JP2003149700A - Image blur correction device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the time untile the precise detection of a blur quantity after supplying power in a blur correction device for optical equipment. SOLUTION: The output signal of an angular velocity sensor 51 (52) is inputted to CPU 31 via a high-pass filter HF51 (HF52), which has a capacitor C51 (C52), a resistor R51 (R52) and a switch SW51 (SW52). When the switch SW51 (SW52) is turned on, the resistor R51 (R52) is short-circuited. Just after supplying power to a camera, the switch SW51 (SW52) is turned on. The switch SW51 (SW52) keeps ON state, in the shortest, until blur detection processing based on the output signal of the angular velocity sensor 51 (52) is carried out just after the supply of power, and in the longest, until just before blur detection processing by the CPU 31 is carried out just after the start of exposure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image blur correction device for correcting image blur of an optical device caused by camera shake or the like.

[0002]

2. Description of the Related Art Conventionally, an image blur correction device for correcting image blur of an optical device is provided with an angular velocity sensor for detecting an image blur of an optical device and a correction provided so as to constitute a part of a photographing optical system. And an optical system. The shake amount of the optical device is C
It is calculated by integrating the output signal of the angular velocity sensor in a control device such as a PU, and by driving the correction optical system based on the calculation result, the image plane of the camera,
For example, the movement of the subject image on the film surface or the image plane of the photoelectric conversion element is corrected.

A gyro sensor, for example, is used as the angular velocity sensor. The output of the gyro sensor may include a direct current component such as a null voltage or a residual direct current component immediately after the pan operation of the optical device, and thus an error may be included in the calculation of the shake amount. Therefore, in order to efficiently remove these DC components, an image blur correction device has been proposed that appropriately changes the cutoff frequency of the output signal of the gyro sensor.

By the way, the output signal of the gyro sensor is
Even if the angular velocity is zero, it changes depending on temperature drift (change in output at rest due to changes in ambient temperature) and the passage of time. Therefore, in order to eliminate the influence of temperature drift and the like, a high-pass type DC cut filter, which is generally composed of a capacitor and a resistor, is connected to the gyro sensor.

The time constant of such a DC cut filter must be set to be relatively large in order to remove a frequency lower than the cutoff frequency when removing the DC component due to the null voltage or the pan operation. This is because the DC component removal process in the image shake correction apparatus does not function normally when the signal input to the image shake correction apparatus has already been removed to a high frequency component.

[0006]

However, setting the time constant of the DC cut filter to a large value means that after the power is turned on, the signal that passes through the DC cut filter and is input to the image blur correction apparatus described above is stable. It means that the time will be longer. Therefore, in the image blur correction apparatus, the phenomenon in which the input signal fluctuates with a long time constant occurs even though the DC component removal processing is performed. In other words, there is a problem that it takes some time before the accurate blur amount is actually detected even though the image blur correction apparatus starts the process for detecting the accurate blur amount.

The present invention is intended to solve the above problems, and it is an object of the present invention to reduce the time required to accurately detect a shake amount after power is turned on in an image shake correction apparatus.

[0008]

SUMMARY OF THE INVENTION An image blur correction apparatus according to the present invention comprises a blur detecting means for detecting blur of an optical axis of an optical device, and a blur amount for calculating a blur amount based on a detection result of the blur detecting means. Based on the calculation means, the correction optical system for correcting the shake of the optical axis, the driving means for driving the correction optical system, and the shake amount calculated by the shake amount calculation means, the observation caused by the shake of the optical axis A shake correction control means for controlling the driving means so that the correction optical system is driven to follow the shake of the optical axis in order to eliminate the shake of the body image, and an initialization means for initializing the output signal of the shake detecting means are provided. During the execution of the shake detection process by the shake detection unit that is started after the power of the optical device is turned on, the initialization process is performed by the initialization unit for a predetermined period immediately after the power is turned on.

Preferably, the initialization means includes a timer means for measuring a predetermined period, and the initialization means short-circuits a capacitor and a resistor for removing a low frequency component contained in the output signal of the shake detection means. A high-pass filter having a switch means, and immediately after the power is turned on, the switch means is turned on to short-circuit the resistor, and after the shake detection processing by the shake detection means is started, the elapse of a predetermined period is measured by the timer means. The switch means is turned off.

For example, in the case of being applied to a camera, the predetermined period starts immediately after the power is turned on and ends before the blur detection by the blur detection means is performed immediately after the release operation is started.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a camera 1 having an image blur correction function according to this embodiment. The camera 1 includes an objective optical system 2, an image blur correction unit 40, a quick return mirror 3, a finder optical system (penta prism) 4, and an AF.
A sensor 7, a sub-mirror 8, a shutter button 20, a film F on which a subject image is formed, and a control means 30 for controlling the entire camera 1 are provided. The image blur correction unit 40 includes a correction lens 401 (correction optical system). In the camera 1, the photographing optical system includes the objective optical system 2 and the correction lens 401. The subject light is the objective optical system 2 and the correction lens 40.
After passing through 1, the light enters the quick return mirror 3. The subject light reflected by the quick return mirror 3 is guided to the photographer's eye by the finder optical system 4, and the subject light transmitted through the quick return mirror 3 is reflected by the sub mirror 8 and guided to the AF sensor 7. The image blur correction means 4
Details of 0 and the correction lens 401 will be described later.

Further, the camera 1 includes angular velocity sensors 51 and 52 functioning as shake detecting means for detecting shake of the photographing optical system with respect to a subject, and lens movement detection for detecting movement of a lens in the photographing optical system in the optical axis direction. Means 60 are provided.

The shutter button 20 is a two-step switch, and when it is pressed one step, the photometric switch is turned on.
Then, when it is pushed in two steps, the release switch turns on.
The ON / OFF information of these switches is the control means 30.
Entered in.

The angular velocity sensor 51 detects the angular velocity of the rotational movement of the camera in the vertical direction (vertical direction) of FIG. 1, and outputs to the control means 30 a voltage corresponding to the angular velocity in that direction due to camera shake or the like. The angular velocity sensor 52 is a sensor that detects the angular velocity of the rotational movement of the camera in the direction (horizontal direction) orthogonal to the paper surface of FIG. 1, and outputs a voltage according to the detected angular velocity to the control means 30.

The image blur correction means 40 constitutes a part of the photographic optical system as described above, and comprises the correction lens 401 for deflecting the optical axis of the photographic optical system and the driving means for driving the correction lens 401. It is configured. The drive unit drives the correction lens 401 based on a command from the control unit 30 so as to cancel the movement of the subject image formed by the photographing optical system on the film surface F, and sets the optical axis of the photographing optical system to the paper surface. Deflection is independent of each other in the vertical direction and the direction parallel to the paper surface.

The control means 30 drives the image shake correction means 40 based on the input signals from the angular velocity sensors 51 and 52 during the photographing operation to drive the image shake on the film surface F and within the viewfinder field. To correct.

Although the objective optical system 2 is shown as one lens in FIG. 1, it is actually composed of a plurality of lenses or a plurality of lens groups, and a part thereof is used for focusing or zooming. , Or all of them are movable in the optical axis direction. In the present embodiment, the lens movement detection unit 60 detects movement for focusing of a lens group related to focusing (hereinafter, referred to as “focusing lens”) among the lenses forming the objective optical system 2.

At the time of observation, the quick return mirror 3 is shown in FIG.
It is positioned at the position shown in. Therefore, the objective optical system 2 including the focusing lens and the image blur correction means 40
The luminous flux of the subject incident through the correction lens 401 of
It is reflected by the quick return mirror 3 and guided to the focusing screen B. The image of the subject on the focusing screen B is inverted by the pentaprism 4, and the observer can observe the image on the focusing screen B as an erect image through the eyepiece lens 9. That is, in this embodiment, the finder optical system is
An objective optical system 2 including a focusing lens, a correction lens 401, a quick return mirror 3, a focusing screen B, a pentaprism 4, and an eyepiece lens 9 are provided.

The quick return mirror 3 and the sub mirror 8 are retracted to a position facing the focusing screen B by a mirror driving mechanism (not shown) at the time of photographing. As a result, at the time of shooting, the light flux of the subject is guided to the film surface F through the objective optical system 2 including the focusing lens and the correction lens 401, and a subject image is formed on the film surface F. In this way, the subject image is exposed on the film surface F and the subject image is recorded.

The focusing lens is configured to move in the optical axis direction by a known cam mechanism (not shown) by rotating the lens barrel 5. The lens barrel 5 is rotationally operated by a motor provided in the body of the camera 1 or a lens unit, or by a manual operation of the focusing operation ring 55 by the photographer himself.

The AF sensor 7 is a conventionally known sensor that detects the defocus amount of the photographing optical system by the phase detection method. An image sensor (not shown) in the AF sensor 7 is arranged at a position optically equivalent to the focusing screen B and the film surface F. Therefore, the focus state on the focusing screen B is the film surface F.
The focus state is equivalent to the above focus state, and when the image on the focusing plate B formed by the photographing optical system is imaged, in other words, when the focus position by the photographing optical system matches the focusing plate B, the focus state is achieved. It is in a state.

The AF sensor 7 detects the focus state of the image on the film surface F (planned focal plane) formed by the photographing optical system as a defocus amount. That is, the AF sensor 7
Detects a defocus amount indicating in what direction on the optical axis the focal position of the image formed by the photographing optical system at the present time is displaced from the focusing screen B or the film surface F. The control unit 30 calculates the driving direction and the driving amount of the focusing lens based on the defocus amount detected by the AF sensor 7, and the focusing lens is driven based on the calculation result of the control unit 30 for automatic focus adjustment. Done.

The lens movement detecting means 60 is a pinion gear 61 that meshes with a rack 5a provided on the outer periphery of the lens barrel 5.
And a slit plate 62 provided coaxially with the pinion gear 61, and a photo interrupter 63 provided so as to sandwich the slit plate 62. Slit plate 62
Is provided with a large number of slits radially around the rotation axis. The photo interrupter 63 is composed of a light emitting portion 63a and a light receiving portion 63b which are opposed to each other with the slit plate 62 interposed therebetween.
A periodic signal corresponding to the light and darkness of light is output in accordance with the rotation of. As described above, the lens barrel 5 is rotated by the motor provided in the body of the camera 1 or the lens unit in the case of autofocus, and is manually rotated by the photographer in the case of manual focus. Therefore,
A pulse signal is output from the light receiving portion 63b in accordance with the rotation of the slit plate 62 that is interlocked with the rotation of the lens barrel 5 due to focusing.

The correction mode selection button 80 is used for the image blur correction processing (the angular velocity sensors 51, 5) by the control means 30 described above.
This is a button for selecting the execution timing of the processing for correcting the image blur on the film surface F and in the viewfinder field by controlling the drive of the image blur correction unit 40 based on the input signal from the input device 2. In the present embodiment, the image blur correction process is performed during the photometric process, and the image blur correction process is continuously performed during the release operation, and the second image blur correction process is performed only during the release operation.
There is a correction mode of. By operating the correction mode selection button 80, one of the correction modes is selected.

FIG. 2 shows the structure of the image blur correction means 40. The correction lens 401 that constitutes the correction optical system is fixed to the first rotating plate 420 while being fitted in the lens frame 410, and the first rotating plate 420 is provided with the second rotating plate 430 via the rotating shaft 421. Is rotatably attached to. Further, the second rotating plate 430 is rotatably attached to the substrate 440 via a rotating shaft 431 that is provided to project 90 degrees away from the rotating shaft 421 about the optical axis O of the photographing optical system. Board 440
Is fixed to the camera 1.

With the above arrangement, the correction lens 401 is
By rotating the first and second rotating plates 420 and 430, the optical axis O
In the plane perpendicular to the direction indicated by arrow V in the figure (vertical direction described above), the direction indicated by arrow V (horizontal direction described above)
Is held so that it can be displaced.

The lens frame 410 has a large diameter portion 411 and a small diameter portion 412, and the small diameter portion 412 is fitted into the opening 422 of the first rotating plate 420. The rotating shaft 4 of the first rotating plate 420
21 is inserted into a shaft hole 439 formed in the second rotating plate 430. An arm 424 having a screw hole 423 is provided on the opposite side of the rotating shaft 421 with the opening 422 interposed therebetween.

A screw member 426 connected to the rotation shaft of the motor 425 via a flexible joint is screwed into the screw hole 423. The motor 425 uses the second rotating plate 4
It is fixed on 30. When the motor 425 is driven, the first rotation plate 420 is driven to rotate about the rotation shaft 421 in the direction indicated by the arrow V according to the rotation direction of the screw member 426.

The permanent magnet 4 is attached to the tip of the drive arm 424.
27 is provided, and MR (Magnetic) for detecting the position of the permanent magnet 427 is provided on the second rotating plate 430.
(Resistance) sensor 428, the permanent magnet 42
It is provided so as to face 7. The control means 30 detects the displacement of the lens 401 in the direction of arrow V based on the output signal of the MR sensor 428.

The rotating shaft 431 of the second rotating plate is connected to the substrate 440.
It is inserted into the shaft hole 449 formed in the. Second rotating plate 43
An opening 432 through which the small diameter portion 412 is inserted is formed at 0. The opening 432 has a size that does not hinder the movement of the small diameter portion 412 due to the rotation of the first rotating plate 420 when the first rotating plate 420 is assembled to the second rotating plate 430.

A drive arm 434 having a screw hole 433 is provided on the opposite side of the rotating shaft 431 with the opening 432. A screw member 436 connected to the rotation shaft of the motor 435 via a flexible joint is screwed into the screw hole 433. When the motor 435 is driven, the second rotating plate 430 is rotationally driven around the rotating shaft 431 in the direction indicated by the arrow H according to the rotating direction of the screw member 436.

The permanent magnet 4 is attached to the tip of the drive arm 434.
37 is provided, and the MR sensor 438 is arranged on the substrate 440. The control means 30 uses the MR sensor 4
A displacement of the lens 401 in the arrow H direction is detected by the output signal of 38.

The substrate 440 is provided with an opening 442 through which the small diameter portion 412 is inserted. The opening 442 has a size that does not hinder the movement of the small diameter portion 412 due to the rotation of the first and second rotating plates.

In FIG. 3, the image blur correction means 40 is viewed from the objective optical system 2 side in a state where the lens frame 410, the first rotary plate 420, the second rotary plate 430, and the substrate 440 are combined. It is a figure. FIG. 3 shows a reference state in which the optical axis of the correction lens 401 coincides with the optical axis O of the photographing optical system. In the reference state, the center of the rotation shaft 421 of the first rotation plate 420, the optical axis O, the permanent magnet 427, and the MR sensor 428 are arranged on the straight line a. Similarly, the center of the rotation shaft 431 of the second rotation plate 430,
The optical axis O, the permanent magnet 437, and the MR sensor 438 are arranged on the straight line b.

FIG. 4 is a block diagram for explaining input / output signals of the CPU 31 constituting the control means 30 described above.
The ON / OFF information of the photometric switch 21 and the release switch 22 which are linked to the shutter button 20 is a 1-bit digital signal, which is the port P1 of the CPU 31.
1 and P12 are input. The ON / OFF information of the correction mode switch 23 linked with the correction mode selection button 80 is also input to the port P13 of the CPU 31 as a 1-bit digital signal. In the present embodiment, when the correction mode selection button 80 is operated to select the first correction mode described above, the correction mode switch 23 is turned off, and when the second correction mode is selected, the correction mode switch 23 is turned on. Turns on.

A high-pass filter HF51 including a capacitor C51, a resistor R51 and a switch SW51 is connected to the angular velocity sensor 51. The capacitor C51 is
It is connected to the sensor output terminal of the angular velocity sensor 51 that outputs the angular velocity. The resistor R51 is connected to the capacitor C51 and the reference output terminal of the angular velocity sensor 51 that outputs the reference voltage. When the switch SW51 is turned on, the resistance R5
1 is short-circuited. The angular velocity output from the sensor output terminal of the angular velocity sensor 51 is input to the A / D conversion port AD1 of the CPU 31 via the high pass filter HF51.

Similarly, the angular velocity sensor 52 is connected to a high pass filter HF52 having a capacitor C52, a resistor R52 and a switch SW52. The circuit configuration of the high-pass filter HF52 is the same as that of the high-pass filter HF51, and when the switch SW52 is turned on, the resistance R5 is generated.
2 is short-circuited. The angular velocity output from the sensor output terminal of the angular velocity sensor 52 is input to the A / D conversion port AD2 of the CPU 31 via the high pass filter HF52.

The switches SW51 and SW52 are CP
It is connected to the output port P21 of U31, and ON / OFF is controlled by a control signal output from the output port P21. The switches SW51 and SW52 are turned on when the output voltage of the output port P21 is at a high level and turned off when the output voltage is at a low level.

The voltage outputs from the MR sensors 428 and 438 are input to the A / D conversion ports AD3 and AD4, respectively.

D / A output ports DA1 and D of the CPU 31
A motor 425 that drives the first rotary plate 420 and a motor 435 that drives the second rotary plate 430 are connected to A2 via motor drive circuits 461 and 462, respectively. The CPU 31 converts the amount of movement of the correction lens 401 required to correct the image blur based on the above-mentioned input signal into the drive amount of the motor 425 and the motor 435 for calculation,
The voltage corresponding to the drive amount is output from the ports DA1 and DA2.

When the shutter button 20 is half-pressed, the photometric switch 21 is turned on and the first input port P11 is turned on.
When the signal is input, the CPU 31 executes the photometric operation of the subject light to calculate the exposure value (Ev), and based on the exposure value, the aperture value (Av) and the exposure time (T) required for shooting.
v) is calculated. When the shutter switch 20 is fully pressed to turn on the release switch 22 and an ON signal is input to the second input port P12, the CPU 31
Drives a diaphragm mechanism (not shown) in accordance with the above-mentioned diaphragm value to flip up the quick return mirror 3 and drive a shutter mechanism (not shown) at a predetermined shutter speed.

Image blur correction processing in the CPU 31 will be described below with reference to the flow charts shown in FIGS. As described above, the angular velocity sensor, MR sensor, and
Although driving means and the like are provided, only the processing in the vertical direction is shown in the flowchart to avoid duplication of description.

When the power of the camera 1 is turned on and the processing is started, the output voltage of the output port P21 is set to the high level (Hi) in step S100. As a result, the switch SW51 of the high pass filter HF51 turns off.
N. Next, in step S102, a correction mode check routine is executed to confirm which correction mode is set.

FIG. 8 is a flow chart showing the processing procedure of the correction mode check routine executed in step S102. In step S200, the input signal to the port P13 of the CPU 31 is checked, and the ON / OFF state of the correction mode switch 23 is confirmed. When the correction mode switch 23 is OFF and it is confirmed that the first correction mode is selected, the process proceeds to step S202. In step S202, a flag M indicating the correction mode is set.
"0" is set in ODE. Then, step S2
In step 04, "200" is set to the variable ON_TIME for controlling the number of executions of the interrupt processing routine activated every 1 ms (milliseconds), that is, the elapsed time from the present time. The interrupt processing routine will be described later.

On the other hand, if it is confirmed in step S200 that the correction mode switch 23 is ON and the second correction mode is selected, the process proceeds to step S206.
In step S206, "1" is set in the flag MODE. Next, in step S208, the variable is turned on.
"1000" is set in _TIME.

When the correction mode is checked in step S102 of FIG. 5, the routine proceeds to step 104, where "0" is set in the counter T_CNT for measuring the number of executions of the interrupt processing routine, that is, the elapsed time from the present time, and the initial value is set. The interrupt processing routine is started every 1 ms.

Next, in step S106, the digital variable value V3 and the digital swing displacement value V4 are set to "0" and initialized, and in step S108, the elapsed time since the photometric switch 21 was turned on is measured. The counter TT of is set to "0" for initialization. The digital variable value V3 includes the angular velocity sensor 51.
Vertical DC component based on the null voltage output from
That is, the vertical offset value of the camera shake detection signal and the vertical DC component based on the slow shake of the camera 1 are stored. The digital swing displacement value V4 stores the drive amount of the first rotating plate 420 driven to correct the image blur to the target position.

In step S110, the output signal (analog) from the angular velocity sensor 51 is the A / D conversion port A.
It is A / D converted by D1 and set to the digital detection value V1. Next, in step S112, the digital variable value V3 is subtracted from the digital detection value V1 and set to the angular velocity value V2. That is, the angular velocity value V2 is set to a value corresponding to the angular velocity from which the DC component has been removed.

Next, in step S114, the value of the digital variable value V3 is updated. The value obtained by dividing the angular velocity value V2 obtained in step S112 by the coefficient K1 is added to the digital variable value V3, and the value is set to the digital variable value V3. That is, the DC component to be removed is updated according to the changing angular velocity.

In step S116, the state of the photometric switch 21 is checked, and if it is confirmed that the photometric switch 21 is OFF, the process returns to step S108. That is, the processes of steps S108 to S114 are repeatedly executed until the photometric switch 21 is turned on.

Immediately after the power of the camera 1 is turned on, the angular velocity sensor 51 may output a large voltage value due to the electric charge remaining in each circuit in the camera 1. Further, before the photometric processing is executed, an operation in which the angular velocity greatly changes, such as an operation of directing the camera 1 toward a target subject such as a pan operation, is frequently performed. That is, the output of the angular velocity sensor contains a relatively large DC component from when the power is turned on to when the photometric processing is started. Therefore, the coefficient K1 is set to a relatively small value.

At step S116, the photometric switch 21 is turned off.
If it is confirmed that N has occurred, the process proceeds to step S118 in FIG. In step S118, photometric processing is executed, and the aperture value, exposure time, etc. are calculated. Then step S12
0, the value of the coefficient Kx is set based on the value of the counter TT, and the counter TT is set in step S122.
The value of is incremented.

In steps S124 to S128, the same processes as those in steps S110 to S114 of FIG. 5 are executed. That is, the output signal of the angular velocity sensor is A
/ D converted and set to digital detection value V1 (S1
24), the value obtained by subtracting the DC component from the digital detection value V1 is set as the angular velocity value V2 (S126), and the updating process of the digital variable value V3 based on the angular velocity value V2 and the coefficient Kx is executed (S128).

Next, in step S130, the value of the flag MODE is checked. If the value of the flag MODE is "0" and it is confirmed that the first correction mode, that is, the correction mode for starting the image blur correction during photometry is selected, the process proceeds to step S132. In step S132, the integration processing of the angular velocity value V2 is performed and the digital swing displacement value V4 is set. Step S134
Then, the output signal of the MR sensor 428 is A / D converted at the A / D conversion port AD3 and set to the digital detection value V5. That is, the current displacement of the correction lens 401 in the vertical axis direction is calculated. In step S136, the difference between the digital swing displacement value V4 and the digital detected value V5 is calculated and set to the digital swing drive value V6 as a voltage value corresponding to the further drive amount of the correction lens 401. Next, in step S138, the digital swing drive value V6 is converted into an analog signal via the D / A output port DA1 and output to the motor drive circuit 461. The motor drive circuit 461 controls the drive of the motor 425 based on the analog swing drive value input from the output port DA1. Then, the process proceeds to step S140.

On the other hand, if it is confirmed in step S130 that the value of the flag MODE is "1" and the second correction mode, that is, the correction mode for executing the image blur correction only during the release operation is selected, Step S1
The processing of 32 to S138 is skipped, and step S14 is performed.
Go to 0.

In step S140, the ON / OFF state of the release switch 22 is checked. If it is confirmed that the release switch 22 is OFF, the process returns to step S116 of FIG. 5 and the subsequent processing is repeated.
Therefore, by repeatedly executing step S120, the value of the coefficient Kx continuously increases according to the elapsed time after the start of the photometric processing.

On the other hand, if it is confirmed that the release switch 22 is ON, the process proceeds to step S142 in FIG.
In step S142, the diaphragm is narrowed down to a predetermined aperture, the quick return mirror 3 and the sub mirror 8 are retracted to the position facing the focusing screen B, and the shutter is driven at a predetermined shutter speed.

Then, in steps S144 to S156, the same processes as steps S124 to S138 except step S130 in FIG. 6 are executed. That is, the DC component is removed from the output signal of the angular velocity sensor 51 (S146), the DC component is updated (S148),
The integration processing of the angular velocity value (S150), the calculation of the voltage value corresponding to the further drive amount of the correction lens 401 (S154), and the like are performed, and the drive control of the motor 425 is performed.

At the stage of the release operation, the camera 1 is already aimed at the subject, and it is desirable that the relatively low frequency fluctuation contained in the output signal of the angular velocity sensor 51 is also reflected in the image blur correction. Therefore, the coefficient K2 used in the process of step S148 during the release operation is set to a value larger than the coefficient K1 described above.

Next, in step S158, it is checked whether the exposure time calculated in step S118 of FIG. 6 has elapsed. If the exposure time has not elapsed, the process returns to step S144, and the subsequent processes are repeated to execute the image blur correction process. If it is confirmed that the exposure time has elapsed, the process proceeds to step S160, the shutter is closed and driven, the quick return mirror 3 is returned to the reflection position,
The aperture is driven to open, and a series of shooting operations is completed.

Here, the interrupt processing routine activated every 1 ms will be described with reference to FIG. In step S300, it is checked whether the output voltage of the output port P21 is set to the low level (Lo).
When it is confirmed that the output voltage of the output port P21 is at the high level and the switch SW51 of the high pass filter HF51 is turned on, the process proceeds to step S302.

In step S302, the counter T_CN
The value of T is incremented by "1". Next, in step S304, the value of the counter T_CNT is set to the variable O.
It is compared with the value of N_TIME. If it is confirmed that the value of the counter T_CNT has not reached the value of the variable ON_TIME (YES in step S304), the output port P
The output voltage of 21 is maintained at the high level.
When it is confirmed that the value of the counter T_CNT has reached the value of the variable ON_TIME (NO in step S304),
In step S306, the output voltage of the output port P21 is set to the low level.

As described above, the correction mode check process (FIG. 8) sets the variable ON_TIME to "200" when the first correction mode is selected,
When the second correction mode is selected, "1000" is set. On the other hand, this routine is executed every 1 ms, and the counter T_CNT is incremented by "1" in S302. That is, in the case of the first correction mode, the level of the output voltage of the output port P21 is 200 mse after being set to the high level in step S100 of FIG.
During c, the high level state is maintained. In the second correction mode, the output voltage level of the output port P21 is maintained at the high level for 1000 msec after being set at the high level in step S100 of FIG.

Therefore, the switch SW51 of the high-pass filter HF51 is in the ON state for 200 msec when the first correction mode is selected, and is ON for 1000 msec when the second correction mode is selected.
It becomes a state. In other words, the switch SW51 of the high-pass filter HF51 is turned on immediately after the camera 1 is powered on, and is 200 in the first correction mode after that.
It turns off after msec, and in the case of the second correction mode,
It turns off after 1000 msec.

Here, the operation of the present embodiment will be described with reference to FIGS. FIG. 10 is a graph showing the difference in the image blur detection waveform depending on the length of the ON time of the switch SW51. The vertical axis represents the voltage value at the α point (see FIG. 4) of the high-pass filter HF51, and the horizontal axis represents the passage of time. L
Reference numeral 1 shows a change in voltage value at the point α when the switch SW51 is always turned off. Switch SW51 is OF
When F is set, the voltage value at the α point is
Changes with a predetermined time constant (hereinafter, time constant CR) which is determined by the capacitance value of R1 and the resistance value of the resistor R51. L2 represents a change in the voltage value at the point α when the switch SW51 is always turned on. Since the resistor R51 is short-circuited when the switch SW51 is turned on, the voltage value at the point α is the time constant C.
It changes with a time constant smaller than R (hereinafter, time constant CRon). ST is a voltage value (reference value without blurring) output from the angular velocity sensor 51 when no camera shake occurs.

The switch SW51 switches from time t00 to t01.
When the switch SW51 is turned on at the time t01, that is, when the switch SW51 is turned on for the time P1, the voltage value at the α point changes with the time constant CRon as shown by L2 during the time P1. , V01 is reached. Then V
While changing from 01 to the time constant CR, the angular velocity sensor 51
The blur detection value due to is reflected and changes (TR1).

The switch SW51 switches from time t00 to t02.
When the switch SW51 is turned on at the time t02, that is, when the switch SW51 is turned on for the time P2, the voltage value at the point α changes with the time constant CRon as shown by L2 during the time P2. , V02 is reached. Then V
While changing from 02 with the time constant CR, the angular velocity sensor 51
The shake detection value due to is reflected and changes (TR2).

When the switch SW51 is turned on for the time P2, the time constant C is also maintained from the time t01 to t02.
Since it changes with Ron, the level V02 at which the shake detection value of the angular velocity sensor 51 starts to be reflected is a value closer to the shake-free reference value than the level V01. That is, the switch S
The longer the time when W51 is turned on, the longer it is changed by the time constant CRon that is shorter than the time constant CR. Therefore, the level at which the blur detection value of the angular velocity sensor 51 starts to be reflected depends on the non- blur reference value. It is a close value. Therefore,
From the viewpoint of the accuracy of shake detection, it is preferable that the switch SW51 is on for a longer time.

FIG. 11 shows the start timing of image blur detection and the OF of the switch SW51 of the high-pass filter HF51.
It is a graph which shows the difference of the change of the voltage value in alpha point based on the relative relationship with F time.

The switch SW51 is turned off at time t12.
It becomes FF and is in the ON state until then. In FIG. 11, ST is a reference value without blur, as in FIG.
The waveform TR3 is a waveform showing a change in the voltage at the point α, and the waveform TR4 is a shake waveform until time t12. Time t1
Up to 2, since the switch SW51 is ON, the voltage value at the point α changes with the time constant CRon. At the time when the switch SW51 is turned off at time t12, the voltage value at the point α changes to a value corresponding to the camera shake detected by the angular velocity sensor 51 and changes.

Here, the start time of the image blur correction is time t1.
The case before and after 2 will be compared. When the above-described image blur detection by the CPU 31 is started from time t11 before time t12, the image blur detection process is executed with the voltage value at the point α at time t11 as a reference value (start reference value). The voltage value at the subsequent α point changes with this start reference value as a reference. Similarly, from time t13 after time t12, the CPU
When the above-described image blur detection process by 31 is started, time t
The image shake detection process is executed with the voltage value at the α point at 13 as the start reference value, and the voltage value at the subsequent α point changes with the start reference value at time t13 as the reference.

As described above, the switch SW51 is ON at the time t11, and the voltage value at the point A reaches the unblurred reference value with a small time constant regardless of the camera shake detected by the angular velocity sensor 51. Is changing towards. That is, as shown in FIG. 11, the start reference value at time t11 is close to the unblurred reference value. In other words, time t1
If the image blur detection process is started at 1, the voltage value with a small offset amount from the blur-free reference value is used as a reference, and the accuracy of image blur detection is high.

On the other hand, at time t13, the switch SW51 has already been turned off, and the change in the voltage value at the point α shows a large amplitude corresponding to the actual camera shake.
Therefore, the start reference value at time t13 is likely to be a value that is largely offset from the unblurred reference value. That is, when the image blur detection process is started after turning off the switch SW51, the start reference value is highly likely to be largely offset from the non-blur reference value.

Based on the above consideration, the operation of the OFF timing of the switch SW51 in this embodiment will be described with reference to FIGS. The step numbers in FIGS. 12 to 14 correspond to the step numbers in the flowcharts in FIGS.

In the present embodiment, the image blur detection process is started immediately after the camera 1 is powered on (S11).
0). In addition, as described above, when the first correction mode is selected and the image blur correction process is started during the photometry process, the ON time of the switch SW51 is set to 200 msec, and the second correction mode is selected. When the image blur correction process is performed only during the release operation, the ON time of the switch SW51 is set to 1000 msec. In any of the correction modes, in the loop processing of steps S108 to S114, the switch SW51 is ON at least until step S110 in the first loop processing.
(See FIG. 12). In other words, during the image blur detection process immediately after the power is turned on, the switch SW is
51 is turned on, and the charging voltage of the capacitor C51 that is unrelated to the actual detection output of the angular velocity sensor 51 is used. Then, after a lapse of a predetermined period, the switch SW51 is turned off after the blur detection value used for blur correction reaches a level close to the non-blurring reference value, and the actual detection output of the angular velocity sensor 51 is reflected.

Further, the ON time of the switch SW51 when the second correction mode is selected is 1000 msec, and the switch SW51 is switched on during the photometric processing after the power of the camera 1 is turned on.
The ON state of 51 continues (see FIGS. 12 and 13). Therefore, in the image blur detection after the release operation is started, the voltage value at the point α changes to a level closer to the non-blurring reference value, and then the fluctuation in which the blur detection value of the angular velocity sensor 51 is reflected is started. . As a result, highly accurate image shake detection / correction processing (see FIG. 14) during the release operation can be performed.

Here, in the case of the second correction mode, the switch SW51 is turned off after the power is turned on for 1000 seconds.
Consider the timing after msec.
As described above, it is preferable to set the ON time of the switch SW51 longer so that the voltage value at the α point is as close as possible to the reference value without blurring. However, the actual camera shake is reflected during the release operation (during exposure). Image blur correction must be executed based on the output signal of the angular velocity sensor 51.

Generally, there is preparation work for photographing such as confirmation of framing and exposure conditions after the power is turned on until the release switch 22 is turned on. Therefore, the time required for these preparations for photographing is switched. It can be assigned to the time for which the SW 51 is kept in the ON state. Therefore, in the second correction mode, the time during which the switch SW51 is on can be set to be relatively long.
However, if the ON time of the switch SW51 is set too long, appropriate image blur detection / correction cannot be performed when the release switch 22 is turned ON. Taking these points into consideration, the O of the switch SW51 under the second correction mode is set.
N hours is set to 1000 msec. By this setting, at least steps S144 to S156 during exposure are performed.
The switch SW51 is turned off by the time the step S144 is started in the first execution of the loop process (1) (see FIG. 14). Therefore, in the image blur correction process during release, it is possible to perform the calculation process based on the output signal of the time constant CR of the high pass filter HF51.

There is a time lag due to mechanical operation of the release mechanism after the release switch 22 is turned on until the release mechanism actually operates. Therefore, even if the shutter button 20 is pushed down by two steps immediately after the power is turned on to the camera 1 and the second correction mode is selected, the switch SW51 is operated according to the present embodiment. 1000msec after power on, OF
Since it is F, the release mechanism is turned off before it actually operates.

In this embodiment, the angular velocity sensor 5
The removal of the DC component such as the null voltage included in 1, 52 is C
Although it is performed by software processing under the control of the PU 31, it is not limited to this. For example, Japanese Patent Application 2000-1
As shown in Japanese Patent No. 94261, it is also possible to adapt to a camera in which a DC component is removed by hardware by a circuit including a plurality of resistors having different resistance values. At that time, the high-pass filter HF51 is interposed between the angular velocity sensor 51 and the circuit.

The flowcharts of FIGS. 5 to 7 and FIGS.
Although only the vertical direction has been described with reference to the timing chart of FIG. 14, it goes without saying that the same processing is executed in the horizontal direction in the actual image blur correction processing.

[0082]

As described above, according to the present invention, in the image blur correction apparatus using the angular velocity sensor, the time until the correct blur detection is started immediately after the power is turned on is shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a camera having an image blur correction function according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a correction lens driving mechanism of the camera of the embodiment.

FIG. 3 is a front view of the drive mechanism of FIG. 2 viewed from the side of an objective optical system.

FIG. 4 is a block diagram showing a configuration of a control system of the camera of the embodiment.

FIG. 5 is a flowchart showing a processing procedure until the photometric switch is turned on in the control sequence of the camera of the embodiment.

FIG. 6 is a flowchart showing a processing procedure until the release switch is turned on in the camera control sequence of the embodiment.

FIG. 7 is a flowchart showing a processing procedure during a release operation in the control sequence of the camera of the embodiment.

FIG. 8 is a flowchart showing a processing procedure of a correction mode check.

FIG. 9 is a flowchart showing the processing contents of interrupt processing activated every 1 msec.

FIG. 10 is a graph showing a difference in image blur detection waveform depending on the length of ON time of the switch means of the high pass filter.

FIG. 11 is a graph showing a difference in change in voltage value at a point based on a relative relationship between the start timing of image blur detection and the OFF state of the switch of the high pass filter.

FIG. 12 is a timing flowchart showing a blur detection / correction process until the photometric switch is turned on, and the state of the switch of the high-pass filter.

FIG. 13 is a timing flowchart showing a blur detection / correction process until the release switch is turned on, and the state of the switch of the high-pass filter.

FIG. 14 is a timing flowchart showing a shake detection / correction process during a release operation and a switch state of a high pass filter.

[Explanation of symbols]

1 camera 2 Objective optical system 4 Finder optical system 7 AF sensor 20 shutter button 21 Photometric switch 22 Release switch 30 control means 31 CPU 40 Image blur correction means 51, 52 Angular velocity sensor HF51, HF52 High pass filter SW51, SW52 switch 60 Lens movement detecting means 401 correction lens 420 First rotating plate 430 Second rotating plate 440 substrate

Claims (3)

[Claims] 1. A shake detecting means for detecting a shake of an optical axis of an optical device, a shake amount calculating means for calculating a shake amount on the basis of a detection result of the shake detecting means, and for correcting a shake of the optical axis. Correction optical system, driving means for driving the correction optical system, and the correction for eliminating the blurring of the observation object image due to the blurring of the optical axis, based on the blurring amount calculated by the blurring amount calculating means. The optical system includes a shake correction control unit that controls the drive unit so that the optical system is driven to follow the shake of the optical axis, and an initialization unit that initializes the output signal of the shake detection unit. An image blur correction apparatus characterized in that, during execution of a blur detection process by the blur detection unit started after turning on, an initialization process by the initialization unit is executed for a predetermined period immediately after power-on. 2. A timer means for measuring the predetermined period, wherein the initialization means includes a capacitor and a resistor for removing a low frequency component contained in an output signal of the shake detection means, and a resistor for removing the low frequency component. A high-pass filter having switch means for short-circuiting, immediately after power is turned on, the switch means is turned on to short-circuit the resistor, and after the shake detection processing by the shake detection means is started,
The image blur correction apparatus according to claim 1, wherein the switch means is turned off when the elapse of the predetermined period is measured by the timer means. 3. When applied to a camera, the predetermined period starts immediately after power is turned on and ends immediately before execution of blur detection by the blur detection means immediately after start of release operation. The image shake correction apparatus according to Item 1.