JP2013186190A - Imaging device and control method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a correction effect on image blur by expanding a drive range of correction optical means to an extent not to affect on image deterioration due to deterioration of optical performance according to an imaging scene.SOLUTION: An imaging device includes: correction optical means movable for correcting image blur; vibration detection means for detecting vibration added to the imaging device; calculation means for calculating a movement target position of the correction optical means according to a blur signal from the vibration detection means; driving means for driving the correction optical means to the movement target position; and drive range changing means (S103 to S106) for changing a drive range in which the correction optical means is driven on the basis of information on a peripheral area image among photographed images.

Description

  The present invention relates to an imaging apparatus having an image blur correction function and a control method thereof.

  In an imaging apparatus typified by a still camera or a video camera, a method such as optical camera shake correction is used as a method of correcting shake given from the outside.

  For example, in Patent Document 1, a high-quality image can be recorded by driving a correction lens to correct lens characteristics of a zoom lens group generated at each zoom position, for example, a shift in the center position and a peripheral light amount. An image recording apparatus has been proposed.

JP 2006-64986 A

  However, in the conventional technique disclosed in Patent Document 1 described above, the image stabilization performance inherently provided in the correction lens mechanism is limited because the optical characteristics of the lens are kept good while the driving range of the correction lens is limited. At the same time, there is a problem that the improvement of the image stabilization performance is hindered.

(Object of invention)
An object of the present invention is to increase the drive range of the correction optical means to a range that does not affect image degradation due to optical performance degradation according to the imaging scene, and an imaging device capable of improving the correction effect on image shake and its It is to provide a control method.

  In order to achieve the above object, an image pickup apparatus according to the present invention includes a correction optical unit that is movable to correct image shake, a vibration detection unit that detects a shake applied to the image pickup apparatus, and a shake signal of the vibration detection unit. The correction optical means based on the information on the peripheral area image in the captured image, the calculation means for calculating the movement target position of the correction optical means, the driving means for driving the correction optical means to the movement target position. Drive range changing means for changing the drive range in which the means is driven.

  According to the present invention, the correction effect for image blur can be improved by expanding the drive range of the correction optical means to a range that does not affect image degradation due to optical performance degradation according to the imaging scene.

1 is a block diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention. It is a block diagram which shows the internal structure of the correction lens drive control part shown by FIG. It is a block diagram which shows the detailed structure of the PID control part shown by FIG. It is a figure which shows the four corner area which is an example of the peripheral area of a picked-up image. 6 is a flowchart illustrating a correction lens driving range expansion operation during still image shooting according to the embodiment. It is a flowchart which shows the correction | amendment lens movable range calculation operation | movement of an Example. It is a figure which shows an example of the relationship between the luminance value and resolution in an Example, and a correction lens drive range expansion value. It is a flowchart which shows the correction lens drive range expansion operation | movement at the time of the video recording of an Example.

  The mode for carrying out the present invention is as described in the following examples.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of an imaging apparatus according to an embodiment of the present invention.

  The imaging apparatus includes a zoom unit 401 including a zoom lens that performs zooming, and a zoom drive control unit 402 that drives and controls the zoom unit 401. The imaging apparatus also has a correction lens 403 as a shake correction optical system that can move in a plane substantially perpendicular to the optical axis as a movable correction optical means, and a correction lens that drives and controls the correction lens 403. A drive control unit 404 is provided.

  Note that the zoom drive control unit 402 and the correction lens drive control unit 404 stop supplying the drive power to the zoom unit 401 and the correction lens 403, for example, during power saving.

  The imaging apparatus further includes an aperture / shutter unit 405 that performs the aperture operation and shutter operation of the optical system, and an aperture / shutter drive control unit 406 that drives and controls the aperture / shutter unit 405. In addition, the lens includes a lens for performing focus adjustment, a focus unit 407 for performing focus adjustment, a focus drive control unit 408 for driving and controlling the focus unit 407, and imaging for converting an optical image that has passed through each lens group into an electrical signal. An imaging unit 409 including an element is provided.

  In the imaging apparatus, the conversion process of the electrical signal output from the imaging unit 409 into a video signal is performed by the imaging signal processing unit 410, and the processing according to the use of the video signal output from the imaging signal processing unit 410 is a video. This is performed by the signal processing unit 411.

  In the imaging apparatus, a display unit 412 including a display displays an image as necessary based on a signal output from the video signal processing unit 411.

  The imaging apparatus operates the power supply unit 413 that supplies power to the entire imaging apparatus according to the application, the external input / output terminal unit 414 for inputting / outputting communication signals and video signals to / from the outside, and the imaging apparatus. The operation unit 415 is provided. Various data such as video information obtained by shooting is stored in the storage unit 416, and the control of the entire imaging apparatus is performed by the control unit 417.

  Next, an operation in the imaging apparatus configured as described above will be described. The operation unit 415 has a shutter release button (not shown) configured to turn on the first switch (SW1) and the second switch (SW2) in order according to the amount of pressing. The first switch (SW1) is turned on when the shutter release button is depressed approximately halfway, and the second switch (SW2) is turned on when the shutter release button is depressed to the end.

  When the first switch (SW1) is turned on, the focus drive control unit 408 drives the focus unit 407 to perform focus adjustment, and the aperture / shutter drive control unit 406 drives the aperture / shutter unit 405 to perform exposure. Set the volume appropriately. When the second switch (SW2) is turned on, an optical image is exposed to the imaging unit 409, and image data obtained based on the electrical signal converted by the imaging element is stored in the storage unit 416.

  At this time, if there is an instruction to turn on image blur correction from the operation unit 415, the control unit 417 instructs the correction lens correction lens drive control unit 404 to perform an image blur correction operation, and the correction lens drive control unit 404 that has received this instruction Then, the image blur correction operation is performed until an instruction to turn off the image blur correction is given.

  In addition, when the operation unit 415 has not been operated for a certain period of time, the control unit 417 issues an instruction to shut off the power source of the display included in the display unit 412 in order to save power.

  In addition, the imaging apparatus can select one of the still image shooting mode and the moving image shooting mode by operating the operation unit 415, and in each shooting mode, each actuator (movable element) constituting the imaging device. The operating conditions can be changed.

  When an instruction for zooming with the zoom lens is input via the operation unit 415, the zoom drive control unit 402 that has received the instruction via the control unit 417 drives the zoom unit 401 to indicate the zoom position indicated. Move the zoom lens to. Further, based on the image information processed by the imaging signal processing unit 410 and the video signal processing unit 411, the focus drive control unit 408 drives the focus unit 407 to perform focus adjustment.

  FIG. 2 is a block diagram showing an internal configuration of the correction lens drive control unit 404. The correction lens drive control unit 404 includes a pitch direction gyro unit 501 and a yaw direction gyro unit 502 as vibration detection means for detecting vibration applied to the imaging apparatus. The pitch direction gyro unit 501 detects the shake in the vertical direction (pitch direction) of the imaging apparatus in the normal posture (the posture in which the length direction of the image frame substantially matches the horizontal direction), and the yaw direction gyro unit 502 is in the normal posture. The shake in the horizontal direction (yaw direction) of the imaging device is detected.

  Based on the shake signal of the pitch direction gyro unit 501, the image blur correction control unit 503 calculates a correction lens correction position control signal in the pitch direction. Similarly, based on the shake signal from the yaw direction gyro unit 502, the image blur correction control unit 504 calculates a correction lens correction position control signal in the yaw direction. The hall element 509 and the hall element 510 are position detection means for detecting the positions of the correction lens 403 in the pitch direction and the yaw direction, respectively.

  The PID unit 505 and the PID unit 506 as feedback control means are respectively derived from deviations of the correction lens correction position control signal in the pitch direction and the yaw direction, and the positional signals of the Hall element 509 and the Hall element 510 indicating the position of the correction lens 403. The control amount is obtained and a drive command signal is output. The drive unit 507 and the drive unit 508 are drive units that drive the correction lens 403 based on drive command signals sent from the PID unit 505 and the PID unit 506, respectively. In this way, the PID units 505 and 506 perform feedback control so that the position signal converges on the corrected lens correction position control signal sent from the image blur correction control units 503 and 504, respectively.

  The correction lens correction position control signal in the pitch direction of the image blur correction control unit 503 calculated based on the shake signal from the pitch direction gyro unit 501 is a signal representing the movement target position (shake correction position) in the pitch direction. Similarly, the correction lens correction position control signal in the yaw direction of the image blur correction control unit 504 calculated based on the shake signal from the yaw direction gyro unit 502 is a signal representing a movement target position (shake correction position) in the yaw direction. is there.

  Therefore, the position of the correction lens 403 is moved in a direction in which image blur due to camera shake is corrected by the correction lens correction position control signals output from the image blur correction control units 503 and 504, respectively. In this way, even if the correction lens 403 that performs shake correction moves in the vertical and horizontal directions orthogonal to the optical axis and camera shake occurs in the imaging apparatus, image blur can be prevented. The drive range setting unit 511 drives the correction lens 403 by setting the output range of the correction lens correction position signal of the image blur correction control units 503 and 504 and changing the output of the Hall elements 509 and 510. Set the drive range. The drive range setting unit 511 constitutes drive range changing means.

  FIG. 3 is a block diagram showing a detailed configuration of the PID unit 505 shown in FIG. The PID unit 505 and the PID unit 506 are different in direction (pitch direction / yaw direction) but have the same configuration. Therefore, the PID unit 505 in the pitch direction will be described as an example.

  First, a correction lens correction position control signal that is an output value from the image blur correction control unit 503 and an output value of the Hall element 509 that is a position signal of the correction lens 403 are A / D converted by the A / D conversion unit 607. A difference (deviation) from the actual position (digital signal) is calculated by the deviation calculation unit 601. Based on this deviation, calculation is performed in the proportional control unit 602 (P control unit), the differential control unit 603 (D control unit), and the integral control unit 604 (I control unit).

  The proportional control unit 602 performs control to bring the deviation closer to zero, that is, control to bring the shake correction position that is the movement target position closer to the actual position. However, since the offset component is steadily added to the deviation only by the proportional control unit 602, the integral control unit 604 performs control to make the offset component asymptotic to zero. Further, in order to improve the responsiveness of the correction lens 403, differential control is performed on the deviation by the differential control unit 603.

  Finally, the result of the proportional control unit 602, the result of the differential control unit 603, and the result of the integration control unit 604 are added together by the sum calculation unit 605, and then converted into an analog signal by the D / A conversion unit 606, Then, the correction lens 403 is driven.

  FIG. 4 is a diagram exemplifying a peripheral area image for calculating the luminance level and resolution when the drive range setting unit 511 sets the drive range of the correction lens 403 based on the captured image processed by the video signal processing unit 411. . The four corner areas 702 of the captured image 701 are extracted, and the luminance values and resolutions of the four extracted peripheral area images are calculated.

  Next, the operation when the drive range setting unit 511 sets the drive range of the correction lens 403 during still image shooting will be described with reference to the flowchart of FIG.

  First, it is determined whether or not the camera shake correction function is enabled (step S101). If the camera shake correction function is disabled, the camera shake correction is stopped (step S110), and it is determined whether SW2 is pressed (step S111). When SW2 is pressed, exposure starts (step S112). When a predetermined exposure time elapses, exposure ends (step S113) and the flow ends. On the other hand, when the camera shake correction function is valid, a camera shake correction operation is performed (step S102). Next, a correction lens movable range determination image is acquired (step S103), and a correction lens movable range is calculated based on the acquired image (step S104).

  Next, it is determined whether or not SW2 is pressed (step S105). If not pressed, step S103 and step S104 are repeated, and the correction lens movable range is calculated until SW2 is pressed. On the other hand, when SW2 is pressed, the drive range is set so as to be the calculated correction lens movable range, the correction lens drive range is expanded (step S106), and exposure starts with the correction lens drive range expanded. (Step S107). When the predetermined exposure time elapses, the exposure ends (step S108), and then the correction lens driving range is returned to the normal driving range (step S109), and the flow ends.

  Next, the correction lens movable range calculation method in step S104 will be described with reference to the flowchart of FIG.

  The image size of the correction lens movable range determination image (hereinafter referred to as an acquired image) acquired in step 103 of FIG. 5 is acquired (step S201), and the zoom position at the time of capturing the acquired image is acquired (step S202). Next, the brightness value of the four corner areas 702 shown in FIG. 4 is calculated from the acquired image (step S203), and the correction lens driving range expansion value (correction lens movable value) is calculated based on the acquired image size, zoom position, and calculated brightness value. Range) is calculated (step S204). Next, the resolution of the four corner areas 702 shown in FIG. 4 is calculated from the acquired image (step S205), and the corrected lens driving range expansion value is calculated based on the acquired image size, zoom position, and calculated resolution (step S206). ).

  FIG. 7 is a diagram showing an example of the corrected lens driving range expansion value calculated by the driving range setting unit 511 from the luminance values and resolutions of the four corner areas 702 acquired in FIG. When the luminance value and the resolution are large, it is determined that the scene has a large image deterioration due to the expansion of the correction lens driving range. Therefore, the correction lens driving range is not expanded and the normal correction lens driving range is set. As the brightness value and the resolution become smaller, it is determined that the scene is such that the image degradation due to the correction lens drive range expansion becomes small, so the correction lens drive range is expanded. However, the maximum value of the correction lens drive range expansion value is determined from the control performance of the correction lens 403 and the limitation of the correction lens drive range of the mechanical mechanism. Since the image quality differs depending on the image size, the influence on the luminance value and the resolution due to the correction lens driving range expansion is different, and therefore the correction lens driving expansion value differs depending on the image size. In addition, since the optical performance differs depending on the zoom position, the correction lens drive range expansion value varies depending on the zoom position because the influence of the correction lens drive range expansion on the luminance value and resolution differs.

  Next, the distortion of the acquired image is calculated (step S207), and the corrected lens driving range expansion value is calculated based on the calculated distortion (step S208). At this time, if the distortion is large, it is determined that the image deterioration due to the correction lens driving range expansion is small, and if the distortion is small, it is determined that the image deterioration due to the zoom lens driving range expansion is large, Based on the acquired image size, zoom position, and calculated distortion, a correction lens driving range expansion value is calculated.

  Thereafter, the minimum correction value of the correction lens driving range expansion value calculated in step S204, step S206, and step S208 is calculated as the optimum correction lens movable range of the shooting scene currently being shot (step 209).

  Next, an operation when the drive range setting unit 511 sets the drive range of the correction lens 403 during moving image shooting will be described with reference to the flowchart of FIG.

  First, it is determined whether or not the camera shake correction function is enabled (step S301). If the camera shake correction function is disabled, camera shake correction is stopped (step S313), and it is determined whether or not moving image recording is started (step S314). When the recording is started (step S315), the moving image up to the end of recording (step S316) is recorded, and the flow ends. On the other hand, when the camera shake correction function is valid, a camera shake correction operation is performed (step S302). Next, it is determined whether moving image recording is started (step S303). When recording is started (step S304), a correction lens movable range determination image is acquired (step S305). The brightness values of the four corner areas 702 shown in FIG. 4 are calculated from the acquired image (step S306), the image size of the acquired image is acquired (step S307), the zoom position at the time of capturing the acquired image is acquired (step S308), Based on the acquired image size, zoom position, and calculated luminance value, a correction lens driving range expansion value (correction lens movable range) is calculated (step S309). The drive range is set so as to be the calculated correction lens movable range, the correction lens drive range is set (step S310), and steps 305 to 310 are repeated until the moving image recording is completed (step S311). When moving image recording ends, the correction lens driving range is returned to the normal driving range (step S312), and the flow ends.

  As mentioned above, although the preferable Example of this invention was described, this invention is not limited to this Example, A various deformation | transformation and change are possible within the range of the summary.

  For example, in the embodiment, the feedback control method is used to move the correction lens to the movement target position, but an open control method may be used. Further, although a correction lens is used as the correction optical means, a variable apex angle prism or the like may be used even if it is a type that drives an image sensor.

401 Zoom unit 402 Zoom drive control unit 403 Correction lens 404 Correction lens drive control unit 417 Control unit 501 Pitch direction gyro unit 502 Yaw direction gyro unit 503, 504 Image blur correction control unit 507, 508 Drive unit 511 Drive range setting unit

Claims (6)

Correction optical means movable to correct image blur;
Vibration detecting means for detecting shake applied to the imaging device;
Calculating means for calculating a movement target position of the correcting optical means according to a shake signal of the vibration detecting means;
Driving means for driving the correction optical means to the movement target position;
An imaging apparatus comprising: a drive range changing unit that changes a drive range in which the correction optical unit is driven based on information of a peripheral area image in the captured image. A zoom unit that performs zooming, and zoom drive control means for driving and controlling the zoom unit;
2. The imaging apparatus according to claim 1, wherein the drive range changing unit changes the drive range of the correction optical unit based on an image size of the captured image and a zoom position of the zoom drive control unit.   The imaging apparatus according to claim 2, wherein the driving range changing unit changes the driving range of the correction optical unit based on a luminance value of the peripheral area image.   The imaging apparatus according to claim 2, wherein the driving range changing unit changes a driving range of the correction optical unit based on a resolution of the peripheral area image.   The imaging apparatus according to claim 2, wherein the driving range changing unit changes the driving range of the correction optical unit based on distortion of the peripheral area image. A method for controlling an imaging apparatus having correction optical means movable to correct image blur,
A vibration detecting step for detecting a shake applied to the imaging device;
A calculation step of calculating a movement target position of the correction optical means according to a shake signal from the vibration detection step;
A driving step of driving the correction optical means to the movement target position;
A control method for an image pickup apparatus, comprising: a drive range change step for changing a drive range in which the correction optical means is driven based on information of a peripheral area image in a picked-up image.

Images