JP2005114845A - Vibration detecting device and blurring correcting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a space-saved inexpensive vibration detecting device and a blurring correcting device capable of improving the blurring correcting effect even in the case photographing magnification is high. <P>SOLUTION: In an angular velocity reference value calculating part 81, an angular velocity reference value ω<SB>0</SB>(t) is subtracted from an angular velocity signal ω(t), then, an angular velocity detection signal ω'(t) is generated. In an acceleration reference value calculating part 82, an acceleration reference value a<SB>0</SB>(t) is subtracted from an acceleration signal a(t), then, an acceleration detection signal a'(t) is generated. In a rotation center calculating part 85, a rotation center position signal n'(t) is calculated based on the angular velocity detection signal ω'(t) and a velocity detection signal v(t) calculated by an acceleration integration calculating part 84. In a driving signal calculating part 86, a driving signal (p) for driving a blurring correction lens 110 is calculated based on an angle detection signal θ(t) calculated by an angular velocity integration calculating part 83, the rotation center position signal n'(t) and positional information Ir etc., of the blurring correction lens 110 outputted by a driving part 100. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shake detection apparatus and a shake correction apparatus that correct image blur by moving part or all of a lens with an optical apparatus such as a camera, a lens, a video, and binoculars.

  In recent years, in order to prevent camera shake, the technology of a shake correction device that detects camera shake and moves part of the lens along the camera shake has been established. It is being done.

FIG. 7 is a block diagram showing an outline of a conventional blur correction apparatus. Here, the blur correction device 300 is built in an optical device such as a camera or binoculars, and corrects image blur due to hand shake of a photographer or the like when the optical device is used by hand. It is effective for.
The shake correction apparatus 300 includes, for example, an angular velocity sensor 10, a reference value calculation unit 52, an integration unit 54, a target drive position calculation unit 56, a drive signal calculation unit 58, a position signal output unit 78, and a shake correction lens. 80, a shake correction unit 310, and the like.

  The shake correction unit 310 is a unit that holds and drives the shake correction lens 80 and outputs current position information of the shake correction lens 80 to the position signal output unit 80, for example, a lens that holds the shake correction lens 80. An actuator for driving a shake correction lens 80 including a chamber 82, a yoke 71, a magnet 72, and a coil 73, an infrared light emitting diode (hereinafter referred to as IRED) 74, a slit plate 75, a slit 76, and a PSD (Position Sensitive Device) 77. And an optical position detecting device for detecting the position of the blur correction lens 80.

Next, the operation principle of the shake correction apparatus 300 will be described.
First, the shake of an optical device such as a camera is detected by the angular velocity sensor 10. The angular velocity sensor 10 normally uses a piezoelectric vibration type angular velocity sensor that detects Coriolis force. The output of the angular velocity sensor 10 is transmitted to the reference value calculation unit 52. The reference value calculation unit 52 calculates a shake reference value from the output of the angular velocity sensor 10 and transmits a value obtained by subtracting the reference value from the shake signal that is the output of the angular velocity sensor 10 to the integration unit 54.

  The integrating unit 54 time-integrates the shake signal expressed in the unit of angular velocity and converts it into a shake angle. The target drive position calculation unit 56 drives the shake correction lens 80 based on various information such as a focal length obtained from a zoom encoder, a focusing encoder, etc. (not shown) based on the shake angle transmitted from the integration unit 54. Target drive position information is calculated.

The drive signal calculation unit 58 takes the difference between the target drive position information and the current position information of the shake correction lens 80 in order to drive the shake correction lens 80 in accordance with the target drive position information, and supplies a drive current to the coil 73. Output.
The coil 73 is provided in a lens chamber 82 that holds the shake correction lens 80, and is further disposed in a magnetic circuit formed by the yoke 71 and the magnet 72. For this reason, when a driving current flows through the coil 73, a driving force is generated in the actuator according to Fleming's left-hand rule. The blur correction lens 80 and the lens chamber 82 can be driven in a direction substantially perpendicular to the optical axis I, for example, and the blur correction lens 80 is driven in a direction substantially perpendicular to the optical axis I by the driving force of the actuator. The

  Further, the position of the blur correction lens 80 is monitored by the optical position detection device described above. Specifically, the light emitted from the IRED 74 passes through the slit 76, so that the width of the light beam is reduced and reaches the PSD 77. The PSD 77 is a position detection element that can output a signal corresponding to the position of light on the light receiving surface.

  Since the slit plate 75 is provided in the lens chamber 82, the movement of the blur correction lens 80 corresponds to the movement of the slit 76 and further the movement of light on the light receiving surface of the PSD 77. Accordingly, the position of the light on the light receiving surface of the PSD 77 is equivalent to the position of the shake correction lens 80, and the signal detected by the PSD 77 is fed back to the position signal output unit 78 as current position information of the shake correction lens 80. .

Here, the image blur amount due to the shake of the optical device (for example, camera) provided with the blur correction device 300 will be described in principle.
In general, an image blur amount Di due to camera shake is expressed by the following equation.
Di = Dθ + Dp = βθ (R−n) + βd (1)
In this equation (1), Dθ represents image blur due to angular shake (hereinafter referred to as angle blur), Dp represents image blur due to shift shake (hereinafter referred to as shift blur), β represents a photographing magnification, and θ Is the amount of angular shake, R is the distance from the subject to the imaging plane, n is the distance from the center of angular shake rotation to the imaging plane, and d is the shift shake amount.

As described above, the blur correction apparatus 300 uses the angular velocity sensor 10 to correct image blur, and detects the angular shake amount θ by integrating the output of the angular velocity sensor 10 with the integrating unit 54. Can do.
The shooting magnification β and the distance R from the subject to the imaging surface can be measured from the focal length of the lens, for example. In addition, it is known that the distance n from the rotational center of angular shake to the imaging surface is usually almost no problem even if the value is 0, and n = 0 in Expression (1). Therefore, it is sufficiently possible to correct the angle shake with high accuracy by the conventional shake correction apparatus 300.

Here, the influence of shift blur will be described.
For example, if the distance R from the subject to the imaging surface is large and the imaging magnification β is small, the influence of shift blur can be almost ignored. However, when the distance R from the subject to the imaging surface is small and the imaging magnification β is large, the influence of shift blur cannot be ignored, which causes a reduction in blur correction effect.
Since the shift shake amount d cannot be detected by the angular velocity sensor 10, the shake correction apparatus 300 that performs the shake correction according to the conventional operating principle cannot correct the shift shake.

As a blur correction device considering the effect of this shift blur, for example,
(1) There is one that completely detects the movement of a camera by using an acceleration sensor for three axes and an angular velocity sensor for three axes (for example, Patent Document 1).
(2) There is one in which three-dimensional acceleration sensors are installed apart from each other, and an angular shake amount and a shift shake amount are obtained using the three-dimensional acceleration sensor (for example, Patent Document 2).

However, the blur correction apparatus that takes into account the effects of shift blur described above has the following problems.
(1) The blur correction device using the acceleration sensor for three axes and the angular velocity sensor for three axes completely detects the movement of the camera, so that it can be used not only for blur correction but also for auto focus and the like. However, it is not a practical device due to space problems caused by an increase in the number of sensors and complicated computation.
(2) In a shake correction apparatus using a three-dimensional acceleration sensor, when an error is included in an acceleration component, for example, a slight error is accumulated when integrated twice, so that shift shake can hardly be calculated accurately. The effect of blur correction could not be expected. In addition, two acceleration sensors are required for each axis to be detected, which may cause a problem in space and increase costs.
JP 07-225405 A JP 09-301157 A

  An object of the present invention is to provide a shake detection device and a shake correction device that can improve the effect of shake correction even when the photographing magnification is high, and that are space-saving and inexpensive.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to the Example of this invention is attached | subjected and demonstrated, it is not limited to this. In other words, the invention according to claim 1 is based on the angular velocity detector (10) for detecting the angular velocity of shake, the speed calculator (82, 84) for calculating the velocity of shake, and the angular velocity and the velocity. And a rotation center calculation unit (85) for calculating the rotation center position of the camera.

  According to a second aspect of the present invention, in the shake detection device according to the first aspect of the present invention, the shake detection device further includes an acceleration detection unit (20) that detects an acceleration of the shake, and the speed calculation unit (82, 84) is based on the acceleration of the shake. The shake detection apparatus is characterized by calculating the acceleration reference value and calculating the speed by integrating a value obtained by subtracting the acceleration reference value from the acceleration.

According to a third aspect of the present invention, in the shake detection device according to the second aspect, the rotation center calculation unit (85) determines the distance r (t) from the acceleration detection unit (20) to the rotation center position as the distance r (t). Based on the velocity V (t) and the angular velocity ω (t),
r (t) = V (t) / ω (t)
The shake detection apparatus is characterized by being calculated using

According to a fourth aspect of the present invention, in the shake detection device according to the second aspect, the rotation center calculation unit (85) determines the distance r (t) from the acceleration detection unit (20) to the rotation center position as the value. Based on the constant C for preventing the velocity V (t), the angular velocity ω (t), and the r (t) from diverging,
r (t) = V (t) / (| ω (t) | + C)
However, ω (t) ≧ 0
r (t) = − V (t) / (| ω (t) | + C)
However, ω (t) <0
The shake detection apparatus is characterized by being calculated using

According to a fifth aspect of the present invention, in the shake detection device according to the second aspect, the rotation center calculation unit (85) determines a distance r (t) from the acceleration detection unit (20) to the rotation center position as the distance r (t). Based on the function C {ω (t)} having the variable the angular velocity ω (t) for preventing the divergence of the velocity V (t), the angular velocity ω (t), and the r (t),
r (t) = V (t) / [ω (t) + C {ω (t)}]
The shake detection apparatus is characterized by being calculated using

According to a sixth aspect of the present invention, there is provided a shake detection device according to any one of the first to fifth aspects, a blur correction optical member (110) for optically correcting image blur, and the blur correction optical member. A driving unit (100) for driving (110), a lens eigenvalue of the blur correction optical member (110), a photographing magnification, a first distance between a subject and a surface disposed on the optical axis, and the acceleration detecting unit (20 ) And a second distance between the surface disposed on the optical axis, and an information input unit that measures and / or stores the angular distance, calculates an angular velocity reference value based on the angular velocity, and subtracts the angular velocity reference value from the angular velocity By integrating the obtained values, angle calculation units (81, 83) for calculating angular shake, a position detection unit (100) for detecting the current position of the shake correction optical member (110), and the shake correction optical member (110) Target drive position And a drive control unit (86) for controlling the drive unit (100) based on the current position and the target drive position of the blur correction optical member (110). The target drive position calculation unit (86) includes a target drive position L (t), a distance r (t) from the acceleration detection unit (20) to the rotation center position, and the angular shake θ ( t) and the lens eigenvalue K measured and / or stored by the information input unit, the imaging magnification β, the first distance R, and the second distance D,
L (t) = Kβθ (t) (R−D + r (t))
This is a blur correction device characterized by being calculated using.

  The invention according to claim 7 is the shake correction apparatus according to claim 6, wherein the surface arranged on the optical axis is an imaging surface.

  The shake detection device according to the present invention is (1) based on the angular velocity output from the angular velocity detection unit that detects the angular velocity of shake and the velocity output from the speed calculation unit that calculates the shake speed. Since the rotation center calculation unit for calculating the position is provided, the rotation center position of the shake can be detected in real time, and the calculation load when calculating the rotation center position can be reduced.

(2) Since the speed calculation unit calculates the acceleration reference value based on the acceleration of shake and integrates the value obtained by subtracting the acceleration reference value from the acceleration, the speed calculation unit calculates the acceleration reference value from the acceleration. The value obtained by subtracting the value needs to be integrated only once, the error accumulation can be reduced, the rotation center position can be detected accurately, and the calculation load can be greatly reduced.

(3) The rotation center calculation unit calculates the distance r (t) from the acceleration detection unit to the rotation center position based on the velocity V (t) and the angular velocity ω (t) as follows:
r (t) = V (t) / ω (t)
Therefore, when calculating r (t) from the velocity v (t) and the angular velocity ω (t), a theoretical formula can be applied.

(4) The rotation center calculation unit is based on a constant C for preventing the velocity V (t), the angular velocities ω (t), and r (t) from diverging, from the acceleration detection unit to the rotation center position. And the following formula:
r (t) = V (t) / (| ω (t) | + C)
However, ω (t) ≧ 0
r (t) = − V (t) / (| ω (t) | + C)
However, ω (t) <0
Therefore, divergence of r (t) at ω = 0 can be prevented.

(5) The rotation center calculation unit calculates the distance r (t) from the acceleration detection unit to the rotation center position as the angular velocity ω (t) for preventing the velocity V (t), the angular velocity ω (t), and r (t) from diverging. ) As a variable, based on the function C {ω (t)},
r (t) = V (t) / [ω (t) + C {ω (t)}]
When the absolute value of ω (t) is equal to or greater than a predetermined value, when calculating r (t), the following equation, which is a theoretical formula,
r (t) = V (t) / ω (t)
Can be used.

In the shake correction apparatus of the present invention, (6) the target drive position calculation unit calculates the target drive position L (t), the distance r (t) from the acceleration detection unit to the rotation center position, and the angular shake θ (t). Based on the lens eigenvalue K, the photographing magnification β, the first distance R, and the second distance D measured and / or stored by the information input unit,
L (t) = Kβθ (t) (R−D + r (t))
Thus, the fluctuation of the distance r (t) from the acceleration detection unit to the rotation center position can be calculated in real time, and the target drive position L (t) can be calculated accurately, and the imaging magnification β Even if the magnification is high, the effect of blur correction can be improved.

(7) Since the surface arranged on the optical axis is an imaging surface, the distance from the subject to the imaging surface (film surface) is the first distance, and the distance from the acceleration detector to the imaging surface is the second distance. can do.

  The best mode for carrying out the invention will be described below with reference to the drawings and the like.

FIG. 1 is a block diagram showing an embodiment of a shake correction apparatus 200 according to the present invention. Here, an outline of the camera system will be described focusing on the shake correction apparatus 200. In the present specification, blur correction refers to correction in the pitching direction (X-axis direction) and yawing direction (Y-axis direction).
In FIG. 1, for the shake correction apparatus 200, each member in the X-axis direction (indicated by “a” in the drawing) and each member in the Y-axis direction (in the same manner, “b” in the symbol). However, for the convenience of explanation, the direction is not particularly described in detail.

  As for the camera system, a single-lens reflex camera is assumed here. However, for example, not a replaceable type such as a single-lens reflex camera but a non-replaceable type such as a compact camera may be used. The image recording may be a silver salt film or a digital image sensor such as a CCD. Note that the camera system is shown as an example of an optical apparatus including the shake correction apparatus 200. For example, the shake correction apparatus 200 may be mounted on an appropriate optical device such as a telescope or binoculars.

The shake correction apparatus 200 according to the present embodiment includes a lens barrel 150, a camera body 160 to which the lens barrel 150 is attached, and the like.
The lens barrel 150 includes an angular velocity sensor 10, an acceleration sensor 20, an angular velocity amplification unit 30, an acceleration amplification unit 40, a lens CPU 120, a drive unit 100, a shake correction lens 110, and the like. The lens CPU 120 includes A / D converters 50, 60, and 70, a drive signal calculation unit 80, a D / A converter 90, and the like. The camera body 160 includes a half-push switch SW1, a full-push switch SW2, a half-push timer 130, a power supply unit 140, and the like.

The camera body 160 will be described. The half-press timer 130 is, for example, a timer that is turned on at the same time as the half-press switch SW1 is turned on, and remains on while the half-press switch SW1 is pressed. Even after being turned off, it remains on for a certain period of time.
For example, while the half-press timer 130 is ON, the power supply unit 140 continues to supply power to a place where power is required in the camera system, such as an angular velocity sensor 10 described later. Further, the power supply unit 140 stops the supply of power when the half-press timer 130 is OFF. Therefore, camera vibration can be detected by the angular velocity sensor 10 only when the half-press timer 130 is ON.

The half-push switch SW1 is, for example, a switch that is turned on in conjunction with a half-push operation of a release button (not shown). When this switch is turned on, photometry calculation by an unshown photometry unit, autofocus drive Etc. is started. If the half-press timer 130 is OFF, the half-press timer 130 is turned ON in synchronization with the half-press switch SW1 being turned ON.
The full-press switch SW2 is, for example, a switch that is turned on in conjunction with a full-press operation of a release button (not shown). When this switch is turned on, a series of shooting operations (a shutter using a shutter mechanism (not shown)) Opening and closing, image capturing by an image sensor, etc.).

  The lens barrel 150 will be described. The angular velocity sensor 10 is, for example, a sensor that detects vibration applied to the camera with an angular velocity value, detects the angular velocity using the Coriolis force applied to the angular velocity sensor 10, and outputs the detection result as a voltage signal. The voltage signal output from the angular velocity sensor 10 is transmitted to the angular velocity amplification unit 30. The angular velocity sensor 10 can detect the angular velocity only while the power is supplied from the power supply unit 140.

For example, the angular velocity amplifier 30 amplifies the output of the angular velocity sensor 10 and transmits the amplified angular velocity signal to the A / D converter 50. The reason for amplifying the output of the angular velocity sensor 10 is that the output of the angular velocity sensor 10 itself is generally small, so even if it is digitized by the A / D converter 50 and processed in the lens CPU 120 as it is, the resolution of the angular velocity value is low. For example, it is too low (the angular velocity value per bit is too large), so that accurate vibration detection cannot be performed, and the accuracy of blur correction cannot be raised. Therefore, if the angular velocity signal is amplified in advance before being input to the A / D converter 50, the resolution of the angular velocity value in the lens CPU 120 can be increased (the angular velocity value per bit is reduced), and the accuracy of blur correction is increased. Can be raised.
The angular velocity amplifying unit 30 is provided corresponding to each of the angular velocity sensors 10 (here, two), which not only amplifies the signal but also reduces high frequency noise included in the output of the angular velocity sensor 10. A low-pass filter function may be added.

  The A / D converter 50 converts, for example, an analog angular velocity signal sent from the angular velocity amplification unit 30 into a digital signal, and outputs the angular velocity signal converted into the digital signal to the drive signal calculation unit 80. The A / D converter 50 converts the angular velocity signal into a digital signal, so that arithmetic processing can be performed in the lens CPU 120.

  The acceleration sensor 20 is, for example, a sensor that detects vibration applied to the camera by an acceleration value, detects the detected acceleration, and outputs the detection result as a voltage signal. The voltage signal output from the acceleration sensor 20 is transmitted to the acceleration amplification unit 40. The acceleration sensor 20 can detect acceleration only while power is supplied from the power supply unit 140. Further, the acceleration sensor 20 is not limited to the capacitance type, and an appropriate type may be applied.

  For example, the acceleration amplifying unit 40 amplifies the output of the acceleration sensor 20 and transmits the amplified acceleration signal to the A / D converter 60. The purpose of the acceleration amplifying unit 40 is the same as that of the angular velocity amplifying unit 30 described above. The acceleration amplifying unit 40 is provided corresponding to each acceleration sensor 20 (two here), and not only amplification but also a low-pass filter function may be added.

  For example, the A / D converter 60 converts an analog acceleration signal sent from the acceleration amplifying unit 40 into a digital signal, and outputs the acceleration signal converted into the digital signal to the drive signal calculation unit 80. The acceleration signal is converted into a digital signal by the A / D converter 60, so that arithmetic processing can be performed in the lens CPU 120.

  The drive signal calculation unit 80, for example, includes angular velocity signals and acceleration signals transmitted from the A / D converters 50 and 60, and position information Ir (described later) of the shake correction lens 110 transmitted from the A / D converter 70. Based on the above, a drive signal p (digital signal) for driving the blur correction lens 110 is calculated and this drive signal p is output to the D / A converter 90 (details will be described later: FIGS. 3 and 4). reference).

  For example, the D / A converter 90 converts the drive signal p calculated by the drive signal calculation unit 80 into an analog signal, and transmits the converted analog signal to the drive unit 100.

  The drive unit 100 is a unit that drives the shake correction lens 110 based on the drive signal p (analog signal) transmitted from the D / A converter 90, for example, an actuator for driving the shake correction lens 110. (VCM), a position detection sensor (PSD) for detecting the position of the blur correction lens 110, and the like. The output of the position detection sensor is transmitted as position information Ir of the blur correction lens 110 to the drive signal calculation unit 80 via the A / D converter 70. For example, two drive units 100 are provided to drive the blur correction lens 110 in two dimensions.

  As described above, the A / D converter 70 converts the position information Ir (analog signal) of the shake correction lens 110 transmitted from the drive unit (in this case, PSD) 100 into a digital signal and converts the converted blur information. The position information Ir of the correction lens 110 is transmitted to the drive signal calculation unit 80.

  The blur correction lens 110 is, for example, a single lens (or a lens group including a plurality of lenses) that is disposed in the imaging optical system of the camera system and can move in a plane substantially orthogonal to the optical axis I. . The blur correction lens 110 is driven by the drive unit 100 in a direction substantially orthogonal to the optical axis, and deflects the optical axis I of the imaging optical system.

  The lens CPU 120 may not only perform control of each member described above, but also control, for example, auto focus drive (not shown). Here, the lens CPU 120 includes the A / D converters 50, 60, and 70 and the D / A converter 90. However, the lens CPU 120 is not limited thereto, and external A / D converters and D / A converters are appropriately used. You may make it use.

  Here, the camera system provided with the shake correction apparatus 200 includes vibration detection sensors such as the angular velocity sensor 10 and the acceleration sensor 20, and the vibration applied to the camera is detected by these vibration detection sensors. In the camera system, if the vibration applied to the camera is detected, the movement of the image on the imaging surface can be detected. Therefore, the blur correction lens 110 is driven by the drive unit 100 so that the movement of the image on the imaging surface stops. The movement of the image on the imaging plane (that is, image blur such as a photograph) can be corrected by moving the image by. Note that image blur occurs, for example, when an image on the imaging surface moves during exposure due to vibration applied to the camera, such as camera shake.

FIG. 2 is a flowchart for explaining a sequence in a camera system provided with the shake correction apparatus 200 according to the present invention. Note that the following steps indicate each process of the lens CPU 120 and the like.
First, it is determined whether or not the half-press switch SW1 is ON (S10). If the half-press switch SW1 is OFF, the process proceeds to step S120 (described later). If the half-press switch SW1 is ON, the counter Tsw1 is reset and the count value is set to 0 (S20). The counter Tsw1 is a counter for measuring an elapsed time after the half-press switch SW1 is turned off, and the count value is an integer. This counter remains 0 while the half-press switch SW1 is ON, and operates only while the half-press switch SW1 is OFF and the half-press timer 130 is ON.

  Next, it is determined whether or not the half-press timer 130 is OFF (S30). If half-press timer 130 is ON, the process proceeds to step S150 (described later). If the half-press timer 130 is OFF, the counter t is reset and the count value is set to 0 (S40). The counter t is a counter for measuring the time during which the half-press timer 130 is ON. This counter is an integer value counter, and starts counting as soon as the half-press timer 130 is turned ON, and continues counting while the half-press timer 130 is ON.

After step S40, half-press timer 130 is turned on (S50), angular velocity sensor 10 is turned on, and angular velocity detection is started (S60). Further, the acceleration sensor 20 is turned on and the detection of acceleration is started (S70).
Next, calculation of the drive signal p for driving the blur correction lens 110 is started (S80). Here, the calculation of the drive signal p uses the output of the angular velocity sensor 10 and the sensor output of the acceleration 20 as described above.
After step S80, driving of the blur correction lens 110 is started (S90), and a series of operations relating to exposure (mirror unillustrated up / down operation, driving of the shutter mechanism, etc.) are performed (S100).

Next, the counter t of the half-press timer 130 is incremented by 1 (S110), and it is determined whether or not the half-press timer 130 is ON (S120). If the half-press timer 130 is OFF, the process returns to step S10 and the detection of the half-press switch SW1 is continued. If the half-press timer 130 is ON, the process proceeds to step S130.
At the time of proceeding to step S130, the camera is in a state where the half-press switch SW1 is OFF and the half-press timer 130 is ON, and the counter Tsw1 is advanced by one in order to measure the time during which this state continues. (S130).

It is determined whether or not the value of the counter Tsw1 is smaller than the threshold value T_SW1 (S140). Here, the threshold value T_SW1 is a constant for determining the upper limit of the counter Tsw1, and determines the time from when the half-push switch SW1 is turned off to when the half-push timer 130 is turned off.
When the counter Tsw1 is less than the threshold value (that is, in the case of an affirmative determination), the half-press timer 130 is not turned off, the angular velocity sensor 10 is kept on, and angular velocity is detected (S150).

  On the other hand, when the counter Tsw1 becomes equal to the threshold value (that is, when a negative determination is made in step S140), the driving of the blur correction lens 110 is stopped (S190), and the power supply to the acceleration sensor 20 is turned off. After the supply is stopped and the acceleration sensor 20 is turned off (S200) and the supply of power to the angular velocity sensor 10 is stopped and the angular velocity sensor 10 is turned off (S210), the half-press timer 130 is turned off. (S220), the process returns to step S10, and the state of the half-press switch SW1 is detected.

  In addition, after step S150, the acceleration sensor 20 is kept on to detect the acceleration (S160), and the output of the angular velocity sensor 10 and the driving for driving the blur correction lens 110 from the output of the acceleration sensor 20 are performed. After the calculation of the signal p is continued (S170: see FIGS. 3 and 4 for details later), the blur correction lens 110 is continuously driven (S180), and the process proceeds to step S100 described above.

FIG. 3 is a block diagram showing details of the drive signal calculation unit 80.
The drive signal calculation unit 80 includes an angular velocity reference value calculation unit 81, an acceleration reference value calculation unit 82, an angular velocity integration calculation unit 83, an acceleration integration calculation unit 84, a rotation center position calculation unit 85, and a drive signal calculation unit 86. Etc.

  The angular velocity reference value calculation unit 81 calculates, for example, the angular velocity reference value used when integrating the angular velocity signal from the angular velocity signal transmitted from the A / D converter 50. Ideally, the angular velocity reference value is an output (angular velocity zero output) value when the angular velocity sensor 10 is completely stationary. However, since this zero angular velocity output value fluctuates due to environmental conditions such as drift and temperature, it cannot be made a fixed value by performing measurement in advance. Therefore, it is necessary to calculate the reference value from the actually used state, that is, the angular velocity signal of the camera shake of the photographer or the like to obtain the zero angular velocity output.

Here, an example of the reference value calculation of the angular velocity reference value calculation unit 81 is shown below.

This equation (2) represents a moving average of the angular velocity signal, ω is an angular velocity signal, and ω ₀ is a reference value of the angular velocity. A subscript (suffix) t attached to these variables is a variable representing elapsed time (sampling; integer value).
The frequency of the zero angular velocity output signal is much lower than that of camera shake by the photographer. Therefore, the reference value is calculated by calculating the moving average of the angular velocity signal because the low-frequency component of the angular velocity signal may be extracted as the reference value. Further, in order to extract only the lowest frequency component as much as possible, the number of data used for the moving average is increased. Note that the calculation of the reference value of the angular velocity signal is not limited to the moving average as expressed by Equation (2), and a low pass filter or the like may be used.

Next, when the calculation of the reference value of the angular velocity signal is completed, the angular velocity detection signal ω ′ is calculated by the following equation by subtracting the reference value from the angular velocity signal.
ω ′ = ω (t) −ω ₀ (t) (3)
Here, ω ′ is an angular velocity detection signal, and this angular velocity detection signal is transmitted to the angular velocity integration calculation unit 83 and the rotation center position calculation unit 85.

  The acceleration reference value calculation unit 82 calculates an acceleration reference value for integrating the acceleration signal from the acceleration signal transmitted from the A / D converter 60, for example. Ideally, the acceleration reference value is an output (acceleration zero output) value when the acceleration sensor 20 is completely stationary. However, the acceleration zero output value cannot be set to a fixed value because it fluctuates due to environmental conditions, similar to the above-described zero angular velocity output value. Therefore, it is necessary to calculate a reference value from an actually used state, that is, an acceleration signal of a camera shake of a photographer or the like to obtain a zero acceleration output.

Here, an example of the reference value calculation of the acceleration reference value calculation unit 82 is shown below.

Equation (4) represents a moving average of acceleration signals, where a is an acceleration signal and a ₀ is a reference value of acceleration. The suffix t attached to these variables is a variable representing elapsed time (sampling; integer value). Note that the calculation of the reference value of the acceleration signal is not limited to the moving average as shown in Equation (4), and a low-pass filter or the like may be used.

Next, when the calculation of the reference value of the acceleration signal is completed, the acceleration detection signal a ′ (t) is calculated by the following equation by subtracting the reference value from the acceleration signal.
a ′ (t) = a (t) −a _O (t) (5)
Here, a ′ is an acceleration detection signal, and this acceleration detection signal is transmitted to the acceleration integration calculation unit 84.

For example, the angular velocity integration calculation unit 83 integrates the angular velocity detection signal ω ′ and converts it into an angle detection signal θ (t). The calculation content here is expressed by the following equation.
θ (t) = θ (t−1) + ω ′ (t) (6)
Here, θ is an angle detection signal, and this angle detection signal is transmitted to the drive signal calculation unit 86.

For example, the acceleration integration calculation unit 84 integrates the acceleration detection signal a ′ and converts it into a speed detection signal v (t). The calculation content here is expressed by the following equation.
v (t) = v (t-1) + a '(t) (7)
Here, v is a speed detection signal, and this speed detection signal is transmitted to the rotation center position calculator 85.

Based on the angular velocity detection signal ω ′ transmitted from the angular velocity reference value calculation unit 81 and the velocity detection signal v transmitted from the acceleration integration calculation unit 84, the rotation center position calculation unit 85 Position).
Specifically, assuming that the acceleration sensor 20 is moving at a velocity v and an angular velocity ω, a distance r from the acceleration sensor 20 to the rotation center position of the angular shake is calculated by the following equation.
r (t) = v (t) / ω ′ (t) (8)

This equation (8) is a theoretical equation for calculating the rotation center position from the velocity v and the angular velocity ω. However, equation (8) is not practical because r diverges when ω = 0. Therefore, in the present embodiment, the following expression obtained by adding a constant term C to the denominator of Expression (8) is used (for example, a state where the camera system is moving in parallel: ω = 0 is considered).
r (t) = Sign {ω ′ (t)} V (t) / (| ω ′ (t) | + C) (9)
However, when ω ′ (t) ≧ 0, Sign {ω ′ (t)} = 1
When ω ′ (t) <0, Sign {ω ′ (t)} = − 1
It is.
In Equation (9), C is a fixed value. However, the value is not limited to this. For example, if ω is large, C is decreased, and if ω is small, C is increased. May be.

Next, the rotational center position n ′ (t) of the angular shake is calculated from the film surface by the following equation (hereinafter, n ′ (t) is referred to as the rotational position signal of the angular shake).
n ′ (t) = D−r (t) (10)
Here, D is the distance from the acceleration sensor 20 to the film surface. The rotational position signal of the angular shake calculated by Expression (10) is transmitted to the drive signal calculation unit 86.

For example, the drive signal calculation unit 86 is based on the angular velocity detection signal θ (t) transmitted from the angular velocity integration calculation unit 83 and the rotation center position signal n ′ (t) transmitted from the rotation center position calculation unit 85. A drive signal p for driving the blur correction lens 110 is calculated.
First, the target drive position L (t) of the lens is calculated by the following equation.
L (t) = Kβθ (t) {R−n ′ (t)} (11)
Here, K is a constant (lens specific value) determined by the optical conditions of the blur correction lens 110, and R is the distance from the subject to the film surface. The values of K, β, R, and D used in equations (10) and (11) are stored in an appropriate memory in the drive signal calculation unit 80, and the drive signal calculation unit 86 and the rotation center position calculation unit 85 are These values may be read from the memory and the above-described calculation may be performed.

  When the calculation of the target drive position L (t) is completed, a deviation from the position information Ir of the shake correction lens 110 transmitted from the A / D converter 70 is obtained, and the shake correction lens 110 is driven based on this deviation. The signal p is calculated. The calculation of the drive signal p is generally so-called PID control in which the drive signal p is calculated by adding a term proportional to the deviation, a term proportional to the integral of the deviation, and a term proportional to the derivative of the deviation. Not limited to this, an appropriate method may be used.

FIG. 4 is a flowchart showing the operation of the drive signal calculation unit 80. Each of the following steps corresponds to the function of each member of the drive signal calculation unit 80, and shows the above-described step S170 (see FIG. 2) in detail, and description of overlapping portions is omitted as appropriate. .
After step S160 described above, the drive signal calculation unit 80 executes steps S500 to S610 described below, and then proceeds to step S180 described above.
The output of the angular velocity sensor 10 is A / D converted and the angular velocity signal ω (t) is read (S500).
The output of the acceleration sensor 20 is A / D converted and the acceleration signal a (t) is read (S510).
The position information Ir of the blur correction lens 110 output by the driving unit 100 is A / D converted and read (S520).

An angular velocity reference value ω ₀ (t) is calculated from the angular velocity signal ω (t) (S530).
The angular velocity reference value ω ₀ (t) is subtracted from the angular velocity signal ω (t) to generate an angular velocity detection signal ω ′ (t) (S540).
An acceleration reference value a ₀ (t) is calculated from the acceleration signal a (t) (S550).
The acceleration reference value a ₀ (t) is subtracted from the acceleration signal a (t) to generate an acceleration detection signal a ′ (t) (S560).
The acceleration detection signal a ′ (t) is integrated and converted into a speed detection signal v (t) (S570).
A rotation center position signal n ′ (t) is calculated from the angular velocity detection signal ω ′ (t) and the velocity detection signal v (t) (S580).
The angular velocity detection signal ω ′ (t) is integrated and converted into an angle detection signal θ (t) (S590).
Based on the angle detection signal θ (t), the rotation center position signal n ′ (t), the position information Ir of the shake correction lens 110, and the like, a drive signal p for driving the shake correction lens 110 is calculated ( S600).
The drive signal p is output to the drive unit 100 via the D / A converter 90 (S610).

Here, the effect of the blur correction in the camera system provided with the blur correction apparatus 200 in the present embodiment will be described using the above-described formula (1).
First, when the formula (1) representing the blur amount of the image plane including the angle blur and the shift blur is modified, it can be expressed as follows.
Di = βθ {R− (nd−θ)} (12)
This equation (12) indicates that the rotational center position of the angular blur is shifted due to the shift blur. Therefore, if the rotational center position can be detected, the shift blur can also be corrected, and as a result, the photographing magnification β becomes a high magnification. This shows that the effect of blur correction can be improved.

  In the camera system according to the present embodiment, as described above, the rotation of the angular shake is calculated using the output of the angular velocity sensor 10 and the output of the acceleration sensor 20, particularly based on the formulas (9) and (10). Since the fluctuation of the center position signal n ′ (t) is calculated in real time (suffix t attached to n ′ is a variable representing elapsed time), blur correction is performed even when the imaging magnification β is high. The effect can be improved.

FIG. 5 is a diagram showing the effect of blur correction between the conventional blur correction apparatus and the blur correction apparatus 200 according to the present invention. Also, the horizontal axis represents the shooting magnification, and the vertical axis represents the effect of blur correction. The blur correction effect of the conventional blur correction device is indicated by a broken line, and the blur correction effect of the blur correction device 200 according to the present invention is indicated by a solid line.
As shown in the drawing, the blur correction effect of the blur correction device 200 does not decrease even when the photographing magnification is increased as compared with the conventional blur correction device.

According to the present embodiment, (1) shift blur is detected by detecting the rotational center position of angular shake in real time, so that the effect of blur correction can be improved even when the photographing magnification is high. Can do.
(2) The acceleration detection signal a ′ (t) is integrated only once, and the accumulated error can be significantly reduced as compared with a conventional system that performs integration twice. Therefore, improvement in detection accuracy is expected. In addition, the calculation load on the lens CPU 120 can be significantly reduced.
(3) Since only one acceleration sensor 20 is required in each of the X-axis direction and the Y-axis direction (two in total), space saving and cost reduction can be achieved.

(Modification)
The present invention is not limited to the embodiments described above, and various modifications and changes are possible, and these are also within the equivalent scope of the present invention.
(1) The reason why the constant term is provided in the denominator in Equation (9) described above is that r diverges when ω = 0. However, when the absolute value of ω is large, the divergence is not particularly problematic. Therefore, the distance r (t) from the acceleration sensor 20 to the rotational center position of the angular shake may be calculated by the following equation.
r (t) = V (t) / [ω ′ (t) + C {ω ′ (t)}] (13)

Here, C (ω ′) is a function of the angular velocity detection value, and an example thereof is shown below.
FIG. 6 is a diagram showing a function C (ω ′) of the angular velocity detection value.
For example, C (ω ′) is a function that increases as the absolute value of ω ′ decreases, and conversely decreases as the absolute value of ω ′ increases.
According to this function C (ω ′), the divergence of r at ω ′ = 0 can be prevented, and if the absolute value of ω ′ is equal to or larger than a predetermined value, A certain numerical formula (8) can be used, and as a result, the rotation center position can be calculated more accurately. This function C (ω ′) can prevent the divergence of r when ω ′ = 0, and when the absolute value of ω ′ is equal to or larger than a predetermined value, the equation (13) is changed to the equation (8). Any function that can be approximated may be used.
Therefore, by using Expression (13), the shake correction apparatus 200 can further improve the shake correction effect when the shooting magnification is high.

(2) Although the values n ′ (t) and D used in the equation (10) are both based on the film surface, the present invention is not limited to this, and the surface disposed on the optical axis I (located in the camera system). , A fixed member), an appropriate member may be used as a reference.

It is a block diagram which shows the Example of the blurring correction apparatus 200 by this invention. It is a flowchart explaining the sequence in the camera system provided with the blurring correction apparatus 200 by this invention. 4 is a block diagram showing details of a drive signal calculation unit 80. FIG. 4 is a flowchart showing the operation of a drive signal calculation unit 80. It is a figure which shows the effect of the blur correction of the conventional blur correction apparatus and the blur correction apparatus 200 by this invention. It is a figure which shows the function C (omega ') of an angular velocity detection value. It is a block diagram which shows the outline of the conventional blurring correction apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Angular velocity sensor 20 Acceleration sensor 30 Angular velocity amplification part 40 Acceleration amplification part 50, 60, 70 A / D converter 80 Drive signal calculation part 81 Angular velocity reference value calculation part 82 Acceleration reference value calculation part 83 Angular velocity integration calculation part 84 Acceleration integral calculation Unit 85 rotation center position calculation unit 86 drive signal calculation unit 90 D / A converter 100 drive unit 110 blur correction lens 120 lens CPU
130 half-press timer 140 power supply unit 150 lens barrel 160 camera body 200 blur correction device

Claims (7)

An angular velocity detector that detects the angular velocity of the shake,
A speed calculation unit for calculating the speed of deflection;
Based on the angular velocity and the velocity, a rotation center calculation unit that calculates a rotation center position of shake;
A shake detection device comprising: The shake detection apparatus according to claim 1,
It further includes an acceleration detection unit that detects acceleration of shake,
The speed calculation unit calculates an acceleration reference value based on the acceleration, and calculates the speed by integrating a value obtained by subtracting the acceleration reference value from the acceleration;
A shake detection device characterized by the above. In the shake detection device according to claim 2,
The rotation center calculation unit calculates a distance r (t) from the acceleration detection unit to the rotation center position based on the velocity V (t) and the angular velocity ω (t) as follows:
r (t) = V (t) / ω (t)
To calculate using
A shake detection device characterized by the above. In the shake detection device according to claim 2,
The rotation center calculation unit is a constant for preventing the velocity V (t), the angular velocity ω (t), and the r (t) from diverging the distance r (t) from the acceleration detection unit to the rotation center position. Based on C, the following formula:
r (t) = V (t) / (| ω (t) | + C)
However, ω (t) ≧ 0
r (t) = − V (t) / (| ω (t) | + C)
However, ω (t) <0
To calculate using
A shake detection device characterized by the above. In the shake detection device according to claim 2,
The rotation center calculation unit is configured to prevent a distance r (t) from the acceleration detection unit to the rotation center position so that the velocity V (t), the angular velocity ω (t), and the r (t) do not diverge. Based on the function C {ω (t)} with the angular velocity ω (t) as a variable,
r (t) = V (t) / [ω (t) + C {ω (t)}]
To calculate using
A shake detection device characterized by the above. The shake detection device according to any one of claims 1 to 5,
A blur correction optical member for optically correcting image blur;
A drive unit for driving the blur correction optical member;
And measuring a lens eigenvalue of the blur correction optical member, a photographing magnification, a first distance between the subject and a surface disposed on the optical axis, and a second distance between the acceleration detection unit and the surface disposed on the optical axis. And / or an information input unit for storing;
Calculating an angular velocity reference value based on the angular velocity, and by integrating a value obtained by subtracting the angular velocity reference value from the angular velocity, an angle calculation unit that calculates angular deflection;
A position detector for detecting a current position of the blur correction optical member;
A target drive position calculator for calculating a target drive position of the blur correction optical member;
A drive control unit that controls the drive unit based on the current position and the target drive position of the blur correction optical member;
The target drive position calculation unit measures the target drive position L (t) by a distance r (t) from the acceleration detection unit to the rotation center position, the angular shake θ (t), and the information input unit. And / or based on the stored lens eigenvalue K, the imaging magnification β, the first distance R, and the second distance D,
L (t) = Kβθ (t) (R−D + r (t))
To calculate using
A blur correction device characterized by the above. The blur correction device according to claim 6,
The surface disposed on the optical axis is an imaging surface;
A blur correction device characterized by the above.

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