JP7770880B2 - Optical device, imaging system, and method for calculating correction amount in imaging system - Google Patents

Description

The present invention relates to technology for correcting image shake in an imaging device, and in particular to image shake correction during continuous shooting.

Image capture devices equipped with an image stabilization device have the ability to generate panoramic images. When using this function to generate a panoramic image, the photographer pans at any speed while taking continuous shots. The image capture device uses an image stabilization unit to correct the amount of image blur caused by the photographer's panning movements or camera shake during each exposure period during the continuous shooting, and then combines these captured images to create a panoramic image (hereafter, this shooting method will be referred to as panoramic photography).

In order to use this panoramic shooting function to obtain images 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.

Patent Document 1 discloses a function that uses a shake detection means provided in the imaging device body to correct the output of a shake detection means provided in a lens device in order to accurately correct camera shake. When the second shake detection means provided in the imaging device is more accurate than the first shake detection means provided in the lens device, the imaging device described in Patent Document 1 calculates a correction amount for the 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.

By using the above configuration, it is possible to improve image stabilization performance in response to the influence of differences in the performance of the shake detection means provided in the lens device and the imaging device body.

Japanese Patent Application Laid-Open No. 2020-91355

However, depending on the shake detection means provided in the lens device or imaging device, sudden fluctuations in the shooting range may occur due to the estimated value of the offset component of the shake detection signal being updated (hereinafter referred to as offset update) during continuous shooting.

For example, some shake detection means can have large errors in the shake detection signal after the imaging device is started, depending on the photographer's operation or handling. When using such detection means, the offset for 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 the correction amount for one shake detection signal based on the other shake detection signal, as in the prior art disclosed in Patent Document 1 above, the estimated value of the offset component may change abruptly, causing abrupt fluctuations in the imaging range.

In particular, continuous shooting often takes a long time when shooting panoramic images, which increases the likelihood of offset updates occurring during continuous shooting, so measures are needed.

Therefore, an object of the present invention is to provide an imaging device that reduces sudden changes in the imaging range caused by updating the offset for the shake detection signal.

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 a first shake detection means for detecting shake, an 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 an offset value set by the offset value setting means, and a first communication means, and further includes a 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, a second shake detection means for detecting shake, and the information received by the second communication means. The system includes an offset correction amount calculation means that calculates an offset correction amount based on information indicating the offset value update timing and a second shake detection signal detected by the second shake detection means, and when a first mode for performing continuous shooting is set, the offset correction amount calculation means selects a calculation method to be used to calculate 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 offset value update timing, and calculates the offset correction amount based on the selected calculation method between each exposure period for the continuous shooting.

Other aspects of the present invention will be made clear in the embodiments described below.

This invention estimates the offset component contained in the detection result of the shake detection means, and when image stabilization is performed using the detection result and the estimated result, it is possible to reduce the sudden shift in the angle of view caused by updating the offset for the shake detection signal.

A block diagram showing an example of the configuration of an imaging device FIG. 1 is a block diagram showing an example of a configuration related to image stabilization control in a first embodiment. Flowchart for image stabilization settings during panoramic photography FIG. 1 is a diagram illustrating exposure timing and the position of the image stabilization lens during panoramic photography. Flowchart for calculating the offset correction amount of the lens shake detection signal (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. FIG. 1 is a diagram showing the timing of calculating the shake offset correction amount during panoramic photography. FIG. 10 is a block diagram showing an example of the configuration related to image stabilization control according to a second embodiment. Flowchart for calculating offset correction amount for camera shake detection signal (A) A diagram illustrating a method for calculating the amount of offset correction on the camera side when it is not the offset update timing. (B) A diagram illustrating a method for calculating the amount of offset correction on the camera side when it is the offset update timing.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

Please note that the following embodiments do not limit the scope of the claimed invention.

The embodiments describe multiple features, but not all of these features are necessarily essential to the invention, and multiple features may be combined in any manner.

Furthermore, in the accompanying drawings, identical or similar components are designated by the same reference numbers and redundant explanations are omitted.

(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 an interchangeable-lens 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 includes an imaging optical system 200. The imaging optical system 200 includes 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 to optically correct 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.

The aperture drive unit 120 and shutter drive unit 135 drive the aperture 104 and shutter 105. The zoom lens drive unit 124 drives the zoom lens 101 to change the angle of view. The zoom lens control unit 127 controls the position of the zoom lens 101 in accordance with zoom operation instructions from the operation unit 114. The focus lens drive unit 121 drives the focus lens 103.

Light that passes through the imaging 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 reduction, gain adjustment, and AD conversion on the image signal read out from the image sensor 106.

The 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 the camera control unit 115. The 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 the internal memory 110.

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 that performs cylindrical coordinate transformation and lens distortion correction, and a compositing circuit that performs trimming and compositing processes. The operation of each circuit is publicly known, so a detailed description will be omitted.

The display unit 111 displays image data stored in the internal memory 110 as well as shooting information. The compression/decompression processing unit 112 compresses or decompresses the data stored in the internal memory 110 according to the image format.

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

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 to detect the subject's face.

In the case of an interchangeable lens camera, information is transmitted between the camera and lens via the camera side communication unit 140 and lens side communication unit 128.

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 drive unit 120 and shutter drive unit 135 of the calculation results 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).

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, it acquires evaluation values, which are the calculation results of the evaluation value calculation unit 138 at each focus lens position. As a result, 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 reaches its peak, and notifies the focus lens drive unit 128. By driving the focus lens drive unit 128 to the defocus position, automatic focusing control (AF control) is performed, in which the light beam is focused 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 known and will not be described here.

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 located on the camera side, a lens-side shake detection unit 125 is also located on the lens side to detect vibration caused by shake and vibration applied to the lens. A gyro sensor, which is an angular velocity sensor, is generally used to detect vibration, and detects the angular velocity of shake and vibration.

Based on shake detection signals detected by the lens-side shake detection unit 125, the camera-side shake detection unit 134, or both, the image stabilization lens control unit 126 calculates the amount of lens shake compensation to suppress shake using the image stabilization lens. Then, based on the calculated lens shake compensation 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 drive unit 122, thereby controlling stabilization using the image stabilization lens. The image stabilization lens drive unit 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 control unit 126. Details of the method for controlling stabilization using the image stabilization lens will be described later.

Based on the shake detection signals detected by the camera-side shake detection unit 134, the lens-side shake detection unit 125, or both, the image capture stabilization control unit 133 calculates the amount of image capture element shake compensation to suppress shake using the image capture element. Then, based on the calculated compensation amount and the position of the image capture element 106 detected by the image capture element position detection unit 132, the image capture stabilization control unit 133 controls image capture element shake compensation by transmitting an image capture element drive signal to the image capture element drive unit 130. The image capture element drive unit 130 drives the image capture element 106 in a direction perpendicular to the optical axis based on the image capture element drive signal received from the image capture stabilization control unit 133. However, in this embodiment, image capture element shake compensation is stopped by fixing the image capture element at a reference position during panoramic shooting, and shake during panoramic shooting is compensated for using an image stabilization lens, so details of the image capture element shake compensation control method are omitted. The reference position may be any location, such as the center of the image capture element's movable range, a position where the center of the effective area overlaps the optical axis of the imaging optical system of the lens device, or another location. The motion vector detection unit 131 uses block matching to calculate the correlation value between the current frame and the previous frame for each block that the frame is divided into. It then searches for the block in the previous frame that minimizes this calculation result, and detects the deviation of other blocks relative to that block as a motion vector.

Figure 2 is a block diagram showing an example configuration of the image stabilization lens control unit 126 and the image capture stabilization control unit 133 in this embodiment.

First, we will explain the configuration of the image stabilization lens stabilization control unit 126 on the lens device side. 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 retaining the determined offset value. This offset value is updated when a predetermined condition is met after startup. The offset value is not updated until the predetermined condition is met. After startup, the offset value is not updated until the update condition is met, and an arbitrary initial value is set. For example, the offset value may be determined by retaining the value α1 indicated by the current gyro detection result as a temporary offset value and performing an arbitrary stability determination process on the difference between this and the value α2 indicated by the gyro detection result obtained at the next timing (α2 - α1). 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 has been 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) that offset value. Then, this timing (offset value update timing) is notified to the camera body 1 side via the lens side communication unit 128 and camera side communication unit 140.

The integration/LPF unit 1263 is an integrator or LPF (low-pass filter) that converts the lens shake detection signal, which indicates angular velocity, into 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 the lens offset correction amount (described below) from the lens shake detection signal detected by the lens shake detection unit. The corrected lens shake signal is then integrated or LPF processed to generate a lens shake angle signal.

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

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, which is based on the lens shake compensation amount calculated by the shake compensation 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 explanation is omitted. The image stabilization lens drive unit 122 is an actuator such as a voice coil motor or 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 imaging stabilization control block 133 can perform image shake correction using the imaging element 106 by driving the imaging element, but image shake correction is stopped during panoramic photography. Therefore, here we will explain the functional block related to calculating the lens offset correction amount, which is involved in obtaining the corrected lens shake signal, which is the 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.

The camera offset determination unit 1331 is a means for determining and storing 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, for example, 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, the still output may be measured in a process before shipping and stored in memory within 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, thereby removing the offset component included in the camera shake detection signal and obtaining the camera shake signal. In this embodiment, the offset value is determined more accurately than by the lens-side offset determination unit 1261.

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 determined by the lens offset determination unit and 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 the lens-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 1262 received via the lens-side communication unit 128 and the camera-side communication unit 140.

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. The method for calculating the lens offset correction amount will be described in detail 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.

In this way, the offset component contained in the lens shake detection signal output by 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.

Next, the process for changing the image stabilization control settings during panoramic photography in this embodiment will be explained using Figure 3.

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

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

In step S303, pan control in image stabilization control is disabled. Pan control refers to control that, when panning by the photographer is detected, weakens the effect of image stabilization control to allow for intentional changes to 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 then 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 in order to use image stabilization to correct as much as possible the changes in the imaging range associated with panning during a single exposure. After step S303 is completed, processing proceeds to step S304.

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

In addition, in this step, during the non-exposure periods between multiple exposures (called inter-frame periods), the image stabilization lens is moved to the center position 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.

Figure 4 shows the exposure timing and image stabilization lens positional relationship during panoramic photography that can be achieved by changing the settings in steps S303 and S304. Figure 4 is explained below.

In Figure 4, the horizontal axis represents time, and the vertical axis represents the exposure timing and the position of the image stabilization lens 102 during continuous shooting for panoramic photography.

In Figure 4, the periods from time t1 to time t2, time t4 to time t5, and time t7 to time t8 are the respective exposure periods, during which any 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.

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 image stabilization impossible. 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.

The periods from time t3 to time t4, time t6 to time t7, and time t9 to time t10, from the end of the centering process 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 the image stabilization control is waited for.

By performing the above control, it is possible to achieve driving of the image stabilization lens 102 suitable for panoramic photography. This concludes the explanation of Figure 4, and we will return to the explanation of the flowchart in Figure 3.

After step S304 is completed, the process proceeds to step S305. In step S305, processing is performed to enable default communication (called panorama control communication) for image stabilization control during panoramic photography.

Here, the panorama control communication process will be explained using Figure 5.

Figure 5 shows the communication and calculation processes 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.

First, we will explain the processing performed by the image stabilization lens 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 shake detection means 125. After step S501 is completed, processing proceeds to step S502.

In step S502, the uncorrected lens shake signal obtained in step S501 and information indicating the offset update timing, which indicates whether the lens-side offset value 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 step S502 is completed, the process proceeds to step S503.

In step S503, the lens offset correction amount transmitted from the camera body in step S515 (described below) is received and used to calculate the lens shake correction amount as the correction amount for the pre-correction lens shake detection signal to be used for 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.

Next, we will explain the processing on the imaging device main body side. This processing is performed by the imaging 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.

After the processing of step S511 is completed, processing is performed in step S512 to acquire the uncorrected lens shake signal transmitted by the lens device in the aforementioned step S502 and information indicating the offset update timing. After the processing of step S512 is completed, processing is performed in step S513.

In step S513, the information indicating the offset update timing acquired in step S512 is referenced to determine whether the timing has come for updating the lens offset. If it is not the timing for updating the lens offset (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 pre-correction lens shake signal and the camera shake signal.

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

Once processing in step S514 or step S516 is completed, proceed to step S515, where the lens offset correction amount calculated in each step is sent to the lens device.

Once step S515 is completed, the camera-side panorama control communication process ends.

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 lens offset value. 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. Details of how to obtain the lens offset correction amount calculated in steps S414 and S416 will be described later.

This concludes the explanation of Figure 5, and we return to the explanation of Figure 3. When step S305 is completed, the process of changing the image stabilization settings when panoramic shooting mode is set is completed. When 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 settings is completed.

The following describes the processing when panoramic shooting mode is not set. If a mode other than panoramic shooting mode is set in step S302 (step S302, No), the process proceeds to step S306, where processing to enable pan control is performed. This is because, for uses other than panoramic shooting, it is considered better to weaken image stabilization in order to follow changes in the shooting range intended by the photographer that occur as the camera pans. Once the processing of step S306 is completed, the process proceeds to step S307.

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 inter-frame correction amount was set to 0 immediately after switching from panoramic shooting mode to another mode, this setting is canceled and inter-frame vibration compensation control is set appropriately in accordance with the current shooting mode and shooting settings.

Once processing in step S307 is complete, proceed to step S308.

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. Once step S308 is completed, the image stabilization setting change processing ends.

Next, the lens offset correction amount calculation process performed by the lens offset correction amount calculation unit 1332 in steps S514 and S516 will be described using Figure 6.

Figure 6 shows the relationship between the lens offset correction amount set in steps S514 and S515 and the amount of blur during the next exposure.

In Figures 6(A) and (B), the horizontal axis represents time, and the vertical axis represents the strength of the lens shake signal and camera shake signal before correction. Figure 6(A) corresponds to the calculation of the lens offset correction amount in step S516, and Figure 6(B) corresponds to the calculation of the lens offset correction amount in step S514. As a premise, under the conditions of this embodiment, the camera shake signal has less offset deviation (the influence of the offset contained in the shake signal) than the lens shake signal before correction.

The lens offset correction amount calculated in step S516 will now be described with reference to Figure 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 the lens offset determination unit 1261 from the output of the lens side shake detection unit 125. Similarly, the camera shake signal represented by dashed line L2 is obtained by subtracting the setting value of the camera offset determination unit 1331 from the output of the camera side shake detection unit 134.

Let ω(t) be the vibration signal to be subjected to image stabilization. Assume that the accuracy of the offset value on the camera side is high, and the error between ω(t) and the camera shake detection signal is kept within a predetermined range and is negligible. Referring to FIG. 6A, 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)...Formula (1)

This is represented by the solid line L3.

Here, ωL is the lens shake signal before correction, and ωc is the camera shake signal, and data used is that chronologically preceding the exposure start time Texp. As a result, 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 via the camera 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.

Next, the lens offset correction amount calculated in step S514 will be explained with reference to Figure 6 (B).

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 the lens offset determination unit 1261 from the output of the lens side shake detection unit 125. Similarly, the camera shake signal, dashed line L2, is obtained by subtracting the value of the camera offset determination unit 1331 from the output of the camera side shake detection unit 134.

Let's assume that the lens offset determination unit 1261 updates the setting value (offset value) at time Tf. Hereinafter, the timing at which the lens offset value is updated will be referred to as the update timing. The uncorrected lens shake signal indicated by dashed line L4 is abruptly 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 based on the lens shake detection signal over a certain period of time, such that the value obtained by subtracting the offset value from the current lens shake detection signal (Tf) is near 0. 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 abruptly 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 be able to accurately correct changes in the shooting range due to camera shake or panning.

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.

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...Formula (2)

This is represented by the solid line L6.

Here, ωc is the camera shake signal, and data from chronologically before the exposure start time Texp is used. Based on the above, the offset correction amount on the lens side is set to -ωc. As in step S516, a finely adjusted value of -ωc can also be used as the offset correction amount.

In this way, by calculating the lens-side offset correction amount based on the camera shake signal rather than the difference between the pre-correction lens shake signal and the camera shake signal, image blur can be reduced with high precision even when the lens-side offset value has been updated.

The magnitude of image blur caused by offset updating is thought to depend on the amount of change in the pre-correction lens shake signal before and after the offset update, and the magnitude of the difference with the camera shake signal (ωL - ωc). Therefore, whether or not to apply equation (2) when updating the offset may be determined 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.

Figure 7 shows the relationship between exposure timing and panorama control communication in this embodiment, including the timing of calculating the offset correction amount and the timing of communication for notifying the calculated offset correction amount.

Figure 7 shows an example of capturing five images using panoramic photography and combining them into a panoramic image. The period when the image readout timing is High outside of the panoramic photography period indicates the live view image readout period. In Figure 7, the live view image is read out twice, followed by five readouts for panoramic photography.

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-mentioned formula (1).

When the first exposure for panoramic photography begins, the lens device acquires a corrected lens shake signal using the lens-side offset value set in the lens offset determination unit 1261 immediately before the start of exposure, the latest offset correction amount 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. Once the first exposure is complete, communication resumes. The lens offset correction amount calculation unit 1332 of the camera body 1 acquires the lens offset update information and the chronologically synchronized uncorrected lens shake detection signal and camera shake detection signal, calculates the lens-side offset correction amount, and notifies the lens device 2 of this calculation. This processing is performed between frames, and the timing of its execution 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 processing is basically performed three times between frames.

The offset correction amount is calculated before exposure and between frames using the above equations (1) and (2). If 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.

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 compared to when it was not updated. In this embodiment, the lens-side offset correction amount determined at the timing indicated by * (method of equation (2)) is fixed, and calculation and updating of the lens-side offset correction amount from this point onward is stopped until the next exposure begins.

On the other hand, the number of communications can also be increased. Depending on the number of communications, it is possible to select whether to calculate the lens offset correction amount using a camera shake detection signal near the lens offset update timing in a chronological order, or to calculate the lens offset correction amount using a camera shake detection signal close to the next exposure.

While this embodiment describes the method for calculating and obtaining the offset correction amount when panorama mode is set, the imaging device of this embodiment is also capable of shooting in modes other than panorama mode. For example, it is also possible to 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 slight deviations in the shooting range between continuous shots are unlikely to be a problem, there is no need to change the calculation method for the offset correction amount depending on whether it is time to update the offset value. For example, formula (1) may always be selected to calculate the offset correction amount. Furthermore, even in modes that do not combine images acquired through continuous shooting, slight deviations in the shooting range are less likely to be a problem than in modes such as panorama mode, in which multiple images are stitched together to form a composite. Therefore, as with single-shot mode, there is no need to change the calculation method for the offset correction amount depending on whether it is time to update the offset value. For example, method (1) may always be selected to calculate the offset correction amount.

Furthermore, if the method for calculating the offset correction amount is not changed in accordance with the offset value update timing, the lens device 2 equipped with the offset value setting means does not need to transmit the offset value update timing to the camera body 1. However, in configurations where it is not possible to obtain information about the shooting mode on the camera body 1, the offset value update timing may always be transmitted regardless of the shooting mode.

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 the calculated amount to the camera body.

The details of this embodiment are described below. The configuration of the imaging device of this embodiment is the same as that shown in FIG. 1, so a detailed description is 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 sensor stabilization control unit 133 calculates the amount of image shake compensation to suppress shake. Then, an image sensor drive signal based on the calculated amount of image shake compensation and the position of the image sensor 106 detected by the image sensor position detection unit 132 is sent to the image sensor driver 130, thereby controlling image shake compensation by the image sensor. Furthermore, in this embodiment, shake during panoramic shooting is compensated for 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; for example, it may be the center of the movable range, or it may be a position where the optical axis of the imaging optical system coincides with the center of the mount of the camera body.

Figure 8 is a block diagram showing an example configuration of the image stabilization lens stabilization control unit 126 and the image stabilization control unit 133 in this embodiment. As described above, the camera body sets the offset value and notifies the other party of the offset value update timing, and the lens device calculates the offset correction amount. First, the configuration of the image stabilization control unit 133 on the camera body will be described. The configuration of the image 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 image 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 means that determines the offset value based on the camera shake detection signal from the camera 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 met after startup and is not updated until the predetermined condition is met. After startup, the offset value is not updated until the update condition is met and an arbitrary initial value is set. The method for determining the offset value is the same as in the first embodiment, so explanation will be omitted.

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.

Like integration/LPF unit 1263, integration/LPF unit 1334 is an integrator or LPF that raises the dimension of the shake detection signal indicating angular velocity by one to a shake angle. Integration/LPF unit 1334 receives the corrected camera shake detection signal, rather than the actual camera shake detection signal detected by 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 camera offset determination unit 1331 and the camera offset correction amount, which will be described later, from the camera shake detection signal detected by camera shake detection unit 134. Then, a camera shake angle signal is generated by integrating or LPF-processing this corrected lens shake signal.

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

The position control unit 1336 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 sensor 106 based on the camera shake compensation amount calculated by the shake compensation amount calculation unit 1335 and the current position of the image sensor 106. The deviation between the target position and the current position is converted into an image sensor drive signal and input to the image sensor drive unit 130. The current position is the detection result of the image sensor position detection unit 132. PID control is a common technique, so a detailed explanation will be omitted.

The image sensor driver 132 drives (displaces) the image sensor 106 in accordance with the image sensor drive signal.

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 the image sensor by driving the image stabilization lens 102, but image stabilization is stopped during panoramic shooting. For this reason, the control block for driving the image stabilization lens 102 is omitted from Figure 8, and instead we will explain the functional block related to calculating the offset correction amount, which is involved in obtaining the corrected camera shake signal. However, as with the block diagram shown in Figure 2, it may also include an integration/LPF unit 1263 that converts angular velocity signals into angle signals, 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.

The lens offset determination unit 1261 is a means for determining and storing an estimated value of the offset (hereinafter referred to as the 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 embodiment 1, 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, for example, the difference. A subtractor subtracts the lens-side offset value stored by 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 by the camera-side offset determination unit 13311.

The camera offset correction amount calculation unit 1267 is a block that calculates the camera offset correction amount that corrects the current camera-side offset value determined by the camera offset determination unit and 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.

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. The method for calculating the camera offset correction amount will be described in detail later. 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.

In this way, the offset component contained in the camera shake detection signal, which 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 for the lens offset value determined by the lens offset correction amount calculation unit 1332 provided on the camera side.

The process for changing the image stabilization control settings during panoramic photography is the same as in the first embodiment and has been explained using Figure 3, so a detailed explanation will be omitted. Furthermore, the relationship between the exposure timing and the position of the image sensor during panoramic photography is the same as that explained using Figure 4 if the "position of the image stabilization lens" in the first embodiment is replaced with the "position of the image sensor," so a detailed explanation will be omitted.

Figure 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 Figure 5, with the roles of the lens device 2 and the camera body 1 swapped. Figure 9 also shows the communication processing and calculation processing between the lens device and the imaging device body, carried out by the image stabilization 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.

First, we will explain the processing performed by the image capture stabilization control unit 133. In step S901, the setting value of the camera offset determination unit 1331 is subtracted from the camera shake detection signal acquired by the camera-side shake detection means 134 to generate a pre-correction camera shake signal. After step S901 is completed, processing proceeds to step S902.

In step S902, the uncorrected camera shake signal obtained in step S901 and information indicating the offset update timing, which indicates whether the camera-side offset value has been updated, 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 step S902 is completed, the process proceeds to step S903.

In step S903, the camera offset correction amount transmitted from the lens device in step S915 (described below) is received and used to calculate the shake correction amount for the image sensor as the correction amount for the pre-correction camera shake detection signal to be used for 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.

Next, we will explain the processing on the lens device side. This processing is performed by the image stabilization lens vibration isolation control unit 126.

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, processing is performed in step S912 to acquire the uncorrected camera shake signal sent by the camera body in the aforementioned step S902 and information indicating the offset update timing. After the processing of step S912 is completed, processing of step S913 is performed.

In step S913, the information indicating the offset update timing obtained in step S912 is referenced to determine whether the camera offset has been updated.

If it is not time to update the camera offset (S913, No), proceed to step S916, where the camera offset correction amount calculation unit 1267 determines the camera offset correction amount based on the difference between the pre-correction camera shake signal and the lens shake signal.

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

Once processing in step S914 or step S916 is complete, proceed to step S915, where the camera offset correction amount calculated in each step is sent to the camera body.

Once step S915 is completed, the lens-side panorama control communication process ends.

The above flow allows an appropriate camera offset correction amount to be set before exposure begins, 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 using Figure 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 device side are swapped in the lens offset correction amount calculation process in the first embodiment.

Figure 10 shows the relationship between the camera offset correction amount and the amount of blur during the next exposure.

In Figures 10(A) and (B), the horizontal axis represents time, and the vertical axis represents the strength of the lens shake signal and the camera shake signal before correction. Figure 10(A) corresponds to the calculation of the camera offset correction amount in step S916, and Figure 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 contained in the shake signal) than the camera shake signal before correction.

The lens offset correction amount calculated in step S916 will be explained below with reference to Figure 10(A).

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 the camera offset determination unit 1331 from the output of the camera shake detection unit 134. Similarly, the lens shake signal, dashed line L8, is obtained by subtracting the value of the lens offset determination unit 1261 from the output of the lens shake detection unit 125.

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 predetermined range and is negligible. Referring to FIG. 10A, 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)

This is represented by the solid line L9.

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. As a result, 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, the offset correction amount may be a value obtained by fine-tuning ωc - ωL, for example, using an adjustment value associated with the configuration of the imaging device.

Next, we will explain the camera offset correction amount calculated in step S914 with reference to Figure 10 (B).

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 the camera offset determination unit 1331 from the output of the camera shake detection unit 134. Similarly, the lens shake signal, dashed line L11, is obtained by subtracting the value of the lens offset determination unit 1261 from the output of the lens shake detection unit 125.

Let's assume that the offset value is updated by the camera offset determination unit 1331 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.

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.

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

This is represented by the solid line L12.

Here, ωL is the lens shake signal, and data from chronologically before the exposure start time Texp is used. Based on the above, the offset correction amount on the camera side is set to -ωL. As in step S916, a finely adjusted value of -ωL may be used as the offset correction amount.

In this way, by calculating the camera-side offset correction amount based on the lens shake signal rather than the difference between the pre-correction camera shake signal and the lens shake signal, image shake can be reduced (corrected) with high accuracy even when the camera-side offset value is updated.

The magnitude of image blur caused by offset updating is thought to depend on the amount of change in the pre-correction camera shake signal before and after the offset update, and the magnitude of the difference with the lens shake signal (ωc - ωL). Therefore, whether or not to apply equation (4) when updating the offset may be determined 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.

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 from those of 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 means and a second optical device equipped with a shake detection means and having a shake detection signal with a more accurate offset value than the first optical device. Then, based on the shake detection signal of the shake detection means of the second optical device and the offset value of that 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.

The above describes preferred embodiments of the present invention, but the present invention is not limited to these embodiments, and various modifications and variations are possible within the scope of the invention.

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 an uncorrected shake signal obtained by subtracting an offset value from the shake detection signal, which is the detection result of the shake detection means. However, the detection result of the shake detection means and the offset value may also be transmitted separately. The party that receives the signal and calculates the offset correction amount can then subtract the offset value from the shake detection signal as necessary.

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 (Figure 2), and the image stabilization control unit 133 has the configuration of the second embodiment (Figure 8). However, the offset value with higher 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 device. For example, if the camera body 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, 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 amount of lens shake before correction as the lens offset correction amount. The camera-side shake correction amount calculation unit 1335 calculates the amount of shake correction to be performed on the camera side based on the amount of camera shake from which the camera offset value has been subtracted. Meanwhile, the lens-side shake correction amount calculation unit 1264 calculates the amount of shake correction to be performed 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.

In addition, in the first and second embodiments, the offset correction amount calculation unit is provided on the side with the higher offset value accuracy, and this offset correction amount calculation unit calculates the offset correction amount on the other side. However, the offset correction amount calculation unit may also be provided on the side with the lower offset value accuracy. 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 stabilization 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.

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

Claims (21)

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; 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. 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. 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. 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 . The second optical device according to any one of claims 1 to 5, characterized in that the first mode is a mode in which a composite image is obtained by combining multiple images acquired by continuous shooting. The second optical device according to claim 6, wherein the first mode is a mode in which the composite image is obtained by stitching multiple images acquired by continuous shooting. 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. 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. 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. 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. An imaging system capable of continuous photography with multiple exposures is constructed,
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. 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. 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. 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,
The first optical device according to any one of claims 12 to 14, characterized in that the image blur correction amount is calculated 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, the shake detected by the first shake detection means before exposure, and the shake detected by the second shake detection means before exposure. 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. 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. 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. The first optical device according to claim 12, wherein the image blur 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 blur correction amount based on the corrected offset value and a first shake detection signal detected by the first shake detection means. 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; 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.