JP2005202018A - Image blur correcting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image blur correcting device capable of speedily and accurately discriminating between pan/tilt operation and vibration to be corrected by detecting that the pan/tilt operation is performed by detecting the shake of an optical system by an angular velocity sensor and detecting the direction of the acceleration of the vibration of the optical system and the increase/decrease therein based on angular velocity detected by the angular velocity sensor. <P>SOLUTION: A vibration-proof lens 10 is displaced based on an angular velocity signal from the angular velocity sensor 14 to correct the image blur. When both a one-stage differential value and a two-stage differential value of the angular velocity signal are positive or negative, a pan/tilt detection part 38 judges that the pan/tilt operation is performed, and stops the image blur correction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an image shake correction apparatus, and more particularly to an image shake correction apparatus that corrects (prevents) image shake of a camera due to vibration.

  For example, as an image blur correction device for a television camera, when an anti-vibration lens is arranged in a photographing optical system so as to be movable within a plane perpendicular to the optical axis, and vibration is applied to the camera (camera photographing optical system), the vibration is reduced. There is known a lens in which an image stabilizing lens is corrected by driving an anti-vibration lens with an actuator in a direction to cancel. In such an image shake correction apparatus, vibration applied to the camera is detected by a shake detection sensor (such as an angular velocity sensor or an acceleration sensor), and the image shake is corrected based on the shake signal output from the shake detection sensor. The amount of displacement of the anti-vibration lens is required (for example, see Patent Document 1).

  In addition, the shake signal from the shake detection sensor includes not only signals caused by vibration to be corrected such as camera shake, vibration transmitted from the ground, and shake due to wind, but also intentional actions of the photographer such as pan operation and tilt operation. The signal etc. resulting from camera operation are also included. For this reason, if image blur correction is simply performed based on the shake signal, image blur correction is performed even when the camera is performing pan / tilt operation. Therefore, image blur (shake back) occurs immediately after the pan / tilt operation is stopped. This causes a sense of incongruity in camera operation and video.

Therefore, in Patent Document 2, it is automatically determined whether or not the shake signal output from the shake detection sensor is generated by the pan / tilt operation, that is, whether the pan / tilt operation is performed. It has been proposed to stop the image blur correction when the / tilt operation is performed. According to this, when a shake signal indicating a shake in the same direction is detected for a certain time or more, it is determined that a pan / tilt operation is being performed. There are many proposals regarding processing when it is determined that the pan / tilt operation is performed. For example, Patent Document 3 proposes such processing.
JP 2002-229089 A JP-A-5-142614 Japanese Patent No. 3186219

  However, in the conventional method for detecting the pan / tilt operation, in order to more accurately determine the vibration to be corrected and the pan / tilt operation, the time required to determine the pan / tilt operation tends to increase. . For example, in the case of Patent Document 2, in order to determine the pan / tilt operation, it is a condition that the shake signal is continuously displaced during a predetermined determination time. In order to accurately determine the operation, it is necessary to lengthen the determination time as a condition.

  If the time required for determining the pan / tilt operation becomes longer in this way, the image blur correction is effective for a while after the pan / tilt operation starts, and the screen does not move and the pan / tilt operation is determined. There is a problem of causing unnaturalness that the screen suddenly starts to move from when image blur correction is stopped.

  On the other hand, if an attempt is made to shorten the time required for determining the pan / tilt operation, there is a high possibility that the pan / tilt operation is determined even for a slightly larger vibration. If the pan / tilt operation is erroneously determined for the vibration to be corrected, there is a problem that image blur correction is stopped and image blur occurs.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an image blur correction apparatus that can accurately determine whether pan / tilt operation is performed at high speed.

  In order to achieve the object, an image shake correction apparatus according to claim 1 is an image shake correction apparatus that corrects an image shake caused by a shake of an optical system that forms an image. Pan / tilt detection means for detecting increase / decrease and detecting that the pan / tilt operation of the optical system is performed based on the detected acceleration direction and increase / decrease, and pan / tilt detection by the pan / tilt detection means Correction stop means for stopping correction of image blur when it is detected that an operation is being performed.

  According to the present invention, since the pan / tilt operation can be detected based on the state of acceleration of the shake of the optical system, the pan / tilt operation and the vibration to be corrected can be accurately determined at high speed.

  According to a second aspect of the present invention, in the image blur correction apparatus according to the first aspect, the pan / tilt detection means may perform first-order differentiation of the shake speed in order to detect a direction of acceleration of the shake. To obtain a value obtained by second-order differentiation of the shake speed in order to detect increase / decrease in acceleration of the shake, a value obtained by first-order differentiation of the shake speed is positive, and The determination condition is that the value obtained by second-order differentiation of the speed is positive, or that the value obtained by first-order differentiation of the shake speed is negative and the value obtained by second-order differentiation of the shake speed is negative. When the determination condition is satisfied, it is determined that the pan / tilt operation of the optical system is performed. That is, whether the shake speed is changing while increasing acceleration in the positive direction or the negative direction is detected by the value of the first and second derivative of the shake speed, and if applicable, the pan / tilt operation is performed. Judge that

  According to a third aspect of the present invention, in the image blur correction device according to the first aspect, the pan / tilt detecting means is configured to detect the direction of acceleration of the shake at a predetermined time of the shake speed. In order to detect an increase / decrease in the shake acceleration, a plurality of the change amounts are acquired at different times, the change rate of the shake speed is positive, and the change amount increases with time. Or if the change amount of the shake speed is negative and the change amount decreases with time, and the determination condition is satisfied, the pan / tilt of the optical system is satisfied. It is characterized by determining that the operation is being performed. That is, whether or not the shake speed is changing while increasing acceleration in the positive direction or the negative direction is detected based on the change amount of the shake speed, and if applicable, it is determined that the pan / tilt operation is being performed. When the speed change amount is negative, the change amount decreasing means that the absolute value of the change amount is increasing.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, an angular velocity sensor is provided that detects a shake speed of the optical system. In Claims 2 and 3, the differential value and change amount of the shake speed are obtained based on the output value of the angular velocity sensor.

  According to a fifth aspect of the present invention, in the image blur correction device according to the second or third aspect of the invention, the pan / tilt detection means is configured such that the determination condition is repeated a predetermined number of times or for a predetermined time. If it is satisfied, it is determined that the pan / tilt operation of the optical system is being performed. According to the present invention, the certainty of determination is improved compared to determining that the pan / tilt operation is being performed when the determination condition is satisfied only once.

  According to the image shake correction apparatus of the present invention, the pan / tilt operation and the vibration to be corrected can be accurately discriminated at high speed.

  A preferred embodiment of an image blur correction apparatus according to the present invention will be described below in detail with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram showing an embodiment of an image blur correction apparatus according to the present invention. The image blur correction device is mounted, for example, on a television camera lens device (photographing lens), a movie camera, a still camera, or the like. The image stabilization lens 10 shown in FIG. In an optical system such as a camera, it is arranged so as to be movable up and down (vertical direction) and left and right (horizontal direction) in a plane perpendicular to the optical axis. The anti-vibration lens 10 is driven up and down or left and right by a motor 12, and when vibration occurs in the camera (optical system), a position where image stabilization is prevented by the motor 12. It moves to (position to cancel vibration). Note that when the vibration-proof lens 10 moves vertically and horizontally, the field angle range formed by the optical system is displaced vertically and horizontally. Further, since the anti-vibration lens 10 is driven in the same manner based on vibration generated in each direction in both the vertical direction and the horizontal direction, the direction shown in the figure is one direction (hereinafter, the horizontal direction (pan direction)). Only the configuration for performing image blur correction with respect to is shown, and the configuration is the same for other directions.

  An angular velocity sensor 14 shown in the figure is a gyro sensor, for example, and is used as a shake detection sensor for detecting vibrations of the optical system. The angular velocity sensor 14 is installed, for example, on the upper surface of the lens barrel, detects the angular velocity of vibration in the left-right direction of the lens barrel, and outputs an electric signal having a voltage corresponding to the detected angular velocity. A signal output from the angular velocity sensor 14 is hereinafter referred to as an angular velocity signal.

  The angular velocity signal output from the angular velocity sensor 14 is branched into two lines, and one of them is converted into a digital signal by the A / D converter 16 after low frequency noise is removed by the high pass filter 15. And it is given to CPU24. On the other hand, the angular velocity signal output from the angular velocity sensor 14 is directly converted into a digital signal by the A / D converter 18 and supplied to the CPU 24.

  The processing contents of the CPU 24 will be described later. From the CPU 24, a position command signal indicating the displacement of the image stabilizing lens 10 as a target, that is, a displacement amount with respect to the reference position of the image stabilizing lens 10 is output to the D / A converter 26. It has come to be. The position command signal output to the D / A converter 26 is input to the adder 30 after being converted into an analog voltage signal. The reference position of the anti-vibration lens 10 is, for example, the center of the movable range (center of shake), and the signal value indicating the position at that time is zero. However, the reference position may not be the center of deflection.

  The adder 30 is supplied with a voltage signal from a potentiometer 28 that detects the rotational position of the motor 12 as a position signal indicating the current position of the image stabilizing lens 10, and receives a position command signal from the CPU 24 and a position from the potentiometer 28. A voltage signal indicating a difference from the signal is generated. The voltage signal is supplied to an amplifier (servo amplifier) 32.

  The amplifier 32 amplifies the voltage signal supplied from the adder 30 with a predetermined gain and applies the amplified signal to the motor 12. As a result, the motor 12 is driven so that the voltage signal supplied from the adder 30 becomes zero, and the image stabilizing lens 10 moves to the position commanded by the position command signal from the CPU 24.

  Next, processing of the CPU 24 will be described. The block of the CPU 24 in FIG. 1 shows functional blocks corresponding to each process performed by the CPU 24, and the process of the CPU 24 will be described as the process of each functional block.

  In the CPU 24, only the low frequency component is extracted from the angular velocity signal given from the A / D converter 16 by the low pass filter 34. This process corresponds to the process of integrating the angular velocity signal. The low-pass filter 34 can be changed in filter characteristics (frequency characteristics) by changing parameters, and the filter characteristics can be changed by characteristic control of a pan / tilt detector 38 described later.

  The signal that has passed through the low-pass filter 34 is amplified with a predetermined gain by the gain unit 36, and the signal is output to the D / A converter 26 as the position command signal.

  By such processing of the CPU 24, based on the angular velocity signal given from the A / D converter 16, the position of the image stabilizing lens 10 for correcting (preventing) image blur with respect to vibration applied to the camera, that is, Then, a position command signal indicating the amount of displacement with respect to the shake center of the image stabilizing lens 10 is obtained and output to the D / A converter 26.

  On the other hand, the angular velocity signal given from the A / D converter 18 is read by the pan / tilt detector 38. The pan / tilt detector 38 that has read the angular velocity signal detects a pan / tilt operation (pan / tilt operation) based on the angular velocity signal. That is, whether or not the shake detected by the angular velocity sensor 14, that is, the angular velocity signal output from the angular velocity sensor 14, is caused by the pan / tilt operation of the optical system due to the pan / tilt operation of the operator. to decide.

  The details of the pan / tilt motion detection process will be described later. When the pan / tilt detector 38 has not detected the pan / tilt motion, the angular velocity sensor 14 is used as a parameter for setting the filter characteristics of the low-pass filter 34. A value for effectively performing image blur correction is set for the vibration (angular velocity signal) detected by. For example, the low-pass filter 34 is set to a filter characteristic for appropriately integrating the angular velocity signal in the frequency band of vibration to be corrected.

  On the other hand, when a pan / tilt operation is detected, a value for stopping image blur correction is set as a parameter of the low-pass filter 34. For example, the low-pass filter 34 is set to a filter characteristic that cuts off the frequency component of the angular velocity signal due to the pan / tilt operation, and the vibration-proof lens 10 is returned to the center of vibration and stopped.

  Here, when the pan / tilt operation is detected, the filter characteristic of the low-pass filter 34 is at least for stopping image blur correction for an angular velocity signal having a frequency component that is considered to be caused by the pan / tilt operation. Well, it may be set to a characteristic for performing image blur correction for an angular velocity signal (an angular velocity signal due to vibration to be originally corrected) of a frequency component considered not to be caused by pan / tilt operation, The characteristic for stopping the image blur correction may be set for the angular velocity signal of the frequency component. The filter characteristic for stopping the image blur correction may be, for example, a characteristic for cutting off the angular velocity signal input to the low-pass filter 34 to make the output zero, and immediately returning the anti-vibration lens 10 to the center of shake and stopping it. Alternatively, the characteristics may be such that when the pan / tilt operation is detected, the vibration-proof lens 10 is gradually returned to the center of shake.

  Note that the processing for stopping the image blur correction when the pan / tilt operation is detected is not limited to the above-described case, and may be another processing method. Further, in this specification, when the image shake correction is simply stopped, it means that the image shake correction for the shake (angular velocity signal) caused by the pan / tilt operation is stopped, and the vibration to be originally corrected is not corrected. It is assumed whether or not image blur correction is stopped.

  Next, the pan / tilt operation detection process in the pan / tilt detector 38 will be described in detail. First, the principle will be described. FIGS. 2A and 2B show general waveforms of angular velocity signals detected by the pan / tilt operation, and FIGS. 3A and 3B should be corrected. 2 shows a general waveform of an angular velocity signal detected by vibration. FIGS. 2A and 3A show a case where the optical system moves rightward (positive direction) immediately after time 0, for example. As can be seen by comparing these graphs, panning is performed. In the / tilt operation, the acceleration (angular acceleration) increases from the time when the angular velocity is 0 (the start time of the pan / tilt operation), whereas in the case of vibration, the acceleration is maximum and the angular velocity increases at the time when the angular velocity is 0. There is a feature that acceleration decreases with time.

  That is, when the angular velocity signal y is changing in the positive direction (when the optical system is moving in the positive direction), if the second-order differential value y ″ of the angular velocity signal y is positive, the pan / tilt operation is performed. If it is negative, it can be determined that vibration (vibration to be corrected) has occurred, and if the value y ′ of the first derivative of the angular velocity signal y is positive, it can be determined. For example, it can be determined that the optical system is moving in the positive direction (for example, right direction or upward direction). If the optical system is negative, the optical system is in the negative direction (for example, left direction or downward direction). Judgment can be made.

  On the other hand, when the angular velocity signal y changes in the negative direction (when the optical system moves in the negative direction), the horizontal axis (time axis) in FIGS. 2 (A) and 3 (A) respectively. As shown in FIGS. 2B and 3 which are symmetrical graphs, if the second-order differential value y ″ of the angular velocity signal y is negative, it is determined that the pan / tilt operation is being performed. If it is positive, it can be determined that vibration has occurred.

  Therefore, the pan / tilt detection unit 38 performs pan / tilt detection processing for detecting whether or not the pan / tilt operation is performed by detecting the acceleration direction and increase / decrease of the angular velocity signal acquired from the angular velocity sensor 14. Has been done.

  Next, a first embodiment of pan / tilt detection processing in the pan / tilt detector 38 will be described. The pan / tilt detector 38 acquires the first-order differential value and the second-order differential value based on the angular velocity signal acquired from the angular velocity sensor 14, for example, using a differential processing means such as a high-pass filter, and the first-order differential value of the angular velocity signal. Whether the pan / tilt operation is being performed is determined based on whether the value of the second derivative is positive or negative.

  A specific processing procedure in the pan / tilt detector 38 will be described with reference to the flowchart of FIG. First, when the processing of this flowchart is started, it is assumed that the filter characteristic of the low-pass filter 34 is set to a characteristic for executing image blur correction and the image blur correction is being executed. First, the pan / tilt detection unit 38 acquires an angular velocity signal from the angular velocity sensor 14, and determines whether or not the value (angular velocity) y of the angular velocity signal at that time satisfies the condition of y = 0 (step S10). . While the determination is NO, the process of step S10 is repeated.

  If YES is determined in step S10, then the count value n is initialized (n = 0) (step S12), and the first-order differential value y 'of the angular velocity y and the angular velocity y are differentiated by the differential processing means. Is obtained (step S14). The first-order derivative value y 'and the second-order derivative value y "of the angular velocity y are based on the angular velocity signal obtained from the angular velocity sensor 14. Sequentially updated to the latest value.

  Next, it is determined whether or not y ′ and y ″ acquired in step S14 satisfy the conditions (y ′> 0) and (y ″> 0) (step S16). That is, as shown in FIG. 2A, it is determined whether or not the waveform of the angular velocity signal at the time of pan / tilt operation when the angular velocity signal (optical system) is changing in the positive direction is shown.

  If YES is determined in step S16, the differential processing means obtains a first-order differential value y ′ of the angular velocity y and a second-order differential value y ″ of the angular velocity y (step S18). It is determined whether or not y ′ and y ″ satisfy the conditions (y ′> 0) and (y ″> 0) that are the same as those in step S16 (step S20). The count value n is incremented by 1 (ie, n = n + 1) (step S22), and it is determined whether or not the count value n has exceeded a predetermined value N (step S24). While the determination is being made, the process returns to step S18, and the processing from step S18 is repeated.

  If YES is determined in step S24, the pan / tilt detector 38 determines that the pan / tilt operation is being performed, and stops image blur correction (step S26). That is, the filter characteristic of the low-pass filter 34 is set to a characteristic when image blur correction is stopped.

  On the other hand, when it determines with NO in the said step S20, it returns to step S10 and performs the process from step S10 again.

  If NO is determined in step S16, whether or not y ′ and y ″ acquired in step S14 satisfy the conditions (y ′ <0) and (y ″ <0). Determination is made (step S30). That is, as shown in FIG. 2B, it is determined whether or not the waveform of the angular velocity signal during the pan / tilt operation when the angular velocity signal (optical system) changes in the negative direction is shown. If NO is determined, it is determined that the pan / tilt operation is not performed, and the process returns to step S10.

  On the other hand, if YES is determined in step S30, the differential processing means obtains a first-order differential value y ′ of angular velocity y and a second-order differential value y ″ of angular velocity y (step S32). It is determined whether or not these values y ′ and y ″ satisfy the same condition (y ′ <0) and (y ″ <0) as in step S30 (step S34). The count value n is incremented by 1 (ie, n = n + 1) (step S36), and it is determined whether or not the count value n exceeds a predetermined value N (step S38). If NO is determined in step S32, the process returns to step S32 to repeat the processing from step S32.

  If YES is determined in step S38, the pan / tilt detector 38 determines that the pan / tilt operation is being performed, and stops image blur correction (step S26). That is, the filter characteristic of the low-pass filter 34 is set to a characteristic when image blur correction is stopped.

  On the other hand, when it determines with NO in the said step S34, it returns to step S10 and performs the process from step S10 again.

  If YES is determined in step S24 or S38 and image blur correction is stopped in step S26, the pan / tilt detection unit 38 determines whether the pan / tilt operation is subsequently stopped (step S26). S28). Whether or not the pan / tilt operation has stopped is determined, for example, based on whether or not the absolute value of the angular velocity signal from the angular velocity sensor 14 has become smaller than a predetermined threshold. In this case, it is determined that the pan / tilt operation has stopped. Note that the determination of whether the pan / tilt operation has stopped is not limited to this. If YES in step S28, that is, if it is determined that the pan / tilt operation has been stopped, the process returns to the start state and image blur correction is resumed.

  In the flowchart of FIG. 4 described above, even if the determination condition in step S16 or the determination condition in step S30 is satisfied, the pan / tilt operation is not immediately determined thereby, and the same steps as in step S16 are performed. When the determination condition in S20 or the determination condition in step S34 equivalent to step S30 is continuously satisfied a predetermined number of times, the pan / tilt operation is determined. However, the determination condition in step S16 or the determination in step S30 When the condition is satisfied, the pan / tilt operation may be immediately determined. Further, the pan / tilt operation may be determined not when the determination condition is continuously satisfied but when the determination condition is satisfied for a predetermined time or longer.

  In the above embodiment, the angular velocity signal (angular velocity y) obtained from the angular velocity sensor 14 is differentiated to obtain the first and second derivative values y ′ and y ″ of the angular velocity y. 14, an angular acceleration sensor is installed, and the first-order differential value y ′ of the angular velocity y is directly obtained from the angular acceleration sensor, and the second-order differential value y ″ is obtained by differentiating y ′. Also good.

  Next, a second embodiment of the pan / tilt detection process in the pan / tilt detector 38 will be described. In the first embodiment, the pan / tilt operation is detected based on the differential value of the angular velocity signal. In the second embodiment, the pan / tilt operation is detected based on the change amount (difference value) of the angular velocity signal. The pan / tilt detector 38 samples the value of the angular velocity signal from the angular velocity sensor 14 (angular velocity y (n): n is an integer) at regular time intervals, and the angular velocity y (n) sampled at a certain point in time. A difference D (n) = y (n−1) −y (n) from the previously sampled angular velocity y (n−1) is obtained, and the pan / tilt operation is performed by positive / negative and increase / decrease of the value of D (n). Determine whether it is done. For example, when the angular velocity signal changes in the positive direction (when the optical system moves in the positive direction), as shown in FIG. 5A, time t (0) = 0, t ( 1), y (0) = 0, y (1), y (2), y (3) sampled at t (2), t (3) D (1), D (2), D ( If the magnitude relationship of 3) is D (1) <D (2) <D (3), it can be determined that the optical system is moving while increasing the acceleration and the pan / tilt operation is being performed. . On the other hand, as shown in FIG. 5B, if the magnitude relationship of D (1), D (2), and D (3) is D (1)> D (2)> D (3), the optical system is It is moving with decreasing acceleration, and can be determined as vibration to be corrected.

  A specific processing procedure in the pan / tilt detector 38 will be described with reference to the flowchart of FIG. First, similarly to the flowchart of FIG. 4, when the processing of this flowchart is started, the filter characteristic of the low-pass filter 34 is set to a characteristic for executing image blur correction, and the image blur correction is being executed. To do. The pan / tilt detection unit 38 first acquires an angular velocity signal from the angular velocity sensor 14, and determines whether or not the value (angular velocity) y of the angular velocity signal at that time satisfies the condition of y = 0 (step S50). . While the determination is NO, the process of step S50 is repeated.

If it is determined as YES in step S50, next, the angular velocity y is acquired from the angular velocity sensor 14 (step S52). Then, the angular velocity y is substituted into y (1) and D (1) is set to y (1) (step S54). That is,
y (1) = y
D (1) = y (1)
And Further, the count value n is set to 2 (n = 2) (step S56).

  Next, the pan / tilt detector 38 determines whether or not D (1) is greater than 0 (step S58). That is, it is determined whether or not the angular velocity signal is changing in the positive direction.

If it is determined as YES in step S58, the angular velocity y is acquired from the angular velocity sensor 14 (step S60). And the following formula:
y (n) = y
D (n) = y (n) -y (n-1)
To calculate y (n) and D (n) (step S62).

  Subsequently, the pan / tilt detector 38 determines whether D (n) is greater than D (n−1) (step S64). If it is determined YES, the count value n is incremented by 1 (ie, n = n + 1) (step S66), and it is determined whether or not the count value n exceeds a predetermined value N (step S68). While it determines with NO by this step S68, it returns to step S60 and repeats the process from step S60.

  If YES is determined in step S68, the pan / tilt detector 38 determines that the pan / tilt operation is being performed, and stops image blur correction (step S70). That is, the filter characteristic of the low-pass filter 34 is set to a characteristic when image blur correction is stopped.

  On the other hand, when it determines with NO in the said step S64, it returns to step S50 and performs the process from step S50 again.

If NO is determined in step S58, it is determined that the angular velocity signal has not changed in the positive direction, and then the angular velocity y is acquired from the angular velocity sensor 14 (step S74). And the following formula:
y (n) = y
D (n) = y (n) -y (n-1)
To calculate y (n) and D (n) (step S76).

  Subsequently, the pan / tilt detector 38 determines whether D (n) is smaller than D (n−1) (step S78). If YES is determined, the count value n is incremented by 1 (ie, n = n + 1) (step S80), and it is determined whether or not the count value n exceeds a predetermined value N (step S82). While it determines with NO by this step S82, it returns to step S74 and repeats the process from step S74.

  If YES is determined in step S82, the pan / tilt detector 38 determines that the pan / tilt operation is being performed, and stops image blur correction (step S70). That is, the filter characteristic of the low-pass filter 34 is set to a characteristic when image blur correction is stopped.

  On the other hand, when it determines with NO in the said step S78, it returns to step S50 and performs the process from step S50 again.

  If YES is determined in step S68 or step S82 and image blur correction is stopped in step S70, the pan / tilt detector 38 determines whether the pan / tilt operation is subsequently stopped (step S70). S72). Whether the pan / tilt operation has been stopped is determined in the same manner as in FIG. 4. If it is determined that the pan / tilt operation has stopped, the process returns to the start state and image blur correction is resumed.

  In the flowchart of FIG. 6 described above, the pan / tilt operation is determined when the determination condition in step S64 or the determination condition in step S78 is continuously satisfied a predetermined number of times. It may be determined that the pan / tilt operation is satisfied when only the above is satisfied.

  In the above-described embodiment, the case where the image blur is prevented by the anti-vibration lens that is displaced in the plane perpendicular to the optical axis of the optical system has been described. However, the present invention is also applicable to an image blur correction apparatus using another method. it can. For example, the present invention can be applied to an image blur correction apparatus that uses an electronic method that corrects image blur by shifting the range in which a video signal is cut out from an image sensor.

  The present invention can also be applied to image blur correction other than the camera.

FIG. 1 is a configuration diagram showing an embodiment of an image blur correction apparatus according to the present invention. FIG. 2 is a diagram showing a general waveform of the angular velocity signal during the pan / tilt operation. FIG. 3 is a diagram showing a general waveform of the angular velocity signal when the vibration to be corrected is generated. FIG. 4 is a flowchart showing the first embodiment of the pan / tilt detection process. FIG. 5 is an explanatory diagram used for explaining the second embodiment of the pan / tilt detection process. FIG. 6 is a flowchart showing a second embodiment of the pan / tilt detection process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Anti-vibration lens, 12 ... Motor, 14 ... Angular velocity sensor, 15 ... High pass filter, 16, 18 ... A / D converter, 20 ... Zoom position detector, 24 ... CPU, 26 ... D / A converter, 28 ... Potentiometer, 30 ... Adder, 32 ... Amplifier, 34 ... Low-pass filter, 36 ... Gain section, 38 ... Pan / tilt detection section

Claims (5)

In an image shake correction apparatus that corrects image shake caused by shake of an optical system that forms an image,
Pan / tilt detection means for detecting the direction and increase / decrease of acceleration of the shake, and detecting that the pan / tilt operation of the optical system is being performed based on the detected direction and increase / decrease of acceleration;
Correction stop means for stopping correction of image blur when the pan / tilt detection means detects that pan / tilt operation is being performed;
An image blur correction apparatus comprising: The pan / tilt detection means obtains a value obtained by first-order differentiation of the shake speed in order to detect the direction of the shake acceleration, and sets the shake speed to 2 to detect increase / decrease in the shake acceleration. Get the value of the derivative,
The first-order differential value of the shake speed is positive, and the second-order differential value of the shake speed is positive, or the first-order differential value of the shake speed is negative, and 2. A determination condition that a value obtained by second-order differentiation of the shake speed is negative, and it is determined that a pan / tilt operation of the optical system is performed when the determination condition is satisfied. Item 1. The image blur correction device according to Item 1. The pan / tilt detection means obtains a change amount of the shake speed in a predetermined time in order to detect a direction of acceleration of the shake, and varies the change amount in order to detect increase / decrease in the shake acceleration. Get multiple times
The amount of change in the shake speed is positive and the amount of change increases with time, or the amount of change in the shake speed is negative and the amount of change decreases with time. The image blur correction apparatus according to claim 1, wherein the determination is made that the pan / tilt operation of the optical system is performed when the determination condition is satisfied.   4. The image blur correction device according to claim 2, further comprising an angular velocity sensor that detects a blur speed of the optical system.   The pan / tilt detection means determines that the pan / tilt operation of the optical system is performed when the determination condition is satisfied a predetermined number of times or continuously for a predetermined time. The image blur correction device according to claim 2 or 3.

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