JP2015037248A - Imaging device, control method for imaging device, program, and storage medium - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance operability for a user by preventing frequent zoom operations when adjusting framing by an automatic zoom operation.SOLUTION: An imaging device comprises: shake correction means; subject detection means that detects a subject from an image; and control means that controls drive of the shake correction means, and controls a zoom position. The control means controls drive of the shake correction means in accordance with the position of the subject detected by the subject detection means, and when the subject is included in the outside of a first angle of view, controls the zoom position to be moved to a wide-angle side.

Description

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

  Some imaging devices such as a digital camera have an optical scaling function by driving a zoom lens (optical zoom) and an electronic scaling function (electronic zoom) function for enlarging a part of an imaged area. is there. With recent improvements in zoom lens performance, it is possible to shoot from a super wide angle to a super telephoto lens with a single lens. It is becoming possible.

  In an imaging apparatus having a high-magnification zoom function, out-of-frame may occur due to slight movement of the subject when the angle of view is adjusted in the telephoto state. In addition, the angle of view can be greatly shifted by slightly moving the camera. Thus, a method has been proposed for enabling a subject to be re-acquired with a simple operation even when the subject is out of frame.

  In Patent Document 1, a framing assist zoom (FA zoom) that zooms out the angle of view to make it easier to search for a subject while a predetermined operation switch is pressed and zooms in to the original zoom position when the operation switch is released. The function is disclosed. According to this function, even when the subject goes out of the frame, the photographer can take a picture at a desired angle of view while immediately recapturing the subject with a simple operation.

  Also, a so-called auto zoom function is known as a function for detecting a subject in the screen with a camera and automatically changing the zoom position according to the subject detection information. Japanese Patent Application Laid-Open No. 2004-228688 proposes a method of zooming out the zoom position in the wide-angle direction when the subject reaches the limit position of a specific area in the screen. Japanese Patent Application Laid-Open No. 2004-228561 presents a method of zooming in on the zoom position in the telephoto direction when the subject is in the center of the screen.

  On the other hand, as a subject tracking function of the imaging apparatus, there is also a function of supporting a framing by changing a direction in which the angle of view is captured by driving a part of the lens optical system perpendicularly to the optical axis. Patent Document 3 realizes subject tracking by driving a variable apex angle prism that is a part of the optical system, and Patent Document 4 drives a mirror perpendicular to the optical axis.

  However, in the function of tracking a subject by driving a part of an optical system perpendicular to the optical axis as in Patent Document 4, there is a problem that the driving range is limited and the tracking amount of the limit is narrow. There is also.

JP 2012-60595 A Japanese Patent No. 20526553 JP 08-29826 A JP 2007-228007 A

  With the FA zoom function of Patent Document 1, zooming out and zooming in are performed according to the operation of the photographer. Here, in order to improve the convenience of the photographer, it is assumed that the zoom operation can be automatically performed in the FA zoom function according to the state of the subject. In that case, depending on the position of the subject within the angle of view, the zooming operation is frequently repeated, and there is a possibility that it takes time for framing.

  An object of the present invention is to improve user operability by preventing frequent zoom operations when adjusting framing by an automatic zoom operation.

  According to one aspect of the present invention, according to one aspect of the present invention, a shake correction unit, a subject detection unit that detects a subject from an image, and driving of the shake correction unit are controlled, and a zoom position is controlled. An image pickup apparatus including a control unit, wherein the control unit controls driving of the shake correction unit according to a position of the subject detected by the subject detection unit, and the subject is out of a first angle of view. If included, an imaging apparatus is provided that controls to move the zoom position to the wide-angle side.

  ADVANTAGE OF THE INVENTION According to this invention, when adjusting framing by automatic zoom operation | movement, a user's operativity can be improved by preventing that zoom operation | movement is performed frequently.

1 is a block diagram illustrating a configuration example of an imaging apparatus according to an embodiment. The figure which illustrates the angle of view in the subject search state and the angle of view in the shooting preparation state. The block diagram which shows the structure of the camera-shake correction control system which concerns on embodiment. 5 is a flowchart illustrating camera shake correction control processing according to the embodiment. 5 is a timing chart of camera shake correction control according to the embodiment. The flowchart which shows the process of the framing assistance function which concerns on embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment, It shows only the specific example advantageous for implementation of this invention. Moreover, not all combinations of features described in the following embodiments are indispensable for solving the problems of the present invention.

  FIG. 1 is a block diagram illustrating a configuration of an imaging apparatus according to the present embodiment. This imaging device is, for example, a digital camera mainly for taking still images and moving images. This imaging apparatus has an automatic framing support function (automatic framing assist function, hereinafter referred to as automatic FA function) that automatically supports framing. In FIG. 1, a zoom unit 101 includes a zoom lens for performing zooming. The zoom drive control unit 102 controls the drive of the zoom unit 101. Reference numeral 103 denotes an aperture / shutter unit. The aperture / shutter drive control unit 104 controls the drive of the aperture / shutter unit 103. The camera shake correction unit 105 as a shake correction unit includes a camera shake correction lens for camera shake correction. The camera shake correction control unit 106 controls driving of the camera shake correction unit 105. The focus unit 107 includes a focus lens that performs focus adjustment. The focus drive control unit 108 controls the drive of the focus unit 107.

  The imaging unit 109 converts an optical image (subject image) that has passed through each lens group into an electrical signal. The imaging signal processing unit 110 converts the electrical signal output from the imaging unit 109 into an imaging signal. The video signal processing unit 111 processes the imaging signal output from the imaging signal processing unit 110 according to the application. The display unit 112 performs image display as necessary based on the signal output from the video signal processing unit 111. The power supply unit 113 supplies power to the entire system according to the application. The external input / output terminal unit 114 inputs and outputs communication signals and imaging signals with the outside. The operation unit 115 includes operation buttons, switches, and the like for operating the system. The storage unit 116 stores various data such as image information. A camera shake detection unit 117 serving as a shake detection unit detects the amount of camera shake applied to the camera.

  A subject detection unit 118 serving as a subject detection unit detects the main subject from the signal of the imaging signal processing unit 110 and converts the main subject at which position in the imaging field angle into coordinate information. The FA control unit 119 (framing assist control unit) performs appropriate zoom / focus / hand operation based on information from the subject detection unit 118, information from the CZ control unit 120 (computer zoom control unit), and information from the camera shake correction control unit 106. Command the position of the image stabilization unit. The CZ control unit 120 simultaneously gives commands to the zoom drive control unit 102 and the focus drive control unit 108 in order to drive the focus unit 107 to an appropriate focus position according to the position of the zoom unit 101. A camera system control unit 121 as a control unit controls the entire system.

  The configuration of the imaging apparatus in the present embodiment is generally as described above. Next, a schematic operation of the imaging apparatus will be described. The operation unit 115 includes an image stabilization switch that enables selection of a shake correction (image stabilization) mode. When the shake correction mode is selected by the image stabilization switch, the camera system control unit 121 instructs the camera shake correction control unit 106 to perform the image stabilization operation. Upon receiving this instruction, the camera shake correction control unit 106 performs the image stabilization operation until an instruction to turn off the image stabilization is given. In addition, the operation unit 115 includes a shooting mode selection switch for selecting one of the still image shooting mode and the moving image shooting mode, and the operating conditions of each actuator can be changed in each shooting mode. it can.

  Further, the operation unit 115 includes a shutter release button configured such that the first switch (SW1) and the second switch (SW2) are sequentially turned on according to the amount of pressing. The switch SW1 is turned on when the shutter release button is depressed approximately half, and the switch SW2 is turned on when the shutter release button is depressed to the end. When the switch SW1 is turned on, the focus drive control unit 108 drives the focus unit 107 to perform focus adjustment, and the aperture / shutter drive control unit 104 drives the aperture / shutter unit 103 to set an appropriate exposure amount. To do. When the switch SW2 is turned on, image data obtained from the light image exposed to the imaging unit 109 is stored in the storage unit 116.

  The operation unit 115 includes a moving image recording switch. Movie recording starts after the switch is pressed, and recording is ended when the switch is pressed again during recording. The operation unit 115 also includes a playback mode selection switch for selecting a playback mode, and stops the image stabilization operation in the playback mode. Furthermore, the operation unit 115 includes a zooming switch for instructing zoom zooming. When an instruction for zooming magnification is given by the zooming switch, the zoom drive control unit 102 that has received the instruction via the camera system control unit 121 drives the zoom unit 101 to move the zoom unit 101 to the instructed zoom position. Let At the same time, the focus drive control unit 108 drives the focus unit 107 to adjust the focus based on the focus signal generated by each signal processing unit (110, 111) from the image pickup signal sent from the image pickup unit 109. .

  The operation unit 115 includes a switch for turning on / off the automatic FA mode. When ON (second mode), the appropriate zoom / camera correction unit position is recalculated from the current subject information and the position of the zoom / focus / camera correction unit. Commands are given to the control unit 106. When it is OFF (first mode), the above processing is not executed and the zoom operation is driven only by the zoom switch, and the camera shake correction unit 105 is driven only by the signal obtained from the camera shake detection unit 117.

Next, an outline of the automatic FA function will be described. In a camera not equipped with an FA function, the photographer needs to perform the following operation when the subject moves out of the frame while framing in the telephoto state and waiting for a photo opportunity.
(1) The subject is searched by zooming out by operating the zoom operation member.
(2) Adjust the angle of view by zooming until the desired angle of view is reached again.

  On the other hand, in the digital camera having the automatic FA function according to the present embodiment, when the subject is likely to be lost in a state where the angle of view is adjusted before photographing (hereinafter referred to as a photographing preparation state), the photographer switches the FA function switch Is turned on to switch to the automatic FA mode. When the FA control unit 119 is switched to the automatic FA mode, the camera shake correction control unit 106 is first switched to the subject tracking mode. In the subject tracking mode, the camera shake correction unit 105 is controlled to drive to track the subject or to execute subject tracking drive and camera shake correction drive in parallel. Here, in the camera shake correction drive, the camera shake correction unit 105 is driven so as to correct the camera shake based on the signal representing the detection result from the camera shake detection unit 117. On the other hand, in the subject tracking drive, the camera shake correction unit 105 is driven so as to maintain the subject detected by the subject detection unit 118 at the center of the screen.

  When the automatic FA mode is switched, the subject tracking drive by the camera shake correction unit 105 is first performed. When the subject reaches the tracking drive limit and the subject deviates from the angle of view (is likely to deviate), the FA control unit 119 stores the zoom position of the optical zoom in the storage unit 116, and performs subject tracking by zooming out. Execute. The FA control unit 119 instructs the CZ control unit 120 to zoom out to the wide angle side in accordance with the processing procedure of FIG. 6 to be described later, and the state where the field angle is zoomed out from the shooting preparation state (hereinafter referred to as subject search). Called state).

  Next, the operation during the automatic FA mode will be described with reference to FIG. 2A and 2D show the angle of view in the zoomed-in state (shooting preparation state), and FIGS. 2B and 2C show the angle of view in the zoom-out state (subject search state). Indicates. When it is difficult for the photographer to frame the subject in the shooting preparation state, the photographer presses the FA operation switch. As described above, when the FA operation switch is pressed, subject tracking by the camera shake correction unit 105 is executed in the shooting preparation state. When the driving limit of the camera shake correction unit 105 is reached and the subject deviates from the angle of view (that is, when the subject is included outside the angle of view)) (FIG. Transition to the search state (FIG. 2B). When a desired subject is found in the subject search state, the photographer performs framing so that the subject fits within the FA zoom frame 200 (FIG. 2C). Furthermore, when the camera shake correction unit 105 returns to the vicinity of the center of the drivable range, the FA control unit 119 performs a zoom-in operation to the stored zoom position in the shooting preparation state. Thus, an optimum framing state as shown in FIG.

  Next, details of the subject tracking function by the camera shake correction unit 105 will be described. When the camera shake correction function is turned off by the user setting, the camera shake correction unit 105 executes only the subject tracking operation. On the other hand, when the camera shake correction function is ON, the camera shake correction unit 105 performs both the camera shake correction drive and the subject tracking drive in parallel. In the following, processing when camera shake correction driving and subject tracking driving are performed in parallel will be described.

  FIG. 3 is a control block diagram for processing, in the camera shake correction control unit 106, a camera shake signal representing the camera shake detection information output from the camera shake detection unit 117. The AD converter 301 converts the analog camera shake signal acquired by the camera shake detection unit 117 into a digital signal. The HPF 302 (high pass filter) removes an offset component or a low-frequency component of a camera shake signal. The HPF 302 is configured to be able to change the cutoff frequency. The LPF 303 (low-pass filter) integrates and converts a camera shake signal, which is an angular velocity signal, into angle data. A sensitivity multiplier 304 as a shake correction amount calculation unit is a multiplier for converting angle data into a camera shake correction amount (drive distance of a camera shake correction unit). The limiter 305 is a limiter for clamping the output signal of the sensitivity multiplier 304 at a predetermined upper and lower limit value. This is to prevent deterioration of optical characteristics with respect to driving of the camera shake correction unit. The PID control unit 306 calculates an appropriate driver output value from the difference between the lens drive command value and the feedback signal. The driver 307 drives the camera shake correction unit 105 based on the driver output value calculated by the PID control unit 306. The position detection unit 308 detects the position of the camera shake correction unit 105. The AD converter 309 converts the analog output signal of the position detection unit 308 into a digital signal. The gain multiplier 310 is a multiplier for converting the output signal of the subject detection unit 118 into a camera shake correction unit drive amount.

  Normally, when the automatic FA function is turned off, the signal from the subject detection unit 118 is not necessary, and the lens is driven based on the signal from the camera shake detection unit 117. When the FA operation switch is pressed to start subject tracking, the cutoff frequency of the HPF 302 is gradually increased, and only the high frequency is driven as camera shake correction. At the same time, the drive limiter for correcting camera shake is gradually narrowed, while the drive limiter for tracking the subject is gradually widened to make a state transition. When the FA function state transition is completed and the FA function is turned on, the subject tracking drive command value is reflected in the lens drive and tracking is started.

  FIG. 4 is a flowchart showing the state transition process described above, and FIG. 5 is a time-series graph. When the FA operation switch is pressed in S401 of FIG. 4 and the automatic FA function is switched from OFF to ON, the processes of S402 to S405 are performed. That is, the cutoff frequency of the HPF 302 and the subject tracking drive command value limiter are gradually raised over T times, and the camera shake correction drive command value limiter is gradually lowered over T times. On the other hand, if the FA function is switched from ON to OFF in S406, in S407 to S410, the cutoff frequency of the HPF 302 and the drive command value limiter for subject tracking are gradually lowered over T times, and on the contrary, for camera shake correction The drive command value limiter is gradually increased over T times.

  In FIG. 5, the upper row is a graph of the camera shake correction drive command value, the middle row is the horizontal axis for subject tracking, and the automatic FA function is OFF until time T1, and the state transition starts from T1. . From time T1 to time T2, the cutoff frequency (lower graph) of the HPF increases from f0 to f0 + α, the low frequency band is cut, and only the high frequency band is obtained. In addition, the upper and lower limit values of the limiter with respect to the subject tracking drive command value are gradually widened, and transition from 0 to ± β from time T1 to time T2. That is, after time T2, driving for subject tracking can be performed within β. On the other hand, the upper and lower limit values of the limiter for the camera shake correction drive command value are gradually narrowed, and transition from ± C to ± (C−β) from time T1 to time T2. That is, after time T2, the lens is driven within a narrow drivable range C-β for camera shake correction.

  Next, details of the entire automatic FA control including subject tracking by zooming will be described with reference to the flowchart of FIG. The flow of FIG. 6 starts in response to the FA function operation switch of the operation unit 115 being pressed in the shooting preparation state. First, in step S <b> 601, the FA control unit 119 records the zoom position at the start of the FA function in the storage unit 116. In step S <b> 602, the FA control unit 119 notifies the camera shake correction control unit 106 of the start of transition to the subject tracking control state by the above-described camera shake correction unit. In S603, it is determined whether or not the transition to the subject tracking control state has been completed. If completed, the process proceeds to S604 and subject tracking by the camera shake correction unit is started.

  In S605, it is determined whether or not the FA function is turned off by pressing the FA function operation switch of the operation unit 115. When the FA function is OFF, the process jumps to S616, and the transition to the subject tracking stop state by the camera shake correction unit is started. In step S617, it is determined whether or not the transition to the subject tracking stop state has been completed. If the transition has not been completed, the process returns to step S616 to repeat the stop state transition, and if completed, the FA function is terminated.

  On the other hand, if the FA function is not turned off in S605, the process proceeds to S606. In step S606, it is determined based on the subject position information whether or not the subject is within the predetermined field angle (1) (in the first field angle). Here, the predetermined angle of view (1) is, for example, 90% of the angle of view when the FA function is started. If the subject is within the predetermined angle of view (1) in S606, the process returns to S605, and the FA function OFF is monitored again.

  If the subject is not within the predetermined angle of view (1) in S606, the zooming framing support is activated, and the process enters S607. The case where the process proceeds to S <b> 607 is a case where the camera shake correction unit is driven to the drive limiter for tracking the subject and the subject is not within the predetermined angle of view (1). That is, in the present embodiment, subject tracking is first performed by the camera shake correction unit. The zoom-out operation is performed after the camera shake correction unit alone is unable to track. By adopting such control, it is possible to prevent frequent zoom operations for supporting framing.

  In step S607, the FA control unit 119 calculates and acquires the zoom-out drive amount. The zoom-out drive amount here is calculated based on the size of the subject with respect to the angle of view at that time. In step S608, the FA control unit 119 sets a zoom position based on the zoom-out drive amount calculated in step S607, and performs a zoom-out operation in step S609. In step S <b> 610, the FA control unit 119 displays the FA zoom frame 200 on the display unit 112. When the above operation is completed, the subject search state is entered (FIG. 2B).

  Even in the subject search state, whether or not the FA function is turned off by pressing the FA function operation switch in S611 is monitored. When the FA function is turned off, the process jumps to S616 and enters the stop process as described above.

  On the other hand, if the FA function is not turned off, it is determined in S612 whether the subject is within the predetermined field angle (2) (within the second field angle) and the position of the camera shake correction unit is within the predetermined range. Here, the predetermined angle of view (2) is an angle of view corresponding to the FA zoom frame 200 of FIG. 2 or an angle of view of a predetermined ratio (for example, 80%) with respect to the angle of view of the FA zoom frame 200. The predetermined range of the position of the camera shake correction unit is, for example, 10% of the maximum drive amount β when the angle of view returns to the zoom-in position stored in S601. The smaller this value is, the wider the subject tracking range by the camera shake correction unit when the angle of view returns to the telephoto side, so that the problem that the framing support by the zoom operation is frequently repeated is reduced. However, if it is too small, the condition for returning from the subject search state to the shooting preparation state becomes severe, and it takes time for the angle of view to return even if the subject is found, so an appropriate value obtained experimentally in advance is set. Is done.

  As described above, in the present embodiment, the zoom-in operation is started after the camera shake correction unit returns to a range where the subject tracking by the camera shake correction unit is sufficiently possible. Therefore, even when the zoom position returns to the telephoto side, it is possible to prevent the zoom-out operation from being resumed immediately after the subject is out of frame again. If the subject is within the predetermined angle of view (2) in S612 and the position of the camera shake correction unit is within the predetermined range, the process proceeds to S613.

  In step S613, the FA control unit 119 reads the return zoom position stored in step S601 from the storage unit 116. The FA control unit 119 sets a zoom-in position in S614, and performs a zoom-in operation in S615. When the zoom-in operation is completed, the process returns to S604, and it is again monitored on the telephoto side whether the subject is within the predetermined angle of view (1).

  As described above, in the automatic FA function of this embodiment, the subject tracking is first performed by the camera shake correction unit in the shooting preparation state, and the zoom-out operation is started after the subject tracking by the camera shake correction unit becomes impossible. . In the present embodiment, the zoom-in operation is started after the subject is caught near the center of the screen in the subject search state and the subject tracking unit can sufficiently track the subject. As described above, according to the present embodiment, by performing control using subject tracking by the camera shake correction unit, it is possible to prevent frequent zoom operations for framing support, and to improve user operability. Can be increased.

(Other embodiments)
The present invention can also be realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or a storage medium, and a computer (or CPU, MPU, etc.) of the system or apparatus reads the program code. It is a process to be executed. In this case, the program code and the storage medium storing the program constitute the present invention.
Examples of the storage medium for supplying the program code include a flexible disk, a hard disk, an optical disk, and a magneto-optical disk. Further, a CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD-R, magnetic tape, nonvolatile memory card, ROM, or the like can also be used.
Further, by making the program code read by the computer executable, the functions of the above-described embodiments are realized. Furthermore, when the OS (operating system) running on the computer performs part or all of the actual processing based on the instruction of the program code, the functions of the above-described embodiments are realized by the processing. Is also included.
Furthermore, the following cases are also included. First, the program code read from the storage medium is written in a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer. Thereafter, based on the instruction of the program code, the CPU or the like provided in the function expansion board or function expansion unit performs part or all of the actual processing.
Further, the present invention is not limited to a device mainly intended for shooting such as a digital camera, and includes an imaging device such as a mobile phone, a personal computer (laptop type, desktop type, tablet type, etc.), a game machine, or the like. Applicable to any device to be connected. Therefore, the “imaging device” in this specification is intended to include any electronic device having an imaging function.

Claims (11)

Shake correction means,
Subject detection means for detecting a subject from an image;
Control means for controlling the drive of the shake correction means and the zoom position;
The control unit controls driving of the shake correction unit according to the position of the subject detected by the subject detection unit, and moves the zoom position to the wide angle side when the subject is included outside the first angle of view. An imaging device that is controlled to perform.   The control means includes the subject included in a second angle of view in a state where the zoom position is moved to the wide angle side according to the position of the subject detected by the subject detection means, and the position of the shake correction means. The imaging apparatus according to claim 1, wherein the zoom position is controlled to move to a telephoto side when is within a predetermined range.   The control means stores the first zoom position before moving to the wide-angle side when moving the zoom position to the wide-angle side according to the position of the subject detected by the subject detection means, and sets the zoom position to the wide-angle side. The imaging apparatus according to claim 2, wherein the zoom position is controlled to move to the first zoom position when moving from the side to the telephoto side again. A shake detecting means for detecting a shake amount applied to the imaging device;
2. The shake correcting unit is configured to be capable of executing driving based on a detection result of the shake detecting unit and driving based on a position of a subject detected by the subject detecting unit. 4. The imaging device according to any one of 3. A first mode for driving the shake correction unit without using the detection result of the subject detection unit; and a second mode for driving the shake correction unit using the detection result of the subject detection unit;
The imaging apparatus according to claim 4, wherein when the control for maintaining the subject within the angle of view is instructed, the imaging mode is switched from the first mode to the second mode.   6. The imaging apparatus according to claim 5, wherein a driveable range of the shake correction unit based on a detection result of the shake detection unit in the second mode is smaller than the driveable range in the first mode. . A high-pass filter that removes a low-frequency component of the signal output by the shake detection means;
The imaging apparatus according to claim 5 or 6, wherein a cutoff frequency of the high-pass filter in the second mode is higher than the cutoff frequency in the first mode. A low-pass filter for integrating the output of the high-pass filter and converting it into angle data;
A shake correction amount calculating means for multiplying the angle data, which is an output of the low-pass filter, by sensitivity and converting it to a camera shake correction amount;
The imaging apparatus according to claim 7, wherein the control unit controls driving of the shake correction unit based on an output signal of the correction amount calculation unit. A method for controlling an imaging apparatus having shake correction means,
Detecting a subject from the image;
Controlling the drive of the shake correction means;
Controlling the zoom position,
The imaging is characterized in that the driving of the shake correcting means is controlled according to the detected position of the subject, and the zoom position is controlled to move to the wide angle side when the subject is included outside the first angle of view. Control method of the device.   A program configured to cause a computer to execute each step of the control method for an imaging apparatus according to claim 9.   A storage medium storing the program according to claim 10.

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