Detection part, 113 ... Control part

Claims (11)

Imaging means configured to be able to bend the imaging surface;
Driving means for bending the imaging surface of the imaging means;
Control means for controlling the curvature of the imaging surface by driving the driving means in accordance with photographing conditions;
An imaging device comprising:   The control unit is configured such that the curvature of the imaging surface is a first curvature that reduces curvature of field aberration generated at a focal length of the imaging optical system or a curvature smaller than the first curvature according to the photographing condition. The imaging device according to claim 1, wherein the imaging device is controlled to have a second curvature.   3. The control unit according to claim 2, wherein the control unit controls the curvature of the imaging surface to be the second curvature when a predetermined photographing condition in which the influence of field curvature aberration is reduced. The imaging device described. The control means includes
If the subject brightness is greater than or equal to a predetermined brightness value, control to achieve the first curvature,
The imaging apparatus according to claim 2, wherein when the subject brightness is lower than the predetermined brightness value, control is performed so that the second curvature is obtained. The imaging means further includes a diaphragm,
The control means includes
When the aperture value of the aperture is greater than or equal to a predetermined aperture value, control to be the first curvature,
The imaging apparatus according to claim 2, wherein when the aperture value of the aperture is smaller than the predetermined aperture value, control is performed so that the second curvature is obtained. The control means includes
When the amount of movement of the imaged subject or the amount of movement of the entire screen is equal to or less than a predetermined amount of movement, control is performed so as to achieve the first curvature,
4. The imaging apparatus according to claim 2, wherein when the amount of motion is larger than the predetermined amount of motion, control is performed so that the second curvature is obtained. 5.   The said control means controls the curvature of the said imaging surface by supplying the electric power for driving the said drive means to the said drive means, The any one of Claim 1 thru | or 6 characterized by the above-mentioned. Imaging device. The imaging means outputs video data imaged using the curvature of the imaging surface controlled by the control means,
The imaging apparatus according to claim 1, further comprising recording means for recording the output video data. The imaging means outputs video data imaged using the curvature of the imaging surface controlled by the control means,
The imaging apparatus according to claim 1, further comprising display means for displaying the output video data. An imaging apparatus control method comprising imaging means configured to be able to bend an imaging surface,
A driving step in which the driving means curves the imaging surface of the imaging means;
A control step of controlling the curvature of the imaging surface by driving the driving unit according to a shooting condition;
A method for controlling an imaging apparatus, comprising:   The program for functioning a computer as a control means of the imaging device of any one of Claims 1 thru | or 9.

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