JPH06165020A - Shake corrector - Google Patents

Abstract

PURPOSE:To enable optimum shake correction corresponding to various photographic conditions and environments by detecting the main frequency band of shake at the time of photographing from the output signal of a shake detecting means and using the detected main frequency band for control. CONSTITUTION:An angular velocity signal outputted from an amplifier 3 is converted to a digital signal by an A/D converter 4. An HPF 10 is provided with a function for varying the characteristic in any arbitrary band. An integration circuit 5 calculates the angle displace signal of a prescribed frequency component extracted by the HPF 10 by integrating the signal of that frequency component. According to a frequency detecting means, a phase/gain correcting circuit 11 corrects the phase and gain of an integrated output signal outputted from the integration circuit 5, namely, of the angle displace signal. When angular velocity is fixed and the angle displace signal integrating the angular velocity signal shows monotonous increase, a pan/tilt judging circuit 12 judges panning or tilting, cuts the low frequency of an HPF 10 and changes the characteristic so that a shake correcting means can not respond to the low frequency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shake correction device suitable for use in a photographing device such as a camera.

[0002]

2. Description of the Related Art Conventionally, in the field of photographing devices such as cameras, automation and multi-functionalization have been achieved in all respects such as exposure setting and focus adjustment so that good photographing can always be performed regardless of the photographing environment. I'm running.

However, it is often camera shake that actually deteriorates the quality of a captured image, and in recent years, various shake correction devices for correcting this camera shake have been proposed and are attracting attention.

The shake correction apparatus is roughly divided into a correction system for optically correcting and a correction system for electrically correcting by image processing, and a detection system for physically detecting vibration.
It is roughly classified into one that detects a motion vector of an image by image processing, and many forms are conceivable.

FIG. 19 shows an example of the configuration of a conventional shake correction apparatus.

In FIG. 1, reference numeral 1 denotes an angular velocity detector including an angular velocity sensor such as a vibration gyro, which is attached to a photographing device such as a camera. 2 is the angular velocity detector 1
It is a DC cut filter that cuts off the DC component of the speed signal output from the device and passes only the AC component, that is, the vibration component. As the DC cut filter, a high pass filter (hereinafter referred to as HPF) that cuts off a signal in an arbitrary band may be used. An amplifier 3 amplifies the angular velocity signal output from the DC cut filter to an appropriate sensitivity.

Reference numeral 4 is an A / D converter for converting the angular velocity signal output from the amplifier 3 into a digital signal, and 5 is an integrator for integrating the output of the A / D converter 4 and outputting an angular displacement signal, 6
Is a pan / tilt determination circuit for determining panning and tilting from the integrated signal of the angular velocity signal output from the integration circuit 5, that is, the angular displacement signal, and 7 is the output of the pan / tilt determination circuit as an analog signal or a pulse output such as PWM. It is a D / A converter for converting and outputting. The A / D converter 4, the integrator 5, the pan / tilt determination circuit 6, and the D / A converter 7 are configured by, for example, a microcomputer (hereinafter referred to as a microcomputer) COM1. Reference numeral 8 is a drive circuit for driving the image correcting means in the subsequent stage so as to suppress the shake based on the displacement signal output from the microcomputer, and 9 is the image correcting means, for example, by displacing the optical optical axis to cancel the shake. Or an electronic correction means that electronically shifts the read position of the image from the memory storing the image to offset the shake.

[0008]

However, the above shake correction apparatus has the following problems.

FIG. 4 shows a frequency characteristic of a vibration component signal obtained by the image correction means 9 when a device such as a camera equipped with a shake correction device using an existing angular velocity sensor is excited with a constant amplitude.

Focusing on the characteristic at 10 Hz in the frequency characteristic of FIG. 4, the gain characteristic is almost 0 dB, but the phase is deviated by about 7.5 deg. Due to this phase shift as a main factor, the applied vibration is suppressed to 1/100 or less at 3 Hz, but it can only be suppressed to about 1/8 at 10 Hz. ing.

Considering the effect of the shake correction in this characteristic as described above, even if a sufficient effect can be expected in normal photographing, vibration of a frequency near 10 Hz is continuously applied to a device such as a camera. When it is present, its periodic vibrations are more noticeable.

As described above, in the present shake correction apparatus using the angular velocity sensor as described above, when continuous vibration continues to be applied in a frequency band where a sufficient vibration suppressing effect cannot be expected, the magnitude of the applied vibration is increased. Depending on the size, it was a problem that the rest of the correction was noticeable.

Therefore, the present applicant detects the shake applied to the image pickup apparatus including the shake correction mechanism, that is, the center frequency of the shake to be corrected, changes the gain characteristic and the phase characteristic according to the output, and shakes the shake. We proposed to correct the gain deviation and phase deviation of the center frequency of the
No. 3485), however, the shake frequency detecting means was prepared independently from the outside, so there was still room for improvement in terms of simplification of the configuration and adjustment.

Therefore, an object of the present invention is to solve the above-mentioned problems and further improve the prior application by the applicant.

[0015]

In order to achieve the above-mentioned object, a first detecting means for detecting a vibration of a device, a correcting means for correcting a motion of an image due to the vibration, and the first:
Of the vibration based on the output of the first detecting means and the first controlling means for controlling the correcting means based on the output of the detecting means of the first driving means to drive the correcting means in the direction of correcting the movement of the image. Second detection means for detecting frequency and amplitude;
Second control means for controlling the characteristic of the first control means based on the output of the second detection means.

[0016]

With this, the main frequency band of the shake at the time of shooting can be detected and used for control from the output signal of the shake detecting means used for shake detection, and can be used for control in accordance with various shooting conditions and environments. Optimal shake correction is possible.

Further, by detecting the frequency using the angular velocity signal output from the angular velocity detecting means, the construction, adjustment and control are facilitated, and the angular displacement signal obtained by integrating the angular velocity signal is simultaneously used to detect the frequency. Can be improved.

[0018]

Embodiments of the present invention will now be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the main construction of the first embodiment of the shake correcting apparatus according to the present invention. In the figure, the same components as those of the preceding example shown in FIG. 19 described above are designated by the same reference numerals, and detailed description thereof will be omitted.

In the figure, an angular velocity detecting means 1 including an angular velocity sensor such as a vibration gyro attached to a photographing device such as a camera, a DC cut filter (or HPF) for cutting off a DC component of a velocity signal output from the angular velocity detecting means 1. ), An amplifier 3 for amplifying the angular velocity signal to a predetermined sensitivity,
Regarding the drive circuit 8 and the image correction means 9, the above-mentioned 19th
The same configuration as that of the preceding example shown in the figure can be used, and the difference in the present invention is the internal configuration of the microcomputer COM2 that controls the entire apparatus. In this embodiment, for example, a variable apex prism (VAP) described later or a memory control system is used as the image correction means 9.

Looking at the internal configuration of the microcomputer COM2, the A / D converter 4 for converting the angular velocity signal output from the amplifier 3 into a digital signal, the HPF 10 and the HPF 10 having the function of changing the characteristics in an arbitrary band are used. An integrating circuit 5 for integrating the signal of a predetermined frequency component extracted in this way to obtain an angular displacement signal in the frequency component, an integrated output signal output from the integrating circuit 5, that is, a phase and a gain of the angular displacement signal, which will be described later in frequency detection. According to the means, a phase / gain correction circuit 11 for correction and a D / A converter 7 for converting an output signal of the phase / gain correction circuit 11 into an analog signal or a pulse output such as PWM and outputting the analog signal or pulse output are provided.

Numeral 12 determines the panning, tilting and photographing state from the angular velocity signal output from the A / D converter 3 and the displacement signal output from the integrating circuit 5.
It is a pan / tilt determination circuit that changes the characteristics of the HPF according to the determination result.

The specific operation of the pan / tilt determination circuit is to input the presence / absence of vibration of the angular velocity signal output from the A / D converter 4 and the angular displacement signal output from the integration circuit 5 to obtain a constant angular velocity. When the angular displacement signal obtained by integrating the angular velocity signal shows a monotonic increase, it is determined that the panning or tilting is performed. In such a case, the HPF 10
The cutoff frequency in the low frequency range is changed to a higher frequency and the characteristic is changed so that the shake correction system does not respond to the low frequency.

When panning / tilting is detected, the VAP is gradually centered on the center of the moving range. During this time, the angular velocity signal and the angular displacement signal are detected, and when the panning / tilting is completed, the cutoff frequency in the low frequency range is lowered again to expand the shake correction range.

Reference numeral 13 is a frequency detecting means for detecting the vibration applied to the device from the angular velocity signal output from the A / D converter 3 and controlling the characteristics of the phase and gain correction circuit 11 according to the vibration frequency. .

Here, the drive circuit 8 and the image correction means 9 for actually correcting the shake of the image in accordance with the control signal output from the microcomputer COM2 will be explained with examples.
For example, the ones shown in FIGS.

FIG. 8 shows a variable vertical angle prism (hereinafter VAP:
Varriable angle prisum) 306 and a voice coil as a drive system, and a closed loop control system that controls the drive amount by encoder-detecting angular displacement and feedback to the drive system. Is.

First, the VAP will be described in detail. As shown in FIG. 12, the variable apex angle prism 306 has a transparent high refractive index (refractive index n) between two transparent parallel plates 340a and 340b facing each other. The transparent parallel plate 34 is filled with the elastic body or the inert liquid 342 in a sandwiched manner, and the outer periphery thereof is elastically sealed with a sealing material 341 such as a resin film.
0a and 340b are swingable, and the transparent parallel plates 340a and 340b are swung to displace the optical axis and correct the shake.

FIG. 13 shows a variable vertical angle prism 30 of FIG.
6 one of the transparent parallel plates 340a is attached to the swing shaft 301 (31
Incident light flux 34 when rotated by angle σ around 1)
4 is a diagram showing a passing state of the light beam of FIG. 4, and the light beam 344 incident along the optical axis 343 is deflected by an angle φ = (n−1) σ according to the same principle as the wedge prism, as shown in FIG. Emit. That is, the optical axis 343 is decentered (deflected) by the angle φ.

Returning to the description of FIG. 8, the VAP described above is explained.
306 is fixed to the lens barrel 302 via a holding frame 307 so as to be rotatable around 301 and 311.

313 is a yoke, 315 is a magnet, 3
Reference numeral 12 denotes a coil, which constitutes a voice coil type actuator capable of varying the apex angle of VAP around 311 by passing a current through the coil 312. 31
Reference numeral 0 is a slit for detecting the displacement of the VAP, which is a rotary shaft 31.
The position is displaced by rotating together with the holding frame 307, that is, the VAP 306 coaxially with 1. 308 is a slit 310
Is a light emitting diode that detects the position of the
sition Sensing Detector) and light emitting diode 3
By detecting the displacement of the slit 310 together with 08, an encoder for detecting the angular displacement of the VAP apex angle is configured.

Then, the light flux whose incident angle is changed by the VAP 306 is CC by the photographing lens unit 303.
An image is formed on the image pickup surface of the image pickup element 304 such as D.

Reference numeral 305 indicates the center of the other rotation axis orthogonal to the rotation axis composed of the axes 301 and 311 of the holding frame 307.

Next, the basic structure and operation of the control circuit for driving and controlling the VAP will be described with reference to the block diagram of FIG.

In the figure, 306 is a VAP, 322 is an amplifier, 323 is a driver for driving an actuator, 324 is a voice coil type actuator for driving the VAP 306 described above, 326 is an encoder for detecting a vertical displacement of VAP, 325. Is a micro computer CO
A shake correction control signal 320 output from M2 and an output signal of the angular displacement encoder 326 are added with opposite polarities, and the shake correction control signal 320 output from the micro computer COM2 and the angular displacement encoder. Three
Since the control system operates so as to be equal to the output signal of the V.26, the VAP 306 is driven so that the control signal 320 is equal to the output of the encoder 326 as a result, and the VAP is moved to the position designated by the microcomputer COM2. Is controlled.

FIG. 10 shows another example of the image correction means, which is constructed such that the VAP described above is driven not by a voice coil type actuator but by a stepping motor.

This is about the rotary shaft 301 as the center of rotation.
The stepping motor 401 drives the VAP via the holding frame 307. That is, a stepping motor 401 having a lead screw 401a arranged on its rotation axis is attached to a support frame 403 attached to the lens barrel 302, and the guide frame 405 of the support frame 403 allows the stepping motor 401 to move in the optical axis direction. The guided motor 404 is constantly meshed with the lead screw 401a, and the carrier 404 is rotatably connected to the connecting rod 407 fixed to the support frame 307 by the rotating shaft 406. Is rotated to move the carrier 404 in the optical axis direction, and the holding frame is rotated about the rotating shafts 301 and 311 via the connecting rod 407.
It drives P. Reference numeral 402 is a reset sensor for detecting the VAP reference position. A VAP drive mechanism similar to this is also provided for the shaft 305, but description thereof will be omitted.

The circuit configuration for driving and controlling the system of FIG. 10 is as shown in the block diagram of FIG.

In FIG. 11, the microcomputer C
The control signal 320 output from the OM2 is subjected to drive calculation in the drive calculation circuit 410, converted into a VAP drive signal, and output to the driver / IC 411. Then, the stepping motor 401 is driven by the driver IC to change the apex angle of VAP.

FIG. 14 shows a third example of the image blur correction means, which stores image information in the memory and sets the cut-out range of the image from the memory to be smaller than the stored image. It is configured to correct the shake by shifting the position where the image is cut out from the memory in a direction that cancels the movement of the image, and further expands the cut out image signal to correct the screen size before outputting. 2 illustrates a memory control type image shake correction means. This system is characterized in that shake correction can be performed electronically without using an optical correction mechanism such as VAP.

In the figure, 100 is a zoom lens and 1 is a zoom lens.
01 is an image pickup device (CCD image sensor or the like) for converting an optical image into an electric signal, 102 is an A / D converter, and 103 is
Control signal (runout signal) input from the microcomputer COM2
Based on 110, a shake correction process for correcting the shake of the image by shifting the cut-out position of the predetermined image information from the field memory 106 so as to reduce the shake component in the image pickup signal, and enlarging the read image from the field memory 106. This is an image processing circuit that constitutes a view angle correction processing unit that performs processing to perform so-called electronic zooming and converts it into a normal screen size, and is realized by a microcomputer.

Reference numeral 104 is an interpolation process for interpolating one pixel signal from image information of two or more adjacent pixels by zoom information when performing electronic zoom for correcting an image read from the field memory to a normal angle of view. It is a means.
For this interpolation method, well-known means may be used,
For example, the average value between adjacent pixels may be used to interpolate between pixels. Further, 105 is a D / A converter, and 107 is an encoder for detecting the zoom magnification ratio of the zoom lens 100.

Next, the operation will be described. Zoom lens 10
The optical image that has passed 0 is converted into an electrical signal by the image sensor 101 and output as an image signal. The image pickup signal is converted into a digital signal by the A / D converter 102, and the image information for one field is written in the memory 106 via the memory control unit 103. Here, the cut-out position of the image signal from the field memory 106, that is, the read range and its read position are determined by the shake signal input from the microcomputer COM2 and the zoom information from the encoder 107.

Next, in order to convert the signal read from the field memory 106 into the original size of the scanning width of the output image, that is, the angle of view, according to the cutout size, the number of pixels in the normal one pixel output period is increased. Whether or not to output is determined, and the interpolation processing circuit 104 performs the interpolation processing on the pixel having no pixel information. Then, this signal is converted into an analog signal by the D / A converter 105 and output.

The specific examples of the image correcting means for correcting the shake have been described above.

Next, the processing operation of the microcomputer COM2 in this embodiment shown in FIG. 1 will be described with reference to the flow chart of FIG. In the figure, when control is started, in step S201, the DC signal is removed via the DC cut filter 2 and the amplifier 3, and the angular velocity signal from the angular velocity detecting means 1 amplified to a predetermined level is A / D converted. It is converted into a digital signal by the device 4 and taken into the microcomputer COM2.

Subsequently, in step S202, the panning / tilting and photographing states are performed by the angular displacement signal obtained by integrating the angular velocity signal and the predetermined high frequency component extracted from the angular velocity signal by the HPF 10 by the integrating circuit 5. Make a decision.

In step S203, the coefficient for setting the characteristics of the HPF 10 is read from a table (not shown) prepared in advance in the microcomputer COM2 according to the result of the determination. That is, if the HPF 10 is configured by a digital filter, the characteristics of the HPF 10 can be freely changed by reading and setting a predetermined coefficient from a table storing the coefficient. The coefficients according to these panning / tilting and shooting conditions are empirically determined.

In step S204, the HPF 10 is calculated by the coefficient for setting the characteristic and the characteristic is set, and in step S205, the signal output from the HPF 10 is integrated by the integrating circuit 5, and the angular displacement signal ( Shake signal).

In step S206, the frequency detecting means 1
3, the angular velocity signal output from the A / D converter 4 is calculated to detect the center frequency of the shake, and step S2
At 07, the correction coefficient of the phase and gain correction circuit 11 corresponding to the center frequency of the shake obtained at step S206 is read from a table (not shown) prepared in advance in the microcomputer COM2.

The phase and gain correction circuit 11 is for compensating the deterioration of the shake correction characteristic due to the phase delay of the shake correction system, has a phase lead element, and is composed of, for example, a digital filter as described later. The correction coefficient is read out from the digital filter, and the phase and gain correction characteristics corresponding to the shake frequency are set.

In step S208, step S207
A correction calculation is performed using the coefficient obtained in step S209, and the calculation result obtained in step S209, that is, the corrected angular displacement signal is converted into an analog signal by the D / A converter 7,
Alternatively, as a pulse output such as PWM, the microcomputer COM2
Output more.

Since the HPF 10, the integrator circuit 5, and the phase and gain correction circuit 11 use digital filters or the like, the sampling time must be relatively high (for example, about 1 kHz), but panning / tilting and photographing are performed. The determination circuit 12 that determines the state and the frequency detection unit 13 may perform processing at a relatively slow cycle (for example, 100 Hz). In other words, it can be changed according to the situation.

As the frequency detecting means 13 using the angular velocity signal shown in FIG. 1, for example, a threshold value is provided near the center of the signal, and the detection can be performed by the time when the center is crossed or the number of times of crossing in a certain time. But with this method,
It depends on the stability of DC signals. In other words, when shooting with a handheld device, it is difficult to detect the shake frequency accurately because low frequency components are included considerably.

Therefore, in this embodiment, the frequency is detected by focusing on the increase and decrease of the signal for each sampling. That is, one set of increase / decrease of the signal is regarded as one shake, and the frequency is calculated depending on how many sets are detected within a predetermined time. With this method,
It is possible to detect every 1 Hz for 1 second and every 0.5 Hz for 2 seconds.

Frequency detecting means 1 in this embodiment
An example of the method and operation of No. 3 will be described with reference to the flowchart shown in FIG. It should be noted that this process is repeatedly performed once every fixed time.

In step S301, the frequency detection time T
Of the clock function counter t, that is, the count operation of the counter is started in step S302, the frequency detection time T is compared with the clock counter t in step S303, and the count value of the clock counter is read. It is determined whether or not t has reached the predetermined time T, and if the clock counter t has reached T, the process proceeds to step S319.
If not reached, the process proceeds to step S304.

In step S304, "1" is added to the clock counter. Therefore, this "1" count-up coincides with the processing time when the processing shown in the flow chart of FIG. 3 is executed once.

In step S305, an increase flag 1 for confirming whether the increase of the angular velocity signal has occurred up to the previous time.
To load. The increase flag is set to "H" when the increase has occurred up to the previous time, and is set to "L" when the increase has not occurred in the past.

In step S306, whether or not the increase in the angular velocity signal has occurred up to the previous time is determined by the flag 1, and if flag 1 = “H”, it is determined that the increase has occurred in the past and step S307. Go to, flag 1 =
If "L", it is determined that the increase has not occurred in the past, and the process proceeds to step S312.

In step S306, if the increase in the angular velocity signal has occurred up to the previous time, step S30
At 7, the decrease flag 2 is loaded to see if the decrease has occurred by the previous time. Decrease flag 2 is
If the decrease has occurred up to the previous time, "H" is set, and if the decrease has not occurred in the past, "L" is set.

In step S308, it is determined whether or not the decrease has occurred up to the previous time by the flag 2, and the flag 2 =
If "H", that is, a decrease has occurred in the past, the process proceeds to step S309, and if flag 2 = "L", that is, a decrease has not occurred in the past, the process proceeds to step S312.

In step S309, the shake counter N1 for counting the number of shakes (vibrations) is loaded, and in step S310, "1" is added to the shake counter N1, and then the process proceeds to step S311 to increment the increase flag. 1, the reduction flag 2 is reset, and the process is ended.

On the other hand, when it is determined in step S306 that the increase flag 1 is not "H" and when it is determined in step S308 that the decrease flag 1 is not "H", that is, when neither increase nor decrease has occurred in the past. To step S312 and one sampling before (previous processing)
Angular velocity data ω-1 at step S3 is loaded, and then step S3
In step 13, the current angular velocity data ω detected by the angular velocity detecting means 1 is loaded.

In step S314, the threshold value level "a" for the change that determines that the angular velocity data has increased or decreased within one sampling period is loaded. By this threshold level a and sampling time,
The value can be set according to the frequency and amplitude.

In step S315, the absolute value of the change amount of the angular velocity data within one sampling period is compared with the threshold level a, and if it has not reached it, step S32 is performed.
If the absolute value of the change amount is equal to or higher than the threshold level a, the process proceeds to step 4
In step S16, it is determined whether the amount of change in angular velocity during one sampling period is positive (increase) or negative (decrease). If positive, the flow advances to step S317 to set the increase flag 1 to "H". If it is not positive (if it is decreased), the process proceeds to step S318 and the decrease flag 2 is set to "H".
Is set to step S324, and the process proceeds to step S324 to end the process.

By the way, if the count value of the clock counter t has reached the frequency detection time T in the above-mentioned step S303, the process proceeds to step S319, the shake counter N1 is loaded, and the shake is counted in step S320. The number of times N1 is divided by the detection time T to obtain the number of shakes (runout frequency F) per unit time (1 second).

Subsequently, the shake counter N1 is cleared in step S321, and the clock counter t is cleared in step S322.
Is cleared, the shake frequency F is stored in a predetermined storage area in step S323, and the process proceeds to step S304. The subsequent operation is as described above.

As described above, by considering the set of the increase / decrease of the angular velocity signal as one vibration, it is easy to detect the shake in the low frequency range (for example, 1 Hz or less), and the threshold level is set. The influence of noise components can be eliminated by setting a. Further, there is an advantage that it can be easily realized by performing processing using a microcomputer.

In this system, the detection accuracy can be varied by setting the frequency detection time T. For example, if it is 1 second, the resolution is 1 Hz, and if it is 2 seconds, it is 0.
It has a resolution of 5 Hz.

Therefore, by changing the frequency detection time T according to the detected shake frequency F, the detection accuracy according to the detected frequency can be realized. For example, when the detection frequency F is -10 Hz, T = 2 [SEC] is detected with an accuracy of 0.5 Hz, and when F = 10 Hz is detected, T = 1 [SEC] is detected with an accuracy of 1 Hz. Thus, the time required to detect the shake frequency can be shortened.

According to this method, when a low frequency swing and a high frequency swing occur simultaneously, a high swing frequency can be extracted.

Usually, the correction frequency range in such a shake correction device is about 1 to 15 Hz for camera shake, but depending on the shooting condition, for example, an amplitude of about 3 to 5 Hz for still shooting is 6 to 10 Hz on a vehicle. It is known that the shake with a relatively large amplitude is distributed in a narrow range (band) of the frequency to some extent depending on the skill of the photographer and the shooting condition such that the amplitude is large. Further, when a tripod is used, high-frequency vibration is anxious, and the component is distributed up to 20 to 30 Hz or higher.

The effects of the above embodiment will be described. First, since the center frequency of shake is detected,
As described above, this is effective as one item for determining the shooting state.

Further, by previously combining with the phase and gain correcting means, the optimum correction can be performed according to the skill level of the photographer, the photographing state, and the like.

It is assumed that the sufficient shake correction effect can be obtained if the residual shake component is -30 dB or less with respect to the applied shake, then the shake correction state is sufficient. According to this assumption, since the focal length of the photographing device has a large effect on the shake correction effect, for example, if the focal length is simply doubled, an image obtained without double the suppression effect is obtained. This is because the same effect cannot be obtained in.

However, in the overall shake suppression effect including the shake sensor for detecting shake and the image correction system, at present, the residual shake amount after shake correction is -30 dB with respect to shake.
The range that can be suppressed to is only obtained in a narrow range as compared with the above-described shake band of the correction target (for example, 1 to 15 Hz).

In order to give a concrete example, it is assumed that the frequency characteristics obtained by the current angular velocity sensor and the image correction means shown in FIG. 8 are as shown in FIG.

This shows the frequency characteristic of the image correction system with respect to the input of the sine wave-like shake applied to the shake sensor 1 which is the angular velocity detecting means of FIG. The upper diagram shows the gain characteristic, and the lower diagram shows the phase characteristic. The vertical axis represents gain (upper diagram) and phase (lower diagram), and the horizontal axis represents frequency (1 to 50 Hz).

It is characteristic 1 in FIG. 5 that the range is expanded. Focusing on the phase of this characteristic 1, the phases match at 3 Hz, and at frequencies before and after that, the HPF 5 (here, the cutoff frequency is 0.06 Hz) or the lower frequency side. When the phase advances due to the influence of the integrating circuit 6 (the cutoff frequency is 0.07 Hz) and goes toward the high frequency side, the angular velocity detecting means 1
The phase is delayed due to the influence of the image correction means 9. The gain is almost constant up to about 1 to 10 Hz.

FIG. 7 shows the damping characteristic at this time.
6 is the characteristic 6, and the same figure shows the effect of correction on the frequency (horizontal axis) (vertical axis, expressed in dB). As can be seen from this figure, the best suppression is possible at 3 Hz where the phases match, and the suppression of -30 dB is almost achieved at 2 to 4 Hz, but at 10 Hz, the suppression effect is about -18 dB. ing.

That is, this phase shift causes deterioration of the shake suppression effect.

Here, in order to correct the phase delay of the characteristic 1, a characteristic having a phase lead element represented by a transfer function of H (S) = a (S + z) (1) If they are connected in series, the phase can be corrected at a predetermined frequency. This is to set the frequency higher than the range of shake suppression and advance the phase. This is performed by the phase and gain correction circuit 11.

For example, focusing on the phase delay at 10 Hz of the characteristic 1, it is delayed by about 7.5 deg. Therefore, 10
By advancing the 7.5 deg phase at Hz, this phase delay can be corrected, and eventually a sufficient vibration suppressing effect can be obtained.

That is, the characteristic 2 is obtained by correcting the phase shift of the characteristic 1 at 10 Hz (matching the phase and matching the gain). This is z (= 0) in equation (1)
Can be set by.

Further, a is adjusted so that the gain becomes 0 dB at 10 Hz. If this is realized by the phase and gain correction circuit 11, the characteristic 1 can be changed to the characteristic 5, and the characteristic 7 showing the vibration suppression effect can be obtained from this. It can be seen from the characteristic 7 that the best vibration suppression effect is obtained at around 10 Hz at this time. The characteristic 7 shows the residual shake component, which is expressed by 20Log (OUT / IN) (2) OUT: residual shake component after shake correction IN: shake amount.

Similarly, at 20 Hz, if the characteristic 4 is realized by the phase and gain correction means 11 with respect to the characteristic 1,
Characteristic 5 can be obtained. The damping effect realized from this characteristic is characteristic 8, and the best damping effect is obtained in the vicinity of 20 Hz.

In order to realize the characteristic of the equation (1) in the phase and gain correction means 11, if a digital filter is used, the desired characteristic can be set only by changing the coefficient (FIG. 1)), it is suitable for control using a microcomputer. If a first-order IIR filter is used for the digital filter at this time, u0 = a0.w0 + a1.w1 w0 = e0 + a2.w1 w1 = w0 (w1 is a state variable) e0: input u0: output a0 , A1, a1: can be realized by calculating the filter coefficients, and filter coefficients a0, a1, a2
Since the frequency characteristic can be set by changing, the data of the filter coefficients a0, a1 and a2 corresponding to the shake frequency is prepared as a table, and the IIR filter can be calculated by the filter coefficient obtained from the table. .

That is, according to the above-described embodiment, the center frequency of the shake is detected by the frequency detection circuit 13 from the angular velocity signal output from the angular velocity detector 1, and the center frequency of the shake is detected in the entire control system. The phase and gain are 0 deg and 0 dB, respectively, that is, the filter characteristics of the digital filter of the phase and gain control circuit 11 are varied in order to give the control system phase advance compensation so that the best vibration suppression characteristics are obtained. The best suppression effect can always be obtained even with respect to the shake frequency.

More specifically, the phase and gain control circuit 11
Since the characteristics of the digital filter that composes are the frequency characteristics corresponding to each shake frequency, it is only necessary to read and set the filter coefficient prestored in the data table in the microcomputer according to the shake frequency. ,Constitution,
It is easy to control and is particularly suitable for processing by a microcomputer.

For example, when a video movie or the like is hand-held and shot, hand shake is distributed over a relatively wide frequency range, but a shake with a relatively large amplitude is within a narrow range to some extent depending on the skill of the photographer and the shooting condition. To be distributed. Therefore,
If it can be configured to give the best correction effect to the center band of such shake, it is possible to make the optimum correction according to the skill level of the photographer and the shooting condition (handheld, mounted on a tripod, or from the top of the vehicle, etc.) Becomes

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIG. 15. In the circuit configuration of the shake correction apparatus according to the second embodiment, the configuration of FIG. The difference lies in the internal processing of the microcomputer, and the output signal of the integrating circuit 5 in the microcomputer COM3 in FIG. 15 is input to the frequency detecting means 13 and used for the calculation. Both are the same as those in FIG. 1, and description thereof will be omitted.

That is, in the present embodiment, when the angular velocity signal is taken into consideration, the gain becomes low at a low frequency, so that the sensitivity and the accuracy are lowered. Therefore, the integrated output of the existing integrating circuit 5, that is, the angular displacement signal is used. By doing so, the detection capability in the low frequency range is improved, and frequency detection is performed using the angular displacement signal output from the integration circuit 5 by the same method as the frequency detection by the angular velocity signal of the first embodiment. To do.

When the angular velocity signal is used as it is, the detection capability in the low frequency region may be limited due to the dynamic range of the signal to be captured. Therefore, the detection capability in the low frequency range is enhanced by performing detection using the angular displacement signal.

In other words, the angular velocity signal becomes larger as the frequency becomes higher if the vibration has the same amplitude, but the gain is limited to a certain value due to the system configuration. Then, a sufficient signal cannot be obtained in the low frequency region, and the detection capability will be limited.

However, since the angular displacement signal is an integral signal,
If the vibrations have the same amplitude, the amplitude is naturally constant regardless of the frequency. Therefore, it is suitable for the frequency detection of the shake of a relatively low frequency. However, as the frequency becomes higher, the shake tends to become smaller, so that detection in the high frequency range becomes difficult on the contrary.

In consideration of such characteristics of both signals, the accuracy is improved in the low frequency region and the high frequency region by detecting the shake by using the portion having excellent detection capability of both signals. .

The detection from the angular displacement signal output from the integration circuit 5 is limited to a low frequency range, and the sampling cycle of the signal is set to be slower than the sampling cycle of detection in the angular velocity signal.

Finally, the larger one of those detected by both should be taken.

(Third Embodiment) FIG. 16 shows a third embodiment. This is because the HPF 10 also serves as the processing means at the time of panning and the phase and gain correction circuit 11, and as a feature, it is not necessary to provide the gain and phase correction circuit 11 independently, and a frequency lower than the center frequency of shake is used. Because it cuts off, the operability is improved (the lower the low-range vibration suppression performance,
Since the followability of the image blur correction device with respect to the camera is improved, the operability is improved as the cutoff frequency is higher.
In other words, the shake center frequency is sufficiently corrected for shake, and if the shake center frequency is high, the cutoff frequency of the low frequency due to the HPF increases, and the operability is improved.

Next, the microcomputer COM in this embodiment
The processing operation of No. 4 will be described with reference to the flow chart of FIG.

In the figure, when the processing is started, in step S401, the angular velocity signal from the angular velocity detecting means 1 via the DC cut filter 2 and the amplifier 3 is converted into a digital signal by the A / D converter 4 and fetched. In step S402, the panning / tilting and the photographing state are determined based on the angular velocity signal and the angular displacement signal, as in the first embodiment. This is to determine whether the image is held by hand or taken from a vehicle based on the change in shake, and to determine panning or tilting when the angular velocity signal is constant and the angular displacement signal monotonically increases.

In step S403, the angular velocity signal is calculated to detect the center frequency of the shake, and subsequently in step S404, the characteristics of the HPF 10 are set based on the panning / tilting, the determination of the photographing state, and the result of the shake center frequency detection. Read out the characteristic coefficient.

As the method of determining the coefficient at this time, various methods such as a method of searching the data table from both values, a method of comparing the characteristics of each and setting a coefficient having a higher cutoff frequency, etc. However, basically, with the cutoff frequency of the HPF obtained from the shake center frequency detection result as a reference, control is performed so that the cutoff frequency of the HPF goes to a higher frequency side during panning / tilting.

The coefficients according to the panning / tilting and the photographing state are empirically obtained.

In step S405, the HPF 10 is calculated based on the characteristic coefficient, and step S4
At 06, the output signal of the HPF 10 is integrated by the integrating circuit 5 and converted into an angular displacement signal (vibration signal).

In step S407, the result of the integration calculation is
That is, the corrected angular displacement signal is converted into an analog value by the D / A converter 7, or is output from the microcomputer COM4 as a pulse output such as PWM, and the drive circuit 8
The image correcting means 9 is supplied to the image correcting means 9 to move the image correcting means 9 in a direction for correcting the shake to perform the image stabilizing operation.

(Fourth Embodiment) Also, the angular velocity detecting means,
Depending on the image correction system or the combination thereof, when the frequency characteristics of the entire system are taken into consideration, depending on the frequency band, there is a region where the shake correction has an adverse effect at a shake of 30 Hz or more, for example.

This is the limit of the detection characteristics of the angular velocity sensor forming the angular velocity detecting means and the image correcting means such as VAP.
When the vibration frequency becomes high, the shake detection system and the correction system cannot follow without delay, and the phase delay becomes large. Then, at a certain frequency, the vibration phase and the VAP drive phase are in phase with each other, and on the contrary, the vibration may be greatly amplified.

Therefore, when the frequency detecting means continuously detects the frequency in the region where this shake correction has an adverse effect, the movement of the image correction system is stopped to cause the adverse effect state. Can be avoided.

As the circuit configuration, the circuit shown in FIG. 1 may be used, and when the frequency detecting means detects the above-mentioned frequency band, the VAP correction system, for example, is set in the correction center state with respect to the drive circuit 8. The hold signal may be calculated in the microcomputer so as to hold it and output to the drive circuit 8.

The processing operation on the microcomputer in this embodiment will be described below with reference to the flow chart of FIG. It should be noted that the state where the above-mentioned shake correction has an adverse effect is
Hz and above.

In the figure, when control is started, the angular velocity signal from the angular velocity detecting means 1 is first converted into a digital signal by the A / D converter 4 via the DC cut film 2 and the amplifier 3 in step S501. take in.

In step S502, the shake frequency is set to 30.
If Hz is reached, the process proceeds to step S511, and if not reached, the process proceeds to step S503.

In step S503, the panning / tilting and the photographing state are determined based on the angular velocity signal and the angular displacement signal, and in step S504, the coefficient that determines the characteristic of the HPF 10 is read according to the result. The coefficients according to the panning / tilting and the photographing state are empirically obtained.

In step S505, the HPF is calculated using the characteristic coefficient, and in step S506, the HPF1 is calculated.
The signal output from 0 is integrated by the integrating circuit 5 to be converted into an angular displacement signal (shake signal), and in step S507, an angular velocity signal is calculated to detect a shake center frequency.

In step S508, step S507
The coefficient of phase and gain correction corresponding to the shake frequency obtained in step S508 is read out, and in step S509, correction calculation is performed based on the coefficient obtained in step S508.

In step S510, the obtained calculation result, that is, the corrected angular displacement signal is converted into an analog value by the D / A converter 7, or PW is used.
The pulse output of M or the like is output from the microcomputer and supplied to the drive circuit 8, the image correction means 9 such as VAP is driven, and the process ends.

If the shake frequency F is equal to or higher than 30 Hz in step S502, that is, if it is determined that the shake correction is in the frequency range in which the shake correction has the opposite effect, step S is performed.
In step S51, the image correction system is reset and the correction system is held at the midpoint of the shake correction range.
In step 2, the center frequency of the shake is detected from the angular velocity signal, the processing is ended, and the processing of the flow chart in FIG. 18 is ended once.

The flow chart of FIG. 18 shows a single process, and in practice, this flow chart process is repeated.

The resetting means of the image correction system will be described below.
When a motor is used, if no signal is sent, it is stationary in that state, so it is returned to the center position and stopped there.

When a voice coil motor as shown in FIG. 4 is used in the image correction system, the control signal 32
It is sufficient to output the center signal to 0. However, due to the relationship between the mass of VAP and the torque of the voice coil, it may not be possible to maintain the center position sufficiently when a high frequency is applied. Therefore, although not shown, it is desirable to use a mechanical lock mechanism that mechanically holds VAP.

[0123]

As described above, according to the shake correcting apparatus of the present invention, the main frequency band of shake at the time of photographing is detected by the signal of the angular velocity detecting means such as the vibration gyro used for the shake detection. By using this for control, it is possible to perform optimum shake correction according to any shooting condition and environment.

Further, according to the present invention, since the correction effect in the main frequency band applied to the image pickup apparatus including the shake correction mechanism can be maximized, the effect can be greatly improved especially for the vibration having the specific frequency distribution. Has features.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a shake correction apparatus according to the present invention.

FIG. 2 is a flow chart for explaining a control operation in the first embodiment.

FIG. 3 is a flow chart for explaining a shake frequency detection operation in the first embodiment.

FIG. 4 is a frequency characteristic diagram of gain and phase of the angular velocity sensor.

FIG. 5 is a frequency characteristic diagram of gain and phase for explaining the operation of the shake correction apparatus according to the present invention.

FIG. 6 is a frequency characteristic diagram of gain and phase for explaining the operation of the shake correction apparatus according to the present invention.

FIG. 7 is a frequency characteristic diagram showing a vibration suppression characteristic of the shake correction apparatus according to the present invention.

FIG. 8 uses VAP as image correction means,
It is a figure which shows the example which used the voice coil type actuator for the drive system.

9 is a block diagram showing a drive circuit of an image correction means using the VAP of FIG.

FIG. 10 is a diagram showing an example in which a VAP is used as an image correction means and a step motor is used in a drive system.

FIG. 11 is a block diagram showing a drive circuit of an image correction means using the VAP of FIG.

FIG. 12 is a diagram for explaining the configuration and operation of VAP.

FIG. 13 is a diagram for explaining the configuration and operation of VAP.

FIG. 14 is a block diagram showing an example in which a memory control method for electronically performing shake correction is used as image correction means.

FIG. 15 is a block diagram showing the configuration of a second embodiment of the shake correction apparatus according to the present invention.

FIG. 16 is a block diagram showing the configuration of a third embodiment of the shake correction apparatus according to the present invention.

FIG. 17 is a flow chart for explaining the operation of the third embodiment shown in FIG.

FIG. 18 is a flow chart showing a fourth embodiment of the shake correcting apparatus in the present invention.

FIG. 19 is a block diagram showing the configuration of a conventional shake correction apparatus.

Claims (8)

[Claims] 1. A first detection means for detecting a vibration of a device, a correction means for correcting a movement of an image due to the vibration, and a control means for controlling the correction means based on an output of the first detection means, First control means for driving the correction means in a direction to correct the movement of the image; second detection means for detecting the frequency and amplitude of the vibration from the output of the first detection means; A second control means for controlling the characteristic of the first control means on the basis of the output of the detection means. 2. The integration means for integrating the output of the first detection means, and the frequency detection means for detecting the frequency of vibration from the output signal of the integration means. A shake correction apparatus comprising: 3. The shake correction apparatus according to claim 1, further comprising display means for displaying the frequency and amplitude of the vibration detected by the second detection means. 4. The shake correction apparatus according to claim 1, further comprising holding means for holding the output of the first detection means at the same level for a certain period. 5. The method according to claim 1, wherein the second detecting means is configured to detect a frequency by increasing or decreasing a discrete value signal output from the first detecting means. Shake correction device. 6. The first detection means according to claim 1, wherein the first detection means detects an angular velocity and an angular displacement, and the second detection means responds to the angular velocity or the angular displacement detected by the first detection means. The shake correction apparatus is configured so as to change the sampling time for frequency detection. 7. The shake correction apparatus according to claim 1, wherein the second control means is configured not to perform phase and gain correction when the shake is very small. 8. The shake correction apparatus according to claim 1, further comprising a prohibition unit that stops the shake correction operation outside the shake correction range.