JP2010278779A - Imaging device and method for controlling imaging device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce power consumption involved in detecting the posture of an imaging device in a mode in which a photographing operation is not performed. <P>SOLUTION: The imaging device having a first mode for performing a photographing operation and a second mode for performing no photographing operation detects the positions of a correction optical system including an element to be driven to be driven in a direction intersecting an optical axis and the element to be driven, determines, in the first mode, a target position at which the element to be driven should be driven, performs feedback control of a driving means so as to drive the element to be driven to the determined target position in accordance with the detected position of the element to be driven, and detects the posture of the imaging device in accordance with a change in the position of the element to be driven due to gravity acting on the element to be driven. In the second mode, it changes the target position determined so as to come close to the changed position of the element to be driven. A feedback control means performs feedback control of the driving means such that the element to be driven is driven to the target position changed by a changing means. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an imaging apparatus and a method for controlling the imaging apparatus.

  2. Description of the Related Art Conventionally, there has been known an imaging apparatus including a shake correction apparatus that detects a shake of the imaging apparatus and drives a movable body (correction lens and its holding member) that can move so as to correct the image shake caused by the shake. ing. In the shake correction apparatus, an angular velocity sensor is often used for shake detection. In this angular velocity sensor, a vibrating material such as a piezoelectric element is vibrated at a constant frequency, and the force due to the Coriolis force generated by the rotational motion component is converted into a voltage to obtain angular velocity information. Then, the obtained angular velocity is integrated to calculate a shake amount, and based on this shake amount, a correction position control signal is output, and the movable body is driven in a direction to cancel the image shake. Correction is performed.

  In the driving of the movable body, the current position of the movable body is detected as a movable body position signal, and feedback control is performed in which this is fed back and reflected in the corrected position control signal. In general, feedback control uses the following control method called PID control. The D control (differential control) is used to improve the decrease of the gain margin GM and the phase margin PM due to the overcontrol of the P control (proportional control) and to improve the stability of the feedback control. I control (integral control) is used to improve the offset characteristics of feedback control. Feedback control in which these P control, I control, and D control are selected and combined as necessary is called PID control.

  Japanese Patent Application Laid-Open No. 2004-151561 describes that an image pickup apparatus performs image shake correction control and detects the attitude of the image pickup apparatus based on an integral compensation value of PID control used for image shake correction.

JP 2007-57981 A

  Patent Document 1 does not disclose how the imaging apparatus operates when the attitude of the imaging apparatus is detected in a mode in which no shooting operation is performed.

  An object of the present invention is to reduce power consumption associated with attitude detection of an imaging apparatus in a mode in which no imaging operation is performed in the imaging apparatus.

  An imaging apparatus according to one aspect of the present invention is an imaging apparatus having a first mode in which a photographing operation is performed and a second mode in which the photographing operation is not performed, in a direction intersecting the optical axis by a driving unit. A correction optical system including a driven element to be driven, position detection means for detecting the position of the driven element, and determination means for determining a target position to drive the driven element in the first mode; In the first mode, feedback for performing feedback control of the driving means so that the driven element is driven to the determined target position in accordance with the detected position of the driven element. In the second mode, the control means, the attitude detection means for detecting the attitude of the imaging device in accordance with the change in the position of the driven element due to gravity acting on the driven element, Change means for changing the determined target position so as to be close to the position of the driven element after the change, and the feedback control means is changed by the change means in the second mode. The drive means is feedback-controlled so that the driven element is driven to the target position.

  According to the present invention, in the imaging apparatus, it is possible to reduce power consumption associated with the attitude detection of the imaging apparatus in a mode in which no shooting operation is performed.

1 is a block diagram illustrating a configuration of an imaging apparatus according to a first embodiment. The block diagram which shows the structure of the correction lens drive control part of FIG. The block diagram which shows the structure of the image stabilization control part of FIG. The block diagram which shows the structure of the PID control part of FIG. 6 is a flowchart showing the operation of the imaging apparatus according to the first embodiment. FIG. 3 is a conceptual diagram illustrating an operation of the imaging apparatus according to the first embodiment. 9 is a flowchart showing the operation of an imaging apparatus according to the second embodiment. 10 is a timing chart illustrating an operation of an imaging apparatus according to a third embodiment. The perspective view which shows a part of structure of the imaging device which concerns on 4th Embodiment.

  A configuration of the imaging apparatus 100 according to the first embodiment of the present invention will be described with reference to FIG. The imaging device 100 is a digital camera mainly for taking still images. The imaging apparatus 100 has a first mode for performing a photographing operation and a second mode for not performing a photographing operation. The first mode is, for example, a recording mode (photographing mode). The second mode is, for example, a playback mode. Reference numeral 101 denotes a zoom unit, which includes a zoom lens that performs zooming. Reference numeral 102 denotes a zoom drive control unit, which controls the drive of the zoom unit 101. Reference numeral 103 denotes a correction lens (driven element) whose position can be changed with respect to the optical axis. For example, the correction lens 103 is configured to be drivable in a direction intersecting the optical axis (for example, a direction orthogonal to the optical axis). Reference numeral 104 denotes a correction lens drive control unit that controls the drive of the correction lens 103. In addition, the correction lens drive control unit 104 detects the attitude of the imaging apparatus 100 and generates attitude information. The correction lens drive control unit 104 also controls a main clock cycle and a calculation sampling cycle of a calculation processing unit 118a included in the control unit 118 described later. Reference numeral 105 denotes an aperture / shutter unit. Reference numeral 106 denotes an aperture / shutter drive control unit, which controls the drive of the aperture / shutter unit 105. A focus unit 107 includes a lens that performs focus adjustment. Reference numeral 108 denotes a focus drive control unit, which controls the drive of the focus unit 107. Reference numeral 109 denotes an imaging unit that converts a subject image of light that has passed through the optical system OS into an image signal (analog signal). An imaging signal processing unit 110 converts the image signal (analog signal) output from the imaging unit 109 into an image signal (digital signal). An image signal processing unit 111 generates image data by processing the image signal (digital signal) output from the imaging signal processing unit 110 according to the application. Reference numeral 112 denotes a display unit that performs image display as needed based on the image data output from the image signal processing unit 111. Reference numeral 113 denotes a power supply unit that supplies power to the entire system according to the application. An external input / output terminal unit 114 inputs / outputs communication signals and image signals to / from an external terminal (for example, a personal computer). Reference numeral 115 denotes an operation unit for operating the system. Reference numeral 116 denotes a storage unit that stores various data such as image data. Reference numeral 117 denotes an attitude information control unit which provides the attitude information generated by the correction lens drive control unit 104 to the image signal processing unit 111 and the display unit 112. A control unit 118 controls the entire system. The control unit 118 includes an arithmetic processing unit 118a and a changing unit 118b described later. The zoom unit 101, the correction lens 103, the aperture / shutter unit 105, and the focus unit 107 are included in an optical system OS for forming an image of a subject on the imaging surface of the imaging unit 109. The optical system OS may further include other optical elements. The optical system OS and the imaging unit 109 are included in the correction optical system COS.

  Next, a schematic operation of the imaging apparatus 100 having the above configuration will be described. The operation unit 115 includes a shutter release button 115c configured such that the first switch (SW1) 115a and the second switch (SW2) 115b are sequentially turned on in accordance with the pressing amount. The first switch 115a is turned on when the shutter release button 115c is depressed about half, and the second switch 115b is turned on when the shutter release button 115c is pushed down to the end. When the first switch 115a is turned on, the focus drive control unit 108 drives the focus unit 107 to adjust the focus, and the aperture / shutter drive control unit 106 drives the aperture / shutter 105 to obtain an appropriate exposure amount. Set to obtain. For example, the aperture / shutter drive control unit 106 sets the aperture of the aperture / shutter 105 so that an appropriate exposure amount can be obtained, and the charge accumulation time of the photoelectric conversion unit in the imaging unit 109 via the control unit 118. Set. When the second switch 115b is turned on, image data obtained from the image signal generated by the imaging unit 109 is stored in the storage unit 116. The operation unit 115 includes an anti-shake switch 115d that enables selection of a shake correction (anti-shake) mode. When the shake correction mode is selected by the image stabilization switch 115d, the control unit 118 instructs the correction lens drive control unit 104 to perform the image stabilization operation, and the correction lens drive control unit 104 that receives the instruction instructs the image stabilization off. Anti-vibration operation is performed until In addition, the operation unit 115 includes a shooting mode selection switch 115e that allows selection between one of a still image shooting mode and a moving image shooting mode, and changes the operating condition of each actuator in each shooting mode. be able to. The operation unit 115 also includes a reproduction mode selection switch 115f that can select a reproduction mode, and the image stabilization operation is stopped in the reproduction mode. The operation unit 115 also includes a zooming switch 115g for instructing zoom zooming. When there is an instruction for zooming / magnifying by the zooming switch 115g, the zoom drive control unit 102 that has received the instruction via the control unit 118 drives the zoom unit 101 to move the zoom unit 101 to the instructed zoom position. . At the same time, based on the image information processed by each signal processing unit (110, 111) sent from the imaging unit 109, the focus drive control unit 108 drives the focus unit 107 to perform focus adjustment. The posture of the image data from the image signal processing unit 111 is determined by the posture information from the posture information control unit 117, and the image display direction of the display unit 112 is determined.

  Next, the configuration of the correction lens drive control unit 104 will be described with reference to FIG. Reference numeral 201 denotes a sensor unit (shake detection unit) in the pitch direction, and vibration (shake) in the vertical direction (pitch direction) of the imaging apparatus 100 in a normal posture (a posture in which the length direction of the image frame substantially matches the horizontal direction). Is detected. The sensor unit 201 in the pitch direction is an angular velocity sensor, for example. Reference numeral 202 denotes a yaw direction sensor unit (a shake detection unit) that detects vibration in the horizontal direction (yaw direction) of the imaging apparatus 100 in a normal posture. The sensor unit 202 in the yaw direction is an angular velocity sensor, for example. Reference numerals 203 and 204 denote anti-vibration control units (determination means) in the pitch direction and the yaw direction, respectively, and perform anti-vibration control and correction lens position control according to the situation. In the first mode, the image stabilization controllers 203 and 204 respectively determine target positions for driving so as to cancel the shake of the image of the subject due to the shake of the imaging device 100 detected by the sensor units 201 and 202. Then, a corrected position control signal indicating the determined target position is generated. Reference numerals 205 and 206 respectively denote PID control units, which obtain control amounts from correction position control signals in the pitch direction and yaw direction and position signals indicating the position of the correction lens 103, and output position command signals. Reference numerals 207 and 208 denote drive units (drive means), respectively. Based on the position command signals sent from the PID control units 205 and 206, the correction lens 103 crosses the optical axis (for example, a direct direction). To drive. Reference numerals 209 and 210 denote Hall elements (position detection means), which detect the positions of the correction lens 103 in the pitch direction and the yaw direction, respectively. Reference numeral 211 denotes an attitude detection unit that detects the attitude of the imaging apparatus 100.

  Next, position control of the correction lens 103 by the correction lens drive control unit 104 shown in FIG. 2 will be described. In the position control of the correction lens 103, based on a shake signal (angular velocity signal) indicating a shake in the pitch direction and yaw direction of the imaging device 100 from the sensor unit 201 in the pitch direction and the sensor unit 202 in the yaw direction, in each direction. The correction lens 103 is driven. The correction lens 103 is provided with a magnet. The magnetic field of the magnet is detected by the Hall elements 209 and 210, and position signals indicating the position of the correction lens 103 are sent to the PID control units 205 and 206, respectively. The PID control units (feedback control means) 205 and 206 perform feedback control such that these position signals converge on the corrected position control signals sent from the image stabilization control units 203 and 204, respectively. In the first mode, the PID control units 205 and 206 are configured so that the correction lens 103 is driven to the target position determined by the image stabilization control units 203 and 204 according to the detected position of the correction lens 103. Feedback control of the drive units 207 and 208 is performed. In the second mode, the PID control units 205 and 206 perform feedback control of the drive units 207 and 208 so that the correction lens 103 is driven to the target position changed by the changing unit 118b in the control unit 118. Here, the changing unit 118b in the control unit 118 changes the target position determined in the first mode so that it is close to the position of the correction lens 103 after being changed by gravity in the second mode. . Since the position signals output from the Hall elements 209 and 210 have individual variations, the Hall elements 209 and 210 are controlled so that the correction lens 103 moves to a predetermined position with respect to a predetermined correction position control signal. Output adjustment (calibration) needs to be performed in advance. At this time, the PID control units 205 and 206 perform PID control (first feedback control) that combines P control (proportional control), I control (integral control), and D control (differential control). The posture detection unit 211 detects the posture of the imaging apparatus 100 according to a change in the position of the correction lens 103 due to gravity acting on the correction lens 103. For example, when the PID control unit 205 performs PID control (first feedback control), the posture detection unit 211 performs posture detection using an integral compensation value used for PID control. In addition, when the PID control unit 205 performs PD control (second feedback control), the posture detection unit 211 uses a difference amount (deviation amount) between the target position of the correction lens and the detection position detected by the Hall element. Perform detection. The PD control is a control in which I control (integral control) is not performed, that is, P control (proportional control) and D control (differential control) are combined. The image stabilization controllers 203 and 204 are correction position controls that move the position of the correction lens 103 in a direction for correcting image blur based on shake information from the sensor unit 201 in the pitch direction and the sensor unit 202 in the yaw direction. Each signal is output. As a result, even if camera shake or the like occurs in the imaging apparatus 100, image blur can be prevented.

  Next, the configuration of the image stabilization control unit 203 will be described with reference to FIG. Note that the image stabilization control unit 204 has the same configuration, and a description thereof will be omitted. Reference numeral 301 denotes an A / D converter that converts an angular velocity signal from the sensor unit 201 in the pitch direction into a digital signal. Reference numeral 302 denotes a high-pass filter (HPF), which is a filter capable of changing a cutoff frequency for cutting a DC component. 303 is a low-pass filter (LPF) capable of changing the cut-off frequency, and is a filter for converting an angular velocity signal into an angle signal. Reference numeral 304 denotes an HPF and LPF cutoff frequency switching unit. Further, a phase lead filter (PLF) or a phase delay filter (PDF) may be used as necessary. The angular velocity signal input to the image stabilization control unit 203 is subjected to a series of filter processes and is input to the PID control unit 205 as a corrected position control signal.

  Next, the configuration of the PID control unit 205 will be described with reference to FIG. Note that the PID control unit 206 has the same configuration, and a description thereof will be omitted. 401 is an integral compensator (Ki), 402 is a proportional compensator (Kp), and 403 is a differential compensator (Kd). Reference numeral 404 denotes a PID switch, and reference numeral 405 denotes a switch. Reference numeral 406 denotes an integral compensation value reading unit. A deviation reading unit 407 reads a difference amount (deviation amount) between the target position from the image stabilization control unit 203 and the position signal from the hall element 209. In the PID control unit 205, the PID switch 404 operates the changeover switch 405 to selectively execute PID control or PD control. During PID control, the changeover switch 405 is closed. Further, an integral compensation value that is an output value of the integral compensator (Ki) 401 is input to the integral compensation value reading unit 406, and is used for posture detection during PID control. During PD control, the changeover switch 405 is opened. Further, the deviation amount of the deviation reading unit 407 is used for posture detection. Here, the attitude detection will be described. During PD control during exposure, the position of the correction lens 103 from the hall elements 209 and 210 is deviated from the target value from the image stabilization control unit 203 in the direction of gravity due to the weight of the lens. For example, when the imaging apparatus 100 is in the normal position, the lens is deviated downward in the pitch direction due to its own weight due to the influence of gravity. As described above, the direction in which the deviation is generated is determined by the attitude of the imaging apparatus 100, so that the attitude of the imaging apparatus 100 can be determined by reading from the deviation reading unit 410 in the pitch direction and the yaw direction. Next, in the PID control before and after the exposure, the integral compensation value of the PID control acts so as to correct the deviation. Similarly, the lens is subjected to gravity by reading from the integral compensation value reader 406 in the pitch direction and the yaw direction. The direction can be detected because the direction in which it is located is known. Further, the image stabilization control is stopped in the reproduction mode. Specifically, the lens control is performed so that the correction lens stays at a predetermined position without performing the target value calculation in the image stabilization control unit 203. Attitude detection in the playback mode is not performed with image stabilization control, and the attitude detection method is the same as that described above.

  Next, the operation of the imaging apparatus 100 will be described with reference to FIG. In S101, when it is detected that the power of the imaging apparatus 100 is turned on, the process proceeds to S102, and PID control is executed. PID control is performed when the PID switch 404 closes the changeover switch 405. In next step S103, it is determined whether or not the reproduction mode (second mode) is selected by the mode switch included in the operation unit 115. As a result, if the reproduction mode is selected, the process proceeds to S109, and if the reproduction mode is not selected, it is determined that the recording mode (first mode) is selected, and the process proceeds to S104. In S104, it is determined by the mode switch included in the operation unit 115 whether the shake correction mode is on. As a result, if the shake correction mode is selected, the process proceeds to S108, and if the shake correction mode is not selected, the process proceeds to S105. If the shake correction mode is not selected and the process proceeds from S104 to S105, the correction lens 103 is driven and controlled by PID control in which the target position is fixed at the optical axis center position (center fixed). Thereby, center fixation without an offset is attained. In subsequent S106, posture detection is performed at every fixed period T. Here, for example, the period T is 50 msec. In S107, it is determined whether or not the power switch of the imaging apparatus 100 remains on. If the power switch remains on, the process returns to S102 and the following similar operations are repeated. If it is determined in S103 that the shake correction mode is selected, the process proceeds to S108, and the image stabilization control is performed by PID control. When the recording mode is selected as described above, if the playback mode is selected in S103 by the mode switch included in the operation unit 115, the process proceeds to S109. In the reproduction mode, shooting data stored in the storage unit 116 is displayed on the display unit 112, and information on the imaging unit 109 is not displayed. Therefore, it is not necessary to perform shake correction, and the image stabilization control units 203 and 204 stop the arithmetic processing, and perform lens control for PID control with the target position (Target) held at the previous value. In S109, the shake correction is stopped, the target position holds the previous value, and the process proceeds to S110 to perform posture detection. This posture detection is performed at regular intervals T in S110 as in the recording mode. Next, in S111, it is determined whether or not the absolute value of the integral compensation value Evi for PID control is greater than a threshold value Evi_Th. Here, the changing unit 118b in the control unit 118 sets the target position so that the absolute value | Evi | of the integral compensation value becomes smaller when the absolute value | Evi | of the integral compensation value is larger than the first threshold value. The target is changed by the change amount Δ.

  Here, the reason why the target position Target is changed by the change amount Δ when the absolute value | Evi | of the integral compensation value is large will be described. FIG. 6 shows an example of the relationship between the correction lens position (Position) and the integral compensation value Evi in each posture. FIG. 6A shows the relationship between the correction lens position and the integral compensation value Evi when the posture of the imaging apparatus 100 is the normal position and the reverse position. When the correction lens position increases, the integral compensation value Evi increases in proportion. Further, when the posture changes, an offset occurs while the proportional relationship remains unchanged. Here, when the posture changes, the offset changes, but the slope of the proportional relationship is constant. In the relationship between the integral compensation value Evi and the target position Position, the magnitude of the absolute value of the integral compensation value Evi, how the offset occurs in each posture, the magnitude of the inclination, etc. are largely dependent on the structure of the support, It depends on each configuration. The relationship between the integral compensation value Evi and the target position value Position is different in the pitch direction and the yaw direction, but the behavior is the same. Hereinafter, only one axis will be described unless otherwise specified. Here, assuming that the difference between the target position and the current position for the PID control is the deviation amount e, the feedback amount to be output is expressed as in equation (1). Here, the integral compensation value Evi is Ki∫edt.

PIDout = Kp × e + Kd × (de) / (dt) + Ki∫edt (1)
Here, since the correction lens is to be held at a predetermined position in the reproduction mode, the deviation does not occur so much and it becomes close to a steady state. As a result, the integral compensation value Evi is dominant in the PID control output. That is, the integral compensation value Evi for compensating for the force in the direction of gravity applied to the support is dominant in the output to the correction lens. In other words, when the integral compensation value Evi is set to 0, the output is reduced and power is saved. Further, the positive value and the negative value of the integral compensation value Evi represent the forward direction output and the backward direction output, respectively. As the absolute value | Evi | of the integral compensation value increases, the output increases. Here, as can be seen from FIG. 6A, the value of the integral compensation value Evi varies depending on the correction lens position. For example, when the imaging apparatus 100 is at the positive position, the absolute value | Evi | of the integral compensation value increases when the center position is reached, and the absolute value | Evi | of the integral compensation value decreases when the lens position is moved in the positive direction. Similarly, in the case of the reverse position, the absolute value | Evi | of the integral compensation value becomes smaller when the lens position is closer to 0. This state is shown in FIG. In this way, by moving the correction lens position so that the absolute value | Evi | of the integral compensation value becomes small depending on the attitude of the imaging apparatus 100, the correction lens driving power consumption in the reproduction mode can be reduced. FIG. 6C shows an example of the integral compensation value Evi at the center of the correction lens in each posture. Thus, the integral compensation values in the Pitch direction and the Yaw direction differ depending on the posture.

  Returning to the flow of FIG. If the absolute value | Evi | of the integral compensation value is greater than or equal to the first threshold value Evi_Th in S111, the process proceeds to S112. In S112, it is determined whether or not the target position (Target) is within a predetermined range. Here, the predetermined range can be arbitrarily set, and the entire region that can be selected as the target position may be selected or may be set to the vibration-proof movable range. If the target position (Target) is within the predetermined range in S112, the process proceeds to step 113. In S113, the value of the target position is changed by the change amount Δ so that the absolute value | Evi | of the integral compensation value becomes zero. Here, for example, as shown in FIG. 6A, when Evi is negative and | Evi |> Evi_Th at the positive position, the target position is increased by one. This is performed until the absolute value | Evi | of the integral compensation value becomes smaller than the first threshold value Evi_Th or the target position reaches a predetermined range, and the target position is changed so that | Evi | becomes smaller. Similarly, when the imaging apparatus 100 is in the reverse position, when the integral compensation value Evi is positive and the integral compensation value absolute value | Evi |> Evi_Th, the target position value is decreased by one. In this way, by performing feedback control to increase / decrease the target position so that the absolute value | Evi | of the integral compensation value approaches 0, the driving power of the correction lens can be suppressed without being affected by the attitude of the imaging apparatus 100. Can do. Here, the change amount Δ may be a fixed value such as ± 1, or may be changed in accordance with the value of the integral compensation value Evi. If | Evi | <Evi_Th in S111, and if the target position is out of the predetermined range in S112, the process proceeds to S114 to hold the previous target position.

  Here, assuming that image blur correction control as described in Patent Document 1 is performed in order to perform posture detection even in the second mode (for example, reproduction mode) in which no shooting operation is performed, a correction lens is assumed. The energy for driving the movable body such as is increased more than necessary. Thereby, the power consumption accompanying the attitude | position detection process in a 2nd mode increases more than necessary.

  On the other hand, according to the present embodiment, the driving power of the correction lens can be further reduced by performing feedback control of the target position so that the absolute value | Evi | of the integral compensation value becomes 0 in the reproduction mode. it can. Thereby, the power consumption accompanying the attitude | position detection process of reproduction | regeneration mode can be reduced.

  Next, the imaging device 100 according to the second embodiment will be described with reference to FIG. The circuit configuration of the imaging apparatus 100 according to the second embodiment is the same as the configuration of the first embodiment. Below, it demonstrates centering on a different part from 1st Embodiment. When the power is turned on in S201, it is determined whether or not the playback mode is set in S202. If it is the recording mode, the process proceeds to S203 and PID control is performed. If it is in the playback mode, the process proceeds to S209, the shake correction is stopped, and PD control is performed in S210. The output in PD control is expressed by equation (2).

PDout = Kp × e + Kd × (de) / (dt) (2)
From equation (2), if the proportional compensation coefficient P is small in the steady state, the target position cannot be tracked and an offset occurs, indicating a certain deviation amount e. In the PD control, the deviation amount e is proportional to the driving output of the correction lens. Therefore, if the deviation amount e decreases, the driving output decreases. Therefore, the target position is changed so that the deviation amount e becomes small.

  Referring to the flowchart of FIG. 7, posture detection is performed in S <b> 211, and then in S <b> 212, the magnitude of the deviation amount e is compared with a second threshold value e_Th. The second threshold value e_Th is arbitrarily set (for example, e_Th = 5). If the absolute value | e | of the deviation amount is equal to or greater than the second threshold value e_Th, the process proceeds to S213 to determine whether the target position is within a predetermined range. If the target position is within the predetermined range, the change amount Δ is changed (S214). This is performed until the absolute value | e | of the deviation amount becomes smaller than the second threshold value e_Th or the target position reaches a predetermined range, and the target position is set so that the absolute value | e | of the deviation amount becomes smaller. Change it. In this way, the target position is feedback-controlled so that the absolute value | e | of the deviation amount becomes zero. Here, as in the PID control, the change amount Δ may be a fixed value such as ± 1, or may be changed in accordance with the value of the deviation amount e. If the absolute value | e | of the deviation amount is less than the second threshold value e_Th in S212, and if the target position is out of the predetermined range in S213, the process proceeds to S215, and the previous target position is held.

  According to the second embodiment described above, the driving power of the correction lens can be further reduced by performing feedback control of the target position so that the absolute value | e | of the deviation amount becomes 0 in the reproduction mode. Thereby, the power consumption accompanying the attitude | position detection process of reproduction | regeneration mode can be reduced. Here, the integral compensation value Evi in the PID control and the deviation amount e in the PD control represent the same offset component. It is only described that the parameters used in the first embodiment and the second embodiment differ depending on the control method.

  In the first embodiment and the second embodiment, the drive loop gain of the correction lens is lowered. That is, the imaging apparatus further includes a gain control unit 118c (see FIG. 1) that controls the gains of the PID control units 205 and 206 so that the gain in the second mode is smaller than the gain in the first mode. Good. Methods for lowering the loop gain are shown in equations (3) and (4), respectively. Here, Gain is a coefficient applied to the output of PID control or PD control and represents a decimal number of 1 or less.

PIDout = (Kp × e + Kd × (de) / (dt) + Ki∫edt) × Gain (3)
PDout = (Kp × e + Kd × (de) / (dt)) × Gain (4)
Thereby, since the offset amount between the target position and the lens position increases, the integral compensation value Evi and the deviation amount e can be increased, and the power consumption of the imaging apparatus can be further reduced.

  Next, the imaging device 100 according to the third embodiment will be described. The circuit configuration of the imaging apparatus 100 according to the third embodiment is the same as the configuration of the first embodiment. Below, it demonstrates centering on a different part from 1st Embodiment. FIG. 8 shows the frequency of the main clock and the frequency of the sampling pulse for calculation in the calculation processing unit for shake correction control in each state. FIG. 8A shows the operation of the imaging apparatus in the recording mode (first mode). In the recording mode, since shake prevention is performed, a gyro process for setting a target value is performed in addition to the shift lens control and the attitude detection process. FIG. 8B shows the operation of the imaging apparatus in the reproduction mode (second mode). Since the shake correction is stopped in the playback mode, the gyro process is not performed. Therefore, the calculation load is reduced, and processing can be performed even if the frequency of the main clock is lowered. Further, FIG. 8C shows another operation of the imaging apparatus in the reproduction mode (second mode). In FIG. 8C, the frequency of the main clock is further lowered by lowering the frequency of the calculation sampling pulse for shake correction. This is a possible operation in the playback mode because it does not require high-speed arithmetic processing unlike the recording mode. However, in this case, since the parameter value of the digital filter or the like needs to be changed by changing the frequency of the sampling pulse, it is necessary to set the parameter value according to the changed frequency. That is, the imaging apparatus controls the frequency of the clock signal to be supplied to the PID control units 205 and 206 so that the frequency of the clock signal in the second mode is lower than the frequency of the clock signal in the first mode. A part 118d (see FIG. 1) is further provided.

  Thus, by reducing the frequency of the main clock in the reproduction mode, it is possible to reduce the power consumption of the IC (PID control unit). As a result, the overall power consumption can be further reduced together with the reduction of the power consumption of the drive system (drive unit) performed in the first and second embodiments.

  Next, an imaging apparatus 900 according to the fourth embodiment will be described. Below, it demonstrates centering on a different point from 1st Embodiment-3rd Embodiment. In each of the above embodiments, the correction lens 103 is used as a configuration for correcting image blur. However, in this embodiment, shake correction is performed by moving on a plane perpendicular to the variable apex angle prism or the optical axis. An imaging unit 109 is used. For example, in the case of the imaging unit 109 that performs shake correction by moving on a plane perpendicular to the optical axis, the configuration shown in FIG. 9 can be used. Reference numeral 109 denotes an imaging unit (driven element), reference numerals 901 and 902 denote driving coils (driving means), and reference numerals 903 and 904 denote hall elements (position detecting means) for detecting the position of the movable part. The optical system OS and the imaging unit 109 are included in the correction optical system COS. Reference numerals 905, 906, 907, and 908 denote magnets. Reference numeral 909 denotes a first holding portion, 910 denotes a first guide portion provided on the first holding portion 909, 911 denotes a second holding portion, and 912 denotes a second holding portion 911. A second guide portion 913 provided in the third portion indicates a third holding portion fixed to the housing. Reference numeral 914 denotes a first elastic body provided between the first holding part 909 and a fixing part (not shown). Reference numeral 915 denotes a first elastic part provided between the second holding part 911 and a fixing part (not shown). The 2nd elastic body made is shown. The direction guided by the first guide unit 910 and the direction guided by the second guide unit 912 are orthogonal to each other. In addition, the first holding unit 909 provided with the imaging unit 109 is elastically supported by the first elastic body 914 and the second elastic body 915. With this configuration, the imaging unit 109 can be moved along a plane that intersects the optical axis (for example, an orthogonal plane), and the correction lens 103 included in the optical system OS is substantially moved. The same image stabilization control function as that in the above-described embodiments can be realized.

Claims (7)

An imaging apparatus having a first mode for performing a photographing operation and a second mode for not performing the photographing operation,
A correction optical system including a driven element driven in a direction intersecting the optical axis by a driving unit;
Position detecting means for detecting the position of the driven element;
Determining means for determining a target position to drive the driven element in the first mode;
In the first mode, feedback control for performing feedback control of the driving means so that the driven element is driven to the determined target position according to the detected position of the driven element. Means,
Posture detecting means for detecting the posture of the imaging device according to a change in the position of the driven element due to gravity acting on the driven element;
Changing means for changing the determined target position so as to be close to the position of the driven element after the change in the second mode;
With
In the second mode, the feedback control unit performs feedback control of the driving unit so that the driven element is driven to the target position changed by the changing unit. . Further comprising shake detection means for detecting shake of the imaging device;
The imaging apparatus according to claim 1, wherein the determination unit determines the target position based on an output of the shake detection unit. The feedback control is
A first feedback control that combines proportional control, integral control, and differential control according to a deviation amount that is a difference between the position of the driven element and the target position;
A second feedback control that combines proportional control and differential control according to the deviation amount;
Including
When the first feedback control is performed by the feedback control unit, the posture detection unit detects the posture of the imaging device according to an integral compensation value used for integral control according to the deviation amount, and The imaging apparatus according to claim 1, wherein, when the second feedback control is performed by a feedback control unit, an attitude of the imaging apparatus is detected according to the deviation amount. The changing means changes the determined target position so that the absolute value of the integral compensation value is smaller than a first threshold when the first feedback control is performed by the feedback control means, When the second feedback control is performed by a feedback control unit, the determined target position is changed so that an absolute value of the deviation amount in the second mode is smaller than a second threshold value. The imaging apparatus according to claim 3. The gain control means for controlling the gain of the feedback control means is further provided so that the gain in the second mode is smaller than the gain in the first mode. The imaging apparatus according to item 1. Frequency control means for controlling the frequency of the clock signal to be supplied to the feedback control means so that the frequency of the clock signal in the second mode is lower than the frequency of the clock signal in the first mode; The imaging device according to any one of claims 1 to 5, wherein Control method for an imaging apparatus having a correction optical system including a driven element driven in a direction intersecting the optical axis by a driving unit, a first mode for performing a photographing operation, and a second mode for not performing the photographing operation Because
A position detecting step for detecting a position of the driven element;
A determination step of determining a target position at which the driven element is to be driven in the first mode;
In the first mode, feedback control for performing feedback control of the driving means so that the driven element is driven to the determined target position according to the detected position of the driven element. Steps,
A posture detection step of detecting a posture of the imaging device in accordance with a change in position of the driven element due to gravity acting on the driven element;
In the second mode, a changing step of changing the determined target position so as to be close to the position of the driven element after the change;
With
The feedback control step performs feedback control of the driving means so that the driven element is driven to the target position changed by the changing step in the second mode. Control method.

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