JP2002267685A - Oscillation detecting device and image blur correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit accurate output of oscillation detection in its early stages from a request for the oscillation detection. SOLUTION: These oscillation detecting device and image blur correcting device have a compensating voltage outputting means for outputting a compensating voltage, a comparing means for comparing the output of an oscillation detecting means with the output of the compensating voltage, an offset compensating mean for compensating an offset component of the output of the oscillation detecting means by controlling the compensating voltage on the basis of the output of the comparing means, a stationary state detecting means for detecting the stationary state of the oscillation detecting device, storage means (#202 and #206) for storing an offset compensation value obtained by the offset compensating means when the stationary state is detected by the stationary state detecting means, and a control means for taking the offset compensation value stored in the storage means as an initial value in the case of an request for the output of the oscillation detection, performing offset-compensation on the output of the oscillation detecting means, and taking the output on which the offset-compensation is performed as the output of the oscillation detection.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a vibration detecting device and an image blur correcting device mounted on a camera or the like.

[0002]

2. Description of the Related Art Conventionally, there has been proposed an apparatus for stabilizing an image by correcting shake of an optical system such as a camera, that is, suppressing vibration due to hand shake or the like. As a typical one of the shake correction methods used for a camera or the like, a part or all of an imaging optical system is driven based on shake information of a camera detected by a shake sensor, and the image is formed on an image plane. This is to suppress image blur.

Here, an angular velocity sensor or an acceleration sensor is generally used as the shake sensor.
Since such an angular velocity sensor or acceleration sensor itself outputs only a minute voltage with respect to given vibration,
An appropriate amplifier is provided outside the sensor to output a required voltage. However, sensors that detect such vibrations, especially piezoelectric vibration gyros commonly used in cameras and the like, have an unstable output for several tens to several hundred milliseconds immediately after power-on,
Low frequency drift occurs even after power is turned on. In addition, the static output voltage (null voltage) when no vibration is applied also changes extremely greatly due to individual variations of the vibrating gyroscope and changes in the use environment, particularly, depending on the use temperature. Therefore,
When the output signal is amplified to a required voltage, the drift component and the null voltage component are also amplified, and the signal is saturated. Therefore, in order to amplify the output without saturating the output and obtain a desired output value, a general vibration detecting device performs offset compensation.

[0004]

However, since the offset compensation value of the vibration detecting device fluctuates, an instruction for starting the image blur correcting operation after the power supply to the device is started or the user starts the image blur correcting operation (image blur including the vibration detecting device). The offset compensation calculation must be performed later (for the correction device), and there is a problem that a time delay occurs until the actual image blur correction operation starts.

In order to improve the performance and speed of the offset compensation, there has been a method of detecting a vibration by using the previous offset compensation value as an initial value. There is no guarantee that the device or the like on which the device is mounted is calculated in a stationary state, and it is hard to say that the offset compensation value has high accuracy.

(Object of the Invention) A first object of the present invention is to provide a vibration detecting device capable of transmitting an accurate vibration detection output early after a vibration detection is required.

A second object of the present invention is to provide an image blur correction apparatus capable of performing an image blur correction operation based on an accurate vibration detection output at an early stage from the instruction timing of the image blur correction operation start. is there.

[0008]

In order to achieve the first object, the invention according to any one of claims 1 to 3, comprises a vibration detecting means for detecting vibration, and a compensation voltage for outputting a compensation voltage. An output unit, a comparison unit that compares the output of the vibration detection unit with the compensation voltage output, and controls the compensation voltage based on the output of the comparison unit to compensate for an offset component of the output of the vibration detection unit. A stationary state detecting means for detecting that the vibration detecting apparatus is stationary, and the offset compensating means when the stationary state detecting means detects a stationary state. Storage means for storing the offset compensation value obtained by the means, and when a vibration detection output is requested, the offset compensation value stored in the storage means is used as an initial value, It is an vibration detecting device and a control means for performing offset compensation of the output of the vibration detecting means.

Further, in order to achieve the second object,
An image blur correction device comprising: the vibration detection device according to any one of claims 1 to 3; and an image blur correction unit configured to correct an image blur based on a vibration detection output from the vibration detection device.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 1 is a block diagram of a single-lens reflex camera according to an embodiment of the present invention, in which an image blur correction device including a blur sensor is mounted in an interchangeable lens as an example.

In FIG. 1, reference numeral 101 denotes a lens microcomputer which receives communication from a camera body through communication contacts 109c (for clock signal) and 109d (for camera body → lens signal transmission), and shakes according to the command value. Correction system 102, focus drive system 104, aperture drive system 10
5 is performed. The shake correction system 102 includes a shake sensor 106 for detecting shake, a position sensor 107 for detecting displacement of the corrected lens, and a control signal calculated by the lens microcomputer 101 based on outputs of the shake sensor 106 and the position sensor 107. And a shake correction drive system 108 that drives a correction lens to perform a shake correction operation. Also, 12
Reference numeral 4 (SWIS) denotes an image stabilization switch for selecting a shake correction operation. When selecting a shake correction operation, the image stabilization switch 124 is turned on.

The focus drive system 104 drives a focus adjusting lens in accordance with a command value from the lens microcomputer 101 to perform focusing. The aperture drive system 1
05 is based on a command value from the lens microcomputer 101,
The operation of reducing the aperture to the set position or returning the aperture to the open state is performed. Also, the lens microcomputer 101
Indicates the state inside the lens (focus position, aperture value, etc.) and information about the lens (open aperture value, focal length,
Data necessary for the distance measurement calculation) to the contact 109e for communication.
(For transmission of the signal from the lens to the camera body) is also transmitted to the camera body side. The lens microcomputer 101, the shake correction system 102, the focus drive system 104, and the aperture drive system 105 constitute a lens electrical system 110. The power contact 10 is connected to the lens electrical system 110.
9a, the power supply 11 in the camera through the ground contact 109b.
8, power is supplied.

In the camera body, a distance measuring unit 112, a photometric unit 113, a shutter unit 114, a display unit 115, other control units 116, and operation and start and stop of these units are provided as an electric system 111 in the camera body. A camera microcomputer 117 for performing management, exposure calculation, distance measurement calculation, and the like is built in. Power is also supplied to the in-camera electric system 111 from the in-camera power supply 118. Also, 121
(SW1) is a switch for starting photometry and distance measurement, and 122 (SW2) is a release switch for starting a release operation. These are generally two-stage stroke switches, and are release buttons. The switch 121 is turned on in the first stroke, and the release switch 122 is turned on in the second stroke. Reference numeral 123 (SWM) is an exposure mode selection switch. The exposure mode can be changed by turning the switch ON or OFF, or by operating the switch 123 and other operation members simultaneously.

FIG. 2 is a block diagram showing a specific circuit configuration of the lens microcomputer 101 and the shake correction system 102 of the lens electric system 110.

A vibration gyro 1 which is a shake sensor
The output from is a resistor R1, a resistor R2, a capacitor C1,
The signal is input to an A / D converter 5 of a lens microcomputer 4 (corresponding to 101 in FIG. 1) via an amplifier 3 composed of an operational amplifier 2. The amplification factor in the amplifying unit 3 is determined by “R2 / R1”.
And a first-order high-frequency cutoff filter having a cutoff frequency determined by the resistor R2 and the resistor R2. At the time of initial power-on or the like, the offset compensating means 6 is operated for calculating the offset component of the vibration gyro 1.
The output of the bit D / A converter 7 is controlled.

The output of the D / A converter 7 is connected to the non-inverting input terminal of the operational amplifier 2 of the amplifier 3, and the output of the D / A converter 7 is controlled so that the vibration gyro 1
Is compensated for. Thereafter, the signal whose offset component has been compensated is sent to the image blur correction operation start instructing means 8.
, An instruction to start an image blur correction operation (image blur correction calculation operation) is issued, and a high-pass filter (HPF)
9. The signal is converted into an angular displacement signal via an integrator 10. Then, the output of the position sensor 11 for detecting the position of the correction lens (via the amplifier 12 and the A / D converter 13) is added in reverse polarity and feedback-calculated.
The signal is output as PWM from the output port of the lens microcomputer 4 via the M signal converter 14, and the correction lens is driven by the coil driver 15 to cancel the image blur.

Here, when the stationary state detector 17 detects that the camera is in a stationary state such as being instructed on a tripod, the offset compensation value setting means 16 calculates the offset compensation value by the offset compensating means 6 in the stationary state. The offset compensation value thus set is stored in a storage circuit 18 such as an EEPROM, which can rewrite data and retain data even when power is not supplied. Thereafter, when the user instructs the start of the image blur correction operation by removing the camera from the tripod or the like, the offset compensation value setting means 16 can be used without calculating the offset compensation value again.
The offset is compensated by outputting the offset compensation value stored in a storage circuit (hereinafter referred to as an EEPROM) 18 to the offset compensating means 6 as an initial value, whereby the vibration can be detected promptly, and the image blur correction operation is performed. Be started.

FIG. 3 is a flowchart showing a specific processing operation in the lens microcomputer 4 of FIG.

Here, the image blur correction operation is performed by an interrupt process which is generated at regular intervals (for example, 500 μsec). Then, the control in the first direction, for example, the pitch direction (vertical direction) and the control in the second direction, for example, the yaw direction (horizontal direction) are performed alternately, so that the sampling cycle in one direction in this case is 1 msec. When an interrupt occurs, the lens microcomputer 4 proceeds to step # 10 in the flowchart shown in FIG.
The operation from 1 is started.

In step # 101, it is determined whether the current control direction is the pitch direction or the yaw direction. If it is in the pitch direction, the process proceeds to step # 102, where a data address is set so that various flags, coefficients, calculation results, and the like can be read and written as pitch data, and step # 1 is performed.
Go to 04. If it is in the yaw direction, step # 101
Then, the process proceeds to step # 103, sets a data address so that various flags, coefficients, calculation results, and the like can be read and written as yaw data.

In step # 104, the output of the vibrating gyroscope 1, which is an angular velocity sensor, is A / D converted.
The result is stored in AD_DATA defined in the RAM in advance. Then, in the next step # 105, it is determined whether or not an instruction to start an image blur correction operation has been made. This is, for example, the ON of the switch SWIS and the switch SW1
The image blur correction is started by AND (logical product) of ON. If the start instruction has been issued, the process proceeds to step # 106, and if not, the process proceeds to step # 114.

Here, an instruction to start the image blur correction operation has been issued, and it is assumed that the flow proceeds to step # 106. At the same time, the vibrating gyroscope 1 and the amplifiers 3 and 12 bitA
The power supply operation is performed on the / D converter 7.

In step # 106, a flag for instructing the start of the image blur correction calculation is determined. If the start instruction has been issued, the H level is set, and if not, the L level is set. If the flag is at the L level, the process proceeds to step # 107, in which the initial value of the offset compensation value is set in order to keep the output of the vibration gyro 1 within the dynamic range and output it to a predetermined target value. Thereafter, the process proceeds to step # 114. The detailed operation of step # 107 will be described with reference to the flowchart of FIG.

If the flag is at the H level in step # 106, the process proceeds to step # 108, and after the offset compensation, a high-pass filter (HPF) operation is performed to cut the DC component. And the next step #
At 109, an integration operation for image stabilization control is performed, and the signal is converted into an angular displacement signal (BURE_DATA) of image shake.
Next, in step # 110, the output of the position sensor 11 for detecting the position of the correction lens is fetched and A / D converted (after conversion = PSD_DATA).
1, the feedback operation ｛(BURE_DA
TA)-(PSD_DATA)}. Then, in step # 112, a phase compensation calculation is performed to make a stable control system, and in the next step # 113, PWM output is performed to the coil driver 15. As a result, image stabilization control is performed, and image shake is corrected.

If the instruction to start the image blur correction operation has not been issued in step # 105, or if step # 10
After the completion of the offset calculation in step 7, the process proceeds to step # 114, where the high-pass filter (HPF) calculation and the integration calculation are initialized. At this time, no image blur correction operation is performed, and the correction lens is stationary at a predetermined position.

Next, the offset compensation value setting executed in step # 107 of FIG. 3 will be described with reference to the flowchart of FIG.

First, in step # 201, it is determined whether or not the offset compensation value has already been stored in the EEPROM 18. If it has been stored, the process proceeds to step # 204, where the D / A set value is read from the EEPROM 18, and the process proceeds to step # 205. move on.

On the other hand, if the offset compensation value is
If it is not stored in step # 8, the process proceeds from step # 201 to step # 202, where offset compensation calculation is performed. The detailed operation will be described with reference to the flowchart of FIG. 6 described later, but this step # 202 is performed only when there is no data in the EEPROM 18. Therefore, a still-state interrupt described later occurs, and D / D
After the A set value is stored, there is no need to perform the offset compensation operation. Then, in the next step # 203, the D / A set value (offset compensation value) calculated in the above step # 202 is written in the EEPROM 18.

In the next step # 205, the image blur correction calculation start flag is set to H in order to instruct the start of the image blur correction calculation. This ends the offset compensation value setting. The operation of step # 205 is performed as follows.
The image blur correction calculation start means 8.

Next, the operation when a stationary state detection interrupt occurs will be described with reference to the flowchart of FIG.

As a method of detecting a stationary state, a method of detecting that the camera is attached to a tripod by a mechanical switch, or a method of determining that the apparatus is supported when no vibration is detected for a predetermined time in the camera. For example.

After the occurrence of the interrupt, step # 202 (FIG. 4)
Since the same operation as that of step # 202 is performed, the same step number is assigned), the offset compensation calculation is performed, and the process proceeds to step # 206. The detailed operation of the offset compensation calculation will be described with reference to the flowchart of FIG. Proceeding to step # 206, the above-described step # 20
The data in the EEPROM 18 is rewritten to the D / A set value calculated in Step 2. This rewriting is performed every time the stationary state is detected. That is, at this time, it can be said that the shake sensor is in a stationary state, and therefore, it is possible to always keep the offset compensation value (D / A set value) with high accuracy.

Next, the detailed operation of the above-described offset compensation calculation will be described with reference to the flowchart of FIG.

First, in step # 301, it is determined whether the setting for outputting the initial output from the D / A converter 7 has been made. This is determined, for example, by the H or L level of the flag. If it is not set and output, the process proceeds to step # 302, and if it is set, step # 303 is performed.
Proceed to.

In step # 302, the D / A converter 7 sets an initial D / A output value so that the D / A converter 7 outputs an initial output. Here, as a method of setting the D / A output initial value, for example, the TYP value of the reference voltage of the sensor is used. Here, the setting is made to output 1.35V. The D / A reference voltage of the D / A converter 7 is, for example,
If the voltage is 3.0 V, the resolution is 12 bits = 4096 LSB, so that 1.35 V = 1843 LSB, and the value is set in the D / A converter 7.

In the next step # 303, it is determined whether or not the A / D value of the output signal of the vibration gyro 1 is within the dynamic range. Here, assuming that the A / D reference voltage of the A / D converter 5 is, for example, 3.6 V, it is determined whether the A / D value is 3.5 V or more.
If it is 3.5 V or more, the output is close to saturation or there is a high possibility that it is saturated, so the process proceeds to step # 304. If it is less than 3.5V, the process proceeds to step # 305.

In step # 304, since the A / D value does not fall within the dynamic range and is likely to be saturated on the H level side, the D / D value connected to the non-inverting input terminal of the operational amplifier 2 is high. The output of the A converter 7 is changed to A /
The output is controlled so that the D value does not saturate. Here, the variable amount of the output after amplification is obtained by one D / A converter operation.
It is preferable to set the change amount so as not to exceed the reference voltage amount of A / D. As described above, the A / D converter 5
Assuming that the D reference voltage is, for example, 3.6V, a change amount of less than 3.6V is preferable. This is for the purpose of first outputting a saturated output to an arbitrary level that does not saturate, so that the number of voltage changes is as small as possible.

Here, when the amplification factor (determined by R2 / R1) of the amplification unit 3 is set to, for example, 64, the operational amplifier 2
When the non-inverting input terminal of the amplifier is changed by ΔVref, the amplified output (output before A / D conversion) becomes (amplification factor of the amplifier 3 + 1) ×
ΔVref = 65 × ΔVref. Assuming that the output change after amplification is 3.0 V, for example, ΔVref = 0.0462 V. Therefore, the output of the D / A converter 7 is set to ΔVref = 0.
If the voltage is changed by 4662V, the output after amplification is changed by 3.0V. Since the D / A converter 7 has a resolution of 12 bits = 4096 LSB, the set value is changed by 0.0462 V ≒ 64 LSB. Here, from the current set value, 0.0462V 設定 64LSB
, And set this value as a D / A set value (offset compensation value). As a result, the amplified output decreases by 3.0V. Thereafter, the offset compensation calculation ends.

When the process proceeds to step # 305, it is determined whether the A / D value is 0.1 V or more.
If it is not less than V, the output is not saturated and is within the dynamic range, so the flow proceeds to step # 307.

In step # 306, since the A / D value does not fall within the dynamic range and is likely to be saturated on the L level, the D / D value connected to the non-inverting input terminal of the operational amplifier 2 is high. The output of the A converter 7 is changed to A /
The output is controlled so that the D value does not saturate. For details, in the same way as in step # 204, 0.0462V46264LSB is added to the current set value, and this value is set as the D / A set value (offset compensation value). This allows
The amplified output increases by 3.0V. Thereafter, the offset compensation calculation ends.

That is, by performing step # 304 or step # 306 a plurality of times, the saturation of the amplified output is avoided.

When the process proceeds to step # 307, A / A
Since the D value is equal to or more than 0.1 V and less than 3.5 V, the sensor amplified output exists within the dynamic range where the saturation does not occur at this point. And this output is the target value, for example, 1.8V ±
It is determined whether or not it exists within 0.1 V. Here, the target value is set within ± 0.1 V, but may be limited to a narrower range. If it is within the above range, the offset compensation value calculation is terminated.
Proceed to 8.

In step # 308, the output is not saturated, but the deviation from the target value is large, so that the output of the D / A converter 7 is controlled to output the target value. Here, a deviation amount XX from a target value, for example, 1.8 V = (target value voltage−A / D value) = (1.8V−A / D value) is calculated. Then, in the next step # 309,
From a data table in which the output change amount data of the D / A converter 7 for outputting to the target value corresponding to the value of X is stored in advance, the control data (±
YLSB). Then, in the next step # 310, the output of the D / A converter 7 is changed based on the control data (± YLSB), and the D / A set value is determined. That is, in steps # 309 and # 310, the output value within the dynamic range is output to or near the target value. The D / A output resolution here is 12
Since the reference voltage is 3.0 V in the bit A / D converter,
0.00073V / LSB. Therefore, the minimum controllable resolution of the amplified output is (amplification factor of amplification section 3 + 1) × ΔVref = 65 × ΔVref = 0.0475V.

As described above, the configuration shown in FIG. 2 eliminates the need to perform useless offset compensation calculation.
The offset component superimposed on the shake sensor can be more efficiently compensated.

If the accuracy of the offset compensation value stored in the EEPROM 18 is not sufficient,
What is necessary is just to adjust the stored initial value, and an offset compensation value that is simpler and more accurate than in the past can be determined.

According to the above embodiment, every time a stationary state where the camera is fixed to a device such as a tripod is detected, an offset compensation value in the stationary state is calculated and stored in the EEPROM 18. In addition, at the time of the next vibration detection, that is, when an instruction to start the image blur correction operation is given, the vibration detection is performed using the high-precision offset compensation value stored in the EEPROM 18 as an initial value. Therefore, accurate vibration detection can be performed early from the user's instruction timing for starting the shake correction operation, and as a result, the image shake correction operation can be started quickly.

(Modification) In each of the above embodiments, an example is shown in which a vibration gyro (angular velocity sensor) is used as the vibration detecting means. However, an angular acceleration sensor, an acceleration sensor, a velocity sensor, an angular displacement sensor Any means can be used as long as the shake can be detected, such as a displacement sensor.

As an image blur correction system, a shift optical system for moving an optical member in a plane perpendicular to the optical axis, light flux changing means such as a variable apex angle, and a photographing screen in a plane perpendicular to the optical axis are moved. Any device can be used as long as the image blur can be corrected.

Also, the invention or each embodiment described in each claim may be configured so as to form one device as a whole, or may be separated or combined with other devices. Or it may be like an element making up the device.

The number of stored offset compensation values is not limited to one, but may be plural, and a configuration may be employed in which a highly accurate initial value is selected from the offset compensation values in accordance with use conditions such as temperature.

[0052]

As described above, according to any one of the first to third aspects of the present invention, a vibration detecting device capable of transmitting an accurate vibration detection output early after a vibration detection is requested. Can be provided.

According to the fourth or fifth aspect of the present invention, there is provided an image blur correction apparatus capable of performing an image blur correction operation based on an accurate vibration detection output early from the instruction timing of the image blur correction operation start. It can be provided.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a circuit configuration of a camera system according to an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a specific circuit configuration of a main part according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating an image blur correction interrupt control operation according to the embodiment of the present invention.

FIG. 4 is a flowchart illustrating details of an offset compensation value setting operation according to the embodiment of the present invention.

FIG. 5 is a flowchart illustrating an operation of generating a still state detection interrupt according to the embodiment of the present invention;

FIG. 6 is a flowchart illustrating details of an offset compensation calculation according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Vibration gyroscope 3 Amplification part 4 Lens microcomputer 6 Offset compensation means 7 D / A converter 8 Image blur correction operation start instructing means 9 High pass filter 15 Coil driver 16 Offset compensation value setting means 17 Stationary state detector 18 Storage circuit 101 Lens microcomputer 102 Shake correction system 106 Shake sensor

Claims (5)

[Claims] 1. A vibration detecting means for detecting a vibration, a compensation voltage output means for outputting a compensation voltage, a comparing means for comparing an output of the vibration detecting means with the compensation voltage output, and a signal based on the output of the comparing means. A vibration compensating means for compensating for an offset component of the output of the vibration detecting means by controlling the compensation voltage; a stationary state detecting means for detecting that the vibration detecting apparatus is stationary Storage means for storing an offset compensation value obtained by the offset compensation means when the stationary state is detected by the stationary state detection means; and when the output of the vibration detection means is requested, the storage means The offset compensation of the output of the vibration detecting means is performed with the offset compensation value stored in the Vibration detecting apparatus characterized by a control means for a detection output. 2. The storage unit according to claim 1, wherein the storage unit stores the latest value of the offset compensation value obtained by the offset compensation unit each time the stationary state is detected. The vibration detecting device according to item 1. 3. The vibration detecting device according to claim 1, wherein the storage unit is a rewritable nonvolatile storage memory. 4. An image comprising: the vibration detecting device according to claim 1; and an image blur correcting unit configured to correct an image blur based on a vibration detection output from the vibration detecting device. Image stabilizer. 5. A control means provided in the vibration detection device, when an instruction to start an image blur correction operation is given,
5. The image blur correction apparatus according to claim 4, wherein, when the vibration detection output is requested, the offset-compensated vibration detection output is sent to the image blur correction unit.