Anti-shake control device and method, imaging device, program and storage medium

Abstract

To perform image stabilization in accordance with characteristics of image stabilization performance depending on a focal length.SOLUTION: An image stabilization control apparatus performs image stabilization by controlling first correction means, which drives a correction lens to correct an image blur, and second correction means, which drives an imaging element to correct the image blur. The image stabilization control apparatus acquires a shake amount, selects one of a plurality of control methods including a first control method and a second control method that control a ratio between the respective shake amounts to be corrected by the first correction means and the second correction means on the basis of a focal length, and obtains a correction amount of one of the first correction means and the second correction means on the basis of the shake amount and the selected control method. The first control method is to perform an over-correction using the first correction means and an inverse-correction using the second correction means.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an image stabilization control device and method, a program, and a storage medium. [Background technology]

[0002] In recent years, imaging devices such as still cameras and video cameras are generally equipped with an image stabilization function. In particular, there are two types of optical image stabilization functions. One type realizes image stabilization by moving a correction lens dedicated mainly to image stabilization within a plane perpendicular to the optical axis (hereinafter referred to as "OIS: Optical Image Stabilizer"). The other type realizes image stabilization by moving an imaging element within a plane perpendicular to the optical axis (hereinafter referred to as "IBIS: In Body Image Stabilizer").

[0003] On the other hand, known directions of image blur include pitch blur, which is blur around a horizontal axis perpendicular to the optical axis, yaw blur, which is blur around a vertical axis perpendicular to the optical axis, and roll blur, which is blur around the optical axis, relative to the reference attitude of the imaging device.

[0004] Since IBIS moves the image sensor in a plane perpendicular to the optical axis, it can correct pitch shake and yaw shake, and can also move it in a rotational direction around the optical axis, so it can correct roll shake. On the other hand, OIS can correct pitch shake and yaw shake, but cannot correct roll shake even by rotating the correction lens.

[0005] Therefore, by simultaneously driving the OIS and IBIS (hereinafter referred to as "cooperative control"), it is possible to widen the vibration isolation range for pitch shake and yaw shake and also correct roll shake, compared to when only one of them is driven.

[0006] Furthermore, when the OIS and IBIS are controlled in a coordinated manner, the correction range can be maximized by appropriately setting the ratio between the amount of blur correction by the OIS and the amount of blur correction by the IBIS (see Patent Document 1). [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 6410431 Summary of the Invention [Problem to be solved by the invention]

[0008] However, it has been found that since the optimal amount of blur correction for image blur varies for each image height, blur correction residues at the periphery of the screen may become noticeable. The method disclosed in Patent Document 1 does not take into consideration any measures against the above problems.

[0009] The present invention has been made in consideration of the above-mentioned problems, and has as its object to provide a control device that can appropriately reduce the effects of blur even when the amount of blur caused by the image height varies depending on the image height. [Means for solving the problem]

[0010] In order to achieve the above object, the image stabilization control device of the present invention is an image stabilization control device that performs image stabilization by controlling a first correction means that corrects image shake by driving a correction lens included in an imaging optical system in a direction perpendicular to an optical axis, and a second correction means that corrects image shake by driving an imaging element that photoelectrically converts light incident via the imaging optical system and outputs an image signal in a direction perpendicular to the optical axis, and the first control means controls an acquisition means that acquires a shake amount from a detection means, and a ratio between the shake amount corrected by the first correction means and the shake amount corrected by the second correction means. and a calculation means for calculating a correction amount of either the first correction means or the second correction means based on the amount of shake and the control method selected by the selection means, wherein the first control method is a method for performing overcorrection that excessively corrects beyond the amount of shake within a range in which the first correction means can be driven out of a range in which the amount of shake can be corrected, and performing inverse correction that cancels out the amount of overcorrection by the second correction means. Effect of the Invention

[0011] According to the present invention, it is possible to provide a control device that can appropriately reduce the influence of blur even when the amount of blur caused varies depending on the image height. [Brief description of the drawings]

[0012] [Figure 1] 1 is a block diagram showing an example of the arrangement of a digital camera according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a detailed configuration of an image stabilization system according to the embodiment. [Diagram 3] 5A to 5C are schematic diagrams for explaining features of each method of cooperative control in the embodiment. [Figure 4] 5A and 5B are schematic diagrams illustrating the relationship between the focal length of a zoom lens and the emphasis control method in the first embodiment. [Diagram 5]5 is a flowchart of camera side image blur correction control in the first embodiment. [Figure 6] 5 is a flowchart of lens side image blur correction control in the first embodiment. [Figure 7] 10 is a flowchart of camera side image blur correction control in the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0014] FIG. 1 is a block diagram showing an example of the configuration of a digital camera, which is an embodiment of an imaging device of the present invention.

[0015] In this embodiment, the present invention will be described with respect to a case where it is implemented in a lens-interchangeable digital camera, but any electronic device having a camera function may be used, and in addition to cameras such as digital cameras and digital video cameras, it may also be a camera-equipped mobile phone, a camera-equipped computer, a game machine, etc. Also, the lens may be configured integrally with the camera body.

[0016] First, the configuration of the lens unit 200 will be described. The lens unit 200 includes an imaging optical system 150 including a zoom lens 101 , an image blur correction lens 102 , a focus lens 103 , and an aperture 104 , and a lens side control system 160 that controls the imaging optical system 150 .

[0017] The zoom lens 101 moves in the optical axis direction to optically change the focal length of the imaging optical system 150, thereby changing the imaging angle of view. The image blur correction lens 102 moves in a direction perpendicular to the optical axis to optically correct image blur caused by shaking of the imaging device. The focus lens 103 moves in the optical axis direction to optically adjust the focus position. The aperture 104 is used to adjust the amount of light entering the camera body 100.

[0018] In the lens side control system 160, the zoom lens control unit 127 receives a zoom operation instruction from the operation unit 114 provided in the camera body 100 via the lens side communication unit 128, and drives the zoom lens 101 via the zoom lens driving unit 124. This changes the angle of view (focal length) of the lens unit 200. The focus lens driving unit 121 drives the focus lens 103 based on a drive instruction for the focus lens 103 received from the camera body 100 via the lens side communication unit 128 . The aperture driver 120 controls the aperture 104 based on the aperture value received from the camera body 100 via the lens side communication unit 128 .

[0019] The lens side shake detection unit 125 detects shake of the lens unit 200 and outputs information related to the detected shake. Generally, a gyro sensor is used as a sensor component for detecting shake, and detects the angular velocity of the shake and outputs it to the lens side vibration isolation control unit 126. The lens vibration reduction position detection unit 123 detects the position of the image blur correction lens 102 in a direction perpendicular to the optical axis, and outputs the detected position information to the lens side vibration reduction control unit 126 . A camera information management unit 129 on the lens unit 200 side holds and manages setting information of the camera body 100 and information on the current position and driving limit of the image sensor 106 .

[0020] The lens side vibration reduction control unit 126 determines the amount of vibration reduction and the correction direction for suppressing vibration, based on the amount of vibration detected by the lens side vibration detection unit 125, position information of the image vibration correction lens 102 detected by the lens vibration reduction position detection unit 123, and information managed by the camera information management unit 129. Then, the lens side vibration reduction control unit 126 controls the lens vibration reduction driving unit 122 based on the determined amount of vibration reduction and correction direction, and drives the image vibration correction lens 102 by the amount of vibration reduction in the image vibration correction direction.

[0021] Next, the configuration of camera body 100 will be described. The shutter 105 is a mechanical focal plane shutter and includes a front curtain and a rear curtain. A shutter drive unit 136 drives the shutter 105. The front curtain and the rear curtain are fixed at a position (exposure position) retracted from the optical path during video capture, and allow light incident via the lens unit 200 to pass through, forming an image on the image sensor 106.

[0022] During still image shooting, the front curtain performs exposure travel to move from a light-shielding position on the optical path to an exposure position while the rear curtain is held at the exposure position, thereby passing light. Then, after a preset exposure time (shutter speed) has elapsed since the front curtain was moved, the rear curtain performs light-shielding travel to move from the exposure position to the light-shielding position, completing an exposure operation for one shot. The exposure operation for adjusting the exposure time using the front and rear curtains of the shutter 105 described above is known as a so-called "mechanical shutter system." Also known is a so-called "electronic shutter method" in which the exposure time is controlled by combining electrical reset scanning (electronic front curtain) of the image sensor 106 and the travel of the rear curtain of the shutter 105.

[0023] Light passing through the imaging optical system 150 and the shutter 105 is received by an imaging element 106 using a CCD (charge-coupled device) or a CMOS (complementary metal-oxide semiconductor) sensor, and photoelectrically converted into an electrical signal. Note that the imaging element 106 in this embodiment has a function of optically correcting image blur by moving in a direction perpendicular to the optical axis.

[0024] The AD converter 107 performs noise removal processing, gain adjustment processing, and AD conversion processing on the electrical signal (image signal) read out from the image sensor 106 to generate image data. The timing generator 108 controls the drive timing of the image sensor 106 and the drive timing of the AD converter 107 according to instructions from the camera control unit 143. The image processing circuit 109 performs pixel interpolation processing, color conversion processing, etc. on the image data output from the AD converter 107, and then sends the processed image data to the internal memory 110.

[0025] The display unit 111 displays image data stored in the internal memory 110, shooting information, and the like. The compression / decompression processing unit 112 performs compression processing on the image data stored in the internal memory 110 in accordance with the image format, and stores the compressed image data in the storage memory 113. In addition, the compression / decompression processing unit 112 reads compressed image data from the storage memory 113, performs decompression processing on the image data, and stores the decompressed image data in the internal memory 110. The storage memory 113 stores various data such as parameters in addition to image data. The operation unit 114 is a user interface that allows the user to enter various instructions, including zoom operation instructions and shooting instructions, as well as to perform various menu operations and mode switching operations.

[0026] In the camera-side control system 115, the camera control unit 143 is composed of a calculation unit such as a CPU (Central Processing Unit), and controls the entire imaging device by executing various control programs stored in the internal memory 110 in response to user operations via the operation unit 114. The control programs include, for example, programs for performing zoom control, image blur correction control, automatic exposure control, automatic focus adjustment control, processing for detecting the face of a subject, etc. In the case of a lens-interchangeable camera, the camera-side communication unit 135 and the lens-side communication unit 128 control the transmission of information between the camera body 100 and the lens unit 200.

[0027] The luminance signal detector 142 detects the luminance of the subject and the entire image from the image data output from the AD converter 107 . The exposure control unit 139 calculates the exposure value (aperture value and exposure time) based on the luminance information obtained by the luminance signal detection unit 142, and outputs the aperture value to the aperture drive unit 120 of the lens unit 200 via the camera side communication unit 135, and outputs the exposure time to the shutter drive unit 136. The exposure control unit 139 also simultaneously performs control for the AD converter 107 to perform gain adjustment processing on the imaging signal read out from the imaging element 106, based on the sensitivity set automatically according to the user's operation via the operation unit 114 or the luminance. This performs automatic exposure control (AE control).

[0028] The evaluation value calculation unit 141 extracts a specific frequency component from the luminance information obtained by the luminance signal detection unit 142, and calculates a contrast evaluation value based on the extracted frequency component. The focus lens control unit 140 issues a command to drive the focus lens 103 by a predetermined drive amount over a predetermined range, and acquires a contrast evaluation value that is a calculation result of the evaluation value calculation unit 141 at each focus lens position. Then, based on the focus lens position where the change curve of the contrast evaluation value reaches its peak, the focus lens control unit 140 calculates a defocus amount by the contrast AF method, and transmits the defocus amount to the focus lens driving unit 121 of the lens unit 200 via the camera side communication unit 135. The focus lens driving unit 121 drives the focus lens 103 by the defocus amount, thereby performing automatic focusing control (AF control) in which a light beam is focused on the imaging surface of the imaging element 106. Note that, although the contrast AF method has been described here, a phase difference AF method may be used. The phase difference AF method is well known, and therefore a description thereof will be omitted here.

[0029] The camera-side shake detection unit 134 detects shake of the camera body 100 and outputs information related to the detected shake. As with the lens-side shake detection unit 125, a gyro sensor is generally used as a sensor component for detecting shake vibrations, and detects the angular velocity of the shake and outputs it to the camera-side vibration isolation control unit 133. The image sensor vibration isolation position detection section 132 detects the position of the image sensor 106 in a direction perpendicular to the optical axis, and outputs the detected position information to the camera-side vibration isolation control section 133 . A lens information management unit 137 holds and manages, on the camera body 100 side, optical characteristic information of the image blur correction lens 102, information on the current position, and information on the driving limit.

[0030] The camera-side vibration reduction control unit 133 determines the amount of shake correction and the correction direction for suppressing shake, based on the amount of shake detected by the camera-side vibration detection unit 134, position information of the image sensor 106 detected by the image sensor vibration reduction position detection unit 132, and information managed by the lens information management unit 137. Then, the camera-side vibration reduction control unit 133 controls the image sensor vibration reduction drive unit 130 based on the determined amount of shake correction and correction direction, and drives the image sensor 106 by the amount of shake correction in the image shake correction direction.

[0031] The image synthesis processing unit 131 converts the image blur correction amount calculated by the camera-side vibration reduction control unit 133 into the image shift amount between images by multiplying the amount by an appropriate coefficient. By appropriately controlling the scanning range of the next image to be captured based on this image shift amount, it is possible to correct camera shake occurring between images. By continuously performing this operation, electronic vibration reduction that suppresses image degradation due to camera shake is performed.

[0032] FIG. 2 is a block diagram showing the detailed configuration of an image shake correction system (OIS) on the lens unit 200 side and an image shake correction system (IBIS) on the camera body 100 side.

[0033] First, the image blur correction system (IBIS) on the camera body 100 side will be described. The angular velocity of the shake detected by the camera-side shake detection unit 134 is integrated by a camera-side integration unit 161 of the camera-side vibration isolation control unit 133 and converted into a shake angle. A camera-side shake correction amount calculation unit 162 performs a calculation to determine a shake correction amount that cancels the shake angle, taking into account the frequency band of the shake angle and the range in which the image sensor 106 can be driven.

[0034] The camera-side control method determination unit 166 determines which method of cooperative control of the IBIS and the OIS to select (any of the peripheral blur correction method, cooperative control method 1, and cooperative control method 2). Details of each method and details of the process performed by the camera-side control method determination unit 166 will be described later. Camera side ratio accumulator 163 accumulates the ratio of the shake correction amount provided by the IBIS to the shake correction amount found by camera side shake correction amount calculator 162, based on the cooperative control method selected by camera side control method determiner 166.

[0035] If the target position to which the image sensor 106 is driven based on the amount of shake correction exceeds the driving limit of the image sensor 106, the camera-side driving range limiter 164 limits the amount of shake correction. The camera-side PID control unit 165 performs feedback control using the current position of the image sensor 106 acquired by the image sensor vibration isolation position detection unit 132 so that the image sensor 106 follows the target position to which the image sensor 106 is driven. Note that since PID control is a common technique, details will be omitted. Also, the feedback control method is not limited to PID control.

[0036] Furthermore, the camera-side image stabilization control unit 133 calculates the amount of image shift between the images, and instructs the image synthesis processing unit 131 to perform electronic image stabilization control.

[0037] Next, the image stabilization system (OIS) on the lens unit 200 side will be described. The angular velocity of the shake detected by the lens-side shake detection unit 125 is integrated by a lens-side integration unit 151 of the lens-side image stabilization control unit 126 and converted into a shake angle. A lens-side shake correction amount calculation unit 152 performs a calculation to determine the shake correction amount that cancels the shake angle, taking into account the frequency band of the shake angle and the range in which the image shake correction lens 102 can be driven.

[0038] Lens side ratio accumulation unit 153 accumulates the ratio of the amount of shake correction performed by the OIS to the amount of shake correction calculated by lens side shake correction amount calculation unit 152, based on the method of cooperative control of the IBIS and the OIS selected by camera side control method determination unit 166.

[0039] A lens side driving range limiter 154 limits the amount of blur correction when the target position to which the image blur correction lens 102 is driven based on the amount of blur correction exceeds the driving limit of the image blur correction lens 102 . The image blur correction lens PID control unit 155 performs feedback control using the current position of the image blur correction lens 102 acquired by the lens vibration isolation position detection unit 123 so that the image blur correction lens 102 follows the target position to which the image blur correction lens 102 is driven. Note that PID control is a common technique, so details are omitted. Also, the feedback control method is not limited to PID control.

[0040] Next, the types of cooperative control for simultaneously driving the OIS and IBIS in this embodiment and the characteristics of image blur correction by each cooperative control will be described with reference to Fig. 3. In each graph shown in Fig. 3, the X-axis represents the amount of shake within the range correctable by the OIS and IBIS, and the Y-axis represents the amount of shake correction.

[0041] Of the three control methods shown in FIG. 3, cooperative control methods 1 and 2 are methods that perform control so that the direction of relative movement between the subject image generated by the OIS and the image sensor coincides with the direction of relative movement between the subject image generated by the IBIS and the image sensor. In cooperative control methods 1 and 2, the ratio of the shake correction amount of the OIS and IBIS is less than 100% and is calculated from the movable range of the OIS and IBIS. In other words, neither the OIS correction amount nor the IBIS correction amount exceeds the correction amount corresponding to the detected shake (the correction amount for correcting the detected shake). On the other hand, in the peripheral blur correction method, the ratio of the blur correction amount provided by the OIS is controlled to a state exceeding 100% (hereinafter referred to as "overcorrection control"). Then, the ratio of the blur correction amount provided by the IBIS is controlled in a direction that cancels the amount by which the OIS exceeds 100%, i.e., to a negative state (hereinafter referred to as "reverse correction control"), thereby correcting image blur. In other words, the correction amount provided by the OIS exceeds the correction amount corresponding to the detected blur, and the correction amount provided by the IBIS has an opposite sign (reverse drive direction) to the correction amount corresponding to the detected blur. Details will be explained below.

[0042] In the image stabilization by the cooperative control method 1, the amount of image stabilization is corrected by an amount equal to the amount of shake, so the relationship between the amount of shake and the amount of image stabilization is Y=X. In addition, the ratio between the amount of image stabilization by the OIS and the amount of image stabilization by the IBIS is expressed. In the cooperative control method 1, the amount of image stabilization by the OIS and the amount of image stabilization by the IBIS are increased while maintaining a constant ratio until the maximum movable range of the image stabilization lens 102 driven by the OIS is reached. This constant ratio is determined by the ratio between the maximum movable range of the image stabilization lens 102 driven by the OIS and the maximum movable range of the image sensor 106 driven by the IBIS. For example, if the maximum movable range of the image stabilization lens 102 and the image sensor 106 are the same, the constant ratio is 50%. Note that the ratio of the maximum movable ranges does not refer to the ratio of the distances over which the image stabilization lens 102 or the image sensor 106 can actually be driven, but rather to the ratio of the distances over which relative movement can be caused between the subject image and the image plane of the image sensor by driving the image stabilization lens 102 or the image sensor 106.

[0043] In blur correction using the peripheral blur correction method, overcorrection control is performed so that the amount of blur correction by the OIS exceeds the amount of shake, up to the maximum movable range of the image blur correction lens 102 driven by the OIS. On the other hand, inverse correction control is performed so that the amount of blur correction by the IBIS is set to an amount that cancels the amount of blur correction by the OIS that exceeds the amount of shake.

[0044] As mentioned above, the optimal amount of image blur correction for image shake changes for each image height. The change in the amount of image blur correction for each image height varies depending on the lens characteristics, but is steeper with IBIS. Therefore, when the two types of image blur correction functions mentioned above are operated simultaneously, making the ratio of the amount of image blur correction by OIS larger than the ratio of the amount of image blur correction by IBIS will make the change in the amount of image blur correction for each image height more gradual, making the remaining image blur correction at the edges of the screen less noticeable. Therefore, in the peripheral blur correction method, OIS performs overcorrection control, while IBIS performs inverse correction control to minimize the remaining blur correction at the periphery of the screen. Inverse correction control moves the image sensor in the same direction as the relative movement between the subject image and the imaging surface of the image sensor that occurs due to blur, so inverse correction control is a control that would result in greater blur without overcorrection by OIS. In particular, if the section in which the image blur correction lens 102 is moved so that the amount of blur correction by the OIS is at its maximum ratio is taken as section A, and the remaining section up to the maximum movable range of the image blur correction lens 102 is taken as section B, section A is the section in which the OIS and the IBIS perform overcorrection and reverse correction, respectively, and section B is the section in which the amount of blur correction in excess of the overcorrection and the amount of blur correction in reverse correction gradually decrease.

[0045] Furthermore, if the section of the shake amount after the maximum movable range of the image shake correction lens 102 is exceeded is called section C, then in section C, no further image shake correction can be performed by the OIS, so only the amount of shake correction by the IBIS increases. Therefore, in section C, the ratio of the amount of shake correction by the OIS to the amount of shake correction by the IBIS is not constant, but fluctuates.

[0046] Furthermore, the peripheral blur correction method imposes a significantly larger computational load on the ratio than cooperative control method 1, so in order to suppress the computational load, the movable range of the image sensor 106 used in the IBIS is limited. As a result, with the peripheral blur correction method, the vibration reduction range when the OIS and IBIS are driven simultaneously is narrower than with cooperative control method 1. Therefore, cooperative control method 1 has an advantage in terms of vibration reduction performance.

[0047] This problem does not have a significant effect on vibration isolation performance when the focal length is short (wide side) for the same amount of image blur, since the amount of blur correction is small. However, when the focal length is long (telephoto side), the amount of blur correction required tends to be large, and a small movable range can lead to a decrease in vibration isolation performance. Therefore, in this embodiment, vibration isolation is performed according to the characteristics of the vibration isolation effect depending on the focal length.

[0048] Cooperative control method 2 is based on the same basic concept as cooperative control method 1, but takes into account the optical characteristics of the lens and allocates a particularly high proportion of the image blur correction amount to the OIS. This is because the amount of image blur remaining on the periphery of the image can be reduced by allocating a large amount of image blur correction amount to the OIS, which has a smaller change in image blur correction amount for each image height.

[0049] If the section D is the section in which the amount of shake allocated mostly to the OIS is up to the maximum movable range of the image shake correction lens 102 driven by the OIS, then in section E beyond section D, the OIS cannot perform any more image shake correction, and only the amount of shake correction by the IBIS increases. Therefore, in section E, the ratio of the amount of shake correction by the OIS and the amount of shake correction by the IBIS is not constant, but fluctuates.

[0050] <First embodiment> A first embodiment of the present invention will now be described. FIG. 4 is a schematic diagram illustrating the focal length of a zoom lens and control switching in the first embodiment of the present invention, with the vertical axis showing the focal length for each type of zoom lens, with the focal length increasing further up the graph.

[0051] Zoom lens 1 is an example of a wide-angle zoom lens. When the focal length is short, the amount of blur correction is small, but blur correction residues at the periphery of the screen tend to be noticeable. For this reason, the peripheral blur correction method is selected over the entire range of focal lengths that can be changed by zoom lens 1.

[0052] The zoom lens 2 is an example of a medium telephoto zoom lens whose telephoto focal length is longer than the second predetermined value. When the focal length is long, the amount of blur correction is large, and therefore the vibration reduction performance deteriorates if the movable range is small. However, when the focal length is long, the rate of change of the optimal amount of blur correction for image blur for each image height is small compared to when the focal length is short, so the remaining blur correction at the periphery of the screen becomes less noticeable. Therefore, when the focal length is longer than the first predetermined value, the cooperative control method 1 with a wide vibration reduction range is applied, and when the focal length is equal to or less than the first predetermined value, the peripheral blur correction method is applied. The first predetermined value is a predetermined value that balances the vibration reduction performance and the remaining blur correction at the periphery of the screen.

[0053] Zoom lens 3 is an example of a zoom lens in which the difference between wide and telephoto is equal to or greater than a fifth predetermined value, i.e., the focal length has a large fluctuation range. In this case, when the current focal length is equal to or less than a fourth predetermined value, the peripheral blur correction method is applied, and when the focal length is longer than a third predetermined value, cooperative control method 1 with a wide vibration isolation range is applied. When the focal length is longer than the fourth predetermined value and equal to or less than the third predetermined value, cooperative control method 2, which strikes a balance between the peripheral blur correction method and cooperative control method 1, is applied.

[0054] Next, the above control flow in this embodiment will be described with reference to the flowcharts of Figures 5 and 6. Figure 5 is a flowchart of camera side image blur correction control in the first embodiment, and Figure 6 is a flowchart of lens side image blur correction control in the first embodiment. The controls in Figures 5 and 6 are executed, for example, when lens unit 200 is attached to camera body 100, or in response to a zoom operation on operation section 114 of camera body 100.

[0055] First, the camera side image blur correction control will be described with reference to the flowchart in FIG. When camera-side image blur correction control is started, in S101, the camera-side control method determination unit 166 determines whether or not the difference between the focal length on the telephoto side and the focal length on the wide-angle side of the lens unit 200, acquired by initialization communication when the lens unit 200 is attached to the camera body 100, is equal to or greater than a fifth predetermined value. Here, for example, information on the focal length range may be acquired from the lens unit 200, or information on the focal length range stored in advance in the internal memory 110 of the camera body 100 may be acquired based on model information of the lens unit 200, etc.

[0056] If the difference in focal length is equal to or greater than a fifth predetermined value, the process proceeds to S102, where it is determined whether the current focal length (hereinafter simply referred to as "focal length") is equal to or less than a fourth predetermined value. If the focal length is equal to or less than the fourth predetermined value, i.e., on the wide side, the process proceeds to S104, where camera-side control method determination unit 166 sets a peripheral blur correction method in order to prioritize reduction of the remaining blur correction amount in peripheral image quality. This causes camera body 100 to start preparations for reverse correction using IBIS.

[0057] If the focal length is longer than the fourth predetermined value, in S103 it is determined whether the focal length is longer than a third predetermined value. If the focal length is long, that is, on the telephoto side, the process proceeds to S105, where the camera-side control method determination unit 166 sets cooperative control method 1 to prioritize image stabilization performance.

[0058] If the current focal length is equal to or less than the third predetermined value, that is, if the focal length is an intermediate length, the process proceeds to S106, and the camera-side control method determination unit 166 sets cooperative control method 2, which is a control that balances vibration isolation performance and reduction of residual blur in peripheral image quality.

[0059] On the other hand, if it is determined in S101 that the difference between the telephoto focal length and the wide-angle focal length of the lens unit 200 is smaller than the fifth predetermined value, the process proceeds to S107, where it is determined whether the telephoto focal length of the lens unit 200 is longer than a second predetermined value. If it is equal to or smaller than the second predetermined value, the process proceeds to S104, where the camera-side control method determination unit 166 sets the peripheral blur correction method. This causes the camera body 100 to start preparations for inverse correction using the IBIS.

[0060] On the other hand, if the focal length on the telephoto side of the lens unit 200 is longer than the second predetermined value, the process proceeds to S108 to determine whether the focal length is equal to or less than the first predetermined value. If the focal length is equal to or less than the first predetermined value, that is, if it is on the wide side, the process proceeds to S104, and the camera-side control method determination unit 166 sets the peripheral blur correction method in order to prioritize reduction of the remaining blur correction amount in the peripheral image quality.

[0061] If the focal length is longer than the first predetermined value, that is, on the telephoto side, the process proceeds to S105 and the camera-side control method determination unit 166 sets cooperative control method 1 in order to prioritize image stabilization performance.

[0062] When the control method for image blur correction is set to any one of the peripheral blur correction method, cooperative control method 1, and cooperative control method 2 by the above processing, in S111, lens information is received from the lens unit 200. Here, the lens information includes the maximum movable range of the OIS image blur correction lens 102, the maximum ratio of the OIS shake correction amount, the range of the shake amount for moving the image blur correction lens 102 at the maximum ratio, and the current position of the image blur correction lens 102. These are required for ratio calculation when performing inverse correction by the IBIS.

[0063] In S112, the camera information and the control method of the image blur correction set by the camera-side control method determination unit 166 in the processes of S101 to S108 are transmitted to the lens unit 200. Here, the camera information includes the maximum movable range of the IBIS image sensor 106 and the current position of the image sensor 106. These are required for ratio calculation when the lens unit 200 performs overcorrection by the OIS.

[0064] In S113, it is determined whether or not to start still image shooting. If still image shooting is to be started, in S114, the amount of shake is acquired from the camera-side shake detection unit 134. The unit of the amount of shake at this time is angular velocity. Then, in S115, the amount of shake is integrated by the camera-side integration unit 161, and the angular velocity is converted into an angle (shake angle).

[0065] In S116, camera-side blur correction amount calculation unit 162 calculates a correction amount for canceling the blur angle, taking into consideration the frequency band of the blur angle and the range in which image sensor 106 can be driven. Then, in S117, camera-side ratio accumulator 163 accumulates the calculated correction amount by the ratio calculated based on the control method of image blur correction set by camera-side control method determination unit 166. In the case of the peripheral blur correction method, although it depends on the magnitude of the blur angle, IBIS becomes a negative ratio in the range where the detected blur angle is less than a predetermined value (range A to B in FIG. 3).

[0066] In S118, if the image blur correction amount exceeds the drivable range of the image sensor 106, the camera side driving range limiter 164 performs processing to limit the amount to within the drivable range of the image sensor 106. Then, in S119, the camera side PID controller 165 performs feedback control of the image sensor 106.

[0067] On the other hand, if still image shooting is not started in S113, feedback control is performed in S120 to hold the image sensor 106 at the central position. After the feedback control in S119 or S120 ends, the camera side image blur correction control ends.

[0068] Next, the lens side image blur correction control will be described with reference to the flowchart in FIG. First, in S201, lens information is transmitted to camera body 100, and in S202, camera information and the image blur correction control method set by camera-side control method determination unit 166 by the processes of S101 to S108 described above are received from camera body 100. Then, in accordance with the control method of the image blur correction obtained in S203, one of the peripheral blur correction method, the cooperative control method 1, and the cooperative control method 2 is set in S204 to S206.

[0069] In S207, the amount of shake is obtained from the lens side shake detection unit 125. The unit of the amount of shake at this time is angular velocity. Then, in S208, the amount of shake is integrated by the lens side integration unit 151, and the angular velocity is converted into an angle (shake angle). In S209, lens side blur correction amount calculation unit 152 calculates the amount of correction to cancel the blur angle, taking into consideration the frequency band of the blur angle and the drivable range of the camera. Then, in S210, lens side ratio accumulator 153 accumulates the calculated amount of correction by the ratio calculated based on the control method of the image blur correction set in any of S204 to S206. In the case of the peripheral blur correction method, although it also depends on the magnitude of the blur angle, the correction by OIS will be a ratio exceeding 100% of the correction amount in the range where the detected blur angle is less than a predetermined value (range A to B in FIG. 3).

[0070] In S211, if the image blur correction amount exceeds the driveable range of the image blur correction lens 102, the lens side driving range limiter 154 performs processing to limit the image blur correction lens 102 to the driveable range. Then, in S212, the image blur correction lens PID controller 155 performs feedback control of the image blur correction lens 102, and the lens side image blur correction control ends.

[0071] In addition, in order to make the most of the IBIS, which tends to have a narrow range of motion during cooperative control, at the time of exposure, the OIS will not remain in the center position unless the photographer intentionally turns off the image stabilization function. Therefore, in lens-side image blur correction control, there is no branching process due to the start of still image capture, such as S107 in Figure 5 in camera-side image blur correction control.

[0072] As described above, according to the first embodiment, it is possible to implement control that achieves a good balance between vibration isolation performance and reduction of blur correction remaining at the periphery of the screen, depending on the type and focal length of each zoom lens.

[0073] <Second embodiment> Next, a second embodiment of the present invention will be described.

[0074] In the first embodiment, the control method for image stabilization is set according to not only the current focal length but also the range of focal lengths over which the lens unit 200 can be changed. In contrast, in the second embodiment, a case will be described in which the control method for image stabilization is simply set according to only the current focal length.

[0075] FIG. 7 is a flowchart showing camera side image blur correction control in the second embodiment. When camera-side image blur correction control is started, in S301, it is determined whether the focal length of lens unit 200 is equal to or less than a first predetermined value. Here, the first predetermined value may be the same as the first predetermined value shown in FIG. 4, for example. If the focal length is equal to or less than the first predetermined value, that is, on the wide side, the process proceeds to S302, where camera-side control method determination unit 166 sets a peripheral blur correction method in order to prioritize reduction of the remaining blur correction of peripheral image quality. This causes camera body 100 to start preparation for reverse correction by IBIS.

[0076] On the other hand, if the focal length is longer than the first predetermined value, that is, on the telephoto side, the process proceeds to S303, where the camera-side control method determination unit 166 sets cooperative control method 1 to prioritize image stabilization performance.

[0077] Since the process from S111 onwards is similar to the process from S111 onwards in FIG. 5, the same step numbers are used and the description thereof will be omitted.

[0078] The lens side image blur correction control is the same as the control described above with reference to the flowchart of Fig. 6. However, in S202, instead of the processes of S101 to S108, the control method of the image blur correction set by the camera side control method determination unit 166 in the processes of S301 to S303 described above is received.

[0079] As described above, according to the second embodiment, it is possible to more easily implement control that achieves a good balance between image stabilization performance and reduction of remaining blur correction at the periphery of the screen, depending on the focal length.

[0080] In the above-mentioned first and second embodiments, the case where the control method of the image stabilization is set in the camera body 100 has been described, but the present invention is not limited to this, and the control method may be set in the lens unit 200. In this case, a control method determination unit equivalent to the camera side control method determination unit 166 may be provided in the lens unit 200, which performs the processes of S101 to S108 in FIG. 5 and notifies the camera body 100 of the setting contents. In this way, when the operation member of the zoom lens is in the lens unit 200, it is possible to eliminate the need to notify the camera body 100 of the focal length in order to set the control method of the image stabilization. Also, the camera body 100 and the lens unit 200 may each determine the control method of the image stabilization. In this case, it is not necessary to notify the setting contents.

[0081] Also, in the above-described first and second embodiments, a description has been given of the case where the shake correction amount is calculated for each of the IBIS and the OIS in each of the camera body 100 and the lens unit 200. However, the shake correction amount may be calculated in either the camera body 100 or the lens unit 200, in which case the calculated shake correction amount may be notified to the IBIS and the OIS.

[0082] Also, in the above-mentioned first and second embodiments, the case where three types of control methods are switched has been described. However, the same effect can be obtained by switching between a peripheral blur correction method in which the blur correction amount of the OIS performs overcorrection control exceeding the correction amount corresponding to the detected blur and the IBIS performs correction in the opposite direction to the OIS, and a cooperative control method 1 or 2 in which the blur correction amount of the OIS is equal to or less than the correction amount corresponding to the detected blur and the IBIS and the OIS perform correction in the same direction according to the focal length. Note that performing correction in the opposite direction to the OIS does not mean that the actual drive direction of the image sensor is opposite to the drive direction of the image blur correction lens 102, but means that the direction of the relative movement between the image sensor and the subject image caused by the drive is opposite.

[0083] <Other embodiments> The present invention may be applied to a system made up of a plurality of devices, or to an apparatus made up of a single device.

[0084] The present invention can also be realized by supplying a program for implementing one or more of the functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program. It can also be realized by a circuit (e.g., ASIC) that implements one or more of the functions.

[0085] <Summary> The disclosure of this embodiment includes the following configuration.

[0086] (Configuration 1) An image stabilization control device for performing image shake correction by controlling a first correction means for correcting image shake by driving a correction lens included in an imaging optical system in a direction perpendicular to an optical axis, and a second correction means for correcting image shake by driving an imaging element that photoelectrically converts light incident via the imaging optical system and outputs an image signal in a direction perpendicular to the optical axis, An acquisition means for acquiring an amount of shake from the detection means; a selection means for selecting one of a plurality of control methods including a first control method and a second control method for controlling a ratio between the amount of shake corrected by the first correction means and the amount of shake corrected by the second correction means, based on a focal length of the imaging optical system; a calculation means for calculating a correction amount of either the first correction means or the second correction means based on the shake amount and the control method selected by the selection means, The first control method is a method of performing over-correction that exceeds the amount of shake within a range in which the amount of shake can be corrected and within a range in which the first correction means can be driven, and performing inverse correction that cancels out the amount of over-correction by the second correction means.

[0087] (Configuration 2) The image stabilization control device according to configuration 1, characterized in that the selection means selects the first control method when the focal length is equal to or less than a first predetermined value, and selects the second control method when the focal length is longer than the first predetermined value.

[0088] (Configuration 3) 3. The vibration control device according to configuration 1 or 2, wherein the second control method is a method in which the first correction means performs correction within a range not exceeding the amount of vibration.

[0089] (Configuration 4) The second control method is a method of correcting the amount of shake by using a predetermined constant ratio between the first correction means and the second correction means over a range in which the amount of shake can be corrected.

[0090] (Configuration 5) 4. The image stabilization control device according to configuration 3, wherein the second control method is a method in which the first correction means is given priority over the second correction means in correcting the amount of shake.

[0091] (Configuration 6) The plurality of control methods further includes a third control method, the selection means further selects one of the first control method, the second control method, and the third control method according to a range in which the focal length of the imaging optical system can be changed; The third control method is a method in which the first correction means is made to perform the correction of the shake amount preferentially over the second correction means. 6. An anti-vibration control device according to any one of configurations 1 to 5.

[0092] (Configuration 7) The image stabilization control device according to configuration 6, characterized in that the selection means selects the first control method or the second control method when the range in which the focal length can be changed is smaller than a second predetermined value that is determined in advance.

[0093] (Configuration 8) The anti-vibration control device according to configuration 7, wherein the selection means further selects the first control method or the second control method based on the focal length when the range in which the focal length can be changed includes a focal length longer than a predetermined third predetermined value, and selects the first control method when the range does not include a focal length longer than the third predetermined value.

[0094] (Configuration 9) The image stabilization control device according to any one of configurations 6 to 8, characterized in that the selection means selects the first control method when the range in which the focal length can be changed is equal to or greater than a predetermined second predetermined value and the focal length is equal to or less than a predetermined fourth predetermined value, selects the second control method when the focal length is greater than a predetermined fifth predetermined value that is greater than the fourth predetermined value, and selects the third control method when the focal length is greater than the fourth predetermined value and equal to or less than the fifth predetermined value.

[0095] (Configuration 10) The vibration control device according to any one of configurations 1 to 9, further comprising a notification means for notifying a means for calculating a correction amount of the other of the first correction means and the second correction means of the control method selected by the selection means.

[0096] (Configuration 11) An image stabilization control device for performing image shake correction by controlling a first correction means for correcting image shake by driving a correction lens included in an imaging optical system in a direction perpendicular to an optical axis, and a second correction means for correcting image shake by driving an imaging element that photoelectrically converts light incident via the imaging optical system and outputs an image signal in a direction perpendicular to the optical axis, An acquisition means for acquiring an amount of shake from the detection means; a selection means for selecting one of a plurality of control methods including a first control method and a second control method for controlling a ratio between the amount of shake corrected by the first correction means and the amount of shake corrected by the second correction means, based on a focal length of the imaging optical system; a calculation means for calculating a correction amount for each of the first correction means and the second correction means based on the shake amount and the control method selected by the selection means, The first control method is a method of performing overcorrection that exceeds the shake amount within a range in which the shake amount can be corrected and a reverse correction that cancels the overcorrection by the second correction means, within a range in which the first correction means can be driven, among a range in which the shake amount can be corrected, The second control method is a method of correcting the amount of shake by using a predetermined ratio between the first correction means and the second correction means over a range in which the amount of shake can be corrected. 13. An anti-vibration control device comprising:

[0097] (Configuration 12) A vibration reduction control method for performing image blur correction by controlling a first correction means that corrects image blur by driving a correction lens included in an imaging optical system in a direction perpendicular to an optical axis, and a second correction means that corrects image blur by driving an imaging element that photoelectrically converts light incident via the imaging optical system and outputs an image signal in a direction perpendicular to the optical axis, the method comprising: an acquisition step of acquiring an amount of shake from the detection means; a selection step of selecting one of a plurality of control methods including a first control method and a second control method, which control a ratio between the amount of shake corrected by the first correction means and the amount of shake corrected by the second correction means, based on a focal length of the imaging optical system; a calculation step of determining a correction amount of either the first correction means or the second correction means based on the shake amount and the control method selected in the selection step, the first control method is a method for performing overcorrection that exceeds the amount of shake within a range in which the amount of shake can be corrected and within a range in which the first correction means can be driven, and performing inverse correction that cancels out the amount of overcorrection by the second correction means.

[0098] (Configuration 13) 12. A program for causing a computer to function as each of the means of the vibration isolation control device according to any one of configurations 1 to 11.

[0099] (Configuration 14) A computer-readable storage medium storing the program according to configuration 13.

[0100] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0101] 100: camera body, 200: lens unit, 101: zoom lens, 102: image stabilization lens, 106: image sensor, 110: internal memory, 114: operation unit, 115: camera side control system, 122: lens vibration prevention drive unit, 123: lens vibration prevention position detection unit, 124: zoom lens drive unit, 125: lens side vibration detection unit, 126: lens side vibration prevention control unit, 127: zoom lens control unit, 128: lens side communication unit, 129: camera information management unit, 130: image sensor vibration prevention drive unit, 132: image sensor vibration prevention position detection unit, 133: camera side vibration prevention control unit, 13 4: camera side shake detection unit, 135: camera side communication unit, 137: lens information management unit, 143: camera control unit, 150: imaging optical system, 151: lens side integration unit, 152: lens side shake correction amount calculation unit, 153: lens side ratio accumulating unit, 154: lens side driving range limit unit, 155: image shake correction lens PID control unit, 160: lens side control system, 161: camera side integration unit, 162: camera side shake correction amount calculation unit, 163: camera side ratio accumulating unit, 164: camera side driving range limit unit, 165: camera side PID control unit, 166: camera side control method determination unit

Claims

1. An image stabilization control device for performing image shake correction by controlling a first correction means that corrects image shake by driving a correction lens included in an imaging optical system, and a second correction means that corrects image shake by driving an imaging element that photoelectrically converts light incident via the imaging optical system and outputs an image signal, an acquisition means for acquiring the amount of shake from the detection means; a selection unit that selects one of a plurality of control methods including a first control method and a second control method different from the first control method based on a focal length of the imaging optical system; The image stabilization control device according to claim 1, wherein the first control method is a control method in which the first correction means performs overcorrection by correcting the amount of shake beyond the amount of shake, and the second correction means performs inverse correction.

2. 2. The image stabilization control device according to claim 1, wherein the selection means selects the first control method when the focal length is equal to or less than a first predetermined value, and selects the second control method when the focal length is longer than the first predetermined value.

3. 2. The image stabilization control device according to claim 1, wherein the second control method is a control method in which the first correction means performs correction within a range that does not exceed the amount of shake.

4. 4. The vibration damping control device according to claim 3, wherein the second control method is a control method for correcting the amount of shake by using the first correction means and the second correction means at a predetermined constant ratio over a range in which the amount of shake can be corrected.

5. 4. The image stabilization control device according to claim 3, wherein the second control method is a control method in which the first correction means is made to correct the amount of shake with priority over the second correction means.

6. the plurality of control methods further includes a third control method; the selection means further selects one of the first control method, the second control method, and the third control method according to a range in which the focal length of the imaging optical system can be changed; The third control method is a control method in which the first correction means is made to perform correction of the shake amount preferentially over the second correction means.

5. The vibration isolation control device according to claim 4.

7. 7. The image stabilization control device according to claim 6, wherein the selection means selects the first control method or the second control method when the range in which the focal length can be changed is smaller than a second predetermined value.

8. The image stabilization control device according to claim 7, wherein the selection means further selects the first control method or the second control method based on the focal length when the range in which the focal length can be changed includes a focal length longer than a predetermined third value, and selects the first control method when the range does not include a focal length longer than the third value.

9. The image stabilization control device according to claim 6, characterized in that the selection means selects the first control method when the range in which the focal length can be changed is equal to or greater than a predetermined second predetermined value and the focal length is equal to or less than a predetermined fourth predetermined value, selects the second control method when the focal length is greater than a predetermined fifth predetermined value that is greater than the fourth predetermined value, and selects the third control method when the focal length is greater than the fourth predetermined value and equal to or less than the fifth predetermined value.

10. An anti-vibration control device as described in Claim 1, characterized in that it has a calculation means for determining the correction amount of at least one of the first correction means and the second correction means based on the amount of vibration and the control method selected by the selection means.

11. The calculation means calculates a correction amount for either the first correction means or the second correction means, 11. The image stabilization control device according to claim 10, further comprising a notification means for notifying a means for calculating a correction amount for either the first correction means or the second correction means of the control method selected by the selection means.

12. An anti-shake control device as described in Claim 1, characterized in that the reverse correction is performed by driving the image sensor in a direction that cancels out the amount of correction made by the first correction means that exceeds the amount of shake.

13. The vibration-damping control device described in Claim 12, characterized in that the first control method is a control method in which the first correction means performs over-correction by correcting beyond the amount of shake, and the second correction means cancels out the amount of correction that exceeds the amount of shake, thereby performing the inverse correction.

14. An anti-vibration control device as described in Claim 1, characterized in that each of the multiple control methods is a method for controlling the ratio between the amount of vibration corrected by the first correction means and the amount of vibration corrected by the second correction means.

15. An imaging element that photoelectrically converts incident light via an imaging optical system and outputs an image signal; a second correcting means for correcting image blur by driving the imaging element; an acquisition means for acquiring the amount of shake from the detection means; a selection unit that selects one of a plurality of control methods, including a first control method and a second control method different from the first control method, based on a focal length of the imaging optical system; an imaging device characterized in that the first control method is a control method in which a first correction unit that corrects image blur by driving a correction lens included in the imaging optical system performs over-correction that corrects beyond the amount of shake, and the second correction unit performs inverse correction.

16. A vibration reduction control method for correcting image shake by controlling a first correction unit that corrects image shake by driving a correction lens included in an imaging optical system, and a second correction unit that corrects image shake by driving an imaging element that photoelectrically converts light incident via the imaging optical system and outputs an image signal, comprising: an acquisition step of acquiring the amount of shake from the detection means; a selection step of selecting one of a plurality of control methods including a first control method and a second control method different from the first control method based on a focal length of the imaging optical system, The image stabilization control method according to claim 1, wherein the first control method is a control method in which the first correction means performs overcorrection, which corrects for a shake amount that exceeds the amount of shake, and the second correction means performs inverse correction.

17. A program for causing a computer to function as each of the means of the vibration isolation control device according to any one of claims 1 to 14.

18. A computer-readable storage medium storing the program according to claim 17.

Images