JP6395401B2 - Image shake correction apparatus, control method therefor, optical apparatus, and imaging apparatus - Google Patents

Description

  The present invention relates to an image blur correction technique for correcting an image blur by detecting a shake of an apparatus.

  When an image is picked up by an image pickup apparatus such as a digital camera, a shake (image shake) may occur in a subject image due to a shake of a user holding the camera body. There has been proposed an imaging apparatus including an image blur correcting unit that corrects the image blur. Image blur correction processing includes optical image blur correction processing and electronic image blur correction processing. In the optical image blur correction process, vibration applied to the camera body is detected by an angular velocity sensor or the like, and a correction lens provided in the photographing optical system is moved according to the detection result. Image blur is corrected by moving the image formed on the light receiving surface of the image sensor by changing the optical axis direction of the imaging optical system. In the electronic image blur correction process, the image blur is corrected in a pseudo manner by image processing on the captured image.

  In addition to camera shake, there is a demand for tracking a subject (moving object) with a camera, but it requires a special technique of the photographer. In Patent Document 1, a screen is divided into blocks, a specific subject such as a face is detected by template matching, and subject movement is tracked to drive the image blur correction unit so as to fit within the screen. Technology is disclosed. A first control unit that drives the image blur correction unit so as to correct blur of the subject image, and a second control unit that drives the image blur correction unit so that the position of the main subject approaches a specific position; It can be switched by the shooting operation. Alternatively, the image blur correction unit is driven by a target signal obtained by synthesizing the target signals of the first and second control units.

JP 2010-93362 A

In the method disclosed in Patent Document 1, when a target signal for tracking an object and a target signal for camera shake correction are calculated separately at the same timing, an action of checking each other's operation may be performed by each target signal. There is sex. In other words, the image blur correction operation and the subject tracking operation interfere with each other, so that the image blur correction unit is excessively driven, or an unintended operation is performed in a direction opposite to the original driving direction. There is a possibility that.
The present invention provides an image shake correction apparatus capable of achieving both an image shake correction operation and a subject tracking operation by generating a drive signal of an image shake correction unit based on a relationship between shake applied to the apparatus and subject motion information. And providing a control method thereof.

  An image shake correction apparatus according to the present invention is an image shake correction apparatus that corrects an image shake by a correction unit, and includes a shake detection unit that detects a shake of the apparatus and outputs a shake detection signal, and a subject image in a captured image. A subject detection means for detecting the position; and a control means for controlling the driving of the correction means. The control unit according to an embodiment of the present invention is configured to correct the image shake for the low frequency component extracted from the shake detection signal and the position of the subject image detected by the subject detection unit by driving control of the first correction unit. Control of the subject tracking operation to bring it close to a specific position in the photographing screen is performed, and image blur correction control is performed on the high frequency component extracted from the shake detection signal by the drive control of the second correction unit.

In addition, the control unit according to another embodiment of the present invention controls subject tracking operation that brings the position of the subject image detected by the subject detection unit closer to a specific position in the shooting screen by driving control of the first correction unit. The image blur correction is controlled for the low frequency component and the high frequency component extracted from the shake detection signal by the drive control of the second correction unit.
Further, the control means according to another embodiment of the present invention includes a target position obtained by adding a target position based on a low frequency component extracted from the shake detection signal and a target position based on the output of the subject detection means , and the target position based on the low-frequency component extracted from the shake detection signal, and a target position based on the high-frequency component extracted from the shake detection signal, for controlling the correction means based on.

  According to the image blur correction apparatus of the present invention, it is possible to track the subject without deteriorating the image blur correction performance.

It is a figure which shows the structural example of the imaging device which concerns on embodiment of this invention. It is a figure which shows the structural example of the image blurring correction apparatus which concerns on embodiment of this invention. It is a disassembled perspective view which shows the structural example of a 1st correction lens drive part. It is a figure which shows the positional relationship of the 1st and 2nd correction lens drive part. It is a figure which shows the structural example of the 1st correction control part regarding 1st Embodiment of this invention. It is a flowchart explaining the target position calculation process of the correction lens regarding 1st Embodiment. It is the schematic of the example of an image explaining the to-be-photographed object detection process regarding 1st Embodiment. FIG. 6 is a schematic diagram for explaining an image shake correction target position and a subject tracking target position according to the first embodiment. It is a figure which shows the structural example of the 1st correction | amendment control part regarding 2nd Embodiment of this invention. It is a figure which shows the structural example of the correction control part regarding 3rd Embodiment of this invention.

  Embodiments of the present invention will be described with reference to the accompanying drawings. In each embodiment, an image shake correction apparatus that performs image shake correction of a captured image is illustrated. Image blur correction devices that drive and control movable members for image blur correction can be mounted on optical devices including imaging devices such as video cameras, digital cameras, and silver halide still cameras, and observation devices such as binoculars, telescopes, and field scopes. is there. The image blur correction apparatus can also be mounted on an optical device such as an interchangeable lens for a digital single lens reflex camera. Therefore, an optical device and an imaging device also constitute one aspect of the present invention. Hereinafter, an operation for correcting image blur for a low-frequency component and a high-frequency component extracted from the shake detection signal of the apparatus is referred to as an “image blur correction operation”. In addition, an operation for tracking the subject selected as a target so that the position of the subject image detected in the captured image approaches a specific position in the shooting screen is referred to as a “subject tracking operation”. The specific position is, for example, the center position of the shooting screen or the position designated by the photographer.

[First Embodiment]
FIG. 1 shows a configuration example of an imaging apparatus according to the first embodiment of the present invention. The imaging apparatus shown in FIG. 1 is a digital still camera, for example. Note that the imaging apparatus may have a moving image shooting function.
The imaging apparatus includes a zoom unit 101. The zoom unit 101 is a part of a photographic lens having a variable magnification, which forms an imaging optical system, and includes a zoom lens that changes the photographic magnification. The zoom drive unit 102 drives the zoom unit 101 in accordance with a control signal from the control unit 119. The first correction lens 103 is a first correction member that corrects image blur. The first correction lens 103 is movable in a direction orthogonal to the optical axis direction of the photographing lens. The first correction lens driving unit 104 controls driving of the first correction lens 103 in accordance with a control signal from the control unit 119. The second correction lens 113 is a second correction member that corrects image blur, and is movable in a direction orthogonal to the optical axis direction of the photographing lens. The second correction lens driving unit 114 drives the second correction lens 113 in accordance with a control signal from the control unit 119.

  The aperture / shutter unit 105 has a mechanical shutter having an aperture function. The aperture / shutter driving unit 106 drives the aperture / shutter unit 105 in accordance with a control signal from the control unit 119. The focus lens 107 used for focus adjustment is a part of the photographing lens, and the position can be changed along the optical axis of the photographing lens. The focus driving unit 108 drives the focus lens 107 in accordance with a control signal from the control unit 119.

  The imaging unit 109 converts an optical image formed by the photographing optical system into an electrical signal in pixel units using an imaging element such as a CCD image sensor or a CMOS image sensor. CCD is an abbreviation for “Charge Coupled Device”. CMOS is an abbreviation for “Complementary Metal-Oxide”. The imaging signal processing unit 110 performs A (Analog) / D (Digital) conversion, correlated double sampling, gamma correction, white balance correction, color interpolation processing, and the like on the electrical signal output from the imaging unit 109, and outputs video Convert to signal. The video signal processing unit 111 processes the video signal output from the imaging signal processing unit 110 according to the application. Specifically, the video signal processing unit 111 generates video data for display, and performs encoding processing and data file formation for recording. The display unit 112 displays an image as necessary based on the video signal for display output from the video signal processing unit 111. The power supply unit 115 supplies power to the entire imaging apparatus according to the application. The external input / output terminal unit 116 is used for input / output of communication signals and video signals with an external device. The operation unit 117 includes buttons, switches, and the like for the user to give instructions to the imaging apparatus. The storage unit 118 stores various data including video information and the like.

  The control unit 119 includes, for example, a CPU, a ROM, and a RAM. CPU is an abbreviation for “Central Processing Unit”. ROM is an abbreviation for “Read Only Memory”. RAM is an abbreviation for “Random Access Memory”. The control program stored in the ROM is expanded in the RAM and executed by the CPU, whereby each unit of the imaging device is controlled, and the operation of the imaging device including various operations described below is realized. The operation unit 117 includes a release switch configured such that a first switch (denoted as SW1) and a second switch (denoted as SW2) are sequentially turned on in accordance with the pressing amount of the release button. SW1 is turned on when the release button is pressed halfway, and SW2 is turned on when the release button is fully pressed. When SW1 is turned on, the control unit 119 calculates an AF (autofocus) evaluation value based on the video signal for display output from the video signal processing unit 111 to the display unit 112. Then, the control unit 119 performs automatic focus detection and focus adjustment control by controlling the focus driving unit 108 based on the AF evaluation value. Further, the control unit 119 performs an AE (automatic exposure) process for determining an aperture value and a shutter speed for obtaining an appropriate exposure amount based on the luminance information of the video signal and a predetermined program diagram. When the switch SW2 is turned on, the control unit 119 controls each processing unit to perform imaging with the determined aperture and shutter speed and store the image data obtained by the imaging unit 109 in the storage unit 118.

  The operation unit 117 further includes an operation switch used for selecting an image blur correction (anti-shake) mode. When the image blur correction mode is selected by operating the operation switch, the control unit 119 instructs the first correction lens driving unit 104 and the second correction lens driving unit 114 to perform an image blur correction operation. The first correction lens driving unit 104 and the second correction lens driving unit 114 that have received the control command from the control unit 119 perform an image blur correction operation until an image blur correction OFF instruction is issued. The operation unit 117 includes a shooting mode selection switch that can select one of a still image shooting mode and a moving image shooting mode. A shooting mode selection process is performed by a user operation of the shooting mode selection switch, and the control unit 119 changes the operating conditions of the first correction lens driving unit 104 and the second correction lens driving unit 114. The first correction lens driving unit 104 and the second correction lens driving unit 114 constitute the image blur correction device of the present embodiment. The operation unit 117 has a playback mode selection switch for selecting a playback mode. When the reproduction mode is selected by the user operation of the reproduction mode selection switch, the control unit 119 performs control to stop the image blur correction operation. Further, the operation unit 117 includes a magnification change switch for instructing a zoom magnification change. When an instruction to change the zoom magnification is given by a user operation of the magnification change switch, the zoom drive unit 102 that receives the instruction via the control unit 119 drives the zoom unit 101 and moves the zoom lens to the designated position. Let

FIG. 2 is a diagram illustrating a configuration example of the image blur correction apparatus according to the present embodiment. Hereinafter, the calculation process and the position control of the driving direction and the driving amount regarding the first correction lens 103 and the second correction lens 113 will be described.
The shake detection unit includes a first vibration sensor 201 and a second vibration sensor 202. The first vibration sensor 201 is, for example, an angular velocity sensor, and detects vibration in the vertical direction (pitch direction) of the imaging device in a normal posture (a posture in which the length direction of the captured image substantially matches the horizontal direction). The second vibration sensor 202 is, for example, an angular velocity sensor, and detects vibration in the horizontal direction (yaw direction) of the imaging apparatus in a normal posture. The first correction control unit 203 outputs a correction position control signal for the first correction lens 103 in the pitch direction, and controls the driving of the first correction lens 103. The second correction control unit 204 outputs a correction position control signal for the second correction lens 113 in the yaw direction, and controls driving of the second correction lens 113.

  The first lens position control unit 205 acquires a correction position control signal in the pitch direction from the first correction control unit 203 and position information in the pitch direction of the first correction lens 103 from the first Hall element 209. Perform feedback control. Accordingly, the first lens position control unit 205 controls the first drive unit 207 that is an actuator. Similarly, the second lens position control unit 206 receives the correction position control signal in the yaw direction from the second correction control unit 204 and the position information in the yaw direction of the first correction lens 103 from the second Hall element 210. Obtain and perform feedback control. Accordingly, the second lens position control unit 206 controls the second drive unit 208 that is an actuator.

Next, the drive control operation of the first correction lens 103 by the first correction lens driving unit 104 will be described.
The first correction control unit 203 acquires a shake detection signal (angular velocity signal) that represents a shake in the pitch direction of the imaging apparatus from the first vibration sensor 201. In addition, the second correction control unit 204 acquires a shake detection signal (angular velocity signal) representing the shake in the yaw direction of the imaging apparatus from the second vibration sensor 202.

  The first correction control unit 203 generates a correction position control signal for driving the first correction lens 103 in the pitch direction based on the shake detection signal, and outputs the correction position control signal to the first lens position control unit 205. Further, the second correction control unit 204 generates a correction position control signal for driving the first correction lens 103 in the yaw direction based on the shake detection signal, and outputs the correction position control signal to the second lens position control unit 206. The first Hall element 209 outputs a voltage signal corresponding to the strength of the magnetic field generated by the magnet provided for the first correction lens 103 as position information in the pitch direction of the first correction lens 103. The second Hall element 210 outputs a voltage signal corresponding to the strength of the magnetic field by the magnet provided for the first correction lens 103 as position information of the first correction lens 103 in the yaw direction. The position information is supplied to the first lens position control unit 205 and the second lens position control unit 206, respectively.

  The first lens position control unit 205 uses the first drive unit 207 so that the position detection signal value from the first Hall element 209 converges to the correction position control signal value from the first correction control unit 203. Perform feedback control. Further, the second lens position control unit 206 sets the second drive unit 208 so that the position detection signal value from the second Hall element 210 converges to the correction position control signal value from the second correction control unit 204. To perform feedback control. Since the position detection signal values output from the first Hall element 209 and the second Hall element 210 vary, the first correction lens 103 moves to a predetermined position with respect to a predetermined correction position control signal. Thus, the output adjustment of each Hall element is performed.

  Based on the shake detection information from the first vibration sensor 201, the first correction control unit 203 outputs a correction position control signal for moving the first correction lens 103 so as to cancel the image shake of the subject image. Based on the shake detection information from the second vibration sensor 202, the second correction control unit 204 outputs a correction position control signal for moving the first correction lens 103 so as to cancel the image shake of the subject image. For example, the first correction control unit 203 and the second correction control unit 204 may use a correction speed control signal or a correction position control signal based on shake detection information (angular velocity signal) or a signal obtained by performing filter processing on the shake detection information. Is generated. With the above operation, even if vibration such as camera shake is applied to the imaging apparatus during shooting, image shake can be prevented up to a certain level. Further, the first correction control unit 203 and the second correction control unit 204 acquire a shake detection signal and the like to detect the panning state of the imaging apparatus and perform panning control.

  The drive control operation of the second correction lens 113 is the same as the drive control operation of the first correction lens 103. That is, the first correction control unit 203 generates a correction position control signal for driving the second correction lens 113 in the pitch direction based on the shake detection signal, and outputs the correction position control signal to the third lens position control unit 211. Further, the second correction control unit 204 generates a correction position control signal for driving the second correction lens 113 in the yaw direction based on the shake detection signal, and outputs the correction position control signal to the fourth lens position control unit 212. The third lens position control unit 211 uses the third drive unit 214 so that the position detection signal value from the third hall element 216 converges to the correction position control signal value from the first correction control unit 203. Perform feedback control. The fourth lens position control unit 212 also sets the fourth drive unit 208 so that the position detection signal value from the fourth Hall element 213 converges to the correction position control signal value from the second correction control unit 204. To perform feedback control.

  In the present embodiment, the first correction control unit 203, the first lens position control unit 205, and the first drive unit 207 perform image blur correction and subject tracking in the pitch direction for the low-frequency component of the pitch direction blur signal. The first correction control unit 203, the third lens position control unit 211, and the third drive unit 214 perform image blur correction on the high frequency component of the shake signal in the pitch direction. In addition, the second correction control unit 204, the second lens position control unit 206, and the second drive unit 208 perform image blur correction and subject tracking in the yaw direction for low frequency components of the yaw direction shake signal. The second correction control unit 204, the fourth lens position control unit 212, and the fourth drive unit 215 perform image blur correction on the high frequency components of the yaw direction shake signal.

  FIG. 3 is an exploded perspective view illustrating a configuration example of the first correction lens driving unit 104. The first correction lens driving unit 104 includes a movable lens barrel 122 that holds the first correction lens 103 and a fixed ground plate 123. The movable barrel 122 is supported on the fixed ground plate 123 via a plurality of rolling balls 124. The movable lens barrel 122 is moved by the first electromagnetic driving unit 207 and the second electromagnetic driving unit 208. The first electromagnetic drive unit 207 constitutes the first drive unit of FIG. 2, and includes a first magnet 1251, a first coil 1252, and a first yoke 1253. The second electromagnetic drive unit 208 constitutes the second drive unit of FIG. 2 and includes a second magnet 1261, a second coil 1262, and a second yoke 1263. The first correction lens driving unit 104 includes a plurality of biasing springs 127, a first position sensor (first hall element 209), a second position sensor (second hall element 210), and a sensor holder 129.

  The first correction lens 103 is a correction optical member that is driven and controlled by the first correction control unit 203 and the second correction control unit 204 and corrects image blur by decentering the optical axis by movement. An image blur correction operation for moving the light image that has passed through the photographing optical system is performed, and the stability of the image on the imaging surface is ensured. In this embodiment, a correction lens is used as the correction optical system. However, it is also possible to ensure the stability of the image on the image pickup surface by driving the image pickup device with respect to the photographing optical system. In this case, the image pickup device and its drive mechanism unit constitute an image shake correction unit.

  The movable barrel 122 is a first movable portion that holds the first correction lens 103 in the central opening. The movable barrel 122 holds the first magnet 1251 and the second magnet 1261. The movable lens barrel 122 includes rolling ball receiving portions at three locations, and is supported by a plurality of rolling balls 124 so as to be movable in a plane perpendicular to the optical axis. Further, the movable lens barrel 122 has spring hooking portions at three locations, and one end of the biasing spring 127 is attached.

The fixed ground plate 123 is a first fixed member formed in a cylindrical shape, and includes followers 1231 at three locations on the outer peripheral portion. A movable barrel 122 is disposed in the central opening 123 a of the fixed ground plate 123. Thereby, the movable amount of the movable lens barrel 122 can be limited. The fixed ground plate 123 holds the first coil 1252 and the first yoke 1253 at a position facing the magnetized surface of the first magnet 1251. The fixed ground plate 123 holds the second coil 1262 and the second yoke 1263 at a position facing the magnetized surface of the second magnet 1261. The fixed ground plate 123 includes rolling ball receiving portions at three locations. The movable lens barrel 122 is rolled and supported by the fixed base plate 123 via a plurality of rolling balls 124 that are respectively arranged on the rolling ball receiving portions. The fixed ground plate 123 includes three spring hooking portions, and one end of the biasing spring 127 is attached.
The first electromagnetic drive unit 207 is a voice coil motor. By passing a current through the first coil 1252 attached to the fixed ground plate 123, a Lorentz force is generated between the first magnet 1251 fixed to the movable lens barrel 122 and the movable lens barrel 122 is driven. The second electromagnetic drive unit 208 is configured by rotating a voice coil motor similar to the first electromagnetic drive unit 207 by 90 ° in the direction around the optical axis, and thus detailed description thereof is omitted.

  The urging spring 127 is a tension spring that generates an urging force proportional to the amount of deformation. One end of the biasing spring 127 is fixed to the movable lens barrel 122 and the other end is fixed to the fixed base plate 123, thereby generating a biasing force therebetween. By this urging force, the rolling ball 124 is held, and the rolling ball 124 can be kept in contact with the fixed base plate 123 and the movable lens barrel 122.

  The position sensor is a magnetic sensor using Hall elements 209 and 210 that detect the magnetic fluxes of the first magnet 1251 and the second magnet 1261, respectively. These sensors detect the movement of the movable lens barrel 122 in the plane from the magnetic flux change. The sensor holder 129 has an annular shape and is fixed to the fixed ground plate 123. The sensor holder 129 holds the position sensors (Hall elements 209 and 210) at positions facing the first magnet 1251 and the second magnet 1261, respectively. The sensor holder 129 stores the movable lens barrel 122 in an internal space formed with the fixed ground plate 123. As a result, even when an impact force is applied to the image shake correction apparatus or when the posture difference changes, it is possible to prevent internal components from falling off. With the above-described configuration, the first correction lens driving unit 104 can move the first correction lens 103 to an arbitrary position on a plane orthogonal to the optical axis.

  FIG. 4 is a perspective view showing the positional relationship between the first correction lens driving unit 104 and the second correction lens driving unit 114. In FIG. 4, only a part of the correction lens driving unit is disassembled and shown for explanation. The movable lens barrel 132 is a second movable part provided in the second correction lens driving unit 114. The movable barrel 132 holds the second correction lens 113 in the central opening. The fixed ground plate 133 is a second fixing member provided in the second correction lens driving unit 114. The second correction lens driving unit 114 has the same configuration as that of the first correction lens driving unit 104 except for the shape of the lens and the shape of the movable lens barrel 132 that holds the lens, and a detailed description thereof will be omitted.

FIG. 5 illustrates a control unit that performs image blur correction and subject tracking in the pitch direction. The second correction control unit 204, the second lens position control unit 206, the fourth lens position control unit 212, the second drive unit 208, and the fourth drive unit 215 perform control for performing image blur correction and subject tracking in the yaw direction. The part is composed. The control unit has the same configuration as that shown in FIG.
The first vibration sensor 201 in FIG. 5 detects a shake applied to the imaging apparatus and outputs a shake detection signal (angular velocity signal). The first correction control unit 203 includes low-pass filters (hereinafter abbreviated as LPF) 501, 503, and 504, a pan determination unit 502, and a subtraction unit 500. The output signal of the first vibration sensor 201 is input to the LPF 501, the pan determination unit 502, and the subtraction unit 500, respectively. The output signal of the LPF 501 is input to the LPF 503 and the subtracting unit 500, respectively.

  The LPF 501 extracts a low frequency component from the shake detection signal output from the first vibration sensor 201. The low-frequency camera shake signal extracted by the LPF 501 is integrated by the LPF 503 to generate a shake angle signal in which only the low-frequency component is extracted. The LPF 503 can change the time constant until the filter is stabilized. For example, the LPF 503 can change the cutoff frequency by changing the coefficient value used for the filter operation, or can freely rewrite the buffer holding the filter operation result (intermediate value) at any timing. is there. The pan determination unit 502 determines that the panning operation of the imaging apparatus has been performed, and performs time constant change processing until the LPF 503 and the LPF 504 are stabilized. Specifically, the pan determination unit 502 determines that the panning operation has been performed when the shake detection signal of the first vibration sensor 201 is equal to or greater than a predetermined value (threshold value). Alternatively, the pan determination unit 502 determines that the panning operation has been performed when the current position of the first correction lens 103 or the second correction lens 113 is equal to or greater than a predetermined threshold. Alternatively, the pan determination unit 502 determines that the panning operation has been performed when the movement target position of the first correction lens 103 or the second correction lens 113 is equal to or greater than a predetermined threshold. As a result, when a large shake is applied to the imaging apparatus, the control to drive the first correction lens 103 or the second correction lens 113 beyond the movable range is suppressed, and the captured image is not corrected due to the shake back immediately after the panning operation. It can prevent becoming stable. In the tilting operation, the same processing as that in the panning operation is performed, and thus detailed description thereof is omitted.

  In the present embodiment, a subject detection unit 505, a subject tracking unit 506, a gain unit 507, and an addition unit 509 are provided, and the pan determination unit 502 adjusts the gain coefficient of the gain unit 507. For example, the pan determination unit 502 performs a process of reducing the subject tracking target position by changing the gain coefficient value of the gain unit 507 multiplied by the subject tracking target position output from the subject tracking unit 506 to 1 or less. Do. As for the gain coefficient of the gain unit 507, the coefficient value is set to 1 or less at the start of exposure (when SW2 is operated) according to the operation information of the photographer using the operation unit 117, for example, the operation information of the release switch. Thus, the subject tracking operation may be weakened. In this way, the subject tracking operation can be applied strongly during the period before the start of exposure, and at the start of exposure, subject tracking control is weakened and only image blur correction control is performed. Accordingly, it is possible to prevent the correction lens from reaching the end of the movable range due to the subject tracking operation and the image blur correction performance during the exposure from being deteriorated.

  The subtraction unit 500 of the first correction control unit 203 extracts the high frequency component of the shake detection signal by subtracting the low frequency component extracted by the LPF 501 from the shake detection signal from the first vibration sensor 201. The LPF 504 integrates the high-frequency component extracted by the subtracting unit 500 to convert the angular velocity information into angle information, and generates a camera shake angle signal in which only the high-frequency component is extracted. Note that the output of each filter can be output at an arbitrary magnification by changing the coefficient values of the filter operations of the LPF 503 and the LPF 504.

  In the present embodiment, the subject detection unit 505, the subject tracking unit 506, the gain unit 507, and the addition unit 509 can simultaneously perform subject tracking using the image blur correction unit. For example, the subject detection unit 505 detects a subject using the image signal from the imaging signal processing unit 110 and the subject distance information from the focus driving unit 108, and the subject tracking unit 506 uses a known template matching. Generate a position. The subject distance information is information indicating the distance from the imaging device to the subject, or information such as a focus lens position and a focus detection amount corresponding to the distance.

  The gain tracking unit 506 multiplies the target tracking target position obtained by the subject tracking unit 506 by a predetermined gain coefficient and outputs the result to the addition unit 509. Adder 509 adds the output of gain unit 507 and the output of LPF 503, and outputs the addition result to adder 510. Adder 510 further adds the output of LPF 503 to the output of adder 509. The subject tracking target position calculated in this way and the combined target position of the low frequency component of the camera shake signal are input to the first lens position control unit 205 via the subtraction unit 511. On the other hand, the corrected lens target position generated from the high-frequency component of the camera shake angle signal calculated by the LPF 504 is input to the third lens position control unit 211 via the subtraction unit 512.

  In the feedback control system including the first lens position control unit 205, the position information of the first correction lens 103 detected by the first Hall element 209 is subtracted from the first correction lens target position by the subtraction unit 511. The first drive unit 207 drives the first correction lens 103 in accordance with a control signal output from the first lens position control unit 205, and an image blur correction operation is executed by position feedback control. In the feedback control system including the third lens position control unit 211, the position information of the second correction lens 113 detected by the third Hall element 216 is subtracted from the second correction lens target position by the subtraction unit 512. The third drive unit 214 drives the second correction lens 113 in accordance with a control signal output from the third lens position control unit 211, and an image blur correction operation is executed by position feedback control. For the first lens position control unit 205 and the third lens position control unit 211, any control calculation unit may be used. For example, a P (proportional) I (integral) D (differential) controller can be used.

  As described above, the image blur correction at low frequency and the subject tracking operation are performed by the first correction unit using the first correction lens 103, and the second correction lens 113 is used for image blur correction at the high frequency. This is performed by the second correction means. In this configuration, the first correction lens 103 is mainly used to correct a large shake at a low frequency, and in this case, an angle at which an image shake can be corrected is large. On the other hand, the second correction lens 113 is mainly used to correct only a small high-frequency shake, and in this case, the angle at which image shake correction is possible is small. A mechanism using a correction lens having a large image blur correction angle generally involves an increase in size. Therefore, in this embodiment, the role of the correction lens is shared between the low-frequency image stabilization and the high-frequency image stabilization. Therefore, it is possible to achieve both the image blur correction operation and the subject tracking operation while preventing the mechanism portion from becoming excessively large and the resolution for detecting the position of the lens from excessively increasing.

Next, an example of a correction lens target position calculation process in the present embodiment will be described with reference to the flowchart of FIG. The correction control calculation process is executed at a predetermined cycle according to the control program read from the memory by the CPU of the control unit 119.
First, when the process starts (S101), the first vibration sensor 201 detects camera shake or the like, and acquires a shake detection signal (S102). Subsequently, the LPF 501 performs a calculation for dividing the shake detection signal into frequency band components (S103). The calculation result of the LPF 501 is stored in the memory as a low frequency component of the shake detection signal (S104). Next, the pan determination unit 502 determines whether or not the imaging device is panning (S105). If it is determined that the imaging device is panning, the process proceeds to S106. If it is determined that panning is not being performed, the process proceeds to S107. In step S <b> 106, the pan determination unit 502 uses the gain coefficient of the gain unit 507 that multiplies the subject tracking target position output from the subject tracking unit 506 and the first process of decreasing the time constant until the filter calculation of the LPFs 503 and 504 is stabilized. A second process for setting the value to 1 or less is executed. The second process is performed to weaken the subject tracking operation.

  In S107, the LPF 503 acquires the output value of the LPF 501 stored in the memory in S104, integrates it, and converts the angular velocity information into angular information (S108). In S109, the subject tracking unit 506 performs calculation for subject tracking based on the information from the subject detection unit 505. The adder 509 adds the subject tracking information and the low-frequency image blur correction target position calculated in S108 to calculate the subject tracking target position. Thereafter, the adding unit 510 adds the calculated subject tracking target position and the low-frequency image blur correction target position (S110). The addition result is input to the first lens position control unit 205 (S111), and the first correction lens 103 is driven. Next, the subtraction unit 500 subtracts the output value of the LPF 501 stored in S104 from the shake detection signal acquired in S102 (S112), and a high frequency component of the shake detection signal is extracted. Thus, the shake detection signal is divided into a low frequency component and a high frequency component according to the cutoff frequency set by the LPF 501. The LPF 504 converts the angular velocity signal into an angle signal by integrating the extracted high-frequency component of the shake detection signal (S113). The calculated high frequency shake detection signal is input to the third lens position control unit 211 (S114). As a result, the second correction lens 113 is driven, and a series of processing ends in S115.

Next, an example of the subject tracking operation will be described with reference to FIGS.
At the time of subject tracking, for example, as shown in FIG. 7, a face detection frame 703 of the main subject is automatically set by a known face detection process in a screen 701 of the display unit 112 of the imaging apparatus. From this face detection frame 703, the main subject detection frame 702 is set, and subject tracking calculation starts. The subject tracking calculation is performed on the main subject detection frame 702. An image in the main subject detection frame 702 is set as a template for template matching, and a template matching process is performed on an image input every predetermined time. As a result, a similar image area having a correlation with the template image is searched. The subject detection unit 505 executes the main subject detection process.

  FIG. 8A shows an example of an image assuming that the subject moves to the left from the center of the screen 701. An image similar to the main subject detection frame 702 is searched by the template matching process. When a similar image is detected, the position of the area in the screen 701 is detected. The subject tracking information is detected in the direction of the left-pointing arrow shown in FIG. On the other hand, the low-frequency shake target position output from the LPF 503 related to shake detection of the imaging apparatus is zero because only the subject has moved. Therefore, only the subject tracking information is included in the subject tracking target position calculated by the adding unit 509. Based on the target position calculated by the adding unit 510, image blur correction at a low frequency is not performed on the first correction lens 103. Only the subject tracking operation is executed. On the other hand, when there is a shake detection signal of a high frequency component, image blur correction is performed by the second correction lens 113.

  FIG. 8B shows an image example assuming that the subject remains stationary and the main subject and the background move from the center of the screen 701 to the left due to camera shake. In this case, the main subject is detected as in FIG. 8A, and the subject tracking information is detected in the direction of the left-pointing arrow in FIG. 8B. On the other hand, the low-frequency image shake target position output from the LPF 503 related to the shake detection of the imaging device is similar to the subject tracking information because the subject has moved due to the shake of the imaging device. Is detected in the direction of the left-pointing arrow. The subject tracking target position calculated by the adding unit 509 is zero because subject tracking information (for example, positive value) and low-frequency component shake detection information (for example, negative value) are offset. The adder 510 calculates the target position by adding the subject tracking target position and the image blur target position with the low frequency component, and based on the result, the first correction lens 103 does not perform the subject tracking operation, and is low. Only image blur correction at a frequency is performed. On the other hand, when there is a high-frequency component shake detection signal, image blur correction is executed by the second correction lens 113.

By the above processing, it is automatically determined whether the imaging device has shaken or the subject has actually moved, and the image blur correction unit is driven to perform appropriate image blur correction according to the shooting scene. Is done. Thus, the reason for extracting only the low frequency component of the shake detection signal in the control unit and comparing it with the subject tracking information is to remove the relatively high frequency signal component included in the shake detection signal such as camera shake. This is to improve the accuracy of calculation of the subject tracking target position.
In the present embodiment, the subject tracking target position is calculated by comparing the subject tracking information with the low frequency component of the image blur correction, thereby calculating the shake correction lens target position from both the image blur correction and the subject tracking state. The For this reason, it is possible to achieve both the image blur correction operation and the subject tracking operation without interfering with each other's operations. Therefore, the subject tracking operation can be easily performed without degrading the image blur correction performance.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. Omitting such description is the same in the embodiments described later.
FIG. 9 shows a main part of a configuration example of the imaging apparatus of the present embodiment. Hereinafter, differences from the configuration example shown in FIG. 5 will be described. In the imaging apparatus of the present embodiment, the addition unit 510 that adds the subject tracking target position and the image blur correction target position at a low frequency is deleted, and an addition unit 901 is added.

For the subject tracking target position obtained by the subject tracking unit 506, the gain unit 507 multiplies the gain coefficient. Adder 509 adds the output of LPF 503 to the output of gain unit 507. The signal after the addition is input to the first lens position control unit 205 via the subtraction unit 511, so that the subject tracking operation using the first correction lens 103 is performed. On the other hand, the addition unit 901 adds the correction lens target position generated from the high frequency component of the camera shake angle signal by the LPF 504 and the correction lens target position generated from the low frequency component of the camera shake angle signal by the LPF 503. The combined signal after the addition is input to the third lens position control unit 211 via the subtraction unit 512, and image blur correction control by the second correction lens 113 is performed.
In the present embodiment, by using the first correction lens 103 for the subject tracking operation and using the second correction lens 113 for the image blur correction operation, it is possible to design the subject tracking and the image blur correction separately. For example, for the control frequency band and position control resolution required for subject tracking operation and image blur correction operation, correction lens drive range, etc., design correction lens characteristics and controller suitable for each operation Can do.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 10 shows a main part of a configuration example of the imaging apparatus according to the present embodiment. While the first and second embodiments use a plurality of correction lenses, the imaging apparatus according to this embodiment has a configuration that does not include the second correction lens.
The image blur correction lens target positions at low frequency and high frequency calculated by the LPF 503 and the LPF 504 are added by the adding unit 1001. On the other hand, the subject tracking target position multiplied by the gain coefficient in the gain unit 507 is added to the output of the LPF 503 in the adder 509. The adding unit 510 adds the output of the adding unit 509 and the image blur correction lens target position output from the adding unit 1001. The combined signal after the addition is input to the first lens position control unit 205 via the subtraction unit 511, so that a subject tracking operation and an image shake correction operation are performed.

  In the present embodiment, the subject tracking operation and the image blur correction operation can be performed with one correction lens. Therefore, it is possible to suppress an increase in size and cost of the apparatus due to having a plurality of correction lenses, and it is possible to realize both an image blur correction operation and a subject tracking operation.

DESCRIPTION OF SYMBOLS 103 1st correction lens 104 1st correction lens drive part 113 2nd correction lens 114 2nd correction lens drive part 119 Control part 201,202 Vibration sensor 501,503,504 Filter 502 Pan determination part 505 Subject detection part 507 Gain part

Claims (11)

An image blur correction apparatus that corrects image blur by a first correction unit and a second correction unit,
A shake detection means for detecting a shake of the apparatus and outputting a shake detection signal;
Subject detection means for detecting the position of the subject image in the captured image;
Control means for performing drive control of the first correction means and the second correction means,
The control means controls the image blur correction for the low-frequency component extracted from the shake detection signal and the position of the subject image detected by the subject detection means based on the drive control of the first correction means. An image blur correction apparatus that controls a subject tracking operation to approach a position and controls image blur correction for a high-frequency component extracted from the shake detection signal by driving control of the second correction unit. An image blur correction apparatus that corrects image blur by a first correction unit and a second correction unit,
A shake detection means for detecting a shake of the apparatus and outputting a shake detection signal;
Subject detection means for detecting the position of the subject image in the captured image;
Control means for performing drive control of the first correction means and the second correction means,
The control means controls a subject tracking operation to bring the position of the subject image detected by the subject detection means closer to a specific position in the shooting screen by driving control of the first correction means, and the second correction means An image blur correction apparatus that controls image blur correction for a low-frequency component and a high-frequency component extracted from the shake detection signal by drive control. An image blur correction apparatus that corrects image blur by a correction unit,
A shake detection means for detecting a shake of the apparatus and outputting a shake detection signal;
Subject detection means for detecting the position of the subject image in the captured image;
Control means for performing drive control of the correction means,
Wherein the control means, and the target position obtained by adding the target position based on an output of said object detecting means and the target position based on the low-frequency component extracted from the shake detection signal, the low frequency extracted from the shake detection signal An image blur correction apparatus that controls the correction unit based on a target position based on a component and a target position based on a high frequency component extracted from the shake detection signal . The control means obtains the position of the subject image detected by the subject detection means and a low frequency component extracted from the shake detection signal, and calculates the drive direction and drive amount of the correction means. Item 3. The image blur correction device according to Item 1 or 2 . Filter means for extracting a low frequency component and a high frequency component from the shake detection signal,
5. The image blur correction apparatus according to claim 1, wherein, when panning or tilting is performed, the control unit performs a process of changing a time constant of the filter unit. 6. Gain means for multiplying a target position for subject tracking by a gain coefficient in subject tracking operation,
6. The image blur according to claim 4, wherein, when panning or tilting is performed, the control unit performs a process of changing the value of the gain coefficient to reduce the target position. 7. Correction device.   An optical apparatus comprising the image blur correction device according to claim 1.   An image pickup apparatus comprising the image shake correction apparatus according to claim 1. A control method executed by an image blur correction apparatus that corrects an image blur by a first correction unit and a second correction unit,
A detection step in which the shake detection unit detects the shake of the apparatus, and the subject detection unit detects the position of the subject image in the captured image;
A control step for obtaining a shake detection signal from the shake detection unit and information on a position of the subject image from the subject detection unit, and performing drive control of the first correction unit and the second correction unit. And
In the control step, the control means captures the image shake correction for the low frequency component extracted from the shake detection signal and the position of the subject image detected by the subject detection means by the drive control of the first correction means. A subject tracking operation for bringing the subject closer to a specific position in the screen is controlled, and image blur correction control for a high frequency component extracted from the shake detection signal is performed by driving control of the second correction unit. A method for controlling an image blur correction apparatus. A control method executed by an image blur correction apparatus that corrects an image blur by a first correction unit and a second correction unit,
A detection step in which the shake detection unit detects the shake of the apparatus, and the subject detection unit detects the position of the subject image in the captured image;
A control step for obtaining a shake detection signal from the shake detection unit and information on a position of the subject image from the subject detection unit, and performing drive control of the first correction unit and the second correction unit. And
In the control step, the control means controls a subject tracking operation to bring the position of the subject image detected by the subject detection means closer to a specific position in the shooting screen by driving control of the first correction means, A control method of an image blur correction apparatus, wherein image blur correction is controlled for a low frequency component and a high frequency component extracted from the shake detection signal by driving control of a second correction unit. A control method executed by an image blur correction apparatus that corrects image blur by a correction unit,
A detection step in which the shake detection unit detects the shake of the apparatus, and the subject detection unit detects the position of the subject image in the captured image;
A control unit that obtains a shake detection signal from the shake detection unit and information on a position of a subject image from the subject detection unit, and performs drive control of the correction unit;
In the control step, the control means extracts a target position obtained by adding a target position based on a low frequency component extracted from the shake detection signal and a target position based on the output of the subject detection means, and the shake detection signal. wherein the target position based on the low-frequency component, and a target position based on the high-frequency component extracted from the shake detection signal, the control method of the image blur correcting device and controls the correction means based on being.

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