JP2018013602A - Image shake correction device, lens device, imaging device, and imaging system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image shake correction device that can accurately correct an error in panning.SOLUTION: An image shake correction device comprises: correction means (132) that performs image shake correction; calculation means (124a) that calculates a reference angular velocity during exposure used for a panning shot; and control means (124b) that controls the correction means to perform the panning shot on the basis of the difference between the reference angular velocity during exposure and an angular velocity from an angular velocity sensor. The calculation means calculates the reference angular velocity during exposure according to a reference angular velocity before the start of exposure calculated on the basis of a motion vector and the angular velocity from the angular velocity sensor.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an imaging apparatus capable of easily realizing panning shots by detecting and correcting camera shake.

  In order to correct image blur caused by camera shake or the like generated in the camera, camera vibration is detected, and the optical axis is changed by moving the correction lens or the image sensor in accordance with the detection result. In Patent Document 1, the correction optical system that decenters the photographing optical axis is driven based on such detection information, and the position of the correction optical system is detected and feedback control is performed to suppress image blurring. An anti-vibration device is disclosed.

  On the other hand, there is a panning shot as one of the shooting methods using a camera. However, panning requires experience to make the camera follow the movement of the subject accurately, and the shutter speed also slows down, so that shake tends to occur and is difficult for beginners. Therefore, Patent Document 2 discloses a method for assisting panning using a correction optical system. Specifically, the moving speed of the main subject on the imaging surface is detected, and the panning reference angular speed for optimal panning is calculated from the difference between the detected moving speed and the panning angular speed performed by the photographer. . During the exposure, a difference between the calculated panning reference angular velocity and the panning speed performed by the photographer, that is, a panning speed error (panning error) is detected. By decentering the optical system so as to correct the error, the photographer can take a beautiful panning shot.

JP-A-7-218967 JP 2007-139552 A

  By the way, in the method disclosed in Patent Document 2, it is assumed that correction accuracy is ensured that the panning reference angular velocity of the main subject targeted by the photographer is the same angular velocity between the time of calculation and during exposure. It is a condition. However, for example, in the case of a subject moving from the front obliquely to the front of the photographer, even if the moving speed of the main subject is constant, the panning reference angular velocity for performing the optimum panning is not equal. . In this case, since the panning reference angular velocity is different between the calculated time point and during exposure, it is difficult to correct the panning error with high accuracy.

  Therefore, the present invention provides an image blur correction device, a lens device, an imaging device, and an imaging system that can correct a panning error with high accuracy.

  An image blur correction apparatus according to one aspect of the present invention includes: a correction unit that performs image blur correction; a calculation unit that calculates a reference angular velocity during exposure used for panning shooting; and the reference angular velocity and angular velocity sensor during exposure. Control means for controlling the correction means so as to perform the panning shot based on the difference between the angular velocity and the angular velocity, and the calculating means is calculated based on a motion vector and the angular velocity from the angular velocity sensor. The reference angular velocity during the exposure is calculated according to the reference angular velocity before the start of exposure.

  A lens device according to another aspect of the present invention includes an angular velocity sensor that detects an angular velocity and the image blur correction device.

  A lens apparatus according to another aspect of the present invention is a lens apparatus that can be attached to and detached from an imaging apparatus, an angular velocity sensor that detects an angular velocity, a correction unit that performs image blur correction based on the angular velocity and a motion vector, Control means for controlling the correction means so as to perform panning shooting based on the difference between the reference angular velocity during exposure and the angular velocity, and communication means for communicating with the imaging device, the communication means, An angular velocity is transmitted to the imaging device, a reference angular velocity during exposure is received from the imaging device, and the reference angular velocity during exposure is calculated based on the motion vector and the angular velocity before the start of exposure. Is calculated according to

  An imaging apparatus according to another aspect of the present invention is an imaging apparatus in which a lens apparatus is detachable, and includes a motion vector detection unit that detects a motion vector, and a calculation that calculates a reference angular velocity during exposure used for panning shooting. And a communication means for communicating with the lens device, wherein the communication means receives an angular velocity from an angular velocity sensor from the lens device, and the calculating means calculates based on the motion vector and the angular velocity. The reference angular velocity during the exposure is calculated according to the reference angular velocity before the start of exposure, and the communication means transmits the reference angular velocity during the exposure to the lens device.

  An imaging system according to another aspect of the present invention includes an angular velocity sensor that detects an angular velocity, a motion vector detection unit that detects a motion vector, and the image blur correction unit.

  Other objects and features of the invention are described in the following embodiments.

  According to the present invention, it is possible to provide an image blur correction device, a lens device, an imaging device, and an imaging system that can correct a panning error with high accuracy.

It is a block diagram of the camera system in each embodiment. It is explanatory drawing of panning photographing in each embodiment. It is a signal waveform diagram of panning shooting in each embodiment. It is explanatory drawing of panning photographing in each embodiment. It is a signal waveform diagram of panning shooting in each embodiment. It is a flowchart which shows operation | movement of the camera main body in each embodiment. It is a flowchart which shows operation | movement of the interchangeable lens in each embodiment. It is a flowchart which shows operation | movement of the interchangeable lens at the time of serial communication interruption in each embodiment. 6 is a flowchart illustrating an image blur correction operation according to the first embodiment. 12 is a flowchart illustrating an image blur correction operation according to the second embodiment. 12 is a flowchart illustrating an image blur correction operation according to the third embodiment.

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

[First Embodiment]
First, the configuration of a camera system (imaging system) in the first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of a camera system 100 in the present embodiment. The camera system 100 includes a camera body 111 (imaging device) and an interchangeable lens 112 (lens device) that can be attached to and detached from the camera body 111. However, the present embodiment is not limited to this, and can also be applied to an imaging apparatus in which an imaging apparatus main body and a lens apparatus are integrally configured.

  The imaging light flux from the subject forms an image on the imaging unit 113 via the imaging optical system of the interchangeable lens 112. The formed image is photoelectrically converted by the imaging unit 113 to become an imaging signal. The imaging signal is amplified by a gain control circuit (GC) 115, input to an A / D converter 116, and converted from analog image data to digital image data. The video signal processing circuit 117 performs various signal processing such as filter processing, color conversion processing, and gamma processing on the image data digitized by the A / D converter 116. The video signal processing circuit 117 is a motion vector detection unit that detects (calculates) a motion vector of the subject image. The image signal signal-processed by the video signal processing circuit 117 is stored in the buffer memory 118 and displayed on the LCD 119 (display unit) or recorded on the removable memory card 120 (recording unit).

  The operation unit 121 is a switch for setting the shooting mode of the camera body 111, setting the recording image file size, and releasing at the time of shooting. The camera MPU 114 controls each operation of the camera body 111 and communicates with the lens MPU 124 via the interface circuit (IF) 122 of the camera body 111 and the interface circuit (IF) 123 of the interchangeable lens 112. The interface circuits 122 and 123 are communication means for performing communication between the camera body 111 and the interchangeable lens 112, respectively. In this communication, various data are exchanged between the camera body 111 and the interchangeable lens 112.

  The interchangeable lens 112 is provided with a focus lens 125, a zoom lens 126, an image blur correction lens 127, and a diaphragm 128 as a part of the imaging optical system. The focus lens 125 is driven in a direction (optical axis direction) along the optical axis OA via the focus control circuit 129 and the focus lens drive motor 130 in accordance with a control signal from the lens MPU 124. In addition to the focus lens drive circuit, the focus control circuit 129 includes a focus encoder that outputs a zone pattern signal and a pulse signal according to the movement of the focus lens 125. The subject distance is detected by a focus encoder.

  The zoom lens 126 moves in the optical axis direction when the photographer operates a zoom operation ring (not shown). The zoom encoder 131 outputs a zone pattern signal corresponding to the movement of the zoom lens 126. The photographic image magnification is obtained by the lens MPU 124 reading signals from the focus encoder and zoom encoder 131 and reading out pre-stored photographic image magnification data based on a combination of the subject distance and the focal length.

  The image blur correction lens 127 is driven in a direction (optical axis orthogonal direction) perpendicular to the optical axis OA via the image blur correction control circuit 132 (IS control circuit) and the linear motor 133. The image blur correction control circuit 132 is a correction unit that performs image blur correction. Image blur correction is performed as follows. That is, the shake signal of the angular velocity sensor 135 that detects rotational shake (angular velocity) is processed by the signal processing circuit 136 and input to the lens MPU 124. The lens MPU 124 calculates a corrected lens driving target signal. The lens MPU 124 outputs a drive signal corresponding to the difference between the correction lens drive target signal and the correction lens position signal output from the correction lens encoder 134 to the image blur correction control circuit 132. Image blur correction is performed by feeding back the correction lens position signal output from the correction lens encoder 134 to the image blur correction control circuit 132 in this way. In the present embodiment, the image blur correction control is performed to detect the tilt in the vertical direction (optical axis orthogonal direction) and the horizontal axis (optical axis orthogonal direction) with the camera body 111 as the center. For each of the two yaw axes.

  The lens MPU 124 of this embodiment includes a calculation unit 124a and a control unit 124b. The calculating unit 124a calculates a reference angular velocity during exposure used for panning shots (a panning reference angular velocity). The control unit 124b controls the image blur correction control circuit 132 so as to perform panning shooting based on the difference between the reference angular velocity during exposure and the angular velocity from the angular velocity sensor. The calculating unit 124a calculates a reference angular velocity during exposure according to a reference angular velocity before starting exposure (a panning reference angular velocity) calculated based on the motion vector and the angular velocity from the angular velocity sensor. The lens MPU 124 includes a RAM 140 (storage unit) that stores information such as a reference angular velocity and a lens displacement signal. However, the RAM 140 is not limited to the internal memory of the lens MPU 124, and may be provided outside the lens MPU 124.

  The aperture of the aperture 128 is driven (controlled) through the aperture control circuit 137 and the stepping motor 138 in accordance with a control signal from the lens MPU 124. The switch 139 is a switch for turning on / off image blur correction control and selecting an image blur correction mode. In the present embodiment, one of a normal image blur correction operation and a panning operation mode can be selected as the image blur correction mode.

  Next, a panning method according to this embodiment will be described with reference to FIGS. FIG. 2 shows the movement of the subject and the camera (camera system 100) in the order of FIGS. 2A and 2B when the subject passing in front of the photographer is shot. During panning, by shaking the camera so as to match the moving speed V of the subject even during the exposure period, the motion of the subject is stopped, and a photograph with a background can be taken. However, when the photographer is unfamiliar, the aim may be shifted to the point C1 in FIG. 2B, for example, even if the user is aiming at the center point C0 of the subject and shaking the camera according to the movement of the subject. is there.

  FIG. 3 shows the output waveform of the angular velocity sensor 135 and the signal waveform of the motion vector of the subject image detected by the video signal processing circuit 117 when the aim is shifted in the panning shooting as described above (each waveform and time). Relationship diagram). 3A shows the output waveform (angular velocity) of the angular velocity sensor 135, and FIG. 3B shows the signal waveform of the motion vector. In FIG. 3A, if the subject speed is constant, the ideal panning angular speed at which the subject keeps chasing without shaking becomes a constant angular speed as indicated by a dotted line. If the subject continues to follow without being shaken, the motion vector of the subject in FIG. 3B is “0”. However, it is difficult to keep track of the moving subject accurately, and in actuality, the angular velocity at the time of panning shown by the solid line in FIG. At this time, the motion vector deviates from “0” as shown in FIG.

  Therefore, if the image blur correction lens 127 is driven so as to correct the deviation from the ideal panning angular velocity, the shake of the subject can be corrected. As an actual photographing operation, an ideal angular velocity is calculated before exposure, and the image blur correction lens 127 is driven so as to correct a deviation from the ideal panning angular velocity during exposure. As a method of calculating the ideal panning angular velocity, there is a method of calculating based on the sum of the angular velocity sensor 135 signal and the motion vector signal.

  Here, a case is considered where the photographer shoots and shoots a subject passing in front of his / her eyes from diagonally forward. FIG. 4 shows the movement of the subject and the camera in such a case in the order of FIGS. 4 (a), (b), and (c). If the ideal panning angular velocities at this time are W1, W2, and W3, respectively, even if the subject is moving at a constant speed V, the angular speed is not constant. FIG. 5 is a diagram showing a temporal change in angular velocity at the time of panning shooting. In FIG. 5, the horizontal axis represents time, and the vertical axis represents angular velocity. As shown in FIG. 5, ideal panning angular velocities W1, W2, and W3 are accelerated. In this case, if the timing at which the panning angular velocity is calculated and the timing of exposure are greatly deviated, the accuracy of the panning error correction during exposure deteriorates. In order to cope with this, it is conceivable to predict a change in the panning angular velocity and correct the deviation at the timing of exposure. At this time, for accurate prediction correction, it is a preferable condition that the vehicle is reliably accelerated or decelerated. For example, as a method for determining the prediction, it is determined whether or not the polarity of the change in the panning angular velocity is the same for a predetermined number of times.

  Next, with reference to FIG. 6 to FIG. 9, a shooting operation of the camera system 100 in this embodiment (an operation for panning shooting) will be described. First, the photographing operation of the camera body 111 will be described with reference to FIG. FIG. 6 is a flowchart showing the shooting operation of the camera body 111.

  When the main switch of the camera body 111 is turned on, the camera body 111 starts a shooting operation. First, in step S601, the camera MPU 114 determines whether or not the release switch of the operation unit 121 is half pressed (SW1 ON). If the release switch is pressed halfway, the process proceeds to step S602. On the other hand, if the release switch has not been pressed halfway, this flow ends.

  In step S602, the camera MPU 114 performs status communication with the lens MPU 124 via the interface circuits 122 and 123. Here, the camera MPU 114 transmits the state of the camera body 111 (release switch state SW1 ON, shooting mode, shutter speed, etc.) to the interchangeable lens 112 (lens MPU 124). The camera MPU 114 receives the state of the interchangeable lens 112 (focal length, aperture state, focus lens driving state, etc.) from the lens MPU 124. In FIG. 6, the status communication is described only in main parts, but is performed as needed when the state of the camera body 111 changes or when the camera body 111 wants to check the state of the interchangeable lens 112.

  Subsequently, in step S603, since the release switch is pressed halfway (SW1 ON), the camera MPU 114 performs focus detection and calculates a focus lens drive amount for focusing on the subject. Subsequently, in step S604, the camera MPU 114 transmits data related to the focus lens drive amount (focus lens drive command) to the interchangeable lens 112. This data is transmitted, for example, as a drive target pulse amount of the focus encoder. In step S605, when the focus lens driving is completed, the camera MPU 114 performs refocus detection.

  Subsequently, in step S606, the camera MPU 114 determines whether it is within the in-focus depth (in-focus state) based on the focus detection result. If it is within the in-focus depth, the process proceeds to step S607. In step S607, the camera MPU 114 acquires luminance information from the video signal processing circuit 117, and calculates an exposure time Tv and an aperture value (aperture drive amount) (photometry processing). In step S608, the camera MPU 114 determines the main subject from the image signal of the video signal processing circuit 117.

  Subsequently, in step S609, the camera MPU 114 detects a motion vector (motion vector information) of the main subject. Subsequently, in step S610, the camera MPU 114 calculates a reference angular velocity (a panning reference angular velocity) based on the motion vector information of the main subject detected in step S609 and the angular velocity information transmitted from the lens MPU 124. The angular velocity information is a signal corresponding to the output signal (angular velocity) of the angular velocity sensor 135. The reference angular velocity is an angular velocity for performing optimum panning for the main subject. Subsequently, in step S611, the camera MPU 114 transmits the reference angular velocity calculated in step S610 to the lens MPU 124.

  Subsequently, in step S612, the camera MPU 114 determines whether or not the release switch of the operation unit 121 is fully pressed (SW2 ON). If the release switch is fully pressed, the process proceeds to step S613. On the other hand, if the release switch has not been fully pressed, the process returns to step S601.

  In step S613, the camera MPU 114 transmits the aperture driving amount (aperture driving command) calculated in step S607 to the interchangeable lens 112 to drive the aperture 128. Subsequently, in step S614, the camera MPU 114 resets the charge of the imaging unit 113 and drives the electronic shutter (front curtain shutter). Subsequently, in step S615, the camera MPU 114 exposes the subject image to the imaging unit 113 and accumulates charges. Subsequently, in step S616, when the exposure time has elapsed, the camera MPU 114 drives a rear curtain shutter (not shown) and ends the exposure.

  Subsequently, in step S617, the camera MPU 114 performs charge transfer (reading) from the imaging unit 113. In step S618, the read captured image signal is converted into digital data (captured image data) through the gain control circuit 115 and the A / D converter 116, and stored in the buffer memory 118 (image storage). Subsequently, in step S619, the camera MPU 114 transmits an aperture opening command (aperture driving command) to the interchangeable lens 112, and returns the aperture 128 to the open state.

  Subsequently, in step S620, the camera MPU 114 (video signal processing circuit 117) performs image correction processing such as gamma correction and compression processing on the captured image signal (captured image data). In step S621, the image data subjected to the image correction process is displayed on the LCD 119 and recorded on the memory card 120. As a result, a series of operations up to photographing is completed.

  Next, the operation of the interchangeable lens 112 in panning shot shooting will be described with reference to FIGS. FIG. 7 is a flowchart showing the operation of the interchangeable lens 112. When the interchangeable lens 112 is attached to the camera body 111, serial communication is performed from the camera body 111 to the interchangeable lens 112, and the operation of the interchangeable lens 112 starts from step S701 in FIG.

  First, in step S701, the lens MPU 124 performs initial settings for lens control and image blur correction control. In step S702, the lens MPU 124 detects the state of switches (not shown), the zoom position, and the focus position. Examples of the switches include, but are not limited to, an auto focus / manual focus changeover switch and an image blur correction function ON / OFF switch.

  Subsequently, in step S703, the lens MPU 124 determines whether or not there is a focus drive command communication (focus drive request) from the camera body 111 (camera MPU 114). When the lens MPU 124 receives a focus drive command (when a focus drive request is received), the process proceeds to step S704. On the other hand, when the lens MPU 124 has not received the focus drive command (when the focus drive request has not been received), the process proceeds to step S705.

  In step S <b> 704, the lens MPU 124 performs drive control of the focus lens 125. In the focus drive command communication in step S703, the target drive amount (number of pulses) of the focus lens 125 is also transmitted from the camera body 111. Therefore, the lens MPU 124 detects the number of pulses of the focus encoder of the focus control circuit 129 and performs focus drive control so as to drive the target pulse number.

  In step S <b> 705, the lens MPU 124 determines whether or not there has been an aperture drive command (aperture drive request) communication from the camera body 111. When the lens MPU 124 receives an aperture drive command (aperture drive request), the process proceeds to step S706. On the other hand, if the lens MPU 124 has not received an aperture drive command (aperture drive request), the process proceeds to step S707.

  In step S706, the lens MPU 124 controls the driving of the diaphragm 128. In the communication of the aperture drive command in step S705, the target drive amount of the aperture 128 is also transmitted from the camera body 111. Therefore, the lens MPU 124 drives the diaphragm 128 by a target amount via the diaphragm control circuit 137 and the stepping motor 138.

  In step S <b> 707, the lens MPU 124 determines whether an instruction to stop all driving (an instruction to stop all driving of the actuators in the interchangeable lens 112) has been received from the camera body 111. When no operation is performed via the camera body 111 (the operation unit 121 thereof), a command to stop all driving is transmitted from the camera body 111 after a predetermined time has elapsed. When the lens MPU 124 receives a command to stop all driving, the process proceeds to step S708. On the other hand, if the lens MPU 124 has not received a full drive stop command, the process returns to step S702.

  In step S708, the lens MPU 124 performs full drive stop control. Here, the lens MPU 124 stops driving all the actuators and puts the microcomputer in a sleep (stopped) state. The lens MPU 124 also stops power supply to the image blur correction device. Thereafter, when any operation is performed via the camera body 111 (the operation unit 121 thereof), the camera body 111 (camera MPU 114) sends a communication signal to the interchangeable lens 112 (lens MPU 124) to cancel the sleep state.

  During each step shown in the flowchart of FIG. 7, the lens MPU 124 may receive a request for serial communication interruption or image blur correction interruption by communication from the camera MPU 114. At this time, the lens MPU 124 performs these interrupt processes. When the serial communication interrupt request is received, the lens MPU 124 decodes the communication data, and performs lens processing such as aperture driving and focus lens driving according to the decoding result. Then, SW1ON, SW2ON, shutter speed, camera model, and the like can be determined by decoding the communication data. The image blur correction interrupt is a timer interrupt that occurs at regular intervals. When the image blur correction interrupt request is received, the lens MPU 124 performs image blur correction control in the pitch direction (vertical direction) and yaw direction (horizontal direction).

  First, the operation when the lens MPU 124 receives a serial communication interrupt will be described with reference to FIG. FIG. 8 is a flowchart showing an operation when the lens MPU 124 receives a serial communication interrupt. When the lens MPU 124 receives communication (serial communication interrupt) from the camera body 111 (camera MPU 114), the lens MPU 124 starts its operation from step S801.

  First, in step S801, the lens MPU 124 analyzes a command from the camera body 111 (performs command analysis), and branches to processing corresponding to each command.

  In step S802, the lens MPU 124 receives a focus drive command. In step S803, the lens MPU 124 sets the speed of the focus lens drive motor 130 in accordance with the target drive pulse number, and starts focus lens drive.

  In step S804, the lens MPU 124 receives an aperture drive command. In step S805, the lens MPU 124 drives the aperture 128 based on the aperture drive data transmitted from the camera body 111. At this time, the lens MPU 124 sets the drive pattern of the stepping motor 138 and outputs the set drive pattern to the stepping motor 138 via the aperture control circuit 137 to drive the aperture 128.

  In step S806, the lens MPU 124 receives the status communication. In step S807, the lens MPU 124 transmits the focal length information of the interchangeable lens 112, the IS operation state, and the like to the camera body 111. In addition, the lens MPU 124 receives the status status (release switch status, shooting mode, imaging frame rate, shutter speed, etc.) of the camera body 111.

  In step S808, the lens MPU 124 receives an information transmission / reception command (panning correction information communication) regarding panning correction. In step S809, the lens MPU 124 stores the reference angular velocity (the panning reference angular velocity) received from the camera body 111 in the RAM 140 (storage means) in the lens MPU 124. The lens MPU 124 transmits and receives other panning correction information.

  In step S810, the lens MPU 124 receives other commands, such as focus sensitivity data communication or optical data communication of the interchangeable lens 112. In step S811, the lens MPU 124 performs these processes.

  Next, the operation when the lens MPU 124 receives an image blur correction interrupt will be described with reference to FIG. FIG. 9 is a flowchart illustrating an operation (image blur correction operation) when the lens MPU 124 receives an image blur correction interrupt. When an image blur correction interrupt occurs during the main operation of the interchangeable lens 112, the lens MPU 124 starts image blur correction control from step S901 in FIG.

  First, in step S <b> 901, the lens MPU 124 performs A / D conversion on a signal acquired by processing the output signal (angular velocity) from the angular velocity sensor 135 by the signal processing circuit 136. Subsequently, in step S902, the lens MPU 124 determines whether it is the panning mode or the normal image stabilization mode based on the state of the switch 139. If it is the normal image stabilization mode, the process proceeds to step S903. On the other hand, if it is the panning mode, the process proceeds to step S906.

  In step S903, the lens MPU 124 performs a high-pass filter calculation (HPF calculation) in order to cut a low-frequency component of the signal. The lens MPU 124 switches the time constant of the high-pass filter for a predetermined time from the start of calculation, and also performs an operation for quickly stabilizing the signal. Subsequently, in step S904, the lens MPU 124 performs integration calculation using the result of the high-pass filter calculation as an input signal. As a result, the lens MPU 124 can acquire angular displacement data. Subsequently, in step S905, the lens MPU 124 reads out the image stabilization sensitivity corresponding to the zoom position and the focus position, and calculates the target drive amount of the image blur correction lens 127 from the angular displacement data.

  In step S906, since the panning mode is selected, the lens MPU 124 determines whether SW2 is turned on, that is, whether an exposure operation is selected. If SW2 is OFF, the process proceeds to step S907. On the other hand, if SW2 is turned on, the process proceeds to step S913.

  In step S907, the lens MPU 124 reads a reference angular velocity W (n) (a panning reference angular velocity) stored in the RAM 140 (storage means) in the lens MPU 124. Subsequently, in step S908, the lens MPU 124 calculates the change amount ΔW (n) of the reference angular velocity. Specifically, the lens MPU 124 uses the difference (ΔW (n) = W () between the current reference angular velocity W (n) and the previous reference angular velocity W (n−1) as the change amount ΔW (n) of the reference angular velocity. n) −W (n−1)) is calculated.

  Subsequently, in step S909, the lens MPU 124 determines whether or not the past four variations ΔW (n) to ΔW (n−3) are all the same polarity (positive or negative). If all have the same polarity, the process proceeds to step S910. On the other hand, if the polarity of at least one change amount is different, the process proceeds to step S911. In the present embodiment, the number of change amounts ΔW for determining whether or not they have the same polarity is four (for the past four times), but is not limited to this. It may be determined whether or not the polarities of the plurality of change amounts ΔW (numbers of 3 or less or 5 or more, that is, the past 3 times or less or the past 5 times or more) are all the same.

  In step S910, the amount of change in the past four times has the same polarity in all four times, so the speed change direction is considered to be stable. For this reason, the lens MPU 124 performs prediction correction of the reference angular velocity. Specifically, the lens MPU 124 adds the value (k × ΔW (n)) obtained by multiplying the current change amount ΔW (n) by a predetermined coefficient k to the current reference angular velocity W (n), thereby obtaining the final value. A reference angular velocity Wref (= W (n) + k × ΔW (n)) is calculated.

  In step S911, since the amount of change for the past four times is not the same polarity, the speed change direction is considered to be unstable. In such a case, the error may increase due to the prediction correction. Therefore, the lens MPU 124 does not perform the prediction correction of the reference angular velocity. That is, the lens MPU 124 sets the reference angular velocity W (n) calculated this time as the final reference angular velocity Wref (= W (n)).

  Subsequently, in step S912, the lens MPU 124 sets the target drive amount to zero. This is because the image blur correction lens 127 is electrically held at the center when the SW2 is not ON.

  In step S913, since SW2 is ON, the lens MPU 124 corrects the panning error during exposure. Specifically, the lens MPU 124 (control unit 124b) calculates a panning error We (= Wref−Wa) that is a difference between the reference angular velocity Wref and the angular velocity Wa output from the angular velocity sensor 135. Subsequently, in step S914, the lens MPU 124 (control unit 124b) integrates the panning error We and calculates angular displacement data. This is the angular displacement data of the panning error. Subsequently, in step S915, the lens MPU 124 (control unit 124b) reads out the image stabilization sensitivity corresponding to the zoom position and the focus position, and calculates the target drive amount of the image blur correction lens 127 from the angular displacement data.

  Subsequently, in step S916, the lens MPU 124 A / D converts the signal (lens displacement signal) of the correction lens encoder 134 that detects the amount of eccentricity of the image blur correction lens 127. The lens MPU 124 stores the lens displacement signal after A / D conversion in the RAM 140 (storage means) in the lens MPU 124. Subsequently, in step S917, the lens MPU 124 calculates a difference between the target drive amount and the lens displacement signal, and performs a feedback calculation. Subsequently, in step S918, the lens MPU 124 performs a phase compensation calculation in order to obtain a stable control system. Subsequently, in step S919, the lens MPU 124 outputs the calculation result (drive signal) of step S918 as a PWM to the port of the lens MPU 124, and the image blur correction interrupt ends. The output (drive signal) is input to a driver circuit in the image blur correction control circuit 132, the image blur correction lens 127 is driven by the linear motor 133, and the image blur corresponding to the target drive amount is corrected.

  As described above, if the polarity of the change in the reference angular velocity is the same for a predetermined number of times before exposure, it is determined that the vehicle is stably accelerating or decelerating, and the reference angular velocity is predicted and corrected. During the exposure, by driving the image blur correction lens so as to correct the deviation between the predicted reference angular velocity and the angular velocity, it is possible to take a clean panning photograph in which the panning error is corrected.

[Second Embodiment]
Next, image blur correction according to the second embodiment of the present invention will be described with reference to FIG. FIG. 10 is a flowchart of an image blur correction operation (operation when the lens MPU 124 receives an image blur correction interrupt) in the present embodiment.

  In the present embodiment, as a criterion for determining whether or not to perform predictive correction of the reference angular velocity, both the frame rate for acquiring a motion vector (imaging frame rate) and the continuity of the polarity of the change in the reference angular velocity are considered. . Specifically, the lens MPU 124 changes the number of determinations of the same polarity according to the imaging frame rate, and determines whether to perform prediction correction. The flowchart in FIG. 10 differs from FIG. 9 in that steps S1009 to S1014 are provided instead of steps S909 to S911 in FIG. Steps S1001 to S1008 and steps S1015 to S1022 in FIG. 10 are the same as steps S901 to S908 and steps S912 to S919 in FIG. Note that in this embodiment, the configuration of the camera system (imaging device) is the same as that of the camera system 100 of the first embodiment described with reference to FIG.

  In step S1009, the lens MPU 124 determines whether the imaging frame rate FR is faster than a predetermined frame rate (for example, 30 fps). If the imaging frame rate FR is faster than 30 fps, the process proceeds to step S1010. On the other hand, if the imaging frame rate FR is not faster than 30 fps, the process proceeds to step S1012.

  In step S1010, since the imaging frame rate is faster than 30 fps, the lens MPU 124 determines whether or not the amounts of change ΔW (n) to ΔW (n−3) for the past four times have the same polarity. . If the plurality of change amounts have the same polarity, the process proceeds to step S1011. On the other hand, if the four changes are not the same polarity, the process proceeds to step S1013. As in the first embodiment, the number N1 of the plurality of change amounts to be subjected to polarity determination in step S1010 is not limited to four times.

  In step S1011, the amount of change in the past four times is the same polarity in all four times, so the direction of speed change is considered to be stable. For this reason, the lens MPU 124 performs prediction correction of the reference angular velocity. Specifically, the lens MPU 124 multiplies the current reference angular velocity W (n) by a predetermined coefficient k1 (first coefficient) multiplied by the current change amount ΔW (n) (k1 × ΔW (n)). By adding, the final reference angular velocity Wref (= W (n) + k1 × ΔW (n)) is calculated.

  In step S1012, since the imaging frame rate is not faster than 30 fps, the lens MPU 124 determines whether or not the past two changes ΔW (n) to ΔW (n−1) have the same polarity. . If the two change amounts have the same polarity, the process proceeds to step S1014. On the other hand, if the two variations are not the same polarity, the process proceeds to step S1013. Note that the number N2 of the plurality of change amounts to be subjected to the polarity determination in step S1012 is limited to two if the number N1 of change amounts to be the polarity determination in step S1011 is smaller (N1> N2). It is not a thing.

  In step S1013, the amount of change in the past four times is not the same polarity in step S1010, or the amount of change in the past two times is not the same polarity in step S1012, so the direction of speed change is unstable. it is conceivable that. In such a case, the error may increase due to the prediction correction. Therefore, the lens MPU 124 does not perform the prediction correction of the reference angular velocity. That is, the lens MPU 124 sets the reference angular velocity W (n) calculated this time as the final reference angular velocity Wref (= W (n)).

  In step S1014, since the amount of change for the past two times has the same polarity, the speed change direction is considered to be stable. For this reason, the lens MPU 124 performs prediction correction of the reference angular velocity. Specifically, the lens MPU 124 multiplies the current reference angular velocity W (n) by a predetermined coefficient k2 (second coefficient) multiplied by the current change amount ΔW (n) (k2 × ΔW (n)). By adding, the final reference angular velocity Wref (= W (n) + k2 × ΔW (n)) is calculated.

  In this embodiment, if the polarity of the change in the reference angular velocity is the same for a predetermined number of times before exposure, the reference angular velocity is predicted and corrected. However, by changing the predetermined number according to the imaging frame rate, stable acceleration is performed. Or it can determine more correctly whether it is decelerating. That is, even if the motion vector signal acquisition interval changes, the number of determinations is changed accordingly, so that stable prediction correction can be performed. During the exposure, by driving the image blur correction lens so as to correct the deviation between the predicted reference angular velocity and the angular velocity, it is possible to take a clean panning photograph in which the panning error is corrected.

[Third Embodiment]
Next, image blur correction according to the third embodiment of the present invention will be described with reference to FIG. FIG. 11 is a flowchart of an image blur correction operation (operation when the lens MPU 124 receives an image blur correction interrupt) in the present embodiment.

  In the present embodiment, when the reference angular velocity is larger than the predetermined angular velocity Wc, the operation is performed so as to perform prediction correction of the reference angular velocity. When the reference angular velocity is small, there is little difference from camera shake that is not a panning component, and there is a possibility that an element of camera shake is superimposed on the prediction of the reference angular velocity and an error occurs in the prediction. Therefore, when the reference angular velocity is larger than the predetermined angular velocity Wc, the prediction correction of the reference angular velocity is performed. 11 differs from FIG. 9 in that step S1109 is provided instead of step S909 in FIG. Steps S1101 to S1108 and steps S1110 to S1119 in FIG. 11 are the same as steps S901 to S908 and steps S912 to S919 in FIG. Note that in this embodiment, the configuration of the camera system (imaging device) is the same as that of the camera system 100 of the first embodiment described with reference to FIG. Moreover, this embodiment can also be implemented in combination with the first embodiment or the second embodiment.

  In step S1109, the lens MPU 124 determines whether or not the reference angular velocity W (n) is greater than the predetermined angular velocity Wc. When the panning reference angle W (n) is larger than the predetermined angular velocity Wc (W (n)> Wc), the process proceeds to step S1110, and the lens MPU 124 performs prediction correction of the reference angular velocity. On the other hand, if the panning reference angle W (n) is not larger than the predetermined angular velocity Wc, the process proceeds to step S1111 and the lens MPU 124 does not perform prediction correction of the reference angular velocity.

  As described above, when the reference angular velocity is larger than the predetermined angular velocity before exposure, prediction correction of the reference angular velocity is performed. During the exposure, by driving the image blur correction lens so as to correct the deviation between the predicted reference angular velocity and the angular velocity, it is possible to take a clean panning photograph in which the panning error is corrected.

  In each embodiment, an example of a camera that observes a subject image in live view shooting has been described. However, the same effect can be obtained if vector information of a subject can be calculated by a photometric sensor arranged in an optical viewfinder. be able to.

  As described above, in each embodiment, the image blur correction apparatus includes a correction unit (image blur correction control circuit 132) that performs image blur correction, a calculation unit 124a, and a control unit 124b. The calculating unit 124a calculates a reference angular velocity (Wref) during exposure used for panning shot shooting. The control unit 124b controls the correction unit to perform panning based on the difference between the reference angular velocity (Wref) during exposure and the angular velocity (Wa) from the angular velocity sensor 135. The calculating unit 124a sets the reference angular velocity (W (n)) before the start of exposure calculated based on the motion vector detected by the motion vector detecting unit (video signal processing circuit 117) and the angular velocity from the angular velocity sensor 135. In response, a reference angular velocity (Wref) during exposure is calculated.

  Preferably, when the plurality of reference angular velocity change amounts (ΔW (n) to ΔW (n−3)) continuously calculated before the start of exposure have the same polarity, the calculation unit 124a determines this change amount (exposure). A reference angular velocity during exposure is calculated based on the immediately preceding change amount ΔW (n)) (S909, S910). More preferably, the calculation unit 124a calculates a reference angular velocity (W (n)) calculated last among a plurality of reference angular velocities continuously calculated before the start of exposure when the plurality of variations are not of the same polarity. It is set as a reference angular velocity (Wref) during exposure (S909, S911).

  Preferably, the calculation unit 124a changes the number of a plurality of change amounts used for polarity determination according to a frame rate (drive frame rate) for acquiring a motion vector (S1009, S1010, S1012). More preferably, when the frame rate is faster than a predetermined frame rate (for example, 30 fps), the calculating unit 124a sets the number of the plurality of change amounts to the first number (for example, 4). In addition, when the frame rate is slower than the predetermined frame rate, the calculation unit 124a sets the number of the plurality of change amounts to a second number (for example, 2) smaller than the first number (S1009, S1010, S1012). .

  Preferably, when the reference angular velocity (W (n)) before the start of exposure is greater than a predetermined angular velocity (Wc), the calculation unit 124a can calculate a plurality of reference angular velocity changes (B) continuously calculated before the start of exposure ( Based on ΔW (n)), a reference angular velocity during exposure is calculated. More preferably, when the reference angular velocity (W (n)) before the start of exposure is smaller than the predetermined angular velocity (Wc), the calculating unit 124a calculates the last calculated reference angular velocity (W (n )) Is set as the reference angular velocity (Wref) during the exposure.

  Preferably, the reference angular velocity during exposure is an angular velocity at which the difference between the motion vector and the angular velocity is zero during panning shooting. Preferably, the control unit 124b controls the correction unit so as not to perform image blur correction before the start of exposure.

  In each embodiment, if the change in the reference angular velocity calculated for the panning shot before the start of exposure is continuously the same polarity, there is a high possibility of acceleration or deceleration, so the change in the reference angular velocity is predicted and corrected. It's easy to do. In this case, the reference angular velocity during exposure is predicted and corrected from the amount of change in the reference angular velocity before exposure, and the panning error is corrected using the reference angular velocity that is predicted and corrected during exposure. Correction is possible. Further, when the reference angular velocity calculated before exposure is smaller than the predetermined angular velocity, it is expected that the change in the reference angular velocity is small. In this case, by performing the panning error correction without performing the prediction correction of the reference angular velocity, it is possible to perform the panning correction with high accuracy. Therefore, according to each embodiment, it is possible to provide an image blur correction device, a lens device, and an imaging device that can correct a panning error with high accuracy.

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

  In each embodiment, the image blur correction control circuit 132, the calculation unit 124a, and the control unit 124b are all included in the interchangeable lens 112. However, at least a part of them is included in the camera body 111. It may be configured. For example, the camera main body 111 (camera MPU 114) can be configured to include calculation means for calculating the reference angular velocity. In this case, information indicating the reference angular velocity and a shake signal from the angular velocity sensor 135 are transmitted and received between the camera body 111 and the interchangeable lens 112 via the interface circuits 122 and 123 (communication means).

124 Lens CPU
124a calculation means 124b control means 132 image blur correction control circuit (correction means)

Claims (14)

Correction means for performing image blur correction;
A calculation means for calculating a reference angular velocity during exposure used for panning shooting;
Control means for controlling the correction means to perform the panning shot based on the difference between the reference angular velocity during the exposure and the angular velocity from the angular velocity sensor;
The calculation means calculates the reference angular velocity during the exposure based on a reference angular velocity before the start of exposure calculated based on a motion vector and the angular velocity from the angular velocity sensor. apparatus.   The calculation means calculates a reference angular velocity during the exposure based on the change amount when a plurality of change amounts of the reference angular velocity continuously calculated before the start of exposure have the same polarity. The image blur correction device according to claim 1.   The calculation means sets, as a reference angular velocity during the exposure, a reference angular velocity calculated last among a plurality of reference angular velocities continuously calculated before the start of exposure when the plurality of changes are not of the same polarity. The image blur correction device according to claim 2.   The image blur correction apparatus according to claim 2, wherein the calculation unit changes the number of the plurality of change amounts used for polarity determination according to a frame rate at which the motion vector is acquired. The calculating means includes
When the frame rate is faster than a predetermined frame rate, the number of the plurality of changes is set to a first number,
5. The image blur according to claim 4, wherein when the frame rate is slower than the predetermined frame rate, the number of the plurality of change amounts is set to a second number smaller than the first number. Correction device.   When the reference angular velocity before the start of exposure is greater than a predetermined angular velocity, the calculating means calculates the reference angular velocity during the exposure based on a plurality of reference angular velocity changes continuously calculated before the start of exposure. The image blur correction device according to claim 1, wherein:   The calculating means sets a reference angular velocity calculated last among the plurality of reference angular velocities as a reference angular velocity during the exposure when a reference angular velocity before the start of exposure is smaller than the predetermined angular velocity. The image blur correction device according to claim 6.   The image according to any one of claims 1 to 7, wherein the reference angular velocity during the exposure is an angular velocity at which a difference between the motion vector and the angular velocity is zero at the time of the panning photographing. Blur correction device.   The image blur correction apparatus according to claim 1, wherein the control unit controls the correction unit so as not to perform the image blur correction before the exposure is started. The control means includes
Integrating the difference between the reference angular velocity during the exposure and the angular velocity from the angular velocity sensor to calculate angular displacement data,
The image blur correction apparatus according to claim 1, wherein the correction unit is controlled to perform the image blur correction based on the angular displacement data. An angular velocity sensor for detecting angular velocity;
Correction means for performing image blur correction based on the angular velocity and the motion vector;
A calculation means for calculating a reference angular velocity during exposure used for panning shooting;
Control means for controlling the correction means to perform the panning shot based on the difference between the reference angular velocity during the exposure and the angular velocity;
The lens device according to claim 1, wherein the calculating means calculates a reference angular velocity during the exposure according to a reference angular velocity before the start of exposure calculated based on the motion vector and the angular velocity. A lens device detachable from an imaging device,
An angular velocity sensor for detecting angular velocity;
Correction means for performing image blur correction based on the angular velocity and the motion vector;
Control means for controlling the correction means to perform panning based on the difference between the reference angular velocity during exposure and the angular velocity;
Communication means for communicating with the imaging device,
The communication means includes
Transmitting the angular velocity to the imaging device;
Receiving a reference angular velocity during the exposure from the imaging device;
The lens apparatus according to claim 1, wherein the reference angular velocity during the exposure is calculated according to a reference angular velocity before the start of exposure calculated based on the motion vector and the angular velocity. An imaging device in which a lens device is detachable,
Motion vector detection means for detecting a motion vector;
A calculation means for calculating a reference angular velocity during exposure used for panning shooting;
Communication means for communicating with the lens device,
The communication means receives an angular velocity from an angular velocity sensor from the lens device,
The calculating means calculates a reference angular velocity during the exposure according to a reference angular velocity before the start of exposure calculated based on the motion vector and the angular velocity,
The imaging device, wherein the communication means transmits a reference angular velocity during the exposure to the lens device. An angular velocity sensor for detecting angular velocity;
Motion vector detection means for detecting a motion vector;
Correction means for performing image blur correction based on the angular velocity and the motion vector;
A calculation means for calculating a reference angular velocity during exposure used for panning shooting;
Control means for controlling the correction means to perform the panning shot based on the difference between the reference angular velocity during the exposure and the angular velocity,
The imaging system according to claim 1, wherein the calculating means calculates a reference angular velocity during the exposure according to a reference angular velocity before the start of exposure calculated based on the motion vector and the angular velocity.