JP6613619B2 - IMAGING DEVICE AND IMAGING DEVICE CONTROL METHOD - Google Patents

Description

  The present invention relates to an imaging apparatus including an image blur correction mechanism and a method for controlling the image blur correction mechanism.

  When shooting with an imaging device such as a digital camera, camera shake may occur when the image is taken by hand, and the shot image may be blurred. Therefore, there is a camera shake correction technique in which shooting is performed by driving a part of the image sensor and the imaging optical system (image shake correction mechanism) in a direction perpendicular to the optical axis and canceling the shake. In addition, in a camera equipped with an image blur correction mechanism, the value of the DC component output from the DC component detection unit when the panning detection unit does not detect panning in order to suppress deterioration in accuracy of blur correction due to panning. When the panning detection unit changes from a state where panning is detected to a state where panning is not detected, the DC component detection unit outputs the stored DC component value, and then is detected by the angular velocity detection unit. A configuration is known in which a DC component detection unit is controlled to output a DC component based on the angular velocity thus generated, thereby suppressing deterioration in blur correction accuracy caused by panning (see Patent Document 1).

JP 2013-178503 A

  However, in the configuration of Patent Document 1, if the angular velocity of the imaging apparatus or the direction of panning is changed when performing a panning while using a moving object as a main subject, the accuracy of camera shake correction deteriorates because it cannot follow this. was there.

  An object of the present invention is to accurately perform camera shake correction and capture a good image even when the angular velocity or the direction of panning changes in the imaging apparatus during panning.

An image pickup apparatus according to the present invention includes an image sensor that forms a subject light flux that has passed through an image pickup optical system as a subject image, a shake detection unit that detects shake, an optical element that forms at least a part of the image pickup optical system, and an image sensor. By driving the image shake correction member composed of at least one and the image shake correction member in a direction different from the optical axis of the imaging optical system, the image formation position of the subject image on the image sensor is displaced to reduce image shake. An image pickup apparatus comprising: a drive mechanism for correction; and a drive control unit that controls driving of the image shake correction member by the drive mechanism at a constant control cycle based on a control target position and a current position of the image shake correction member. The drive control unit includes a first filter that inputs a shake signal output from the shake detection unit and a moving state determination unit of the imaging device. The state determination unit determines that the imaging device is in a first state from the shake signal. If it is not the first state, it is determined by the output signal of the first filter whether it is in any state other than the first state including the second state of the imaging device, and the drive control The unit calculates the drive amount of the image blur correction member by the drive mechanism according to the state determined by the state determination unit, and when the state determination unit determines that the second state, the drive control unit The drive amount of the shake correction member is calculated based on a signal obtained by subtracting the output signal of the first filter calculated for each control period from the shake signal sampled every time.

  The state determination unit does not perform image blur correction when determining that the state is the first state. As a result, in a state where the shake detection means cannot detect (such as high-speed panning), image blur correction is not performed, so that deterioration of the captured image due to a reduction in image blur correction performance can be prevented.

  The drive control unit further includes a second filter that inputs the shake signal output from the shake detection unit. When the state determination unit determines that the state is the third state, the drive control unit Based on the output signal, the drive amount of the shake correction member is calculated. Accordingly, it is possible to capture an image with little image blur in both cases by discriminating between the case where panning is detected and the case where it is not (still), and changing the image blur correction control.

  The first filter has a low-pass filter, and the DC component of the shake detection signal can be easily extracted by using the low-pass filter. In addition, the second filter has a high-pass filter, and by using the high-pass filter, the offset component due to the electrical noise constantly placed on the shake detection signal and the environmental temperature change is removed in the case of non-panning shooting. Image blur correction. Note that the offset component due to the electrical noise and environmental temperature change described here is included in the DC component extracted by the low-pass filter during panning, and therefore can be removed without using the high-pass filter.

  In a state other than the first state, when the level of the shake signal is larger than the first threshold value, the state transits to the first state, and in the first state, the level of the shake signal is smaller than the second threshold value. The state transits to a state other than the first state, and the second threshold is equal to or less than the first threshold. By giving hysteresis to the first threshold value and the second threshold value, it is possible to detect the pan state satisfactorily without alternately repeating the pan state and the other state due to noise or the like.

  In the state other than the first state or the second state, when the level of the output signal of the first filter is higher than the third threshold value, the state transits to the first state, and the first filter in the second state When the output signal level is lower than the fourth threshold value, the state transits to a state other than the first state or the second state, and the fourth threshold value is equal to or lower than the third threshold value. Here, by providing hysteresis to the third threshold value and the fourth threshold value, it is possible to detect the panning state satisfactorily without alternately repeating the panning state and the non-shooting state due to noise or the like. .

  In a state other than the first state, when the level of the shake signal is continuously higher than the first threshold for a certain period of time, the state transits to the first state. In the first state, the level of the shake signal continues for a certain period of time. When the value is smaller than the second threshold, the state transits to a state other than the first state, and the second threshold is not more than the first threshold. By performing state transition in a state where the shake signal continuously exceeds the threshold value in this way, it is possible to detect the pan state satisfactorily without alternately repeating the pan state and the other state due to noise or the like. it can.

  In the state other than the first state or the second state, when the level of the output signal of the first filter is continuously higher than the third threshold for a certain time, the state transits to the first state, and the second state Transition to a state other than the first state or the second state when the level of the output signal of the first filter is lower than the fourth threshold value continuously for a certain period of time, and the fourth threshold value is the third threshold value. It is as follows. In other words, by performing state transition in a state where the low-pass filter signal continuously exceeds the threshold value, it is possible to detect the pan state satisfactorily without alternately repeating the pan state and the other state due to noise or the like. .

  The imaging apparatus transitions only from the first state in the pan state to the fourth state that is the reset state, and from the fourth state only transitions to the third state in the normal photographing. By providing the reset state and shortening the settling time of the high-pass filter, a suitable captured image can be obtained in a short time even when the pan state is changed to the stationary state. At this time, for example, the first state corresponds to the pan state, the second state corresponds to the panning state, the third state corresponds to the normal state, and the fourth state corresponds to the reset state.

  An imaging apparatus control method according to the present invention includes: an image sensor that forms a subject light flux that has passed through an imaging optical system as a subject image; a shake detection step that detects shake; and an optical element that forms at least a part of the imaging optical system; By driving the image shake correction member composed of at least one of the image sensors and the image shake correction member in a direction different from the optical axis of the imaging optical system, the imaging position of the subject image on the image sensor is displaced. A drive mechanism for correcting image blur, and a drive control step for controlling the drive of the image blur correction member by the drive mechanism at a constant control cycle based on the control target position and the current position of the image blur correction member In the imaging apparatus having the first digital filter that inputs the shake signal output from the shake detection unit and the state determination step, the control step includes: It is determined from the shake signal whether or not the imaging device is in the first state. If the imaging device is not in the first state, the imaging device is in any one other than the first state including the second state based on the output signal of the first digital filter. The drive control step calculates the drive amount of the image blur correction member by the drive mechanism according to the state determined by the state determination step, and the state determination step determines that the state is the second state. In this case, the drive control step calculates the drive amount of the shake correction member based on a signal obtained by subtracting the output signal of the first digital filter calculated for each control period from the shake signal sampled for each control period. It is characterized by doing.

  In the state determination step, for example, image blur correction is not performed when the first state is determined. The drive control step further includes a second digital filter that inputs the shake signal output from the shake detection step, and when the state determination step determines that the state is the third state, the drive control step includes the second digital filter. Based on the output signal of the filter, the driving amount of the shake correction member is calculated. The first digital filter has a low-pass filter, and the second digital filter has a high-pass filter.

  In the control method of the imaging apparatus, in a state other than the first state, when the level of the shake signal is higher than the first threshold, the transition is made to the first state, and in the first state, the level of the shake signal is the first level. When the threshold value is smaller than 2, the state transits to a state other than the first state, and the second threshold value is less than or equal to the first threshold value. In the state other than the first state or the second state, when the level of the output signal of the first digital filter is larger than the third threshold value, the state transits to the first state, and the first state in the second state. When the level of the output signal of the digital filter is lower than the fourth threshold, the state transits to a state other than the first state or the second state, and the fourth threshold is equal to or lower than the third threshold.

  Further, the control method of the image pickup apparatus transitions to the first state when the level of the shake signal is continuously higher than the first threshold value for a certain time in a state other than the first state, and the first state When the level of the shake signal is lower than the second threshold value for a certain period of time, the state transits to a state other than the first state, and the second threshold value is less than or equal to the first threshold value. Further, in the state other than the first state or the second state, when the level of the output signal of the first digital filter is continuously higher than the third threshold for a certain time, the state transits to the first state, In the second state, when the level of the output signal of the first digital filter is continuously lower than the fourth threshold value for a predetermined time, the state transits to a state other than the first state or the second state, and the fourth threshold value is It is below the third threshold. Furthermore, the imaging apparatus is configured to transition from the first state in the pan state only to the fourth state that is the reset state, and from the fourth state to transition only to the third state for normal photographing. You can also.

  According to the present invention, even when the angular velocity of the imaging apparatus or the direction of the panning changes during the panning, the camera shake can be corrected accurately and a good image can be taken.

1 is a block diagram illustrating a configuration of a main part of an imaging apparatus that is a first embodiment of the present invention. FIG. It is a figure which shows the signal of the deflection angle of the apparatus main body which the gyro sensor (attitude information acquisition part) of the imaging device of FIG. 1 acquires. FIG. 2 is a plan view illustrating a configuration of a main part of an image blur correction device mounted on the imaging device of FIG. 1. FIG. 2 is a side view illustrating a configuration of an image shake correction apparatus mounted on the imaging apparatus in FIG. 1. It is a control block diagram of an image sensor drive circuit (comparative example) by an image blur correction mechanism equipped with only a pan state detection unit. FIG. 3 is a control block diagram of an image sensor driving circuit in the image blur correction mechanism of the first embodiment. It is a flowchart which shows the flow of the whole camera-shake correction process operation | movement in 1st Embodiment. It is a flowchart of a panning and pan state detection process (step S104). It is a flowchart of camera shake correction (SR) control (step S108). It is a flowchart of a panning and pan detection process (step S104) in the second embodiment. It is a figure which shows typically the transitionable relationship between SR states in 3rd Embodiment. It is a flowchart of a panning and pan detection process (step S104) in the third embodiment. It is a flowchart of SR state determination processing in a normal state. It is a flowchart of SR state determination processing in the panning state. It is a flowchart of SR state determination processing in a pan state. It is a flowchart of camera-shake correction (SR) control (step S108) in 3rd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram illustrating a configuration of a main part of the imaging apparatus according to the first embodiment of the present invention. 2 to 4 are a front view and a rear view showing three typical postures of the movable monitor with respect to the imaging device main body.

  The image pickup apparatus according to the first embodiment is, for example, a digital camera 10 and includes a camera body 20 and a photographic lens 30 that can be attached to and detached from the camera body 20 (lens exchangeable). The photographic lens 30 includes, in order from the subject side (left side in FIG. 1) to the image plane side (right side in FIG. 1), a photographic lens group (imaging optical system, image blur correction member) 31, and a diaphragm (imaging optics). System) 32. The camera body 20 includes a shutter (imaging optical system) 21 and an image sensor (image blur correction member) 22 in order from the subject side (left side in FIG. 1) to the image plane side (right side in FIG. 1). Prepare. The camera body 20 also includes an aperture / shutter drive circuit 23 that controls driving of the aperture 32 and the shutter 21 in a state where the camera body 20 is attached to the photographic lens 30.

  A subject image is formed on the light receiving surface of the image sensor 22 by the subject light flux that enters from the photographing lens group 31 and passes through the aperture 32 and the shutter 21. The subject image formed on the light receiving surface of the image sensor 22 is converted into an electrical pixel signal by a large number of pixels arranged in a matrix, and is output to the DSP 40 as image data. The DSP 40 performs predetermined image processing on the image data input from the image sensor 22, displays it on the LCD (monitor) 24, and stores it in the image memory 25. In FIG. 1, the photographic lens group 31 is depicted as a single lens. However, the actual photographic lens group 31 may be, for example, a fixed lens, a variable magnification lens that moves during zooming, or a focusing lens that moves during focusing. It consists of multiple lenses.

  Although not shown, the image blur correction mechanism (image blur correction mechanism) is not limited to a configuration in which the image sensor 22 is driven to perform image blur correction, and a part of the imaging optical system lens or A part of the optical elements up to the image sensor 22 may be used as an image blur correction member and driven to perform image blur correction. In this specification, “the image sensor (image blur correction member) 22 is driven in a plane orthogonal to the optical axis Z of the imaging optical system” means a plurality of configurations including the image sensor (image blur correction member) 22. This means that at least a part of the elements through which the subject luminous flux passes is driven in a plane perpendicular to the optical axis Z of the imaging optical system.

  The photographic lens 30 includes a communication memory 33 that stores various information such as resolving power (MTF) information of the photographic lens group 31 and aperture diameter (aperture value) information of the diaphragm 32. When the photographic lens 30 is attached to the camera body 20, various information stored in the communication memory 33 is read into the DSP 40.

  The camera body 20 includes a shooting operation switch 26 and an image blur correction operation switch 27 connected to the DSP 40. The photographing operation switch 26 includes various switches such as a power switch and a release switch. The image blur correction operation switch 27 drives the image sensor 22 in a plane orthogonal to the optical axis Z of the imaging optical system (hereinafter sometimes referred to as an optical axis orthogonal plane), thereby subjecting the image sensor 22 to the subject. This is a switch for switching whether or not to perform “image blur correction drive” for correcting the image blur by displacing the image formation position of the image. Image blur correction driving of the image sensor 22 will be described in detail later.

  The camera body 20 includes a gyro sensor (posture information acquisition unit, shake detection unit) 28 connected to the DSP 40. The gyro sensor 28 detects a shake detection signal indicating a shake in the plane orthogonal to the optical axis of the camera body 20 by detecting a moving angular velocity (around the X axis and around the Y axis) applied to the camera body 20 of the digital camera 10. . A shake detection signal from the gyro sensor 28 is output to an image sensor drive circuit (drive control unit) 60 described later via the DSP 40. As shown in FIG. 2, the gyro sensor 28 acquires the roll angle θ and the pitch angle φ of the camera body 20 as shake information of the camera body 20.

  As shown in FIGS. 1, 3, and 4, the image sensor 22 is an image blur correction device (drive) that is movable in the X-axis direction and the Y-axis direction (two orthogonal directions) orthogonal to the optical axis Z of the photographing optical system. Mechanism) 50. The image blur correction device 50 includes a fixed support substrate 51 fixed to a structure such as a chassis of the camera body 20, a movable stage 52 slidable with respect to the fixed support substrate 51 to which the image sensor 22 is fixed, and a fixed support substrate. Magnets M1, M2, and M3 fixed to the surface of the movable stage 52 facing the movable stage 52, and the magnets M1, M2, and M3 fixed to the stationary support substrate 51 with the movable stage 52 interposed therebetween. , M3, and yokes Y1, Y2, and Y3 made of a magnetic material constituting a magnetic circuit, and a driving coil that is fixed to the movable stage 52 and generates a driving force by receiving a current in the magnetic field of the magnetic circuit. C1, C2, and C3. Then, the image blur correction device 50 causes the movable stage 52 (the image sensor 22) to light the fixed support substrate 51 by applying (applying) an AC drive signal (AC voltage) to the drive coils C1, C2, and C3. Drive in an axis orthogonal plane. The AC drive signal that flows through the drive coils C1, C2, and C3 is generated by an image sensor drive circuit (drive control unit) 60 described later under the control of the DSP 40. The configuration of the image sensor drive circuit 60 and the AC drive signal generated by the image sensor drive circuit 60 will be described in detail later.

  In the first embodiment, the magnetic drive means including the magnet M1, the yoke Y1, and the drive coil C1, and the magnetic drive means (two sets of magnetic drive means) including the magnet M2, the yoke Y2, and the drive coil C2 are image sensors. The magnetic drive means (a set of magnetic drive means), which is arranged at a predetermined interval in the longitudinal direction (horizontal direction, X-axis direction) 22 and includes the magnet M3, the yoke Y3, and the drive coil C3, is the longitudinal direction of the image sensor 22. They are arranged in a perpendicular direction (vertical (vertical) direction, Y-axis direction).

  Further, the fixed support substrate 51 detects the magnetic force of the magnets M1, M2, and M3 in the vicinity (central space) of each of the driving coils C1, C2, and C3, and is orthogonal to the optical axis of the movable stage 52 (image sensor 22). Hall sensors H1, H2, and H3 for detecting a position detection signal (current position detection signal) indicating a position in the plane (current position) are arranged. The position and tilt (rotation) of the movable stage 52 (image sensor 22) are detected by the hall sensors H1 and H2, and the position of the movable stage 52 (image sensor 22) is detected by the hall sensor H3. The DSP 40 includes a shake detection signal indicating a shake in a plane orthogonal to the optical axis of the camera body 20 detected by the gyro sensor 28 and an image sensor detected by the hall sensors H1, H2, and H3 via an image sensor driving circuit 60 described later. The image sensor 22 is driven in the optical axis orthogonal plane by the image blur correction device 50 based on the position detection signal indicating the position in the optical axis orthogonal plane 22. As a result, the image formation position of the subject image on the image sensor 22 can be displaced, and image shake caused by camera shake can be corrected. In this specification, this operation is referred to as “image blur correction operation (image blur correction drive) of the image sensor 22”.

  Further, when the image blur correction device 50 is not performing the image blur correction operation (image blur correction drive) of the image sensor 22, the image sensor 22 is positioned at the center position of the image blur correction operation range (image blur correction drive range). The holding “center holding operation of the image sensor 22 (center holding driving)” is executed (center holding is performed without performing image blur correction).

  As described above, the digital camera 10 drives the image sensor 22 in the plane orthogonal to the optical axis via the image blur correction device 50 by flowing an AC drive signal through the drive coils C1, C2, and C3. A circuit (drive control unit) 60 is provided, and the overall operation of the image sensor drive circuit 60 is controlled by the DSP 40.

  Next, in order to help understanding of the camera shake correction process of the first embodiment having a panning shot detection function (described later), referring to the block diagram of FIG. 5 for a camera shake correction process in which only the pan state detection function is mounted as a comparative example. explain.

  An image sensor drive circuit 60A used in camera shake correction processing having only a pan state detection function includes an addition unit 61, a gain unit 62, a controller (drive control unit) 63, an HPF unit 64, and a pan state detection unit 65. With. The HPF unit 64 applies an HPF (high pass filter) to the shake detection signal indicating the shake in the optical axis orthogonal plane of the camera body 20 detected by the gyro sensor 28, and removes a steady DC component due to temperature fluctuations and electrical noise. Generated signal. The cutoff frequency of the HPF is desirably set to a low frequency so that a steady DC component can be removed.

  The adding unit 61 performs addition processing on the shake detection signal after the DC component removal generated by the HPF unit 64. The gain unit 62 generates a control target position signal indicating the control target position of the image sensor 22 by amplifying the shake detection signal subjected to the addition process by the addition unit 61. The pan state detection unit 65 determines whether or not the camera body 20 is in the pan state from the shake detection signal detected by the gyro sensor 28. If it is determined that the camera body 20 is in the pan state, the pan state detection unit 65 outputs a control target position signal input to the controller 63. The signal generated by the gain unit 62 is replaced with 0.

  When it is not determined that the pan state is detected by the pan state detection unit 65, that is, in the normal state, the controller 63 generates a control target position signal indicating the control target position of the image sensor 22 generated by the gain unit 62, a hall sensor Based on a deviation signal (difference signal) between the current position detection signal indicating the current position of the image sensor 22 detected by H1, H2, and H3, a PWM signal is output to the driving coils C1 to C3 to correct image blur. The drive of the image sensor 22 by the device 50 (see FIGS. 3 and 4) is feedback-controlled. On the other hand, if the pan state detection unit 65 determines that the pan state is present, the 0 signal replaced by the pan state detection unit 65 and the current position of the image sensor 22 detected by the hall sensors H1, H2, and H3 are displayed. Based on a deviation signal (difference signal) from the current position detection signal shown, a PWM signal is output to the driving coils C1 to C3, and feedback control of the image blur correction device 50 is performed.

  Next, camera shake correction processing according to the first embodiment having a panning detection function will be described with reference to the block diagram of FIG. In the present embodiment, the state in which the camera body 20 is moving at a certain angular velocity or more corresponding to the panning state and the pan state is referred to as the panning state and the pan state according to the magnitude of the angular velocity. It is assumed that the angular velocity when determining the state is larger than the angular velocity when determining the panning state. The angular velocity is calculated from the shake detection signal detected from the gyro sensor 28. The drive mode for driving the image blur correction device 50 corresponding to the panning state and the pan state is divided into the panning mode and the pan mode.

  As shown in FIG. 6, the image sensor drive circuit 60 used in the camera shake correction process of the first embodiment is compared with the image sensor drive circuit 60 </ b> A having only the pan state detection unit 65 described with reference to FIG. 5. In addition, an LPF unit 66 is further provided, and a panning / pan state detection unit (state determination unit) 67 is provided instead of the pan state detection unit 65. The LPF unit 66 applies an LPF (low pass filter) to the shake detection signal detected by the gyro sensor 28 to generate a low frequency signal from which a high frequency including a shake component is removed. The cutoff frequency of the LPF may be one that attenuates part of the camera shake component, and is preferably higher than the cutoff frequency of the HPF of the HPF unit 64.

  The panning / pan state detection unit 67, based on the shake detection signal detected by the gyro sensor 28, determines whether the camera body 20 is in the pan state performed by the pan state detection unit 65 of FIG. It is determined from the low frequency signal generated by the LPF unit 66 whether or not the camera body 20 is in the panning state. Note that a state that is neither a panning state nor a pan state is determined to be a normal state.

  When it is determined that the normal state is detected, the DC component of the shake detection signal detected by the gyro sensor 28 is removed by the HPF unit 64 and sent to the controller 63 through the addition unit 61 and the gain unit 62 for image blur. The correction device 50 is driven in the normal mode to perform camera shake correction processing.

  On the other hand, if it is determined that the camera is in the panning state, the shake detection signal after the DC component removal generated by the HPF unit 64 is used as the low frequency signal generated by the LPF unit 66 from the shake detection signal detected by the gyro sensor 28. The image blur correction device 50 is driven in the panning mode by replacing it with the subtracted signal and inputting it to the adder 61. When it is determined that the camera is in the pan state, the control target position signal input to the controller 63 is replaced with 0, and the image blur correction device 50 is driven in the pan mode. In the image sensor driving circuit 60 according to the first embodiment, except for the functions related to the configuration of the LPF unit 66 and the panning / pan state detecting unit 67, the image sensor driving circuit 60A having only the pan state detecting unit in FIG. This is the same as the function. The shake detection signal is sampled every control cycle, and the output signal of the LPF unit 66 is calculated, for example, every control cycle and subtracted from the shake detection signal.

  Next, camera shake correction processing according to the first embodiment will be described with reference to FIGS. FIG. 7 is a flowchart showing the overall flow of the camera shake correction processing operation during exposure. The DSP 40 determines whether the power of the camera body 20 is ON or OFF (step S100), and if it is OFF, ends the process. If the power is not OFF, the gyro data G is acquired from the gyro sensor 28 (step S102).

  The gyro data G is input to the image sensor driving circuit 60, and the SR state (normal state, panning state and pan state) is determined according to the procedure of FIG. 8 described later (step S104). Thereafter, it is determined whether or not the release switch of the camera body has been pressed (step S106). If the release switch has not been pressed, the process returns to the determination of whether the power is on or off (step S100) and repeats the same operation. . That is, the gyro data is repeatedly updated at a predetermined timing (for example, an extremely short period, several ms, or several tens of μs). In addition, other operation control (not shown) is processed in parallel. In this embodiment, the acquisition of gyro data is a step before the release operation, but it may be performed immediately before the SR control, or may be performed during continuous shooting where the release ON state is continued. good.

  If the release switch is pressed, camera shake correction (SR) control is started according to the procedure of FIG. 9 described later based on the previously determined SR state (step S108). Thereafter, it is determined whether the image sensor 22 has completed exposure (step S110). If the exposure has not been completed, SR control (step S108) is repeated. If the exposure is completed, the process returns to the determination of whether the power is on or off (step S100) and the same processing is repeated.

  Next, the panning and pan state detection process (step S104) of FIG. 7 will be described with reference to the flowcharts of FIGS.

The image sensor driving circuit 60 inputs the input gyro data G to the LPF unit 66, and generates a low frequency signal G _LPF (step S200). The panning / pan state detection unit 67 determines whether the gyro data G is smaller than the pan state detection threshold L _Pan (step S202). If G <L _{Pan is} not satisfied, the SR state is determined to be a pan state. (Step S210). On the other hand, if G <L _Pan, it is determined whether the low frequency signal G _LPF is smaller than the panning state detection threshold L _Follow (step S204). If G _LPF <L _{Follow, the} SR state is the panning state. It is determined that there is (step S208). If G _LPF <L _Follow , it is determined that the SR state is the normal state (step S206). When the SR state is determined by these processes, the panning and pan state detection process (step S104) in FIG. 7 ends.

  Next, the SR control (step S108) in FIG. 7 will be described with reference to the flowcharts in FIGS.

First, the image sensor drive circuit 60 determines whether or not the camera shake correction (SR) function is ON (step S300). If the SR function is not ON, the control target position signal input to the controller 63 is replaced with 0. The camera shake correction is not performed, and the present process is terminated (step S308). If the SR function is ON, the SR state is determined (step S302). If the SR function is the normal state, the calculation control target position is determined based on the DC component removal signal G _HPF generated by inputting the gyro data G to the HPF unit 64. A normal mode for performing signal calculation is set (step S304). On the other hand, in the panning state, a panning mode is set in which the calculation control target position signal is calculated based on a signal obtained by subtracting the low frequency signal G _LPF from the gyro data G (step S306). In the pan state, the control target position signal input to the controller 63 is replaced with 0 to set a pan mode in which camera shake correction is not performed (step S308).

  As described above, according to the first embodiment, even during a period during which panning is detected, by updating the DC component that is removed when camera shake correction is performed, the shake detection signal can be detected according to the change in angular velocity. It is possible to remove the optimal DC component, and even if the angular velocity of the imaging device or the direction of the panning changes during the panning, the camera shake is accurately corrected and a good image is taken. Can do.

If the gyro data G does not contain a steady DC component due to temperature fluctuations or electrical noise, the gyro data G is input to the adder as it is instead of the DC component removal signal G _HPF in the normal mode to control the operation. The target position signal may be calculated. In the panning mode, instead of the signal obtained by subtracting the low frequency signal G _LPF from the gyro data G, a signal obtained by applying an HPF having a cutoff frequency different from that in the normal mode may be used.

  Next, an imaging apparatus according to a second embodiment of the present invention will be described with reference to the flowcharts of FIGS. The configuration of the imaging device of the second embodiment is different from that of the first embodiment only in the configuration of panning and pan state detection processing, and the other configurations are the same as those of the imaging device of the first embodiment. Therefore, the same reference numerals are used for the same configuration, and the description thereof is omitted.

When the panning and pan detection processing of the second embodiment is started, the image sensor driving circuit 60 inputs the input gyro data G to the LPF unit 66 and generates a low frequency signal G _LPF (step S400). . The panning / pan state detection unit 67 determines whether the gyro data G is smaller than the pan state detection threshold L _Pan (step S402). If G <L _{Pan is} not satisfied, the pan state detection counter C _Pan is incremented. (Step S406). On the other hand, if G <L _Pan , the value of the pan state detection counter C _Pan is reset to 0 (step S404).

Next, it is determined whether or not the low frequency signal G _LPF is smaller than the panning state detection threshold L _Follow (step S408). If G _LPF <L _{Follow is} not satisfied, the value of the pan state detection counter C _Follow is incremented (step S412). ). On the other hand, if G _LPF <L _Follow , the value of the pan state detection counter C _Follow is reset to 0 (step S410).

When the value of the pan state detection counter C _Follow is incremented (step S412) or reset to 0 (step S410), it is determined whether or not the value of the pan state detection counter C _Pan is less than or equal to the pan detection counter threshold value T _Pan (step S414). ), If it is larger than the pan detection counter threshold value T _Pan , the pan state is set assuming that the SR state is the pan state (step S422). On the other hand, when the value of the pan state detection counter C _Pan is equal to or smaller than the value of the pan detection counter threshold value T _Pan , it is determined whether or not the panning state detection threshold value L _Follow is equal to or smaller than the value of the panning detection counter threshold value T _Follow (step S416). ), If the panning state detection threshold L _Follow is large, the panning mode is set assuming that the SR state is the panning state (step S420). If the panning state detection threshold L _Follow is equal to or less than the value of the panning detection counter threshold T _Follow , the normal mode is set assuming that the SR state is the normal state (step S418).

  As described above, according to the configuration of the second embodiment, the gyro data G is easily affected by noise by changing to the pan state and the panning state only when the threshold value is continuously exceeded. It is possible to detect the pan state and the panning state well.

  Next, an image pickup apparatus according to a third embodiment of the present invention will be described with reference to FIGS. The configuration of the imaging apparatus of the third embodiment is different from that of the first embodiment only in the configuration of panning and pan state detection processing, and the other configurations are the same as those of the imaging apparatus of the first embodiment. Therefore, the same reference numerals are used for the same configuration, and the description thereof is omitted.

  In general, when transitioning from a panning state that operates at an angular velocity above a certain level to a stationary state, it takes a certain time for the output signal to stabilize due to the characteristics of the high-pass filter, and extra correction is performed during that period. There is. Therefore, when the transition from the pan state to the stationary state is performed, the time until the signal output of the high-pass filter is stabilized can be shortened by performing reset processing on the HPF unit 64. Therefore, in the third embodiment, the period during which the HPF unit 64 is reset is defined as a reset state.

  In the first embodiment and the second embodiment, the SR state is a normal state, a panning state, and a pan state, and can be freely transitioned to each other. On the other hand, in the third embodiment, four states are obtained by adding a reset state to the normal state, and the transition from the normal state to the panning state and the pan state is enabled. It is possible to transition from the panning state to the normal state and the pan state. Then, it is possible to make a transition only from the pan state to the reset state, and it is possible to make a transition only from the reset state to the normal state. FIG. 11 schematically shows the possible transition directions between the normal state, panning state, pan state, and reset state at this time.

  Next, the panning and pan state detection process of the third embodiment will be described with reference to the flowchart of FIG.

In the imaging apparatus of the third embodiment, when the panning and pan state detection processing in step S104 of FIG. 7 is started, the image sensor drive circuit 60 inputs the input gyro data G to the LPF unit 66, and the low frequency A signal G _LPF is generated (step S500). Next, the current SR state is determined (step S502). If it is determined that the current SR state is the normal state, the next SR state to be transitioned is determined according to the flowchart of FIG. 13 described later (step S504). . On the other hand, if it is determined that the current SR state is the panning state, the next transitioning SR state is determined according to the flowchart of FIG. 14 described later (step S506). If it is determined that the current SR state is the pan state, the SR state to be transitioned to next is determined according to the flowchart of FIG. 15 described later (step S508).

On the other hand, when it is determined that the current SR state is the reset state, the value of the reset state counter C _Reset is incremented (step S510), and the value of the reset state counter C _Reset is greater than the value of the reset state counter threshold value T _Reset. It is determined whether it is smaller (step S512). If the value of the reset state counter C _Reset is larger than the value of the reset state counter threshold T _Reset , the value of the reset state counter C _Reset is reset to 0 (step S514), and the SR state is determined to be the normal state and is normal. A mode is set (step S516), and this process ends. On the other hand, if the value of the reset state counter C _Reset is smaller than the value of the reset state counter threshold T _Reset , the HPF unit 64 is reset (step S518), and this process ends.

  Next, with reference to the flowcharts of FIG. 6 and FIG. 13, the determination process of the SR state (drive mode) of the transition destination in the normal state, which is executed in step S504 of FIG.

First, the panning / pan state detection unit 67 determines whether or not the gyro data G is smaller than the pan state detection threshold L _Pan (step S600), and if G <L _{Pan, the} value of the pan state detection counter C _Pan is determined. Increment (step S614). On the other hand, if G <L _Pan , the value of the pan state detection counter C _Pan is reset to 0 (step S602). Next, it is determined whether the low frequency signal G _LPF is smaller than the panning state detection threshold L _Follow (step S604). If G _LPF <L _{Follow is} not satisfied, the value of the pan state detection counter C _Follow is incremented (step S616). ). On the other hand, if G _LPF <L _Follow , the value of the panning state detection counter C _Follow is reset to 0 (step S606), and it is determined whether or not the value of the pan state detection counter C _Pan is equal to or less than the pan detection counter threshold value T _Pan. (Step S608).

When the value of the panning state detection counter C _Pan is determined to be larger than the pan detection counter threshold T _Pan resets the value of the panning state detection counter C _Pan to 0 (step S622), SR state is judged that the shift to the panning state The pan mode is set (step S624), and the panning and pan state detection processing in FIG. 12 is terminated. On the other hand, if it is determined that the value of the pan state detection counter C _Pan is equal to or smaller than the value of the pan detection counter threshold value T _Pan , it is determined whether or not the panning state detection counter C _Follow is equal to or smaller than the panning detection counter threshold value T _Follow (step S610). ).

If it is determined that the panning state detection counter C _Follow is larger than the value of the panning detection counter threshold T _Follow , the value of the panning state detection counter C _Follow is reset to 0 (step S618). Then, it is determined that the SR state has transitioned to the panning state, and the panning mode is set (step S620), and the panning and pan state detection processing in FIG. 12 ends. If the panning state detection threshold L _Follow is equal to or less than the value of the panning detection counter threshold T _Follow , it is determined that the SR state is maintained in the normal state, and the normal mode is set (step S612). The shooting and pan state detection process ends.

  Next, with reference to the flowcharts of FIGS. 6 and 14, the determination process of the SR state (drive mode) of the transition destination in the panning state executed in step S506 of FIG. 12 will be described.

First, the panning / pan state detection unit 67 determines whether the gyro data G is smaller than the pan state detection threshold L _Pan (step S700). If G <L _{Pan is} not satisfied, the value of the pan state detection counter C _Pan is determined. Increment (step S714). On the other hand, if G <L _Pan , the value of the pan state detection counter C _Pan is reset to 0 (step S702). Next, it is determined whether or not the low frequency signal G _LPF is larger than the non-panning state detection threshold L _noFollow (step S704). If G _LPF > L _{noFollow, the} value of the non-panning state detection counter C _Follow is incremented. (Step S716). On the other hand, if G _LPF > L _noFollow , the value of the non-panning state detection counter C _noFollow is reset to 0 (step S706).

Next, it is determined whether or not the value of the pan state detection counter C _Pan is equal to or less than the pan detection counter threshold value T _Pan (step S708). When the value of the panning state detection counter C _Pan is determined to be larger than the pan detection counter threshold T _Pan resets the value of the panning state detection counter C _Pan to 0 (step S722), SR state is judged that the shift to the panning state The pan mode is set (step S724), and the panning and pan state detection processing in FIG. 12 is terminated. On the other hand, if it is determined that the value of the pan state detection counter C _Pan is equal to or less than the value of the pan detection counter threshold value T _Pan , it is determined whether or not the non- _pan shot state detection counter C _noFollow is greater than the non- _pan shot detection counter threshold value T _noFollow. (Step S710).

When the value of the non-panning shot state detection counter C _noFollow is equal to or less than the non-panning shot detection counter threshold T _noFollow, it is determined that the SR state is maintained in the panning shooting state, and the panning mode is set (step S720). The panning and pan state detection process in FIG. On the other hand, when the non-shot state detection counter C _nofollow is determined to be greater than the value of the non-shot detection counter threshold T _nofollow, the value of non-shot state detection counter C _nofollow reset to 0 (step S718). Then, it is determined that the SR state has transitioned to the normal state, the normal mode is set (step S712), and the panning and pan state detection processing in FIG. 12 is terminated.

  Next, with reference to the flowcharts of FIG. 6 and FIG. 15, the determination process of the SR state (drive mode) of the transition destination in the pan state, which is executed in step S508 of FIG.

First, the panning / pan state detection unit 67 determines whether the gyro data G is larger than the non-pan state detection threshold L _noPan (step S800). If G> L _noPan , the value of the non-pan state detection counter C _noPan is reset to 0 (step S802), the SR state is determined to be maintained in the pan state, and the pan mode is set (step S804). ), Panning and pan state detection processing in FIG.

On the other hand, if G> L _{noPan is} not _satisfied , the value of the non-pan state detection counter C _noPan is incremented (step S806), and whether or not the value of the non-pan state detection counter C _noPan is smaller than the non-pan detection counter threshold value T _noPan. Determination is made (step S808). _If the value of the non-pan state detection counter C _noPan is not smaller than the non-pan detection counter threshold value T _noPan , it is determined that the SR state is maintained in the pan state, the pan mode is set (step S804), and FIG. The panning and pan state detection process ends.

On the other hand, when the value of the non-panning state detection counter C _NoPan is determined to be smaller than the non-pan detection counter threshold T _NoPan, the value of the non-panning state detection counter C _NoPan reset to 0 (step S810), the SR state After the reset state (step S812), the HPF unit 64 is reset, and the panning and pan state detection processing in FIG. 12 is terminated.

  Finally, SR control processing in the third embodiment will be described with reference to the flowcharts of FIGS. 6 and 16.

First, the image sensor driving circuit 60 determines whether or not the camera shake correction (SR) function is ON (step S900). If the SR function is not ON, the control target position signal input to the controller 63 is replaced with 0. The camera shake correction is not performed, and the present process is terminated (step S908). If the SR function is ON, the SR state is determined (step S902). If the SR function is the normal state, the calculation control target position is determined based on the DC component removal signal G _HPF generated by inputting the gyro data G to the HPF unit 64. A normal mode for calculating a signal is set (step S904). On the other hand, if the panning state is set, a panning mode is set in which the calculation control target position signal is calculated based on a signal obtained by subtracting the low frequency signal G _LPF from the gyro data G (step S906). If the pan state or the reset state, the control target position signal input to the controller 63 is replaced with 0 to set a pan mode in which camera shake correction is not performed (step S908).

  As described above, according to the third embodiment, in addition to the operations and effects of the first and second embodiments, the state transition of the normal state, the pan state, the panning state, and the reset state is appropriately changed, Optimal camera shake correction can be performed immediately after the state transition.

10 Digital camera (imaging device)
20 camera body 22 image sensor (image blur correction member)
26 Shooting operation switch 27 Image shake correction operation switch 28 Gyro sensor 30 Shooting lens 40 DSP
50 Image shake correction device (drive mechanism)
51 fixed support substrate 52 movable stage 60 image sensor drive circuit (drive control unit)
61 adder 62 gain unit 63 controller (drive controller)
64 HPF unit 66 LPF unit 67 Panning / pan state detection unit (state determination unit)
C1, C2, C3 Driving coil H1, H2, H3 Hall sensor

Claims (16)

An image sensor that forms a subject light flux that has passed through the imaging optical system as a subject image;
Shake detection means for detecting shake;
An image blur correction member including at least one of an optical element forming at least a part of the imaging optical system and the image sensor;
A drive mechanism that corrects image blur by displacing the imaging position of the subject image on the image sensor by driving the image blur correction member in a direction different from the optical axis of the imaging optical system;
A drive control unit that controls driving of the image blur correction member by the drive mechanism at a constant control cycle based on a control target position and a current position of the image blur correction member;
In an imaging apparatus comprising:
The drive control unit includes a low-pass filter that inputs a shake signal output from the shake detection unit and a state determination unit that determines a moving state of the imaging device,
The state determination unit determines that the imaging device is in a pan state when the shake signal is greater than a first state detection threshold, and if the shake signal is not in a pan state, the state determination unit performs a panning of the imaging device based on an output signal of the low-pass filter. Determining that it is in any state other than the pan state including the state,
The drive control unit calculates the drive amount of the image blur correction member by the drive mechanism according to the state determined by the state determination unit,
The state determination section, the vibration signal is determined and the imaging device when greater than smaller second state detection threshold than the first state detection threshold is in the panning state, the drive control unit, the control The driving amount of the image shake correction member is calculated based on a signal obtained by subtracting the output signal of the low-pass filter calculated for each control period from the shake signal sampled for each period. apparatus.   The image pickup apparatus according to claim 1, wherein image blur correction is not performed when the state determination unit determines the pan state. The drive control unit further includes a high-pass filter that inputs a shake signal output from the shake detection unit,
When the state determination unit determines that it is not in the pan state or the panning state, the state determination unit determines that the state is a normal state, and the drive control unit determines the drive amount of the shake correction member based on the output signal of the high-pass filter. The imaging device according to claim 1, wherein the imaging device according to claim 1 is calculated. In a state other than the pan state, when the level of the shake signal is higher than a first threshold, the state transits to the pan state, and in the pan state, the level of the shake signal is lower than a second threshold. Transition to a state other than the pan state,
The imaging device according to any one of claims 1 to 3, wherein the second threshold value is equal to or less than the first threshold value. When the level of the output signal of the low-pass filter is higher than a third threshold value in a state other than the pan state or the panning state, the pan state is entered, and in the panning state, the output signal of the low-pass filter is changed. Transition to a state other than the pan state or the panning state when the level is less than a fourth threshold;
The imaging apparatus according to any one of claims 1 to 4, wherein the fourth threshold value is equal to or less than the third threshold value. In a state other than the pan state, when the level of the shake signal is continuously higher than the first threshold for a certain time, the state transitions to the pan state. In the pan state, the level of the shake signal continues for a certain time. Transition to a state other than the pan state if it is smaller than the second threshold,
The imaging apparatus according to claim 4, wherein the second threshold value is equal to or less than the first threshold value. In the state other than the pan state or the panning state, when the level of the output signal of the low-pass filter is continuously higher than a third threshold for a certain time, the pan state is entered, and in the panning state, the low pass level of the filter output signal is shifted to the panning state or condition other than the panning state is smaller than the fourth threshold value continuously a certain time,
The imaging apparatus according to claim 5, wherein the fourth threshold value is equal to or less than the third threshold value.   The imaging apparatus according to any one of claims 1 to 7, wherein the imaging apparatus transits only from a pan state to a reset state, and transits from the reset state to a normal state only. An image sensor that forms a subject light flux that has passed through the imaging optical system as a subject image;
A shake detection step for detecting shake;
An image blur correction member including at least one of an optical element forming at least a part of the imaging optical system and the image sensor;
A drive mechanism that corrects image blur by displacing the imaging position of the subject image on the image sensor by driving the image blur correction member in a direction different from the optical axis of the imaging optical system;
A drive control step for controlling driving of the image blur correction member by the drive mechanism at a constant control cycle based on a control target position and a current position of the image blur correction member;
Have
The drive control step, the image pickup apparatus having a low-pass staple filter and condition determination step for inputting a vibration signal output from the shake detection unit,
The state determining step determines that the imaging device is in a pan state when the shake signal is greater than a first state detection threshold, and if not, the imaging device is caused to flow by an output signal of the low-pass filter. It is determined that it is in any state other than the pan state including the shooting state,
The drive control step calculates a drive amount of the image blur correction member by the drive mechanism according to the state determined by the state determination step,
The state determination step determines that the imaging device is in the panning state when the shake signal is greater than a second state detection threshold that is smaller than a first state detection threshold, and the drive control step includes the control An imaging device that calculates a drive amount of the shake correction member based on a signal obtained by subtracting an output signal of the low-pass filter calculated for each control cycle from the shake signal sampled for each cycle. Control method. When the state determining step determines the pan state, image blur correction is not performed.
The method for controlling an imaging apparatus according to claim 9. The drive control step further includes a high-pass filter that inputs a shake signal output from the shake detection step,
In the state determination step, when it is determined that the pan state or the panning state is not determined, it is determined that the state is a normal state, and the drive control step determines the drive amount of the shake correction member based on the output signal of the high-pass filter. ,
The method for controlling an imaging apparatus according to claim 9 or 10, wherein: In a state other than the pan state, when the level of the shake signal is higher than a first threshold, the state transits to the pan state, and in the pan state, the level of the shake signal is lower than a second threshold. Transition to a state other than the pan state,
The method of controlling an imaging apparatus according to claim 9, wherein the second threshold value is equal to or less than the first threshold value. When the level of the output signal of the low-pass filter is higher than a third threshold value in a state other than the pan state or the panning state, the pan state is entered, and in the panning state, the output signal of the low-pass filter is changed. Transition to a state other than the pan state or the panning state when the level is less than a fourth threshold;
The method according to claim 9, wherein the fourth threshold value is equal to or less than the third threshold value. In a state other than the pan state, when the level of the shake signal is continuously higher than the first threshold for a certain time, the state transitions to the pan state. In the pan state, the level of the shake signal continues for a certain time. Transition to a state other than the pan state if it is smaller than the second threshold,
The method according to claim 12, wherein the second threshold value is equal to or less than the first threshold value. In the state other than the pan state or the panning state, when the level of the output signal of the low-pass filter is continuously higher than a third threshold for a certain time, the pan state is entered, and in the panning state, the low pass Transition to a state other than the pan state or the panning state when the level of the output signal of the filter is smaller than the fourth threshold continuously for a certain period of time;
The method according to claim 13, wherein the fourth threshold is equal to or less than the third threshold.   The method according to claim 9, wherein the imaging device transitions only from a pan state to a reset state, and transits from the reset state only to a normal state.

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