JP6204805B2 - Imaging apparatus, control method therefor, program, and storage medium - Google Patents

Description

  The present invention relates to an imaging apparatus including an image shake correction apparatus that corrects image shake due to shake such as camera shake.

  Current cameras are fully automated for important shooting tasks such as determining exposure and focusing, and with cameras equipped with image stabilization devices that prevent image blur due to camera shake etc. Almost gone.

  Here, the image blur correction apparatus will be briefly described. Camera shake is usually vibration with a frequency of about 1 to 10 Hz. To enable shooting without image shake even when camera shake occurs at the shutter release time, camera shake due to camera shake is detected, and an image shake correction lens (hereinafter referred to as a correction lens) is detected according to the detected value. I need to move it. At that time, it is important to correct the change of the optical axis due to the shake by accurately detecting the vibration of the camera. In principle, image blurring is suppressed by mounting a vibration detection unit that obtains detection results such as angular velocity and a drive control unit that displaces the correction lens based on the calculation processing result.

  However, there are the following problems in shooting with the main subject moving and shooting on the telephoto side where the focal length increases. When the main subject is moving, the main subject may fall out of the captured image, and a special technique of the photographer is required to track the moving subject by the operation of the photographer. In addition, when performing telephoto shooting with a camera having a telephoto lens with a large focal length, it may be difficult to hold the main subject at the center of the captured image because of the effect of image blur due to camera shake. At that time, even if the photographer operates to fine-tune the camera in order to return the subject to the captured image, the shake amount that the photographer intentionally operates may be determined as camera shake and corrected. is there. Therefore, there are cases where it is difficult to finely adjust the subject within the captured image or the center of the captured image due to the influence of image blur correction control.

  As a technique for tracking a subject, for example, Patent Document 1 proposes a camera that automatically tracks a subject using an image blur correction apparatus that moves a part of the optical system in a direction intersecting the optical axis. Yes. Detects the position of the subject from the image signal from the image sensor, AF information, etc., calculates the subject tracking calculation amount, and synthesizes the subject tracking calculation amount with the shake correction calculation amount, thereby correcting the image blur while tracking the subject. Is possible.

JP 2010-93362 A

  However, in the conventional subject tracking technique disclosed in Patent Document 1, the range in which the image blur correction apparatus can be driven is limited. Therefore, when the subject tracking calculation amount and the shake correction amount are large, the image shake correction member immediately moves to the movable end, and it is difficult to achieve both subject tracking and shake correction control with high accuracy.

  When the subject tracking reaches the shake correction driving limit (end position of the movable range), the photographer operates to perform framing to return the subject to the screen frame. However, there may be a case where the framing operation intended by the photographer is determined as camera shake and image blur correction may be performed, and the shake correction may interfere with the photographer's framing operation, or drive the shake correction. Sometimes it was easy to reach the limit.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an imaging device that can easily shift a main subject to a captured image or the center of the captured image while ensuring an image blur correction effect. It is.

Imaging device according to the present invention is an imaging apparatus, based on the shake amount of the image pickup device detected by the shake detection means for detecting a shake of the image pickup means and the image pickup device for capturing an object image, the imaging calculating means for calculating the shake correction amount for correcting an image blur caused by the shake of the apparatus, position detecting means for detecting the position of the object in the image based on the image signal output from the pre-Symbol imaging means, image In order to perform image shake correction control by shake correction means when block division is performed, and in which block the subject is located in the divided image is detected, and the subject is located in a block away from the center of the image Is changed from the threshold value when the subject is located at the center in the image, and the shake value is corrected when the previous value of the shake correction amount exceeds the changed threshold value. The subtraction amount of the shake correction amount when the difference between the previous positive value and the threshold is greater than a predetermined value, and the difference between the previous value of the shake correction amount and the threshold is less than the predetermined value. A subtraction amount calculation means for making the subtraction amount larger than the subtraction amount , wherein the calculation means subtracts the subtraction amount from a shake amount obtained from the shake detection means, whereby the subject moves toward the center of the image. The shake correction amount is calculated so as to correct the image shake by weakening the shake correction amount.

  According to the present invention, it is possible to provide an imaging apparatus that can easily shift the main subject to the captured image or the center of the captured image while ensuring the image blur correction effect.

1 is a perspective view schematically showing an imaging apparatus provided with an image shake correction apparatus according to a first embodiment of the present invention. FIG. 2 is a top view and a control block diagram of an imaging apparatus provided with an image shake correction apparatus according to the first embodiment. The figure for demonstrating subject position detection performed by dividing a screen into blocks. The figure for demonstrating the angular velocity subtraction amount calculation in 1st Embodiment. The figure for demonstrating the angular velocity subtraction amount calculation in 1st Embodiment. FIG. 5 is a diagram for explaining shake correction amount calculation in the first embodiment. FIG. 5 is a diagram for explaining shake correction amount calculation in the first embodiment. 5 is a flowchart showing the operation of the image shake correction apparatus according to the first embodiment. FIG. 6 is a top view and a control block diagram of an imaging apparatus provided with an image shake correction apparatus according to a second embodiment. FIG. 10 is a diagram illustrating a shake correction range and a field angle according to the second embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a perspective view schematically showing an imaging apparatus 101 including an image shake correction apparatus according to the first embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration of an imaging unit of the imaging apparatus 101 and functional blocks of image blur correction processing executed by a CPU (Central Processing Unit) 105.

  A release button 104 is provided on the main body of the camera 101, and a switch open / close signal generated by operating the release button 104 is sent to a camera CPU (central processing unit) 105. A shake correction lens 115 and an image sensor 106 are positioned on the optical axis 102 of the photographing optical system for forming a subject image. The angular velocity meter 103 is angular velocity detection means for detecting angular fluctuations in the direction of the arrow 103p (pitch direction) and in the direction of 103y (yaw direction). The output of the angular velocity meter 103 is input to the camera CPU 105. An offset component added as detection noise to the angular velocity meter is subtracted from the output of the angular velocity meter 103 by the offset subtracting unit 108. For example, the DC component is cut by HPF (high-pass filter or high-pass transmission filter). The angular velocity after the offset subtraction is integrated by the angle calculation unit 110 and converted into an angle signal after the output of the angular velocity subtraction amount calculation unit 114 is subtracted by the subtractor 109.

  The angular velocity subtraction amount calculation unit 114 calculates the angular velocity subtraction amount based on the subject position from the subject position detection unit 113 and the shake correction target position that is the output of the sensitivity adjustment unit 111. Details of this will be described later.

  The output of the angle calculation unit 110 is input to the sensitivity adjustment unit 111. The sensitivity adjustment unit 111 amplifies the output of the angle calculation unit 110 based on the zoom and focus position information 107 and the focal length and imaging magnification obtained from the information, and sets the angle shake correction target value. This is for correcting the change in the shake correction sensitivity on the camera image plane with respect to the shake correction stroke of the shake correction lens 115 due to a change in optical information such as lens focus and zoom.

  The angular shake correction target value obtained by the sensitivity adjustment unit 111 is output to the drive control unit 112, and the shake correction lens 115 is driven to perform image shake correction. The above is the schematic configuration of the angular shake correction.

  In the example shown in FIG. 2, so-called optical shake correction in which the shake correction lens 115 is moved in a plane perpendicular to the optical axis based on the calculated correction amount is employed as the shake correction means. The image shake correction method is not limited to optical shake correction using a correction lens, and there is a method for performing shake correction by moving the image sensor in a plane perpendicular to the optical axis. Also, there is electronic shake correction that reduces the influence of shake by changing the cut-out position of each shooting frame output by the image sensor, and image shake correction can also be performed by combining a plurality of shake correction methods.

  Next, a description will be given of a method of controlling the correction lens while achieving both image shake correction based on camera shake and subject tracking.

  A subject position detection method in the subject position detection unit 113 will be described below. The image sensor 106 obtains image information by converting reflected light from the subject into an electrical signal. The information is converted into a digital signal. The image information converted into the digital signal is sent to the subject position detection unit 113.

  The subject position detection unit 113 detects the subject position in the image from the AF tracking information. As a method for AF tracking of an arbitrary object, there are a pattern matching method for searching for a region having a high degree of coincidence with a template image that is sequentially updated, a relative difference method for searching for a target position from an image difference between the current frame and the previous frame is there. Also known is a color / luminance matching method for extracting a single or a plurality of colors, luminances or histograms from an object and searching for a region having a high degree of coincidence with them. AF tracking can be performed by any one of these methods.

  Based on the subject position detected by the AF tracking described above, the image is divided into blocks as shown in FIG. 3, and the subject position detection unit 113 outputs to which block the main subject is located. In the present embodiment, the image is divided into nine blocks, but it may be determined more finely by increasing the number of blocks.

  Next, the angular velocity subtraction amount calculation method in the angular velocity subtraction amount calculation unit 114 will be described below. FIG. 4 is a diagram showing time-series data in each control block (108, 109, 110) shown in FIG. Reference numeral 401 in FIG. 4A denotes an angular velocity after the offset is subtracted from the angular velocity 103 by the offset subtracting unit 108. The signal obtained by integrating 401 and calculating the angle is 403 in FIG. 4C. When there is no limitation on the movable range of the shake correction lens 115 and shake correction can be performed, the shake correction target value is 403.

  However, the movable range of the shake correction lens 115 is limited. For example, when the shake correction movable range is limited to between A2 and B2 in FIG. 4C, the signal 403 exceeds the shake correction movable range. As a result, shake correction cannot be performed.

  Therefore, by calculating the angular velocity subtraction amount using the shake correction target value (previous sampling value of the control cycle), and integrating after subtracting the angular velocity subtraction amount from the angular velocity, the shake correction movable range is A2 in FIG. To allow the shake correction target value to be calculated in the state of B2.

  The angular velocity subtraction amount is calculated from the tables shown in FIGS. 4 (d) and 4 (e). In FIG. 4D, the horizontal axis is the shake correction target position, and the vertical axis is the gain α. When the shake correction target position is A1 or less, the gain α is 0, when the shake correction target position is A2 or more, the gain α is 1, and when the shake correction target position is located between A1 and A2, the gain α is A1-A2. It is a value obtained by linear interpolation.

  Also for FIG. 4E, the gain β is obtained by the same method. The horizontal axis is the shake correction target position, and the vertical axis is the gain β. When the shake correction target position is B1 or more, the gain β is 0, when the shake correction target position is B2 or less, the gain β is 1, and when the shake correction target position is located between B1 and B2, the gain β is B1-B2. It is a value obtained by linear interpolation.

  The angular velocity subtraction amount is calculated from the gain α and gain β obtained as described above. The angular velocity subtraction amount is calculated from the equations (1) and (2), and the gain multiplied by the sign of the angular velocity is different. When the sign of the angular velocity that is the output of the offset subtracting unit 108 is plus, the angular velocity is multiplied by a gain α, and when the sign of the angular velocity is minus, the angular velocity is multiplied by a gain β.

Angular velocity is positive: Angular velocity subtraction amount = Angular velocity x α (1)
Angular velocity is in the negative direction: Angular velocity subtraction amount = Angular velocity x β (2)
Reference numeral 402 in FIG. 4B denotes a signal obtained by subtracting the angular velocity subtraction amount calculated by the angular velocity subtraction amount calculation unit 114 from the angular velocity 401. Further, 404 in FIG. 4C is a signal obtained by integrating 402 and calculating an angle, and a shake correction target value is calculated between A2 and B2 which is the shake correction movable range.

  However, in this embodiment, not only the shake correction target position but also the subject position from the subject position detection unit 113 are input to the angular velocity subtraction amount calculation unit 114. The subject position detection unit 113 outputs in which block in FIG. 3 the main subject is located. Here, when the subject position is at 305, shake correction control is performed using the shake correction movable range to the maximum. On the other hand, when the subject position is not at 305, that is, away from the center of the image, the processing of the angular velocity subtraction amount calculation unit 114 is changed as follows.

  The change contents of the angular velocity subtraction amount calculation unit corresponding to the subject position will be described with reference to FIG. When the subject position detection unit 113 detects that the subject is at the position 305, threshold values A1, A2, B1, and B2 are set for performing shake correction control using the shake correction movable range to the maximum. FIG. 5A shows the shake correction movable range and the ranges of threshold values A1, A2, B1, and B2 when the vertical axis represents pitch and the horizontal axis represents yaw. Of the movable range 502 of the shake correction lens centered on the shake correction center position 501, the ranges of the thresholds A1 and B1 are indicated by 503a, and the ranges of the thresholds A2 and B2 are indicated by 504a. By setting the threshold values A1, A2, B1, and B2 in this way, shake correction control can be performed using the shake correction movable range to the maximum.

  On the other hand, when the subject is positioned at 304 and 306 in FIG. 3, the threshold values A1, A2, B1, and B2 of the pitch axis are changed. Here, when the subject is positioned at 304, thresholds A1, A2, B1, and B2 are set for performing control to weaken shake correction in the direction in which the subject moves toward the center of the screen. FIG. 5B shows the shake correction movable range and the threshold values A1, A2, B1, and B2 when the vertical axis represents pitch and the horizontal axis represents yaw. Of the movable range 502 of the shake correction lens centered on the shake correction center position 501, the range of threshold values A1 and B1 is indicated by 503b, and the range of threshold values A2 and B2 is indicated by 504b. By setting the threshold values A1, A2, B1, and B2 in this way, it is possible to perform shake correction control that makes it easy for the subject to transition to the center of the screen.

  When the subject is positioned at 302 and 308 in FIG. 3, the threshold values A1, A2, B1, and B2 of the yaw axis are changed. Here, when the subject is positioned at 302, thresholds A1, A2, B1, and B2 are set for performing control to weaken the shake correction in the direction in which the subject moves toward the center of the screen. FIG. 5C shows the shake correction movable range and the threshold values A1, A2, B1, and B2 when the vertical axis represents pitch and the horizontal axis represents yaw. Of the movable range 502 of the shake correction lens centered on the shake correction center position 501, the ranges of the thresholds A1 and B1 are indicated by 503c, and the ranges of the thresholds A2 and B2 are indicated by 504c. By setting the threshold values A1, A2, B1, and B2 in this way, it is possible to perform shake correction control that makes it easy for the subject to transition to the center of the screen.

  When the subject is located at 301, 303, 307, and 309 in FIG. 3, the threshold values A1, A2, B1, and B2 of the pitch axis and the yaw axis are changed. Here, when the subject is located at 307, thresholds A1, A2, B1, and B2 are set for performing control to weaken the shake correction in the direction in which the subject moves toward the center of the screen. At this time, FIG. 5D shows the shake correction movable range and the ranges of the thresholds A1, A2, B1, and B2 when the vertical axis represents pitch and the horizontal axis represents yaw. Of the movable range 502 of the shake correction lens centered on the shake correction center position 501, the ranges of the thresholds A1 and B1 are indicated by 503d, and the ranges of the thresholds A2 and B2 are indicated by 504d. By setting the threshold values A1, A2, B1, and B2 in this way, it is possible to perform shake correction control that makes it easy for the subject to transition to the center of the screen.

  FIG. 6 shows the control effect in this embodiment. A waveform 601 shows a shake correction target value calculated using the shake correction range of FIG. 5A without performing shake correction control according to the subject position. A waveform 602 shows a shake correction target value when shake correction control according to the subject position is performed. 3 shows time series data of pitch axis shake correction target values when the subject position changes from 305 to 304 in FIG. 3 at Timing 1 and the subject position changes from 304 to 305 in FIG. 3 at Timing 2.

  A shake correction target value is calculated between A2 and B2, and between Time 1 and Time 2, shake correction in the direction of the subject toward 305, that is, the direction of the subject toward the center of the screen is weakened. . By making the subject easily transition to the center of the screen in this way, it becomes possible to easily perform subject tracking while ensuring a certain degree of shake correction performance. In addition, since the subject easily shifts to the center of the screen, the photographer can easily perform the framing operation.

  However, during the shake correction control according to the subject position, the shake correction is weakened to some extent. Therefore, a method for reducing the adverse effect of subject tracking on shake correction control by changing shake correction during still image exposure and other than during still image exposure will be described below.

  In the shake correction control according to the subject position, the shake correction target value is calculated by the method described so far, but the subject position information is not used during still image exposure, and the threshold values A1, A2, B1 and B2 are set, and the shake correction target value is calculated.

FIG. 7 shows time-series data for explaining shake correction during still image exposure and other than during still image exposure. A waveform 701 represents a shake correction target value in the shake correction range of FIG. 5A when the shake correction control according to the subject position is not performed, and a waveform 702 is a shake correction control according to the subject position. This shows the shake correction target value when. Reference numeral 704 denotes an exposure start timing, and reference numeral 705 denotes an exposure end timing. If control is performed at the shake correction target position of the waveform 702 during the period from 704 to 705 during still image exposure, shake correction different from actual camera shake is performed due to the effect of subject tracking, and the effect of shake correction control is reduced. There is a risk that
Originally, during still image exposure between 704 and 705, it is desired to perform shake correction by the shake correction target position 701. Therefore, a difference between 701 and 702 at the timing of 704 is calculated as an offset, and a signal 703 obtained by subtracting the offset from the waveform 701 is used for a period of 704 to 705. When the still image exposure is completed at 705, a signal for returning to the waveform 702 at a constant speed is added to the waveform 703, and this addition is continued until 703 and 702 match.

  As described above, it is possible to eliminate the adverse effect of the shake correction effect reduction of the shake correction control according to the subject position during exposure.

  With reference to the flowchart of FIG. 8, the overall operation of the shake correction control of the present embodiment will be described. This flow starts when the main power of the camera is turned on and is executed at a constant sampling cycle.

  First, in step S801, the state of shake correction SW is detected. If it is ON, the process proceeds to step S802, and if OFF, the process proceeds to step S823. In step S802, the signal of the angular velocity meter 103 is captured.

  In the next step S803, it is determined whether or not the shake correction is possible. If the shake correction is possible, the process proceeds to step S804. If the shake correction is not possible, the process proceeds to step S823. Proceed. In the determination in step S803, it is assumed that shake correction is not possible from the start of power supply until the output of the angular velocity meter 103 is stabilized, and that shake correction is possible after the output of the angular velocity meter 103 is stabilized. . As a result, it is possible to prevent deterioration in shake correction performance due to shake correction performed in an unstable output value immediately after power supply.

  In step S804, it is determined from the image signal and AF information whether there is a tracking target. If there is a tracking target, the subject position is detected in step S806. In step S807, as described with reference to FIG. 5, threshold values A1, A2, B1, and B2 are calculated for the pitch axis and the yaw axis according to the subject position, and the process proceeds to step S808. If it is determined in step S804 that there is no tracking target, it is not necessary to perform shake correction according to the subject position. Therefore, in step S805, thresholds A1, A2, B1, and B2 (FIG. 5A) for performing shake correction control using the shake correction movable range to the maximum are calculated for the pitch axis and the yaw axis, respectively. The process proceeds to S808.

  From step S808 to step S812, an operation for calculating a shake correction target value 1 for performing shake correction according to the subject position is performed. In step S808, the previous sampling value of the shake correction target value 1 is acquired. In step S809, the angular velocity subtraction amount 1 is calculated from the threshold values A1, A2, B1, and B2 obtained in step S805 or step S807 and the shake correction target value 1 and angular velocity of the previous sampling obtained in step S808. . Next, in step S810, the angular velocity subtraction amount calculated in step S809 is subtracted from the angular velocity, and in step S811, the signal obtained in step S810 is integrated to calculate angle 1. In step S812, the shake correction target value 1 is calculated by multiplying the angle 1 by the sensitivity based on the focal length and the imaging magnification obtained from the zoom and focus information 107.

  From step S813 to step S818, an operation for calculating the shake correction target value 2 during still image exposure is performed. In step S813, thresholds A1, A2, B1, and B2 (FIG. 5A) for performing shake correction control using the shake correction movable range to the maximum are calculated for the pitch axis and yaw axis, respectively, and the process proceeds to step S814. move on. In step S814, the previous sampling value of the shake correction target value 2 is acquired. In step S815, an angular velocity subtraction amount 2 is calculated from the threshold values A1, A2, B1, and B2 obtained in step S813, and the shake correction target value 2 and angular velocity of the previous sampling obtained in step S814. Next, in step S816, the angular velocity subtraction amount 2 calculated in step S815 is subtracted from the angular velocity, and in step S817, the signal obtained in step S816 is integrated to calculate angle 2. In step S818, the shake correction target value 2 is calculated by multiplying the angle 2 by the sensitivity based on the focal length and the shooting magnification obtained from the zoom and focus information 107.

  In step S819, it is determined whether still image exposure is started. If the still image exposure state is not set, a shake correction target value 1 is set in step S820, and a shake correction target value corresponding to the subject position is selected. If it is determined in step S819 that the still image exposure state is set, a shake correction target value 2 is set in step S821, and the shake correction target value is selected by the method described with reference to FIG.

  Next, in step S822, the shake correction lens is driven based on the shake correction target value, the shake correction routine is terminated, and the next sampling cycle is awaited. In step S823, the drive of the shake correction lens is stopped, the shake correction routine is terminated, and the next sampling cycle is awaited.

  As described above, in the first embodiment, the position of the subject in the image is detected, and the shake correction control is changed so as to weaken the shake correction in the direction in which the subject moves toward the center of the screen. Accordingly, it is possible to perform shake correction control in which the subject easily shifts to the center of the screen while ensuring the shake correction control effect.

  As described above, it is possible to perform shake correction control in which the photographer can easily perform a framing operation on the main subject within the screen or at the center of the screen while reducing a decrease in shake correction performance even when the main subject is likely to be off the screen.

In the present embodiment, the so-called optical shake correction in which the shake correction lens is moved in a plane perpendicular to the optical axis has been described. However, the present invention is not limited to optical shake correction, and the following configuration may be used.
(1) A configuration in which shake correction is performed by moving the image sensor in a plane perpendicular to the optical axis.
(2) A configuration based on electronic shake correction that reduces the influence of shake by changing the cut-out position of each shooting frame output by the image sensor.
(3) A configuration that performs shake correction by combining a plurality of shake correction controls.

(Second Embodiment)
FIG. 9 is a block diagram of an image pickup apparatus including the image shake correction apparatus according to the second embodiment. The difference from the block diagram of the image shake correction apparatus of the first embodiment shown in FIG. 2 is that zoom and focus position information 107 is input to the angular velocity subtraction amount calculation unit 114.

  In the first embodiment, by changing shake correction control according to the position of the subject in the image, it is possible to perform shake correction control in which the subject easily shifts to the center of the screen while ensuring the shake correction control effect. Explained. However, there is a limit to the shake correction movable range, and when the ratio of the shake correction movable range with respect to the angle of view is small, the rate at which the subject can be tracked decreases, and the subject tracking cannot be performed very effectively. On the other hand, since the shake correction range cannot be used to the maximum extent, only a reduction in the shake correction effect is noticeable.

  FIG. 10A shows an example of the field angle and the shake correction movable angle range. When the horizontal axis represents the focal length and the vertical axis represents the angle, 1001 represents the field angle, and 1002 represents the shake correction movable angle range. When the focal length is small on the Wide side, the ratio of the shake correction movable angle range 1002 to the angle of view 1001 is small, and when the focal distance on the Tele side is large, the ratio of the shake correction movable angle range 1002 to the angle of view 1001 is growing. FIG. 10B is a graph showing the ratio 1003 of the shake correction movable angle range to the angle of view.

  When the ratio of the shake correction angle to the angle of view is large, it is desirable to actively perform subject tracking by changing the shake correction control according to the subject position. On the other hand, when the ratio of the shake correction angle to the angle of view is small, since the ratio of subject tracking is small, subject tracking is not so effective and the shake correction effect is weakened. Therefore, it is not desired to actively perform subject tracking that changes shake correction control according to the subject position. Therefore, in the second embodiment, the above problem is solved by performing control different from that of the first embodiment as follows.

  A ratio 1003 of the shake correction angle with respect to the angle of view in FIG. 10B is calculated from the focal length obtained from the zoom and focus position information 107 and the shake correction movable angle range. Whether or not to perform shake correction control according to the subject position is switched depending on whether the ratio 1003 of the shake correction movable angle range to the angle of view is smaller or larger than the threshold 1004. When the focal length 1003 is smaller than 1004, the threshold values A1, A2, B1, and B2 shown in FIG. 5A are always set, and the shake correction control is performed using the shake correction movable range to the maximum. When 1003 is a focal length of 1004 or more (focal length of a predetermined value or more), threshold values A1, A2, B1, and B2 are set according to the subject position, and shake correction control according to the subject position is performed.

  As described above, in the second embodiment, whether to perform shake correction control according to the subject position is set according to the ratio of the shake correction angle to the angle of view or the focal length. As a result, shake correction control that makes it easy for the subject to transition to the center of the screen is performed only under conditions where subject tracking is effective.In other cases, shake correction control is not performed according to the subject position, and the shake correction movable range is maximized. Used to limit the shake correction. Thereby, the shake correction effect is improved.

(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 various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

  The present invention can be mounted not only on an image blur correction apparatus for a digital single lens reflex camera and a digital compact camera but also in an imaging apparatus such as a digital video camera, a surveillance camera, a Web camera, and a mobile phone.

Claims (8)

An imaging device,
Imaging means for capturing a subject image;
On the basis of the shake amount of the image pickup device detected by the shake detection means for detecting a shake of the image pickup apparatus, a calculation means for calculating the shake correction amount for correcting the image blur caused by the shake of the image pickup device,
Position detecting means for detecting the position of the object in the image based on the image signal output from the pre-Symbol imaging means,
When the image is divided into blocks, it is detected in which block the subject is located in the divided image, and when the subject is located in a block away from the center of the image, image shake correction control by shake correction means is performed. The threshold for performing is changed from the threshold when the subject is positioned at the center in the image, and the previous value of the shake correction amount is changed when the previous value of the shake correction amount exceeds the changed threshold value. The subtraction amount of the shake correction amount when the difference between the value and the threshold value is greater than a predetermined value, and the subtraction amount when the difference between the previous value of the shake correction amount and the threshold value is less than the predetermined value. A subtraction amount calculating means for increasing the comparison ,
The calculation means subtracts the subtraction amount from the shake amount obtained from the shake detection means, thereby reducing the shake correction amount in the direction in which the subject is directed toward the center of the image and correcting the shake. An imaging apparatus that calculates a correction amount. It said position when the detection means can not detect the position of the subject, the imaging apparatus according to claim 1, characterized in that does not change the threshold value according to the position of the object. Further comprising determination means for determining in the still image exposure, the imaging apparatus according to claim 1, during the still image exposure, characterized in that does not change the threshold value according to the position of the object. Further comprising means for calculating a ratio of the corrected movable angular range deflection relative angle, when the ratio of the correction movable angular range deflection relative angle is large, make changes of the threshold value according to the position of the object relative to the angle of view The imaging apparatus according to claim 1 , wherein the threshold value is not changed according to the position of the subject when the ratio of the shake correction movable angle range is small. Further comprising an acquisition means for obtaining the focal length of the photographing optical system, wherein when the focal length is equal to or greater than a predetermined value, to change the said threshold value according to the position of the object, if the focal length is less than the predetermined value The imaging apparatus according to claim 1 , wherein the threshold value is not changed according to the position of the subject. A method for controlling an image pickup apparatus including an image pickup means for picking up a subject image,
On the basis of the shake amount of the image pickup device detected by the shake detection means for detecting a shake of the image pickup apparatus, a calculation step of calculating the shake correction amount for correcting the image blur caused by the shake of the image pickup device,
A position detection step of detecting a position of the object in the image based on the image signal output from the pre-Symbol imaging means,
When the image is divided into blocks, it is detected in which block the subject is located in the divided image, and when the subject is located in a block away from the center of the image, image shake correction control by shake correction means is performed. The threshold for performing is changed from the threshold when the subject is positioned at the center in the image, and the previous value of the shake correction amount is changed when the previous value of the shake correction amount exceeds the changed threshold value. The subtraction amount of the shake correction amount when the difference between the value and the threshold value is greater than a predetermined value, and the subtraction amount when the difference between the previous value of the shake correction amount and the threshold value is less than the predetermined value. And a subtraction amount calculation step for increasing the comparison,
In the calculation step, the shake amount is subtracted from the shake amount obtained from the shake detection means, thereby reducing the shake correction amount in the direction of the subject toward the center of the image and correcting the shake. A method for controlling an imaging apparatus, characterized by calculating a correction amount. The program for making a computer perform each process of the control method of Claim 6 . A computer-readable storage medium storing a program for causing a computer to execute each step of the control method according to claim 6 .

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