JP2007065117A - Image blur correction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image blur correction device capable of more surely exhibit superior vibration-proof function. <P>SOLUTION: The image blur correction device includes a detection section that detects vibration of a photographic system including an photographic optical system for forming a photographing image, and an imaging part for imaging the photographing image; and drive control sections (500, 703, 301Y, 704, 302Y, 705, etc.) that control the drive of at least part of the photographic system, according to the output signal of the detection section, and attenuate blur of the photographing image on the imaging part, wherein the detection section includes high-accuracy detection parts (6p, 6y), capable of detecting the vibration with high accuracy over a long operating time, and high-speed operation detection parts (5p, 5y), capable of detecting the vibration with low accuracy in an operating time shorter than that, and the drive control sections correct the output signal (B) of the high-accuracy detection parts, based on the output signal (A) of the high-speed operation detection parts that has started previously, and controls the drive according to the corrected signal (B<SB>H</SB>). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image blur correction apparatus mounted on a photographing device such as a video camera or a still camera.

When vibration is applied to a camera system such as a still camera from the outside, the captured image is disturbed (image shake). The main cause of this image blur is a camera shake at the time of hand-held shooting, and the type of vibration is a vibration (angle shake) in a direction in which the shooting system is inclined in the case of a general shooting magnification.
In order to avoid this problem, an image blur correction technique represented by Patent Document 1 has been proposed. This technology is equipped with an angular velocity sensor in the camera system, calculates the angular shake amount (tilt angle) of the shooting system by integrating the output of the angular velocity sensor, and controls and drives a part of the shooting system according to the tilt angle This cancels out image blur. Technologies that apply such image blur correction technology are disclosed in Patent Documents 2, 3, 4, and the like.

There are various types of sensors for detecting angular shake, but a vibration gyro that is an angular velocity sensor that can be miniaturized is suitable for a camera system that is a portable device. The vibration gyro has a vibrator that vibrates at a predetermined frequency, and detects a Coriolis force applied to the vibrator. If the detection band of the vibration gyroscope is set to a frequency band of camera shake (for example, 3 Hz to 8 Hz), camera shake can be reliably detected. Incidentally, many of the current camera systems are equipped with ceramic-type vibration gyros that are sensitive to angular fluctuations in this frequency band.
JP 60-143330 A JP-A-7-270847 JP-A-10-161172 JP 2000-180911 A

  By the way, in order to improve the image stabilization performance of the image shake correction apparatus, it is necessary to improve at least the accuracy of angular shake detection. For this purpose, a single crystal or the like is used for the vibrator of the vibrating gyroscope, and the Q value may be set high. However, a vibrator having a high Q value takes a long time from the start of power supply until the vibration state is stabilized, and tends to prolong the startup time of the vibration gyro.

Moreover, it is difficult for an image blur correction apparatus using a vibration gyro to immediately exhibit a high correction function even after the vibration gyro is activated, for the convenience of converting the detected angular velocity into an inclination angle. For this reason, even if a highly accurate vibration gyroscope is used, the accuracy is not necessarily fully produced.
An object of the present invention has been made in view of these problems, and it is an object of the present invention to provide an image blur correction apparatus capable of exhibiting excellent anti-shake performance more reliably.

  An image shake correction apparatus according to the present invention includes a detection unit configured to detect a vibration of a photographing system including a photographing optical system that forms a photographed image and an imaging unit that captures the photographed image, and an output signal of the detection unit. In the image blur correction apparatus including a drive control unit that drives and controls at least a part of the imaging system and attenuates the shake of the captured image on the imaging unit, the detection unit has high accuracy with a long start-up time. A high-accuracy detection unit capable of detecting the vibration, and a high-speed activation detection unit capable of detecting the vibration with a low activation time with a shorter activation time than the high-speed activation unit that has been activated first. The output signal of the high-precision detection unit is corrected based on the output signal of the detection unit, and the drive control is performed according to the corrected signal.

The drive control unit may extract a low frequency component from the output signal of the fast activation detection unit, and perform the correction based on the low frequency component.
The drive control unit may perform the correction based on an offset between the output signal of the high-speed activation detection unit and the output signal of the high-precision detection unit.
Furthermore, the drive control unit may recognize the offset based on the output signal of the fast activation detection unit and the output signal of the high accuracy detection unit at the same timing.

Furthermore, the drive control unit may perform the correction based on a difference in sensitivity between the fast activation detection unit and the high accuracy detection unit.
Further, a vibration gyro may be used for the high-precision detection unit, and a vibration gyro having a vibrator having a Q value lower than that of the vibration gyro may be used for the high-speed activation detection unit.
Further, a quartz-type vibration gyro may be used for the high-accuracy detection unit, and a ceramic-type vibration gyro may be used for the high-speed activation detection unit.

  According to the present invention, it is possible to realize an image blur correction apparatus that can more reliably exhibit excellent image stabilization performance.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. The present embodiment is an embodiment of a still camera system.
First, the overall configuration of the camera system will be described with reference to FIG.
FIG. 1 is an overall configuration diagram of the camera system. The Z direction of the coordinate system shown in FIG. 1 corresponds to the direction of the optical axis 100 of the camera system when image blur correction is not in operation, and the Y direction corresponds to the up and down direction of the camera system during horizontal position shooting. Corresponds to the left-right direction of the camera system during horizontal position shooting. Hereinafter, this coordinate system is used as necessary.

As shown in FIG. 1, the camera system includes a camera body 1 and a lens barrel 2 that can be attached to and detached from the camera body 1. The camera body 1 is, for example, a single-lens reflex type still camera equipped with a quick return mirror and a shutter mechanism, and the lens barrel 2 is an interchangeable lens equipped with an image blur correction function.
The battery of the camera system is mounted on the camera body 1 side, and power is supplied from the camera body 1 to the lens barrel 2 as necessary. The supply start timing is, for example, when the release button of the camera body 1 is half-pressed.

  In the lens barrel 2, as a photographing optical system, for example, a zoom lens having a four-group configuration including a first lens group 201, a second lens group 202, a third lens group 203, and a fourth lens group 204 is used. Is placed. The zooming and focus adjustment are performed by changing the positional relationship of the lens groups 201, 202, 203, and 204 in the Z direction. The movement of the lens group at that time is performed by a cam mechanism (not shown) provided in the lens barrel 2.

The lens barrel 2 forms an image of the subject light flux from the object scene on the imaging surface 101 in the camera body 1. The subject image formed on the imaging surface 101 is captured by an imaging unit such as a silver salt film or a CCD imaging device.
Here, the third lens group 203 has a three-group configuration including lens groups 203 a, 203 b and 203 c, which are housed in the image blur correction unit 3. Among these, the lens group 203b is a correction lens that is driven for image blur correction. Therefore, hereinafter, the lens group 203b is referred to as a “correction lens 203b”.

  The correction lens 203b is supported by the image blur correction unit 3 so as to be movable in the X direction and the Y direction. The image blur correction unit 3 includes an actuator 301X that moves the correction lens 203b in the X direction and an actuator 301Y that moves the correction lens 203b in the Y direction. The image blur correction unit 3 also includes a position detection sensor 302X and a position detection sensor 302Y that individually detect the position in the X direction and the position in the Y direction of the correction lens 203b at that time.

Further, the lens barrel 2 is equipped with high-speed activation sensors 5p and 5y and high-precision sensors 6p and 6y in order to detect angular shake applied to the camera system. The fixing points of these sensors are members (fixed cylinders) that do not rotate during zooming or focus adjustment.
Among these, the high-speed activation sensor 5p and the high-accuracy sensor 6p are angular velocity sensors that detect the angular shake velocity (angular velocity) around the X axis (pitch direction) applied to the camera system. Since the angular shake in the pitch direction causes the image shake in the Y direction, the high speed start sensor 5p and the high accuracy sensor 6p are used for the image shake correction in the Y direction together with the actuator 301Y and the position detection sensor 302Y.

  On the other hand, the high-speed activation sensor 5y and the high-precision sensor 6y are angular velocity sensors that detect the angular shake velocity (angular velocity) around the Y axis (yaw direction) applied to the camera system. Since the angular shake in the yaw direction causes an image shake in the X direction, the fast start sensor sensor 5y and the high accuracy sensor 6y are used for the image shake correction in the X direction together with the actuator 301X and the position detection sensor 302X described above.

Further, the detection bands of the fast start-up sensors 5p and 5y and the high-precision sensors 6p and 6y cover an angular shake frequency band (for example, several Hz to 50 Hz) that can cause image shake.
As the high speed start sensors 5p and 5y, an angular velocity sensor having a relatively short start time and a low accuracy, specifically, a vibration gyro using a vibrator having a low Q value is used. This vibration gyro is, for example, a ceramic vibration gyro using ceramic as a vibrator, and its starting time is about 50 ms to 100 ms.

On the other hand, for the high-precision sensors 6p and 6y, an angular velocity sensor with a relatively long start-up time and a high-precision, specifically, a vibration gyro using a vibrator having a high Q value is used. This vibration gyro is, for example, a crystal-type vibration gyro using crystal as a vibrator, and its activation time is about 300 ms to 500 ms.
The “start-up time” here refers to a period from the start of power supply until a stable signal is output, and is generally also referred to as a “stable standby period”.

Next, details of the image blur correction unit 3 will be described with reference to FIG.
FIG. 2 is a cross-sectional view of the image blur correction unit 3. FIG. 2 is a cross-sectional view in the YZ plane. In this cross-sectional view, an actuator 301Y that moves the correction lens 203b in the Y direction and a position detection sensor 302Y that detects the position of the correction lens 203 in the Y direction appear. ing.

As shown in FIG. 2, in the image blur correction unit 3, the correction lens 203b is held by the holding frame 303, the front lens chamber 304 holding the lens group 203a, and the rear lens holding the lens group 203c. It is arranged in a space between the chamber 305.
The front lens chamber 304 and the rear lens chamber 305 are fixed with screws 306, and the holding frame 303 holding the correction lens 203b corrects a gap between the front lens chamber 304 and the rear lens chamber 305 (not shown). It can be moved by a lens driving mechanism. However, the moving direction is limited only to the X direction and the Y direction, and the holding frame 303 does not rotate around the Z axis.

  The actuator 301Y is made of, for example, a VCM (Voice Coil Motor), and includes a lower yoke 301a fixed to the front lens chamber 304, a permanent magnet 301b magnetized in two poles on the lower yoke 301a, and a holding frame 303. A loop-shaped coil 301c fixed to the rear lens chamber 305, and an upper yoke 301d fixed to the rear lens chamber 305. According to the lower yoke 301a, the permanent magnet 301b, and the upper yoke 301d, a magnetic circuit is formed in the vicinity of the coil 301c. Therefore, the actuator 301 can move the holding frame 303 (and the correction lens 203b) in the Y direction by supplying a driving current to the coil 301c.

  The position detection sensor 302Y includes, for example, an LED (Light Emitting Diode) 302c attached to the front lens chamber 304, a slit 302b formed in the holding frame 303, and a PSD (Position Sensitive Detector) that receives light that has passed through the slit 302b. ) 302a and a substrate 307 that supports the detection unit 302a and fixes it to the rear lens chamber 305 side. The light emitted from the LED 302c enters the PSD 302a through the slit 302b. When the holding frame 303 (and the correction lens 203b) moves in the Y direction, the slit 302b also moves, so that the output signal of the PSD 302a changes. Therefore, the position detection sensor 302Y can detect the position of the correction lens 203b in the Y direction by driving the LED 302c and the PSD 302a.

  Although not shown in FIG. 2, the actuator 301X and the position detection sensor 302X are the same as those obtained by rotating the actuator 301Y and the position detection sensor 302Y shown in FIG. The actuator 301X moves the correction lens 203b in the X direction in the same manner as the actuator 301Y moves the correction lens 203b in the Y direction, and the position detection sensor 302X has a position detection sensor 302Y in the Y direction of the correction lens 203b. The position of the correction lens 203b in the X direction is detected in the same manner as the above.

Next, a mounting form of the fast start sensors 5p and 5y and the high precision sensors 6p and 6y will be described with reference to FIG.
FIG. 3A is a perspective view of the periphery of a fixed cylinder to which the fast start sensors 5p and 5y and the high precision sensors 6p and 6y are fixed. FIG.3 (b) is A view in FIG.3 (a).
The fixed cylinder 403 is a member whose rotational position around the Z axis does not change regardless of zooming or focus adjustment as long as the lens barrel is attached to the camera body. The cam groove 404 provided in the fixed barrel 403 is for moving the first lens group and the second lens group in the lens barrel.

First, the high speed activation sensor 5p is fixed to the fixed cylinder 403 via a mounting substrate 401 made of glass epoxy and a buffer member 406 made of an elastic member such as rubber, and is covered with a sound insulation cover 405p.
Specifically, the mounting board 401 is fixed to the mounting portion 403 a of the fixed cylinder 403 via the buffer member 406 with the mounting screw 407, and the fast start sensor 5 p is mounted on the mounting board 401. A cutout portion 401a is formed on the mounting substrate 401, and the high speed activation sensor 5p is covered by the sound insulation cover 405p by engaging the cutout portion 401a with the mounting protrusion 405a of the sound insulation cover 405p.

The fast start sensor 5y is also mounted on the same mounting substrate 401 as the fast start sensor 5p and is covered with a sound insulation cover 405y.
A part of an analog circuit for processing output signals from the fast start sensors 5p and 5y is also mounted on the mounting board 401 on which these fast start sensors 5p and 5y are mounted. Further, in order to increase the sound insulation effect, a member that absorbs vibration, such as urethane foam, may be interposed between the sound insulation covers 405p and 405y and the high speed activation sensors 5p and 5y.

Next, the high precision sensor 6p is fixed to the fixed cylinder 403 via a mounting substrate 402 made of a flexible printed circuit board.
Specifically, a mounting substrate 402 is affixed to the mounting flat portion 403b provided on the surface of the fixed cylinder 403 by a double-sided tape, and the high-precision sensor 6p is mounted on the affixing surface of the mounting substrate 402. Yes.

The high-precision sensor 6y is also mounted on the same mounting substrate 402 as the high-precision sensor 6p, and is fixed similarly to the high-precision sensor 6p.
A part of an analog circuit for processing output signals from the two high-precision sensors 6p and 6y is also mounted on the mounting substrate 402 on which the high-precision sensors 6p and 6y are mounted.
Next, an image blur correction circuit of the camera system will be described with reference to FIG. FIG. 4 shows only a block diagram of the image blur correction circuit in the Y direction. There are two image blur correction circuits in this camera system: a Y-direction image blur correction circuit and an X-direction image blur correction circuit, but only the sensors and actuators used are different. The circuit configuration is the same. Therefore, only the former will be described here.

  As shown in FIG. 4, the image blur correction circuit in the Y direction includes a fast start sensor 5p, a high precision sensor 6p, amplifiers 501, 601, adders 502, 602, A / D converters 503, 603, and D / A converters. 504, 604, MPU 500, motor driver 703, actuator 301Y, correction lens driving mechanism 704, position detection sensor 302Y, and A / D converter 705. Each block in the MPU 500 indicates a concept of each process by the MPU 500.

  Among these, the high-speed activation sensor 5p, the high-precision sensor 6p, the amplifiers 501, 601, the actuator 301Y, the correction lens driving mechanism 704, and the position detection sensor 302Y are mounted on the lens barrel. It is mounted on the tube or camera body. However, since the characteristics of this circuit are adapted to the specifications of the photographing optical system in the lens barrel, it is preferable that the circuit is mounted on the lens barrel side rather than on the camera body side.

Now, when an angular shake in the pitch direction occurs in the camera system, the angular velocity signal A is output from the high speed activation sensor 5p, and the angular velocity signal B is output from the high accuracy sensor 6p.
The angular velocity signal A is amplified by the amplifier 501 with a predetermined gain. The amplifier 501 is also provided with a low-pass filter function, and its cutoff frequency is set to an appropriate value so that electrical noise is removed from the angular velocity signal A.

  Further, the adder 502 adds a DC signal to the angular velocity signal A output from the amplifier 501. The value of the DC signal is sequentially calculated by the addition output calculation unit 505 in the MPU 500, and is a correction value for adapting the amplitude of the angular velocity signal A to the dynamic range of the A / D converter 503 ( This correction value can take both positive and negative values.) The correction value calculated by the addition output calculation unit 505 is input to the adder 502 via the D / A converter 504.

The angular velocity signal A having an appropriate amplitude in this way is converted into a digital signal by the A / D converter 503 and taken into the MPU 500.
The angular velocity signal A captured by the MPU 500 is input to a low pass filter (LPF) 506 having a cutoff frequency of about 0.1 Hz. The initial value of the LPF calculation by the low-pass filter 506 is set to the same value as the initial value of the angular velocity signal A.

Output signal (LPF output signal) A _L of the low-pass filter 506 is input to the initial value setting unit 710. The initial value setting unit 710 converts the LPF output signal A _L to a value A _L ′ suitable for the angular velocity signal B. In the conversion, the initial value setting unit 710 also refers to the values of the angular velocity signals A and B. The initial value setting unit 710 gives the converted value A _L ′ to a low-pass filter 606 described later.

On the other hand, the angular velocity signal B is amplified by the amplifier 601 with a predetermined gain. The amplifier 601 is also provided with a low-pass filter function, and its cutoff frequency is set to an appropriate value so that electrical noise is removed from the angular velocity signal B.
Further, the adder 602 adds a direct current signal to the angular velocity signal B output from the amplifier 601. The value of the DC signal is sequentially calculated by the addition output calculation unit 605 in the MPU 500, and is a correction value for adapting the amplitude of the angular velocity signal B to the dynamic range of the A / D converter 603 ( This correction value can take both positive and negative values.) The correction value calculated by the addition output calculation unit 605 is input to the adder 602 via the D / A converter 604.

The angular velocity signal B having an appropriate amplitude in this way is converted into a digital signal by the A / D converter 603 and taken into the MPU 500.
The angular velocity signal B taken into the MPU 500 is branched, one of which is input to the subtractor 607 via the low-pass filter (LPF) 606 having the same characteristics as the low-pass filter 506 described above, and the other is directly input to the subtractor 607. Entered. An output from the subtractor 607 is an angular velocity signal B _H obtained by subtracting the output signal (LPF output signal) _BL of the low-pass filter 606 from the angular velocity signal B.

Note that the initial value of the LPF calculation by the low-pass filter 606 is set to the value A _L ′ given from the initial value setting unit 710. Details thereof will be described later.
Then, the angular velocity signal B _H is input to the target position calculation unit 701 in the MPU 500. The target position calculation unit 701 integrates (integrates) the angular velocity signal B _H to calculate the tilt angle in the pitch direction of the camera system. Further, the target position calculation unit 701 is based on the calculated tilt angle and the image plane movement magnification of the photographing optical system (obtained from the focal length and subject distance of the photographing optical system), and the target position in the Y direction of the correction lens 203b. Is calculated. The target position in the Y direction is a position for canceling image blurring that occurs in the Y direction under the tilt angle.

Note that the focal length and subject distance of the photographic optical system are obtained from the positional relationship in the Z direction of the lens group in the lens barrel, and the information is always obtained by the lens CPU via the encoder in the lens barrel. Assume that it is grasped and sent to the MPU 500.
The calculated target position in the Y direction is input to the control unit 702 in the MPU 500. The control unit 702 includes, for example, a PID (Proportional, Integral, Dfferential) controller and the like, and generates a control signal according to a target position and gives it to the motor driver 703. The motor driver 703 drives the actuator 301Y by PWM (Plus Width Modulation), for example, according to the control signal.

  The actuator 301Y drives the correction lens driving mechanism 704 according to the given driving amount, and moves the correction lens 203b to the target position in the Y direction. As a result, the subject image on the imaging surface moves in the Y direction. The movement amount is a value obtained by multiplying the actual movement amount of the correction lens 203b by the image plane movement magnification of the photographing optical system. Therefore, in FIG. 4, the correction lens 203b is represented by an amplifier symbol.

Further, the position of the correction lens 203b in the Y direction is detected by the position detection sensor 302Y. The detection signal is converted into a digital signal by the A / D converter 705 and then input to the subtractor 706 inserted between the target position calculation unit 701 and the control unit 702.
The subtractor 706 obtains a deviation between the Y-direction target position calculated by the target position calculation unit 701 and the Y-direction position detected by the position detection sensor 302Y and supplies the deviation to the control unit 702. The control signal generated by the control unit 702 is a signal for reducing the deviation.

  The control system including the target position calculation unit 701, the subtractor 706, the control unit 702, the motor driver 703, the actuator 301Y, the correction lens driving mechanism 704, the position detection sensor 302Y, and the A / D converter 705 is the same as the correction lens 203b. Feedback control is performed to bring the position in the Y direction closer to the target position. Thus, image blur correction in the Y direction by the angular velocity signal B is achieved.

Here, the low-pass filter 606 that performs LPF processing on the angular velocity signal B has a function of setting an integral constant of integration in the target position calculation unit 701. The LPF output signal B _L corresponds to the integration constant.
However, immediately after the start of the LPF calculation, the information of the angular velocity signal B is insufficient, so the LPF output signal B _L does not immediately take the optimum value but gradually converges toward the optimum value as time passes. To do. This is the reason why it took time until a high correction function was exhibited. On the other hand, in the present embodiment, the initial value of the LPF calculation is set to the value A _L ′ in order to increase the convergence speed. This will be described in detail below.

Next, the operation of the lens MPU 500 immediately after the start of power supply to the lens barrel will be described in detail with reference to FIG.
FIG. 5 shows time-varying waveforms of the angular velocity signals A and B immediately after the start of power supply. These waveforms are output waveforms of the A / D converters 503 and 506 in FIG.
As shown in FIG. 5, the angular velocity signal A fast since activation signal generated by the sensor 5p, begin to stabilize at a timing T _A passed through a relatively short activation time (50 ms to 100 ms) from the start of power supply.

On the other hand, the angular velocity signal B, since the signal generated by the high-precision sensor 6p, begin to stabilize at a timing T _B which has passed through the relatively long start-up time (300ms~500ms) from the start of power supply.
Therefore, the acquisition of the angular velocity signal A and the LPF calculation for the angular velocity signal A are started at the timing T _A. Its initial value of LPF calculation is set to the same value A [T _A] and the angular velocity signal A at the timing T _A. According to this setting, the LPF output signal A _L gradually converges from the value A [T _A ] toward the optimum value, as indicated by the one-dot chain line in FIG.

The initial value setting unit 710 at the timing T _B, the value A _L of LPF output signal A _L [T _B], it is converted to a value A _L suitable for the angular velocity signal _B [T B] '.
This conversion corrects the offset amount between the angular velocity signals A and B from the value A _L [T _B ]. The offset amount is represented by the difference (A [T _B ] −B [T _B ]) between the values A [T _B ] and B [T _B ] of the angular velocity signals A and B at the timing T _B. Therefore, the equation for converting the value A _L [T _B ] into the value A _L [T _B ] ′ is the following equation (1).

A _L [T _B ] ′ = A _L [T _B ] − (A [T _B ] −B [T _B ]) (1)
In this transformation, in addition to the offset amount, it is desirable to consider the sensitivity ratio G = G _B / G _A between the sensitivity G _B Sensitivity G _A and precision sensor side of the high-speed startup sensor side. Sensitivity G _A is the sensitivity of the detection system from the fast startup sensor 5p to A / D converter 503, the sensitivity G _B is the sensitivity of the detection system from the fine sensor 6p to A / D converter 603. Here, it is assumed that the sensitivity ratio G is regarded as a constant, and the MPU 500 stores in advance. If this sensitivity ratio G is taken into consideration, the following equation (2) may be used instead of equation (1).

A _L [T _B ] ′ = B [T _B ] −G (A [T _B ] −A _L [T _B ]) (2)
Then, the angular velocity signal B uptake, and also LPF operation on the angular velocity signal B, is started at the timing T _B. The initial value of the LPF calculation is set to the above-described value A _L [T _B ] ′. According to this setting, the LPF output signal B _L gradually converges from the value A _L [T _B ] ′ toward the optimum value, as indicated by the one-dot chain line in FIG.

Here, in FIG. 5, for comparison, the LPF output signal C _L when the initial value of the LPF calculation is set to the value B [T _B ] is indicated by a two-dot chain line. According to this setting, the LPF output signal C _L gradually converges from the value B [T _B ] toward the optimum value.
As is clear from comparison between the two, the value A _L [T _B ] ′ is closer to the optimum value than the value B [T _B ]. This is because the value A _L [T _B ] ′ is based on the result of LPF calculation (value A _L [T _B ]) executed during the period (T _B −T _A ). Therefore, it is clear that the LPF output signal B _L has a faster convergence speed to the optimum value than the LPF output signal C _L ′.

FIG. 6 is a flowchart showing the operation of the MPU.
That is, when the power supply is started, whether the start-up time T _A of the quick start sensor 5p has elapsed (step S11). Then, when the activation time T _A has elapsed (YES in step S11), the acquisition of the angular velocity signal A and the LPF calculation for the angular velocity signal A are started (step S12).

Then, whether starting time T _B of the accurate sensor 6p has elapsed (step S13). Then, when the start time T _B has elapsed (step S13YES), the initial value of the LPF operation on the angular velocity signal B is set to a value A _L [T _B] '(step S14), and the incorporation of the angular velocity signal B, and LPF calculation for the angular velocity signal B is started (step S15), and image blur correction is performed (step S16).

  As described above, in the camera system of the present embodiment, the angular velocity signal B from the high-precision sensor is reflected in the image blur correction (see FIG. 4), so that the correction accuracy is high. Moreover, the angular velocity signal B is corrected based on the angular velocity signal A from the fast activation sensor that has been activated first (see MPU 500 in FIG. 4). Therefore, the time until the target value of image blur correction approaches the true value is shortened, and a high correction function is exhibited earlier.

Moreover, in the camera system of the present embodiment, when the angular velocity signal B is corrected, the offset amount between the angular velocity signals A and B is taken into consideration, and further up to the sensitivity ratio G (Equation (1) or Equation ( 2)), and the accuracy of the correction is high. Therefore, the period until a high correction function is exhibited is reliably shortened.
[Second Embodiment]
The second embodiment of the present invention will be described below with reference to the drawings. This embodiment is an embodiment of a camera system. Here, only differences from the first embodiment will be described. The difference lies in the difference between the detection band by the high speed activation sensor and the detection band by the high accuracy sensor, and the operation of the MPU 500. In addition, a changeover switch that can be operated by the user is provided at any location (for example, the lens barrel side) of the camera system.

  FIG. 7 is a block diagram of an image blur correction circuit (image blur correction circuit in the Y direction) according to the present embodiment. The image blur correction circuit of this camera system also has two systems, a circuit for correcting image blur in the Y direction and a circuit for correcting image blur in the X direction. The circuit configuration is the same except for the sensors and actuators. Accordingly, only a circuit for correcting image blur in the Y direction will be described here.

  First, in the present embodiment, the detection band width of the detection system on the high speed start sensor 5p side (system from the high speed start sensor 5p to the A / D converter 503) and the detection system on the high precision sensor 6p side (high precision sensor) A difference is provided in the detection band width of the system from 6p to the A / D converter 603). For example, the detection system including the high-speed activation sensor 5p is set to cover a wide band of several Hz to 50 Hz, and the detection system including the high-precision sensor 6p is set to cover a narrow band of several Hz to 10 Hz.

The MPU 500 is provided with a subtracter 507 in order to process the angular velocity signal A in the same manner as the angular velocity signal B. The angular velocity signal A taken into the MPU 500 is branched, one of which is input to the subtractor 507 via the low-pass filter 506, and the other is input to the subtractor 507 as it is. The output from the subtractor 507, from the angular velocity signal A, an angular velocity signal A _H which can by subtracting the output signal (LPF output signal) A _L of the low-pass filter 506. Note that the LPF output signal A _L is input to the initial value setting unit 710 as in the first embodiment.

Further, the MPU 500 is provided with a signal switching unit 711, and an output signal of the changeover switch is input to the signal switching unit 711. Signal switching unit 711, in response to operation of the switch, the angular velocity signal inputted to the target position calculation unit 701, switches between the angular velocity signal A _H and the angular velocity signal B _H.
When switched to the angular velocity signal A _H side, the angular velocity signal A is reflected in the image blur correction. Therefore, the image blur correction in which importance is attached to the frequency band of the image blur to be suppressed rather than the high correction accuracy. Is done.

On the other hand, when switched to the angular velocity signal B _H side, the angular velocity signal B is reflected in the image blur correction, so that the accuracy of the image blur correction is higher than the width of the image blur frequency band to be suppressed. Important image blur correction is performed.
That is, the user of this camera system can switch the mode of the camera system between “broadband mode” and “high accuracy mode”.

FIG. 8 is a flowchart illustrating the operation of the MPU 500 according to the present embodiment. In step S10 in FIG. 8, the same processing (processing for demonstrating a high correction function at an early stage) as in steps S11 to S15 in FIG. 6 is executed.
As shown in FIG. 8, the MPU of the present embodiment has a signal switching unit immediately after the start of power supply (YES in step S1) when the changeover switch is set to the high accuracy mode side (step S2 high accuracy side). 711 is set on the side of the angular velocity signal B (step S3), and after executing processing for exhibiting a high correction function at an early stage (step S10), image blur correction is performed (step S16).

Further, immediately after the start of power supply (YES in step S1), when the changeover switch is set to the wideband mode side (step S2 wideband side), the signal switching unit 711 is set to the angular velocity signal A side (step S2). S4) After taking in angular velocity signals A and B and starting LPF calculation (step S5), image blur correction is performed (step S16).
Also, except immediately after the start of power supply (NO in step S1), the camera system mode is switched according to the changeover switch (steps S2, S3, and S4), and image blur correction is continued as it is (step S16).

(Modification)
Note that the selector switch of the present embodiment may have two systems, a selector switch for an image blur correction circuit in the X direction and a selector switch for image blur correction in the Y direction. However, if there are two selector switches, Since the user operation becomes complicated, a single selector switch may be used for both the image blur correction circuit in the Y direction and the image blur correction circuit in the X direction.

Further, instead of providing a dedicated changeover switch, similar switching may be performed using operation members (setting dial, release button, etc.) provided in advance in the camera body.
[Others]
In each of the embodiments described above, a digital circuit (MPU) is used as the image blur correction circuit. However, part or all of the operation of the digital circuit may be realized by an analog circuit. Further, a part of the operation of the analog circuit of each embodiment described above may be realized by a digital circuit.

In each of the embodiments described above, the mounting destination of the high-speed activation sensors 5p and 5y and the high-precision sensors 6p and 6y is the lens barrel side, but may be the camera body side.
In each of the above-described embodiments, the camera system that drives the correction lens for image blur correction has been described. However, the present invention can also be applied to a camera system that drives an imaging unit (an imaging device or a film).

  In each of the above-described embodiments, a camera system including a camera body and a lens barrel that can be attached to and detached from the camera body has been described. However, the present invention is also applied to a camera system in which the camera body and the lens barrel are integrated. The invention is applicable. Further, the present invention can be applied to a video camera system in addition to a still camera system.

1 is an overall configuration diagram of a camera system according to a first embodiment. 3 is a cross-sectional view of an image blur correction unit 3. FIG. (A) is a perspective view of the periphery of the fixed cylinder which fixed the high speed starting sensors 5p and 5y and the high precision sensors 6p and 6y. FIG.3 (b) is A view in FIG.3 (a). FIG. 3 is a block diagram of an image blur correction circuit (only in the Y direction) according to the first embodiment. It is a figure which shows the time change waveform of the angular velocity signals A and B immediately after the start of the electric power supply with respect to a lens barrel. It is an operation | movement flowchart of MPU of 1st Embodiment. FIG. 6 is a block diagram of an image blur correction circuit (only in the Y direction) of a second embodiment. It is an operation | movement flowchart of MPU of 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Camera body, 2 ... Lens barrel, 5p, 5y ... High speed start sensor, 6p, 6y ... High precision sensor, 203b ... Correction lens, 301X, 301Y ... Actuator

Claims (7)

A detection unit that detects vibration of the imaging system, which includes an imaging optical system that forms a captured image and an imaging unit that captures the captured image;
In an image shake correction apparatus comprising: a drive control unit that drives and controls at least a part of the imaging system according to an output signal of the detection unit and attenuates shake of the captured image on the imaging unit;
In the detection unit,
There is a high-precision detection unit that can detect the vibration with high accuracy in a long activation time, and a high-speed activation detection unit that can detect the vibration with low accuracy in a shorter activation time than that,
The drive control unit
An image blur correction apparatus, wherein the output signal of the high-precision detection unit is corrected based on the output signal of the high-speed activation detection unit activated first, and the drive control is performed in accordance with the corrected signal. The image blur correction apparatus according to claim 1,
The drive control unit
An image blur correction apparatus, wherein a low frequency component is extracted from an output signal of the fast activation detection unit, and the correction is performed based on the low frequency component. The image blur correction device according to claim 2,
The drive control unit
An image blur correction apparatus, wherein the correction is performed based on an offset between an output signal of the high-speed activation detection unit and an output signal of the high-precision detection unit. The image blur correction device according to claim 3,
The drive control unit
The image blur correction apparatus characterized by recognizing the offset based on an output signal of the high-speed activation detection unit and an output signal of the high-precision detection unit at the same timing. In the image blur correction apparatus according to any one of claims 2 to 4,
The drive control unit
An image blur correction apparatus, wherein the correction is performed based on a difference in sensitivity between the high-speed activation detection unit and the high-precision detection unit. In the image blur correction apparatus according to any one of claims 1 to 5,
A vibration gyro is used for the high-precision detection unit,
An image blur correction apparatus, wherein a vibration gyro having a vibrator having a Q value lower than that of the vibration gyro is used for the high-speed activation detection unit. The image blur correction device according to claim 6,
For the high-precision detection unit, a crystal-type vibration gyro is used,
An image blur correction apparatus characterized in that a ceramic-type vibration gyro is used for the high-speed activation detection unit.

Images