Optical device, imaging system, and method for calculating correction amount in imaging system

Abstract

To provide an imaging device that reduces steep changes in an imaging range caused by updating an offset for a shake detection signal.SOLUTION: A second optical apparatus constituting part of an imaging system is capable of attaching a first optical apparatus including first shake detection means 125 / 134 for detecting a shake, offset value setting means 1261 / 1331, and shake correction means. The second optical apparatus includes second shake detection means 134 / 125 for detecting a shake and offset correction amount calculation means 1332 / 1267 for calculating an offset correction amount based on a detection result of the second shake detection means. When a first mode for performing continuous shooting is set, the offset correction amount calculation means 1332 / 1267 selects a calculation method to be used for calculating the offset correction amount from a plurality of calculation methods, based on information received from the first optical apparatus and indicating timing of updating an offset value set in the offset value setting means, and calculates the offset correction amount.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a technique for correcting image shake in an imaging device, and more particularly to image shake correction during continuous shooting. [Background technology]

[0002] There is a function for generating panoramic images using an imaging device equipped with an image stabilization device. When generating a panoramic image using this function, the photographer performs continuous shooting while panning at a desired speed. The imaging device corrects the amount of image blur caused by the photographer's panning movement or camera shake during each exposure period of the continuous shooting using an image stabilization device, and then synthesizes these captured images to obtain a panoramic image (hereinafter, this shooting method will be referred to as panoramic shooting).

[0003] In order to use this panoramic shooting function to obtain an image in which panning and camera shake have been accurately corrected, it is necessary to accurately calculate the offset component of the shake detection signal used to calculate the image shake correction value.

[0004] Patent Document 1 discloses a function for correcting the output of a shake detection means provided in a lens device using a shake detection means provided in the image capture device body in order to accurately correct camera shake. When a second shake detection means provided in the image capture device has higher accuracy than a first shake detection means provided in the lens device, the image capture device described in Patent Document 1 calculates a correction amount for a first detection signal detected by the first shake detection means based on the detection result of the second shake detection means. It then proposes performing image shake correction using the result of correcting the first detection signal using the calculated correction amount.

[0005] With the above-described configuration, it is possible to improve image blur correction performance despite the influence of differences in performance between the shake detection means provided in the lens device and the image pickup device main body. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2020-91355 Summary of the Invention [Problem to be solved by the invention]

[0007] However, depending on the shake detection means of the lens device or imaging device, abrupt fluctuations in the shooting range may occur due to the update of the estimated value of the offset component for the shake detection signal (hereinafter referred to as offset update) during continuous shooting.

[0008] For example, some shake detection means may have large errors in the shake detection signal after the imaging device is started, depending on the photographer's operation or handling. When such a detection means is used, the offset of the shake detection signal may be updated after the shake detection signal has an arbitrary error. In such a case, if image stabilization is performed using a correction amount for one shake detection signal based on the other shake detection signal, as in the prior art disclosed in Patent Document 1, the estimated value of the offset component may change abruptly, which may cause abrupt fluctuations in the imaging range.

[0009] In particular, continuous shooting often takes a long time in panoramic photography, and there is a high possibility that offset updates will occur during continuous shooting, so measures are needed.

[0010] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an imaging apparatus that reduces abrupt changes in the imaging range caused by updating the offset for the shake detection signal. [Means for solving the problem]

[0011] An optical device according to one aspect of the present invention is a second optical device to which a first optical device can be attached, which constitutes an imaging system capable of continuous shooting and includes first shake detection means for detecting shake, offset value setting means, shake correction means for correcting image shake based on a first shake detection signal detected by the first shake detection means and an offset value set by the offset value setting means, and first communication means, and further includes second communication means for receiving from the first communication means information indicating the update timing of the offset value set in the offset value setting means, second shake detection means for detecting shake, and information received by the second communication means. and an offset correction amount calculation means for calculating an offset correction amount based on information indicating an update timing of the offset value and a second shake detection signal detected by the second shake detection means, wherein when a first mode for performing continuous shooting is set, the offset correction amount calculation means selects a calculation method to be used for calculating the offset correction amount from a plurality of calculation methods including a first calculation method and a second calculation method different from the first calculation method based on the information indicating the update timing of the offset value, and calculates the offset correction amount based on the selected calculation method between each exposure period for the continuous shooting.

[0012] Other aspects of the present invention will become apparent from the embodiments described below. [Effects of the Invention]

[0013] According to the present invention, when an offset component included in the detection result of a shake detection means is estimated and image blur correction is performed using the detection result and the estimated result, it is possible to reduce a steep shift in the angle of view caused by updating the offset for the shake detection signal. [Brief explanation of the drawings]

[0014] [Figure 1] A block diagram showing an example of the configuration of an imaging device [Figure 2] FIG. 1 is a block diagram showing an example of the configuration related to image stabilization control in a first embodiment. [Figure 3]Flowchart for image stabilization settings during panoramic photography [Figure 4] FIG. 1 is a diagram illustrating exposure timing and the position of the image stabilization lens during panoramic photography. [Figure 5] Flowchart for calculating the offset correction amount of the lens shake detection signal [Figure 6] (A) A diagram illustrating a method for calculating the offset correction amount on the lens side when it is not the offset update timing. (B) A diagram illustrating a method for calculating the offset correction amount on the lens side when it is the offset update timing. [Figure 7] FIG. 1 is a diagram showing the timing of calculating the shake offset correction amount during panoramic photography. [Figure 8] FIG. 10 is a block diagram showing an example of the configuration related to image stabilization control according to a second embodiment. [Figure 9] Flowchart for calculating offset correction amount for camera shake detection signal [Figure 10] (A) A diagram explaining a method for calculating the amount of offset correction on the camera side when it is not the offset update timing. (B) A diagram explaining a method for calculating the amount of offset correction on the camera side when it is the offset update timing. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0016] It should be noted that the following embodiments do not limit the scope of the invention claimed.

[0017] Although the embodiments describe a plurality of features, not all of these features are necessarily essential to the invention, and the plurality of features may be combined in any desired manner.

[0018] Furthermore, in the accompanying drawings, the same or similar components are given the same reference numerals and redundant explanations are omitted.

[0019] (First embodiment) This embodiment describes a method for acquiring a shake correction amount during panoramic shooting. FIG. 1 is a block diagram showing the configuration of an imaging device, which is an embodiment of the imaging device (imaging system) of the present invention. The imaging device of this embodiment is a lens-interchangeable imaging device, and is composed of an imaging device body (hereinafter referred to as camera body) 1 and a lens device 2 that can be attached to the camera body. The lens device 2 is equipped with an imaging optical system 200. The imaging optical system 200 has a zoom lens 101, an image stabilization lens 102, a focus lens 103, and an aperture 104. The zoom lens 101 moves along the optical axis to optically change the focal length of the imaging optical system (imaging lens) 200 that forms a subject image, thereby changing the imaging angle of view. The image stabilization lens 102 moves in a direction perpendicular to the optical axis, optically correcting image blur caused by shake of the imaging device. The focus lens 103 moves along the optical axis to optically adjust the focus position. The aperture 104 and shutter 105 can adjust the amount of light by opening and closing, and are used for exposure control.

[0020] An aperture driver 120 and a shutter driver 135 drive the aperture 104 and the shutter 105. A zoom lens driver 124 drives the zoom lens 101 to change the angle of view. A zoom lens controller 127 controls the position of the zoom lens 101 in accordance with zoom operation instructions from the operation unit 114. A focus lens driver 121 drives the focus lens 103.

[0021] Light passing through the photographing optical system 200 is received by an image sensor 106, which may be a CCD (charge-coupled device) or a CMOS (complementary metal-oxide semiconductor) sensor, and converted from an optical signal into an electrical signal. An AD converter 107 performs noise removal processing, gain adjustment processing, and AD conversion processing on the image signal read out from the image sensor 106.

[0022] A timing generator 108 controls the drive timing of the image sensor 106 and the output timing of the AD converter 107 in accordance with instructions from a camera control unit 115. An image processing circuit 109 performs pixel interpolation processing, color conversion processing, etc. on the output from the AD converter 107, and then sends the processed image data to an internal memory 110.

[0023] In the panoramic photography function, the image processing circuit 109 performs processing to create panoramic image data from multiple images. Specifically, it includes a circuit for aligning multiple images captured in succession, a geometric transformation circuit for performing cylindrical coordinate transformation and lens distortion correction, a synthesis circuit for trimming and synthesis processing, etc. The operation of each circuit is well known, so a detailed description will be omitted.

[0024] A display unit 111 displays shooting information and the like together with image data stored in the internal memory 110. A compression / decompression processing unit 112 performs compression processing or decompression processing on the data stored in the internal memory 110 according to the image format.

[0025] The storage memory 113 stores various data such as parameters, etc. The operation unit 114 is a user interface that allows the user to perform various menu operations and mode switching operations.

[0026] The camera control unit 115 is composed of a computing device such as a CPU (Central Processing Unit), and executes various control programs stored in the internal memory 110 in response to user operations via the operation unit 114. The control programs are programs for performing, for example, zoom control, image stabilization control, automatic exposure control, automatic focus adjustment control, and processing for detecting the face of a subject.

[0027] In the case of a lens-interchangeable camera, information is transmitted between the camera and the lens via a camera-side communication unit 140 and a lens-side communication unit 128 .

[0028] The luminance signal detection unit 137 detects the signal read out from the image sensor 106 in a shooting preparation state (so-called live view state) and passed through the AD converter 107 as the luminance of the subject and scene. The exposure control unit 136 calculates the exposure value (aperture value and shutter speed) based on the luminance information obtained by the luminance signal detection unit 137, and notifies the diaphragm driving unit 120 and shutter driving unit 135 of the calculation result via the camera side communication unit 140 and lens side communication unit 128. The exposure control unit 136 also simultaneously controls the amplification of the image signal read out from the image sensor 106, thereby performing automatic exposure control (AE control).

[0029] The evaluation value calculation unit 138 extracts specific frequency components from the luminance information obtained by the luminance signal detection unit 137 and then calculates a contrast evaluation value based on the extracted components. The focus lens control unit 139 issues a command to the focus lens drive unit 121 via the camera side communication unit 140 and the lens side communication unit 128 to drive the focus lens 103 by a predetermined drive amount over a predetermined range. At the same time, the evaluation value calculation unit 138 acquires an evaluation value calculated at each focus lens position. The defocus amount in the contrast AF method is calculated from the focus lens position where the curve of the change in the contrast evaluation value peaks, and is notified to the focus lens drive unit 128. The focus lens drive unit 128 drives the lens to the defocus position, thereby performing automatic focusing control (AF control) to focus the light beam on the image sensor 106 surface. While the contrast AF method has been described here, a phase-difference AF method may also be used. The details of the phase-difference AF method are well known and will not be described here.

[0030] The shake detection units (134, 125) detect shake and vibration applied to the imaging device. In addition to the camera-side shake detection unit 134 arranged on the camera side, a lens-side shake detection unit 125 is also arranged on the lens side to detect vibration caused by shake and vibration applied to the lens. Generally, a gyro sensor, which is an angular velocity sensor, is used as a sensor to detect vibration, and detects the angular velocity of shake and vibration.

[0031] The image stabilization lens vibration reduction control unit 126 calculates the lens shake correction amount to reduce shake using the image stabilization lens, based on shake detection signals detected by the lens-side shake detection unit 125, the camera-side shake detection unit 134, or both. Then, based on the calculated lens shake correction amount and the position of the image stabilization lens 102 detected by the image stabilization lens position detection unit 123, it sends a drive signal for the image stabilization lens to the image stabilization lens driver 122, thereby controlling vibration reduction using the image stabilization lens. The image stabilization lens driver 122 drives the image stabilization lens in a direction perpendicular to the optical axis, based on the image stabilization lens drive signal received from the image stabilization lens vibration reduction control unit 126. Details of the method for controlling vibration reduction using the image stabilization lens will be described later.

[0032] The imaging stabilization control unit 133 calculates an image sensor shake correction amount for suppressing shake using the image sensor based on shake detection signals detected by the camera-side shake detection unit 134, the lens-side shake detection unit 125, or both. Then, based on the calculated correction amount and the position of the image sensor 106 detected by the image sensor position detection unit 132, it transmits an image sensor drive signal to the image sensor drive unit 130 to control image sensor shake correction. The image sensor drive unit 130 drives the image sensor 106 in a direction perpendicular to the optical axis based on the image sensor drive signal received from the imaging stabilization control unit 133. However, in this embodiment, image sensor shake correction is stopped by fixing the image sensor at a reference position during panoramic shooting, and shake during panoramic shooting is corrected using an image stabilization lens, so details of the image sensor shake correction control method will be omitted. The reference position may be any location, such as the center of the movable range of the image sensor, a position where the center of the effective area overlaps the optical axis of the shooting optical system provided in the lens device, or another location. The motion vector detection unit 131 uses a block matching method to calculate the correlation value between the current frame and the previous frame for each block obtained by dividing the frame, then searches for the block in the previous frame that minimizes the calculation result, and detects the deviation of other blocks relative to that block as a motion vector.

[0033] FIG. 2 is a block diagram showing an example of the configuration of the image stabilization lens control unit 126 and the imaging image stabilization control unit 133 in this embodiment.

[0034] First, the configuration of the image stabilization lens stabilization control unit 126 on the lens device side will be described. The image stabilization lens stabilization control unit 126 has a lens offset determination unit 1261 that determines an estimated offset value (hereinafter referred to as the offset value) included in the lens shake detection signal from the lens-side shake detection unit. The lens offset determination unit 1261 is a setting unit that determines an offset value based on the lens shake detection signal from the lens-side shake detection unit 125 and sets the offset value by holding the determined offset value. This offset value is updated when a predetermined condition is satisfied after startup, but is not updated until the predetermined condition is satisfied. After startup, the offset value is not updated until the update condition is satisfied, and an arbitrary initial value is set. As a method for determining the offset value, for example, a value α1 indicated by the current gyro detection result is held as a temporary offset value, and an arbitrary stability determination process is performed on the difference (α2 - α1) between this value and a value α2 indicated by the gyro detection result obtained at the next timing. Filtering or other methods may be used to determine the stability. This is performed each time a gyro detection result is obtained, and if an arbitrary stability condition is met for a predetermined period of time, it is determined that the update condition is met, and the temporary offset value α1 is determined and set as the offset value. If the arbitrary stability condition is not met for the predetermined period of time, the offset value is determined in the same way using the value indicated by the gyro detection result at another timing. Furthermore, by performing this process periodically, the offset value is updated. The offset update timing notification unit 1262 detects the timing when the lens offset determination unit 1261 determines the offset value and updates (reflects) the offset value. Then, the timing (offset value update timing) is notified to the camera body 1 side via the lens side communication unit 128 and the camera side communication unit 140.

[0035] The integration / LPF unit 1263 is an integrator or LPF (low-pass filter) for increasing the dimension of the lens shake detection signal indicating angular velocity by one to a shake angle. In this block diagram, the integration / LPF unit 1263 receives a corrected lens shake signal obtained by subtracting the offset value determined by the lens offset determination unit 1261 and a lens offset correction amount (described later) from the lens shake detection signal detected by the lens shake detection unit. Then, the corrected lens shake signal is integrated or LPF processed to generate a lens shake angle signal.

[0036] The shake correction amount calculation unit 1264 calculates the amount of lens shake correction to be corrected by vibration reduction using the image stabilization lens 102 by integrating the lens shake angle signal with gains related to the zoom magnification (focal length) and subject distance.

[0037] The position control unit 1265 is a control unit that performs PID control (ratio control, integral control, and fine control) on the deviation between the target position of the image stabilization lens 102 based on the lens shake correction amount calculated by the shake correction amount calculation unit 1264 and the current position of the image stabilization lens 102. The deviation between the target position and the current position is converted into an image stabilization lens drive signal and input to the image stabilization lens drive unit 122. The current position is the detection result of the image stabilization lens position detection unit 123. Since PID control is a common technique, a detailed description is omitted. The image stabilization lens drive unit 122 is an actuator such as a voice coil motor or an ultrasonic motor, and drives (displaces) the image stabilization lens 102 according to the image stabilization lens drive signal input from the position control unit 1265. Next, the image stabilization control unit 133 on the imaging device main body side will be described. As mentioned above, the image stabilization control block 133 can perform image stabilization using the image sensor 106 by driving the image sensor, but image stabilization is stopped during panoramic shooting. Therefore, here we will explain the functional blocks involved in calculating the lens offset correction amount, which is involved in obtaining the corrected lens shake signal, which is a signal input to the integration / LPF unit, from the lens shake detection signal, which is the output of the lens side shake detection unit 125.

[0038] The camera offset determination unit 1331 is a unit that determines and stores an estimated value of the offset (hereinafter referred to as the offset value) included in the output signal of the camera-side shake detection unit based on, for example, the difference between the camera shake detection signal from the camera-side shake detection unit 134 and the motion vector. This allows the camera-side offset value to be set. Instead of determining the camera-side offset value based on the difference, the camera offset determination unit 1331 may store a value determined in a process before the camera is shipped as the camera-side offset value. For example, a still-state output may be measured in a process before shipping and stored in a memory included in the camera body as the camera-side offset value. A subtractor subtracts the camera-side offset value stored in the camera offset determination unit 1331 from the camera shake detection signal detected by the camera-side shake detection unit 134 to remove the offset component included in the camera shake detection signal and obtain the camera shake signal. In this embodiment, the offset value is determined more accurately than that of the lens-side offset determination unit 1261.

[0039] The lens offset correction amount calculation unit 1332 is a block that calculates the lens offset correction amount that corrects the current lens-side offset value that has been determined by the lens offset determination unit and is being used for the lens shake detection signal. The lens offset correction amount calculation unit 1332 changes the method for calculating the lens offset correction amount depending on whether or not it is the timing to update the lens-side offset value. Whether or not it is the timing to update the offset is determined based on the output from the offset update timing notification unit 1262 received via the lens-side communication unit 128 and the camera-side communication unit 140.

[0040] When the lens-side offset value has been updated, the lens offset correction amount calculation unit 1332 calculates the lens offset correction amount based on the pre-correction camera shake signal. The pre-correction camera shake signal refers to the output signal of a subtractor that subtracts the camera-side offset value from the camera shake detection signal. On the other hand, when the lens-side offset value has not been updated, the lens offset correction amount calculation unit 1332 performs processing to calculate the offset correction amount from the pre-correction lens shake signal and the camera shake signal. A detailed explanation of the method for calculating the lens offset correction amount will be given later. The pre-correction lens shake signal is a signal obtained by subtracting the offset value determined by the lens offset determination unit 1261 from the lens shake detection signal detected by the lens shake detection unit 125.

[0041] In this way, the offset component contained in the lens shake detection signal that is the output of the lens shake detection unit 125 is removed by the setting value of the lens offset determination unit 1261 and the correction amount of the lens offset value determined by the lens offset correction amount calculation unit 1332.

[0042] Next, the process of changing the image stabilization control settings during panoramic photography in this embodiment will be described with reference to FIG.

[0043] First, in step S301, it is determined whether the camera is powered on. If the power is on (step S301, Yes), the process proceeds to step S302. If the power is off (step S301, No), the image stabilization setting change process ends.

[0044] In step S302, the shooting mode setting of the imaging device is confirmed. If the panoramic shooting mode is set here (step S302, Yes), the process proceeds to step S303.

[0045] In step S303, pan control in the image stabilization control is disabled. Pan control refers to control that weakens the effect of image stabilization control when panning by the photographer is detected to allow for intentional changes in the imaging range associated with panning. In panoramic photography, the photographer pans to change the imaging range while performing multiple exposures (continuous shooting), and these are combined to generate a composite image (panoramic image). Therefore, if image stabilization is not performed or its effect is weakened, depending on the exposure time and panning amount, changes in the imaging range associated with panning during a single exposure may appear as image blur in the generated panoramic image. Therefore, in this embodiment, pan control is disabled to compensate for changes in the imaging range associated with panning during a single exposure as much as possible using image stabilization. After the processing of step S303 is completed, the processing proceeds to step S304.

[0046] In step S304, the LPF is set so that the integration characteristics of the integration / LPF unit 1263 during exposure are perfect integration or characteristics close to perfect integration. The reason for this is to correct, as much as possible, by image stabilization, the amount of change in the shooting range that occurs due to panning by the photographer during exposure, as described in step S303.

[0047] Additionally, in this step, during the non-exposure periods between multiple exposures (called inter-frame periods), the image stabilization lens is moved to the center of its movable range (centering) and fixed in that position during the non-exposure periods, so that image stabilization is not performed. This is achieved by setting the amount of lens shake compensation between frames to be fixed at 0.

[0048] The exposure timing and positional relationship of the image stabilization lens during panoramic photography that can be achieved by changing the settings in steps S303 and S304 are shown in Fig. 4. Fig. 4 will be described below.

[0049] In FIG. 4, the horizontal axis represents time, and the vertical axis represents the exposure timing and the position of the image stabilization lens 102 in continuous shooting for panoramic shooting.

[0050] 4, the periods from time t1 to time t2, from time t4 to time t5, and from time t7 to time t8 are the respective exposure periods, during which all changes in the shooting range due to camera shake and panning are corrected. If the panning direction in which the imaging device is swung is constant, the position of the image stabilization lens 102 increases monotonically.

[0051] After each exposure is completed, a centering process is performed from time t2 to time t3, time t5 to time t6, and time t8 to time t9 to return the image stabilization lens 102, which moved toward the movable end during the exposure, to the center. This reduces the risk that the image stabilization lens 102 will hit the movable end at the start of the next exposure, making it impossible to perform image stabilization. During the centering process, the shooting range will change due to the movement of the image stabilization lens 102, so it is desirable to black out the live view display or display the most recently captured image.

[0052] The periods from time t3 to time t4, time t6 to time t7, and time t9 to time t10, from the end of centering processing until the start of the next exposure, are exposure standby periods. During these periods, the image stabilization lens 102 is fixed in the center and waits for the image stabilization control to stabilize.

[0053] By performing the above-described control, it is possible to realize driving of the image stabilization lens 102 suitable for panoramic photography. This completes the explanation of FIG. 4, and we will return to the explanation of the flowchart of FIG.

[0054] After the process of step S304 is completed, the process proceeds to step S305. In step S305, a process is performed to enable predetermined communication (called panorama control communication) for performing image stabilization control during panoramic photography.

[0055] Here, the panorama control communication process will be described with reference to FIG.

[0056] FIG. 5 shows the communication processing and calculation processing between the lens device and the imaging device main body performed by the image stabilization lens control unit 126 and the imaging stabilization control unit 133 before shooting begins or during the period between exposures during continuous shooting.

[0057] First, we will explain the processing performed by the image shake correction lens vibration isolation control unit 126. In step S501, a pre-correction lens shake signal is generated by subtracting the setting value of the lens offset determination unit 1261 from the lens shake detection signal acquired by the lens-side vibration detection means 125. After step S501 is completed, the process proceeds to step S502.

[0058] In step S502, the uncorrected lens shake signal obtained in step S501 and information indicating the offset update timing, which indicates whether the offset value on the lens side has been updated or not, from the offset update timing notification unit 1262 is transmitted to the camera side via the lens side communication means 128 and the camera side communication unit 140. After the processing of step S502 is completed, the processing proceeds to step S503.

[0059] In step S503, the lens offset correction amount transmitted from the camera body in step S515 (described later) is received and used to calculate the lens shake correction amount as the correction amount for the uncorrected lens shake detection signal to be used in the next exposure. Specifically, as described above, the setting value of the lens offset determination unit 1261 and the received lens offset correction amount are subtracted from the lens shake detection signal acquired by the lens-side shake detection means 125. In this way, a corrected lens shake signal is acquired, and the corrected lens shake signal is converted into a lens angle signal to calculate the lens shake correction amount. When the processing of step S503 is completed, the panorama control communication ends.

[0060] Next, we will explain the processing on the imaging device main body side. This processing is performed by the imaging image stabilization control unit 133. First, in step S511, a camera shake signal is generated by subtracting the setting value of the camera offset determination unit 1331 from the camera shake detection signal acquired by the camera-side shake detection means 134.

[0061] After the process of step S511 is completed, the process of step S512 is performed to acquire the uncorrected lens shake signal transmitted by the lens device in the above-mentioned step S502 and information indicating the offset update timing. After the process of step S512 is completed, the process of step S513 is performed.

[0062] In step S513, the information indicating the offset update timing acquired in step S512 is referenced to determine whether it is the timing to update the lens offset. If it is not the lens offset update timing (S513, No), the process proceeds to step S516, where the lens offset correction amount calculation unit 1332 determines the lens offset correction amount based on the difference between the lens shake signal before correction and the camera shake signal.

[0063] On the other hand, if it is time to update the lens offset (S513, Yes), the process proceeds to step S514, where the lens offset correction amount calculation unit 1332 determines the lens offset correction amount based on the camera shake signal.

[0064] After the processing in step S514 or step S516 is completed, the process proceeds to step S515, where the lens offset correction amount calculated in each step is transmitted to the lens device.

[0065] When the process of step S515 is completed, the panorama control communication process on the camera side is completed.

[0066] The above flow allows an appropriate lens offset correction amount to be set before the start of exposure, depending on the timing of updating the offset value on the lens side. If the lens offset correction amount set here is not updated by the start of the next exposure period, it will be used to calculate the shake correction amount during the next exposure period. The detailed method for obtaining the lens offset correction amount calculated in steps S414 and S416 will be described later.

[0067] This concludes the explanation of Fig. 5, and we return to the explanation of Fig. 3. When step S305 is completed, the process of changing the image stabilization setting when the panoramic shooting mode is set is completed. When the panoramic shooting mode is set, this panoramic control communication of step S305 is repeated at a predetermined interval even after the process of changing the image stabilization setting is completed.

[0068] The processing when the panoramic shooting mode is not set will be described. If a mode other than the panoramic shooting mode is set in step S302 (No in step S302), the process proceeds to step S306, where processing to enable pan control is performed. This is because, for purposes other than panoramic shooting, it is considered better to weaken the image stabilization in order to follow the changes in the shooting range intended by the photographer that accompany panning. After the processing in step S306 is completed, the process proceeds to step S307.

[0069] In step S307, the integration characteristics of the integration / LPF unit 1263 during exposure are set. The integration characteristics are set appropriately in accordance with the current shooting mode and shooting settings. Also, if the correction amount between frames has been set to 0 immediately after switching from panoramic shooting mode to another mode, that setting is canceled and image stabilization control between frames is set appropriately in accordance with the current shooting mode and shooting settings.

[0070] When the process of step S307 is completed, the process proceeds to step S308.

[0071] In step S308, processing is performed to end the default communication for image stabilization during panoramic shooting. If the default communication for panoramic shooting has not already been performed, nothing needs to be done. When step S308 is completed, the image stabilization setting change processing is completed.

[0072] Next, the calculation process of the lens offset correction amount performed by the lens offset correction amount calculation unit 1332 in steps S514 and S516 will be described with reference to FIG.

[0073] FIG. 6 is a diagram showing the relationship between the lens offset correction amount set in steps S514 and S515 and the amount of blurring at the time of the next exposure.

[0074] 6A and 6B, the horizontal axis represents time, and the vertical axis represents the intensities of the lens shake signal and camera shake signal before correction. Fig. 6A corresponds to the calculation of the lens offset correction amount in step S516, and Fig. 6B corresponds to the calculation of the lens offset correction amount in step S514. The premise of this embodiment is that the camera shake signal has less offset deviation (the influence of the offset included in the shake signal) than the lens shake signal before correction.

[0075] The lens offset correction amount calculated in step S516 will be described below with reference to FIG. 6(A). Dashed line L1 indicates the lens shake signal before correction, and dashed line L2 indicates the camera shake signal. The lens shake signal before correction represented by dashed line L1 is obtained by subtracting the setting value of lens offset determination unit 1261 from the output of lens side shake detection unit 125. Similarly, the camera shake signal represented by dashed line L2 is obtained by subtracting the setting value of camera offset determination unit 1331 from the output of camera side shake detection unit 134.

[0076] Let ω(t) be the vibration signal to be subjected to image stabilization. Assume that the offset value on the camera side is highly accurate, and that the error between ω(t) and the camera shake detection signal is kept within a specified range and is negligible. Referring to Figure 6(A), the vibration signal ω(t) to be subjected to image stabilization can be formulated as follows using the uncorrected lens vibration signal ωLexp during exposure: ω(t)=ωLexp(t)-(ωL-ωc)...Equation (1)

[0077] This is shown by the solid line L3.

[0078] Here, ωL is the lens shake signal before correction, and ωc is the camera shake signal, and data prior to the exposure start time Texp in a chronological order is used. From the above, in this embodiment, the lens offset correction amount is set to ωL-ωc. Therefore, the lens offset correction amount calculation unit 1332 obtains the lens offset correction amount by subtracting the camera shake signal ωc from the lens shake signal ωL before correction, which is obtained from the lens device side via the camera side communication unit 140. Note that, as long as the value is close to ωL-ωc, a value obtained by fine-tuning ωL-ωc using an adjustment value associated with the configuration of the imaging device may be used as the offset correction amount.

[0079] Next, the lens offset correction amount calculated in step S514 will be described with reference to FIG.

[0080] Dashed line L4 indicates the lens shake signal before correction, and dashed line L5 indicates the camera shake signal. The lens shake signal before correction, dashed line L4, is obtained by subtracting the set value of lens offset determination unit 1261 from the output of lens side shake detection unit 125. Similarly, the camera shake signal, dashed line L2, is obtained by subtracting the value of camera offset determination unit 1331 from the output of camera side shake detection unit 134.

[0081] Assume that the lens offset determination unit 1261 updates the setting value (offset value) at time Tf. The timing at which the lens offset value is updated is hereinafter referred to as the update timing. The uncorrected lens shake signal indicated by dashed line L4 is rapidly returned to near 0 at time Tf, which is the update timing. This is because, as exemplified in the explanation of the lens offset determination unit 1261, the offset value is set to a value such that the value obtained by subtracting the offset value from the current lens shake detection signal (Tf) is near 0 based on the lens shake detection signal over a certain period. This occurs when a predetermined update condition for the lens offset value is met. While the calculation method of equation (1) can be applied near time Tf, which is the update timing, if the lens offset value changes rapidly before and after the update timing, the uncorrected lens shake signal may become unstable near the update timing Tf. As a result, the offset correction amount obtained using equation (1) may not accurately correct changes in the shooting range due to camera shake or panning.

[0082] Therefore, in this embodiment, when the setting value of the lens offset determination unit 1261 is updated, the following equation (2) is used to determine the shake signal ω(t) to be subjected to image shake correction.

[0083] From FIG. 6B, the vibration signal ω(t) to be subjected to image blur correction can be formulated as follows using the lens vibration signal ωLexp before correction during exposure: ω(t)=ωLexp(t)+ωc…Equation (2)

[0084] This is shown by the solid line L6.

[0085] Here, ωc is a camera shake signal, and data from chronologically before the exposure start time Texp is used. From the above, the offset correction amount on the lens side is set to -ωc. As in step S516, a value obtained by finely adjusting -ωc may be used as the offset correction amount.

[0086] In this way, by determining the lens-side offset correction amount based on the camera shake signal, rather than the difference between the lens shake signal before correction and the camera shake signal, image blur can be reduced with high precision even when the lens-side offset value is updated.

[0087] Furthermore, it is considered that the magnitude of image blur caused by offset updating depends on the amount of change in the pre-correction lens shake signal before and after the offset updating, and the magnitude of the difference (ωL-ωc) with the camera shake signal. Therefore, it may be possible to determine whether or not to apply formula (2) when updating the offset based on the magnitude of the lens shake signal at the start of shooting, the magnitude of the lens shake signal during shooting, the magnitude of the camera shake signal during shooting, etc.

[0088] FIG. 7 is a diagram showing the relationship between the exposure timing and the timing of communication for calculating the offset correction amount and notifying the calculated offset correction amount in panorama control communication in this embodiment.

[0089] An example of capturing five images using panoramic shooting and combining them into a panorama is shown in Figure 7. The period when the image readout timing is High outside the panoramic shooting period indicates the period when the live view image is read out. In Figure 7, the live view image is read out twice, followed by five readouts for panoramic shooting.

[0090] During live view, the lens offset correction amount calculation unit 1332 calculates the lens offset correction amount and communicates to notify the calculated offset correction amount at regular intervals. To calculate the lens-side offset correction amount, the lens offset update information and the chronologically synchronized pre-correction lens shake signal and camera shake signal are also acquired at regular intervals. During the live view period before exposure, the lens offset correction amount calculation unit 1332 calculates the lens offset correction amount using the above-described formula (1).

[0091] When the first exposure for panoramic photography begins, the lens device acquires a corrected lens shake signal using the lens offset value set in the lens offset determination unit 1261 immediately before the start of exposure, the latest offset correction value transmitted from the camera before the start of exposure, and the lens shake detection signal received during the exposure period. Based on this, the lens shake correction amount is calculated and image shake correction is performed using the image shake correction lens. After the first exposure ends, communication resumes. The lens offset correction amount calculation unit 1332 of the camera body 1 acquires the lens offset update information and the uncorrected lens shake detection signal and camera shake detection signal, which are synchronized in time series, calculates the lens offset correction amount, and notifies the lens device 2 of this calculation. This process is performed between frames. The timing of this process can be determined based on the communication cycle between the lens device and the camera body and the interval between continuous shots during panoramic photography. It may be performed multiple times between frames. Figure 7 shows an example in which this process is basically performed three times between frames.

[0092] The calculation process for the offset correction amount before exposure and between frames is performed using the above equations (1) and (2), and when the lens offset update information received from the lens indicates that the offset value on the lens side has been updated, the offset correction value is calculated using equation (2). The timing when the offset correction value is calculated using equation (2) is indicated by a star in Figure 7.

[0093] When the lens-side offset value is updated, the number of communications between frames and the number of calculations of the offset correction amount may be changed from when the value was not updated. In this embodiment, the lens-side offset correction amount determined at the timing indicated by * (method of formula (2)) is fixed, and calculation and updating of the lens-side offset correction amount thereafter are stopped.

[0094] Conversely, the number of communications may be increased. Depending on the number of communications, it is possible to select whether to calculate the offset correction amount on the lens side using a camera-side vibration detection signal near the lens offset update timing in a chronological order, or to calculate the offset correction amount on the lens side using a camera-side vibration detection signal near the next exposure.

[0095] Although the present embodiment has described a method for calculating and acquiring an offset correction amount when the panorama mode is set, the imaging device of this embodiment is also capable of capturing images in modes other than the panorama mode. For example, the imaging device can also operate in a typical single-shot mode, in which a single press of the release button results in a single exposure and captures a single image. In this case, since a slight deviation in the capture range between consecutive shots is unlikely to be a problem, there is no need to change the calculation method for the offset correction amount depending on whether or not it is time to update the offset value. For example, the method of equation (1) may always be selected to calculate the offset correction amount. Furthermore, even in a mode in which images captured by consecutive shots are not combined, a slight deviation in the capture range is less likely to be a problem than in a mode in which multiple images are stitched together, such as the panorama mode. Therefore, as with the single-shot mode, there is no need to change the calculation method for the offset correction amount depending on whether or not it is time to update the offset value. For example, the method of equation (1) may always be selected to calculate the offset correction amount.

[0096] Furthermore, in this way, if the calculation method for the offset correction amount is not changed in accordance with the timing of updating the offset value, the lens device 2 equipped with the offset value setting means does not need to transmit the timing of updating the offset value to the camera body 1. However, in a configuration where information on the shooting mode on the camera body 1 side cannot be obtained, the timing of updating the offset value may always be transmitted regardless of the shooting mode.

[0097] (Second embodiment) An imaging device according to a second embodiment of the present invention will now be described. The imaging device of this embodiment is basically the same as that of the first embodiment, except that the roles of the camera body 1 and the lens device 2 in the image shake correction process when panorama mode is set are reversed from those of the first embodiment. That is, in panorama mode, the camera body performs image shake correction by moving the image sensor, sets an offset value, and transmits information indicating the timing to update the offset value to the lens device. Then, based on the information indicating the update timing received from the camera body, the lens device selects an appropriate calculation method from multiple calculation methods, calculates the offset correction amount, and transmits it to the camera body.

[0098] The details of this embodiment will be described below. The configuration of the imaging device of this embodiment is the same as that shown in FIG. 1 , so a detailed description will be omitted. In FIG. 1, the image sensor driver 130 optically corrects image shake by moving the image sensor 106 in a direction perpendicular to the optical axis. As described in the first embodiment, the image stabilization control unit 133 calculates the amount of image shake correction to suppress shake. Then, based on the calculated amount of image shake correction and the position of the image sensor 106 detected by the image sensor position detection unit 132, a drive signal for the image sensor is sent to the image sensor driver 130, thereby controlling image stabilization by the image sensor. In this embodiment, shake during panoramic shooting is corrected using the image sensor 106, and image stabilization by the image stabilization lens 102 is stopped by fixing the image stabilization lens 102 at a reference position. The reference position may be any location, such as the center position of the movable range, or a position where the optical axis of the imaging optical system coincides with the center of the mount of the camera body.

[0099] FIG. 8 is a block diagram showing an example of the configuration of the image stabilization lens control unit 126 and the imaging stabilization control unit 133 in this embodiment. As described above, the camera body sets the offset value and notifies the other party of the timing to update the offset value, and the lens device calculates the offset correction amount. First, the configuration of the imaging stabilization control unit 133 on the camera body side will be described. The configuration of the imaging stabilization control unit 133 in this embodiment is basically the same as the configuration of the lens stabilization control unit 126 in the first embodiment. The imaging stabilization control unit 133 has a camera offset determination unit 1331 that determines the offset value included in the camera shake detection signal from the camera shake detection unit 134. The camera offset determination unit 1331 is a setting unit that determines the offset value based on the camera shake detection signal from the camera shake detection unit 125 and holds the offset value to set the offset value. This offset value is updated when a predetermined condition is satisfied after startup, and is not updated until the predetermined condition is satisfied. After startup, the offset value is not updated until the update condition is satisfied, and an arbitrary initial value is set. The method for determining the offset value is the same as in the first embodiment, and therefore the explanation will be omitted.

[0100] The offset update timing notification unit 1337 detects the timing when the camera offset determination unit 1331 determines an offset value and updates the offset value, and notifies the lens device of the timing via the camera side communication unit 140 and the lens side communication unit 128.

[0101] Similar to the integration / LPF unit 1263, the integration / LPF unit 1334 is an integrator or LPF for increasing the dimension of the shake detection signal indicating angular velocity by one to a shake angle. The integration / LPF unit 1334 receives the corrected camera shake detection signal, rather than the actual camera shake detection signal detected by the camera shake detection unit 134. In this block diagram, the corrected camera shake detection signal is a signal obtained by subtracting the offset value determined by the camera offset determination unit 1331 and the camera offset correction amount, which will be described later, from the camera shake detection signal detected by the camera shake detection unit 134. Then, the corrected lens shake signal is integrated or LPF processed to generate a camera shake angle signal.

[0102] The shake correction amount calculation unit 1335 calculates the amount of camera shake correction to be performed by image stabilization using the image sensor 106 by integrating the camera shake angle signal with gains related to the zoom magnification and subject distance.

[0103] Position control unit 1336 is a control unit for performing PID control (ratio control, integral control, fine control) on the deviation between the target position of image sensor 106 based on the camera shake correction amount calculated by shake correction amount calculation unit 1335 and the current position of image sensor 106. The deviation between the target position and the current position is converted into an image sensor drive signal and input to image sensor drive unit 130. The current position is the detection result of image sensor position detection unit 132. PID control is a common technique, so a detailed description will be omitted.

[0104] The imaging element driver 132 drives (displaces) the imaging element 106 in response to the imaging element drive signal.

[0105] Next, we will explain the image stabilization lens stabilization control unit 126 on the lens device side. The image stabilization control block 133 can perform image stabilization using an imaging element by driving the image stabilization lens 102, but stops image stabilization during panoramic shooting. For this reason, the control block for driving the image stabilization lens 102 is omitted from FIG. 8, and we will explain the functional block related to calculating the offset correction amount, which is involved in obtaining a corrected camera shake signal. However, as in the block diagram shown in FIG. 2, the system may also include an integration / LPF unit 1263 that converts an angular velocity signal into an angle signal, a shake correction amount calculation unit 1264 that calculates the shake correction amount for correction by the image stabilization lens, a position control unit 1265 that performs PID control, and so on.

[0106] The lens offset determination unit 1261 is a unit that determines and stores an estimated value of an offset (hereinafter, referred to as an offset value) included in the output signal of the lens-side shake detection unit based on, for example, the difference between the lens shake detection signal from the lens-side shake detection unit 125 and the motion vector. This sets the lens-side offset value. Similar to the camera offset determination unit 1331 in the first embodiment, the lens offset determination unit 1261 may store a value determined in a process before the camera is shipped as the camera-side offset value, instead of determining the lens-side offset value based on the difference. A subtractor subtracts the lens-side offset value stored in the lens offset determination unit 1261 from the lens shake detection signal detected by the lens-side shake detection unit 125, thereby removing the offset component included in the lens shake detection signal and obtaining the lens shake signal. In this embodiment, it is assumed that the offset value is determined more accurately than that of the camera-side offset determination unit 13311.

[0107] The camera offset correction amount calculation unit 1267 is a block that calculates a camera offset correction amount that corrects the current camera-side offset value that has been determined by the camera offset determination unit and is being used for the camera shake detection signal. The camera offset correction amount calculation unit 1267 changes the method for calculating the camera's offset correction amount depending on whether the camera-side offset value has been updated. Whether it is time to update the offset is determined based on the output from the offset update timing notification unit 11337.

[0108] When the camera-side offset value has been updated, the camera offset correction amount calculation unit 1267 calculates the offset correction amount based on the pre-correction lens shake amount signal (the output signal of a subtractor that subtracts the lens-side offset value from the lens shake detection signal). On the other hand, when the camera-side offset value has not been updated, the camera offset correction amount calculation unit 1267h performs processing to calculate the offset correction amount from the lens shake signal and the pre-correction camera shake signal. A detailed explanation will be given later on about the method for calculating the camera offset correction amount. The pre-correction camera shake signal is a signal obtained by subtracting the offset value determined by the lens offset determination unit 1261 from the lens shake detection signal detected by the lens shake detection unit 125.

[0109] In this way, the offset component included in the camera shake detection signal that is the output of the camera shake detection unit 134 is removed by the lens-side offset value determined by the lens offset determination unit 1261 provided on the lens side and the lens offset correction amount, which is the correction amount of the lens offset value determined by the lens offset correction amount calculation unit 1332 provided on the camera side.

[0110] The process for changing the settings of the image stabilization control during panoramic shooting is the same as in the first embodiment, and has been explained using Fig. 3, so a description thereof will be omitted. Also, the positional relationship between the exposure timing and the image sensor during panoramic shooting is the same as that explained using Fig. 4 if the "position of the image stabilization lens" in the first embodiment is replaced with the "position of the image sensor," so a description thereof will be omitted.

[0111] Fig. 9 shows the flow of communication processing during panoramic photography related to the calculation of the camera offset correction amount. This flow basically corresponds to the flow shown in Fig. 5, with the roles of the lens device 2 and the camera body 1 swapped. Fig. 9 also shows the communication processing and calculation processing between the lens device and the imaging device body, which are carried out by the image shake correction lens vibration reduction control unit 126 and the imaging vibration reduction control unit 133 before photography begins or during the period between exposures during continuous shooting.

[0112] First, we will explain the processing performed by the imaging stabilization control unit 133. In step S901, a pre-correction camera shake signal is generated by subtracting the setting value of the camera offset determination unit 1331 from the camera shake detection signal acquired by the camera-side shake detection means 134. After step S901 is completed, the process proceeds to step S902.

[0113] In step S902, the uncorrected camera shake signal obtained in step S901 and information indicating the offset update timing, which indicates whether the offset value on the camera side has been updated or not, from the offset update timing notification unit 1337 is transmitted to the lens device via the camera side communication means 140 and the lens side communication unit 128. After the processing of step S902 is completed, the processing proceeds to step S903.

[0114] In step S903, the camera offset correction amount transmitted from the lens device in step S915 (described later) is received, and is used to calculate the shake correction amount of the image sensor as the correction amount for the camera shake detection signal before correction to be used in the next exposure. Specifically, as described above, the setting value of the camera offset determination unit 1331 and the received camera offset correction amount are subtracted from the camera shake detection signal acquired by the camera-side shake detection means 134. In this way, a corrected camera shake signal is acquired, and the corrected camera shake signal is converted into a camera angle signal to calculate the camera shake correction amount. When the processing of step S903 is completed, the panorama control communication processing ends.

[0115] Next, the processing on the lens device side will be described. This processing is performed by the image stabilization control unit 126 for the image stabilization lens.

[0116] First, in step S911, a lens shake signal is generated by subtracting the set value of the lens offset determination unit 1261 from the lens shake detection signal acquired by the lens side shake detection means 125. After the processing of step S911 is completed, in step S912, a process is performed to acquire the uncorrected camera shake signal transmitted by the camera body in the above-mentioned step S902 and information indicating the offset update timing. After the processing of step S912 is completed, the process of step S913 is performed.

[0117] In step S913, the information indicating the offset update timing acquired in step S912 is referenced to determine whether or not it is the timing at which the camera offset has been updated.

[0118] If it is not the timing to update the camera offset (S913, No), the process proceeds to step S916, where the camera offset correction amount calculation unit 1267 determines the camera offset correction amount based on the difference between the camera shake signal before correction and the lens shake signal.

[0119] On the other hand, if it is time to update the camera offset (S913, Yes), the process proceeds to step S914, where the camera offset correction amount calculation unit 1267 determines the camera offset correction amount based on the lens shake signal.

[0120] When the processing in step S914 or step S916 is completed, the process proceeds to step S915, where the camera offset correction amount calculated in each step is transmitted to the camera body.

[0121] When the process of step S915 is completed, the panorama control communication process on the lens side is completed.

[0122] Through the above flow, an appropriate camera offset correction amount can be set before the start of exposure, depending on the update timing of the offset value on the camera side. If the camera offset correction amount set here is not updated by the start of the next exposure period, it will be used to calculate the shake correction amount during the next exposure period. Next, the camera offset correction amount calculation process performed by the camera offset correction amount calculation unit 1267 in steps S914 and S916 will be described with reference to FIG. 10. The camera offset correction amount calculation process is also basically a form in which the roles of the camera body side and the lens apparatus side are interchanged in the lens offset correction amount calculation process in the first embodiment.

[0123] FIG. 10 is a diagram showing the relationship between the camera offset correction amount and the amount of shake at the time of the next exposure.

[0124] 10(A) and (B), the horizontal axis represents time, and the vertical axis represents the strength of the lens shake signal and the uncorrected camera shake signal. Fig. 10(A) corresponds to the calculation of the camera offset correction amount in step S916, and Fig. 10(B) corresponds to the calculation of the camera offset correction amount in step S914. As a premise, under the conditions of this embodiment, the lens shake signal has less offset deviation (the influence of the offset included in the shake signal) than the uncorrected camera shake signal.

[0125] The lens offset correction amount calculated in step S916 will be described below with reference to FIG.

[0126] Dashed line L7 indicates the camera shake signal before correction, and dashed line L8 indicates the lens shake signal. The camera shake signal before correction, dashed line L7, is obtained by subtracting the set value of camera offset determination unit 1331 from the output of camera-side shake detection unit 134. Similarly, the lens shake signal, dashed line L8, is obtained by subtracting the value of lens offset determination unit 1261 from the output of lens-side shake detection unit 125.

[0127] Let ω(t) be the vibration signal to be subjected to image stabilization. Assume that the offset value on the lens side is highly accurate, and that the error between ω(t) and the camera shake detection signal is kept within a specified range and is negligible. Referring to Figure 10(A), the vibration signal ω(t) to be subjected to image stabilization can be formulated as follows using the uncorrected camera shake signal ωcexp during exposure: ω(t)=ωcexp(t)-(ωc-ωL)...Equation (3)

[0128] This is shown by the solid line L9.

[0129] Here, ωL is the lens shake signal, ωc is the camera shake signal before correction, and data used is that chronologically preceding the exposure start time Texp. From the above, in this embodiment, the camera offset correction amount is set to ωc-ωL. Therefore, the camera offset correction amount calculation unit 1267 obtains the camera offset correction amount by subtracting the lens shake signal ωL from the camera shake signal ωc before correction, which is obtained from the camera body side via the lens side communication unit 128. Note that, as long as the value is close to ωc-ωL, a value obtained by fine-tuning ωc-ωL using an adjustment value associated with the configuration of the imaging device may be used as the offset correction amount.

[0130] Next, the camera offset correction amount calculated in step S914 will be described with reference to FIG.

[0131] Dashed line L10 indicates the camera shake signal before correction, and dashed line L11 indicates the lens shake signal. The camera shake signal before correction, dashed line L10, is obtained by subtracting the set value of camera offset determination unit 1331 from the output of camera-side shake detection unit 134. Similarly, the lens shake signal, dashed line L11, is obtained by subtracting the value of lens offset determination unit 1261 from the output of lens-side shake detection unit 125.

[0132] Assume that the camera offset determination unit 1331 updates the offset value at time Tf. The uncorrected camera shake signal indicated by dashed line L8 is rapidly returned to near 0 at time Tf, which is the update timing. This is because, as in the first embodiment, the offset value is set to a value such that the value obtained by subtracting the offset value from the current (Tf) lens shake detection signal is near 0. This occurs when a predetermined update condition for the camera-side offset value is met. The calculation method of equation (3) can be applied even near time Tf, which is the update timing. However, if the camera-side offset value changes rapidly before and after the update timing, the uncorrected camera shake signal may become unstable near the update timing Tf. As a result, the offset correction amount obtained using equation (3) may not be able to accurately correct changes in the shooting range due to camera shake or panning.

[0133] Therefore, in this embodiment, when the setting value of the camera offset determination unit 1331 is updated, the following equation (4) is used to determine the shake signal ω(t) to be subjected to image shake correction.

[0134] From FIG. 10(B), ω(t) can be formulated as follows using the uncorrected camera shake signal ωcexp during exposure: ω(t)=ωcexp(t)+ωL…Equation (4)

[0135] This is shown by the solid line L12.

[0136] Here, ωL is a lens shake signal, and data prior to the exposure start time Texp is used in the time series. From the above, the offset correction amount on the camera side is set to -ωL. As in step S916, a value obtained by finely adjusting -ωL may be used as the offset correction amount.

[0137] In this way, by determining the amount of offset correction on the camera side based on the lens shake signal rather than the difference between the camera shake signal before correction and the lens shake signal, image blur can be reduced (corrected) with high accuracy even when the offset value on the camera side is updated.

[0138] Furthermore, it is considered that the magnitude of image blur caused by the offset update depends on the amount of change in the pre-correction camera shake signal before and after the offset update, and the magnitude of the difference (ωc - ωL) with the lens shake signal. Therefore, it may be possible to determine whether or not to apply equation (4) when updating the offset based on the magnitude of the camera shake signal at the start of shooting, the magnitude of the lens shake signal during shooting, the magnitude of the camera shake signal during shooting, etc.

[0139] As described above, the present invention can also be applied to an imaging system in which the roles of the lens device and the camera body are reversed compared to the first embodiment. Because the lens device and the camera body are optical devices, the first and second embodiments are imaging systems that include a first optical device equipped with a shake detection unit and a second optical device equipped with a shake detection unit and having a shake detection signal with a more accurate offset value than the first optical device. Based on the shake detection signal from the shake detection unit of the second optical device and the offset value of the shake detection signal, a correction amount (offset correction amount) for obtaining the amount of shake to be corrected by the first optical device can be obtained. By changing the calculation method for obtaining the offset correction amount in accordance with the update timing of the offset value of the first optical device, changes in the shooting range are less likely to occur between exposures during continuous shooting, even when continuous shooting is performed before and after the update timing.

[0140] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0141] For example, the party for which the offset correction amount is calculated (the lens device in the first embodiment, and the camera body in the second embodiment) transmits to the other party a shake detection signal before correction, which is the detection result of the shake detection means, minus an offset value from the shake detection signal. However, the detection result of the shake detection means and the offset value may be transmitted separately. The party that receives the signal and calculates the offset correction amount may subtract the offset value from the shake detection signal as necessary.

[0142] Furthermore, when a lens device capable of image shake correction by displacing an image stabilization lens is combined with a camera body capable of image shake correction by displacing an image sensor, image shake correction may be performed by displacing both the image stabilization lens and the image sensor, even in panoramic shooting mode. In this case, the image stabilization lens anti-shake control unit 126 has the configuration of the first embodiment (FIG. 2), and the image stabilization control unit 133 has the configuration of the second embodiment (FIG. 8). However, the unit with higher offset accuracy does not have an offset update timing notification unit, but instead has a calculation unit (camera offset correction amount calculation unit 1267 or lens offset correction amount calculation unit 1332) that calculates the offset correction amount of the other unit. For example, if the camera body side has higher accuracy, the camera offset determination unit 1331 determines the camera offset value based on the difference between the motion vector and the camera shake detection result, as in the first embodiment. Then, except for the offset update timing of the lens side, the lens offset correction amount is calculated by subtracting the camera shake amount, obtained by subtracting the camera offset value based on the difference from the camera shake detection signal, from the lens shake amount before correction. Furthermore, at the lens-side offset update timing, the lens offset correction amount calculation unit 1332 sets the lens shake amount before correction as the lens offset correction amount. The camera-side shake correction amount calculation unit 1335 calculates the shake correction amount to be corrected on the camera side based on the camera shake amount from which the camera offset value has been subtracted. Meanwhile, the lens-side shake correction amount calculation unit 1264 calculates the shake correction amount to be corrected on the lens side based on a signal obtained by subtracting the offset value and the offset correction amount from the lens shake detection signal.

[0143] In the first and second embodiments, the device with the higher offset value accuracy has an offset correction amount calculation unit, and this offset correction amount calculation unit calculates the offset correction amount of the other device. However, the device with the lower offset value accuracy may also have an offset correction amount calculation unit. For example, as in the first embodiment, if the offset value accuracy is higher on the camera body side, the lens offset correction amount calculation unit 1332 may be provided inside the image shake correction lens vibration isolation control unit 126. The method of calculating the lens offset correction amount is the same as in the first embodiment, where a camera shake signal is obtained through communication between the lens device and the camera body, and information indicating the offset update timing and the lens shake correction signal before correction are received from within the lens device. [Explanation of symbols]

[0144] 125 Lens side vibration detection unit 134 Camera shake detection unit 1261 Lens offset determination unit 1262 Offset update timing notification part 1331 Camera offset determination unit 1332 Lens offset correction amount calculation unit

Claims

1. Construct an imaging system capable of continuous shooting, A second optical device to which a first optical device can be attached includes: first shake detection means for detecting shake; offset value setting means; shake correction means for correcting image shake based on a first shake detection signal detected by the first shake detection means and an offset value set by the offset value setting means; and first communication means, a second communication means for receiving information indicating an update timing of the offset value set in the offset value setting means from the first communication means; a second shake detection means for detecting shake; an offset correction amount calculation means for calculating an offset correction amount based on information indicating an update timing of the offset value received by the second communication means and a second vibration detection signal detected by the second vibration detection means, When the first mode for continuous shooting is set, The offset correction amount calculation means selecting a calculation method to be used for calculating the offset correction amount from a plurality of calculation methods including a first calculation method and a second calculation method different from the first calculation method, based on information indicating an update timing of the offset value; a second optical device that calculates the offset correction amount based on the selected calculation method between exposure periods during the continuous shooting;

2. The offset correction amount calculation means selecting the first calculation method when it is determined that it is time to update the offset value based on the information indicating the update timing of the offset value; 2. The second optical device according to claim 1, wherein when it is not determined that the offset value has been updated, the second calculation method is selected.

3. The first calculation method includes: a method for calculating the offset correction amount based on the second shake detection signal, The second calculation method includes:

3. The second optical device according to claim 2, wherein the offset correction amount is calculated based on the first vibration detection signal, the second vibration detection signal, and the offset value set by the offset value setting means.

4. The second communication means includes: receiving information corresponding to a signal obtained by subtracting the offset value from the first shake detection signal; 4. The second optical device according to claim 3, wherein the offset correction amount calculation means calculates the offset correction amount based on information corresponding to a signal obtained by subtracting the offset value from the first shake detection signal and the second shake detection signal in the second calculation method.

5. If the first mode is not set, 5. The second optical device according to claim 1, wherein the offset correction amount calculation means does not change the calculation method of the offset correction amount based on information indicating the update timing of the offset value.

6. 6. The second optical device according to claim 1, wherein the first mode is a mode for acquiring a composite image by combining a plurality of images acquired by continuous shooting.

7. 7. The second optical device according to claim 6, wherein the first mode is a mode in which the composite image is obtained by stitching a plurality of images obtained by continuous shooting.

8. The offset correction amount calculation means 8. The second optical device according to claim 1, wherein the number of times the offset correction amount is calculated during a period between exposure periods in the continuous shooting is changed depending on whether it is determined that the offset value has been updated based on information indicating the update timing of the offset value or whether it is determined that the offset value has not been updated.

9. The offset correction amount calculation means 9. The second optical device according to claim 1, wherein the calculation method is selected based on at least one of a detection result of the first shake detection means before start of exposure in the first mode, a detection result of the second shake detection means before start of exposure, a detection result of the first shake detection means during an exposure period, and a detection result of the second shake detection means during the exposure period.

10. the first optical device is a lens device equipped with a photographic optical system, the image stabilization unit includes an image stabilization lens that constitutes the photographing optical system and an actuator that moves the image stabilization lens; 10. The second optical device according to claim 1, wherein the second optical device is an imaging device that includes an imaging element and is capable of performing continuous imaging in the first mode.

11. the first optical device is an imaging device that includes an imaging element and is capable of performing continuous imaging in the first mode, the image stabilization unit includes an image sensor and an actuator that moves the image sensor; 10. The second optical device according to claim 1, wherein the second optical device is a lens device having a photographing optical system.

12. An imaging system capable of continuous photography with multiple exposures, A first optical device to which a second optical device can be attached, the first optical device including a second shake detection means for detecting shake, an offset correction amount calculation means, and a second communication means for transmitting an offset correction amount calculated by the offset correction amount calculation means, a first shake detection means for detecting shake; offset value setting means; a first communication means for receiving the offset correction amount; an image blur correction amount calculation means for calculating an image blur correction amount based on a first shake detection signal detected by the first shake detection means, the offset value set by the offset value setting means, and the offset correction amount received from the first communication means; an image blur control unit that controls the image blur correction unit based on the image blur correction amount calculated by the image blur correction amount calculation unit, When the first mode for performing continuous photography is set, The first communication means includes: information indicating the update timing of the offset value set in the offset value setting means; The first optical device transmits information based on the first vibration detection signal and the offset value to the second communication means.

13. The first communication means includes:

13. The first optical device according to claim 12, wherein information indicating a result of subtracting the offset value from the first shake detection signal is transmitted to the second communication means as information based on the first shake detection signal and the offset value.

14. The first communication means includes:

13. The first optical device according to claim 12, wherein information indicating the first shake detection signal and information indicating the offset value are transmitted to the second communication means as information based on the first shake detection signal and the offset value.

15. The image blur correction amount calculation means When the first mode is set and the first communication means transmits information indicating that it is time to update the offset value to the second optical device, calculating the image blur correction amount based on the shake detected by the first shake detection means during exposure in the first mode, the offset value set by the offset value setting means, and the shake detected by the second shake detection means before exposure; When the first mode is set and the first communication means does not transmit information indicating that it is time to update the offset value to the second optical device, 15. The first optical device according to claim 12, wherein the image blur correction amount is calculated based on a shake detected by the first shake detection means during exposure in the first mode, an offset value set by the offset value setting means, a shake detected by the first shake detection means before exposure, and a shake detected by the second shake detection means before exposure.

16. 16. The first optical device according to claim 12, wherein the image blur control means stops the image blur correction means at a reference position between exposure periods during the continuous shooting.

17. the first optical device is a lens device equipped with a photographic optical system, the image stabilization unit includes an image stabilization lens that constitutes the photographing optical system and an actuator that moves the image stabilization lens; 17. The first optical device according to claim 12, wherein the second optical device is an imaging device that includes an imaging element and is capable of performing continuous imaging in the first mode.

18. the first optical device is an imaging device that includes an imaging element and is capable of performing continuous imaging in the first mode, the image stabilization unit includes an image sensor and an actuator that moves the image sensor; 18. The first optical device according to claim 12, wherein the second optical device is a lens device having a photographing optical system.

19. A first optical device described in any one of claims 12 to 18, characterized in that the image shake correction amount calculation means corrects the offset value set by the offset value setting means based on the offset correction amount received from the first communication means, and calculates the image shake correction amount based on the corrected offset value and the first shake detection signal detected by the first shake detection means.

20. An imaging system capable of continuous shooting, a first shake detection means for detecting shake; offset value setting means; a shake correction means for correcting image shake based on a first shake detection signal detected by the first shake detection means and the offset value set by the offset value setting means; a first optical device having a first communication means; a second shake detection means for detecting shake; a second optical device having a second communication means capable of communicating with the first communication means; offset correction amount calculation means; When the first mode for continuous shooting is set, The offset correction amount calculation means selecting a calculation method to be used for calculating an offset correction amount for correcting the offset value from a plurality of calculation methods including a first calculation method and a second calculation method different from the first calculation method, based on a relationship with an update timing of the set value by the offset value setting means; an imaging system that calculates the offset correction amount based on the selected calculation method between exposure periods during the continuous shooting;

21. a first optical device having a first shake detection means for detecting shake, an offset value setting means, and a shake correction means for correcting image shake based on a first shake detection signal detected by the first shake detection means and an offset value set by the offset value setting means; a second optical device having a second shake detection unit that detects shake, and a method for calculating a correction amount in an imaging system capable of continuous imaging, the method comprising: When the first mode for continuous shooting is set, acquiring information on the timing of updating the set value by the offset value setting means; selecting a calculation method to be used for calculating an offset correction amount for correcting the offset value from a plurality of calculation methods including a first calculation method and a second calculation method different from the first calculation method, based on a relationship with an update timing of the set value by the offset value setting means; calculating the offset correction amount based on the selected calculation method between exposure periods in the continuous shooting.

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