JPH07294979A - Shake correction device - Google Patents

Abstract

(57) [Abstract] [Purpose] The detection speed of the frequency is shortened, the detection accuracy is improved, and optimal shake correction according to the usage environment is possible. A detection means 13 for detecting at least one of a frequency and an amplitude of vibration from two or more detection times different from the output of the vibration detection means 1, and a characteristic of a position control means based on the output of the detection means. The characteristic change means 11 is provided, for example, the minimum detection time is set, one detection means is made to work in time series, and the frequency and amplitude used for controlling the characteristics are obtained from the correlation of a plurality of outputs obtained by different detection times. Or at least one of the frequency and amplitude used for controlling the characteristic is determined from the correlation of a plurality of outputs obtained by a plurality of frequency detection means having two or more different detection times. I am trying.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a shake correction device incorporated in equipment such as a photographing device.

[0002]

2. Description of the Related Art In a conventional photographing device, exposure setting,
It is automated and multifunctional in all respects such as focus adjustment, so that good shooting can be done easily.

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

Correction systems provided in this type of shake correction apparatus are roughly classified into those that are optically corrected and those that are electrically corrected by image processing, and the detection system physically detects vibration. There are many types, each of which can be considered.

FIG. 17 shows an example of the configuration of a conventional shake correction apparatus.

In FIG. 17, reference numeral 1 denotes an angular velocity detector composed of an angular velocity sensor such as a vibration gyro, which is attached to the shake correction device. Reference numeral 2 denotes a DC cut filter that cuts off the DC component of the angular velocity signal output from the angular velocity detector 1 and passes only the AC component, that is, the vibration component. As the DC cut filter 2, a high-pass that cuts off the signal in an arbitrary band is used. Filter (hereinafter referred to as HPF)
May be used. An amplifier 3 amplifies the angular velocity signal output from the DC cut filter 2 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 integrating circuit for integrating the output from the A / D converter 4 and outputting an angular displacement signal, 6 Is a pan / tilt determination circuit that determines the panning / tilting of the image capturing apparatus 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 from the pan / tilt determination circuit 6 as an analog signal or It is a D / A converter that converts and outputs a pulse output such as PWM.

The A / D converter 4, the integration circuit 5, the pan / tilt determination circuit 6, and the D / A converter 7 are, for example, a microcomputer (hereinafter referred to as a microcomputer) COM.
It is composed of 1.

Reference numeral 8 denotes a drive circuit which drives the image correcting means, which will be described later, so as to be suppressed based on the displacement signal output from the microcomputer COM1. Reference numeral 9 denotes an image correcting means, for example, an optical correcting means for displacing the optical optical axis to cancel the shake, or an electronic correcting means for electronically shifting the read position of the image from the memory storing the image to cancel the shake. Correction means are used.

[0010]

By the way, the above-mentioned conventional device has the following problems.

FIG. 18 shows an existing angular velocity sensor as shown in FIG.
When used in the angular velocity detector 1 of No. 7 and the image pickup apparatus including the shake correction apparatus is vibrated with a constant amplitude, the image correction means 9
It is a figure which shows the frequency characteristic of the signal obtained by.

That is, the frequency characteristics of the image correction means 9 with respect to the input of the sine wave-like shake applied to the angular velocity detector 1 are shown. The gain characteristics are shown in the upper figure and the phase characteristics are shown in the lower figure. The vertical axis represents gain (upper figure) and phase (lower figure), and the horizontal axis represents frequency (1 to 100).
Hz).

Focusing on the characteristic at 10 Hz in the frequency characteristic of FIG. 18, the gain is almost 0 dB, but the phase is shifted by about 7.5 deg. This phase shift is the main factor, and the applied vibration is 1/3 at 3Hz.
What is suppressed to a vibration of 100 or less can be suppressed to a vibration of about 1/8 at 10 Hz.

Considering the effect of shake correction in such a characteristic, a sufficient effect can be expected in normal photographing, but when a frequency around 10 Hz is continuously applied, vibration is noticeable. There is.

As described above, when continuous vibration continues to be applied in a frequency band where a sufficient vibration suppressing effect cannot be expected at present, there is a problem that the uncorrected residue is conspicuous depending on the magnitude of the applied vibration.

Therefore, in the prior application, means for detecting the frequency and amplitude of the vibration applied to the image pickup apparatus including the shake correction apparatus, that is, the center frequency of the shake to be corrected, from the output of the vibration detecting means. Therefore, a proposal (Japanese Patent Application No. 4-312089) is made in which the gain characteristic and the phase characteristic are changed according to the output to correct the gain deviation and the phase deviation at the center frequency of the shake. However, due to the correlation between the frequency detection accuracy of the shake and the detection time,
The detection time was longer to improve the detection accuracy.

(Object of the Invention) A first object of the present invention is to reduce the speed of frequency detection, improve the detection accuracy, and perform shake correction that is optimum for the use environment. It is to provide a device.

A second object of the present invention is to use a signal having two different frequency characteristics of angular velocity and angular displacement, so that detection can be performed advantageously for noise (including drive noise of a motor etc.) while maintaining detection accuracy. An object of the present invention is to provide a shake correction device capable of setting sensitivity.

A third object of the present invention is to provide a shake compensating device capable of performing finer detection accuracy at low frequencies and faster measurement at high frequencies according to shake frequencies.

A fourth object of the present invention is to provide a shake correction device capable of outputting the frequency detection result at the fastest speed.

[0021]

In order to achieve the above first object, the present invention according to claim 1 provides at least the frequency and amplitude of vibration by two or more detection times different from the output of the vibration detection means. Detecting means for detecting one side, and a characteristic changing means for changing the characteristic of the position control means based on the output of the detecting means are provided, for example, a minimum detection time is set, and one detecting means is operated in time series, From the correlation of multiple outputs obtained by different detection times, determine at least one of frequency and amplitude used to change the characteristics,
Alternatively, at least one of the frequency and the amplitude used for changing the characteristic is determined based on the correlation of the plurality of outputs obtained by the plurality of frequency detecting means having two or more different detection times.

In order to achieve the second object,
According to a second aspect of the present invention, an integrating means for integrating the output of the vibration detecting means and a detecting means for detecting at least one of the frequency and the amplitude of the vibration from the output of the integrating means are provided, and two of the angular velocity and the angular displacement are provided. Signals with different frequency characteristics are used.

Further, in order to achieve the third object,
According to a third aspect of the present invention, the changing means for changing the detection accuracy of the detecting means based on the detection result of at least one of frequency and amplitude is provided, and the detecting means of the detecting means is changed based on the detection result of at least one of frequency and amplitude. The detection accuracy is changed.

In order to achieve the above-mentioned fourth object,
According to a fourth aspect of the present invention, two or more detection means having different detection times are provided, and the detection results of the outputs of these detection means are synchronized to detect at least one of the frequency and the amplitude of vibration. ing.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on the illustrated embodiments.

FIG. 1 is a block diagram showing the schematic arrangement of a shake correction apparatus according to the first embodiment of the present invention, and shows an example incorporated in a photographing apparatus. The parts having the same functions as those in FIG. 17 are designated by the same reference numerals.

In FIG. 1, an angular velocity detector 1 comprising an angular velocity sensor such as a vibration gyro attached to the device, and a DC cut filter (or HPF) for cutting off the DC component of the angular velocity signal output from the angular velocity detector 1. 2. With respect to the amplifier 3 for amplifying the angular velocity signal to a predetermined sensitivity, the drive circuit 8, and the image correction means 9, those having the same configuration as the conventional one shown in FIG. 17 can be used, and in the present embodiment. The difference is the internal configuration of the microcomputer COM2 that controls the entire apparatus. In this embodiment, as the image correcting means 9, for example, a variable apex angle prism described later or a memory control method is used.

The structure of the microcomputer COM2 will be described below.

Reference numeral 4 is an A / D converter for converting the angular velocity signal output from the amplifier 3 into a digital signal, 10 is an HPF having a function capable of varying in an arbitrary band, and 5 is an HPF 10.
Is an integration circuit that integrates a signal of a predetermined frequency component extracted by to calculate an angular displacement signal in the frequency component. Reference numeral 11 denotes a phase / gain correction circuit that corrects the phase and gain of the integrated signal output, that is, the angular displacement signal output from the integration circuit 5, and the correction of the phase and gain is changed by the output of the frequency / amplitude detection means described later. .

Reference numeral 12 is a judging means for judging the panning / tilting and photographing state from the angular velocity signal and the angular displacement signal output from the integrating circuit 5, and 13 is the angular velocity signal and the angular displacement signal output from the integrating circuit 5 is input. , A frequency / amplitude detecting means for detecting the frequency and amplitude thereof, and this output is output to the phase / gain correction circuit 11 described above. Reference numeral 7 denotes a D / A converter that converts the output signal of the phase / gain correction circuit 11 into an analog signal or a pulse signal such as PWM and outputs the converted signal.

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. 2 shows a variable vertical angle prism (hereinafter referred to as VA).
P: Variable angle prisum) 306 is used,
A voice coil type actuator is used for the drive system,
The control system constitutes a closed loop in which the angular displacement is detected by an encoder and is fed back to the drive system to control the drive amount.

First, the VAP 306 will be described in detail.

As shown in FIG. 3, the VAP 306 includes a transparent elastic body or an inert liquid 342 having a high refractive index (refractive index n) between two transparent parallel plates 340 a and 340 b facing each other.
Are sandwiched between the transparent parallel plate 3 and the outer periphery of the transparent parallel plate 3 which is elastically sealed with a sealing material 341 such as a resin film.
40a, 340b has a structure in which it can swing,
By swinging the transparent parallel plates 340a and 340b,
The optical axis is displaced to correct shake.

FIG. 4 is a diagram showing the passing state of the incident light beam 344 when one transparent parallel plate 340a of the VAP 306 of FIG. 3 is rotated about the axis 301 (311) by an angle σ. As shown in the figure, the light beam 344 incident along the optical axis 343 has the same principle as that of the wedge prism.
It is deflected by an angle φ = (n−1) σ and emitted. That is,
The optical axis 343 is decentered (deflected) by an angle φ.

Returning to the explanation of FIG. 4, the VAP3 explained above is explained.
06 is fixed to the lens barrel 302 so as to be rotatable about the shafts 301 and 311 via the holding frame 307.

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 the VAP 306 about the shaft 311 by passing a current through the coil 312. Reference numeral 310 is a slit for detecting the displacement of the VAP 306, which is coaxial with the shaft 311 and holds the holding frame 307, that is, the VAP.
It rotates together with 306 to displace its position. 308 is a light emitting diode for detecting the position of the slit 310, 309
Is a PSD (Position Sensing Detector) and constitutes an encoder for detecting the angular displacement of the VAP apex angle by detecting the displacement of the slit 310 together with the light emitting diode 308.

Then, the light flux whose incident angle is changed by the VAP 306 is imaged on the image pickup surface of the image pickup device 304 such as CCD by the taking lens unit 303.

Reference numeral 305 indicates the center of the other rotation axis orthogonal to the rotation axis formed by the shafts 301 and 311 of the holding frame 307.

Next, the basic structure of the control circuit for driving and controlling the VAP 306 and its operation will be described with reference to the block diagram of FIG.

In FIG. 5, 306 is a VAP, 322 is an amplifier, 323 is a driver for driving an actuator,
Reference numeral 324 is a voice coil type actuator for driving the VAP 306 described above, and 326 is an encoder for detecting the vertical angle displacement of the VAP 306. 325 is a microcomputer COM
2 is an adder that adds the shake correction control signal 320 and the output signal of the angular displacement encoder 326 with opposite polarities, and the shake correction control signal 320 and the angular displacement encoder 326 output from the microcomputer COM2. Since the control system operates so as to be equal to the output signal of the VAP306, the VAP306 is driven so that the control signal 320 coincides with the output of the encoder 326, so that the VAP306 is moved to the position instructed by the microcomputer COM2. Controlled.

FIG. 6 shows a second example of the image correction means 9, in which the above-mentioned VAP 306 is driven by using a stepping motor instead of a voice coil type actuator.

This is because the stepping motor 401 rotates the shaft 301 as the center of rotation and the V
It is configured to drive the AP 306.

That is, a stepping motor 401 having a lead screw 401a on its rotation axis is attached to a support frame 403 attached to a lens barrel 302, and a guide shaft 405 of the support frame 403 allows the stepping motor 401 to move in the optical axis direction. The guided carrier 404 is always meshed with the lead screw 401a, and the carrier 404 is fixed to the support frame 307.
By rotatably connecting the holding frame, the stepping motor 401 is rotated to move the carrier 404 in the optical axis direction, and the holding frame is connected to the shafts 301 and 311 via the connecting rod 407.
The VAP 306 is driven by rotating it around.

Reference numeral 402 is a reset sensor for detecting the reference position of the VAP 306. In addition, V similar to this
An AP drive mechanism is also provided for the shaft 311, but a description thereof will be omitted.

The circuit configuration for driving and controlling the system of FIG. 6 is as shown in the block diagram of FIG.

In FIG. 7, the control signal 320 output from the microcomputer COM2 is drive-calculated in the drive arithmetic circuit 410 to be converted into a drive signal for the VAP 306 and output to the driver IC 411. And the driver IC4
11 drives the stepping motor 401,
The apex angle of 306 is changed.

FIG. 8 shows a third example of the image correction means 9.

This is to store the image information in the memory, set the cut-out range of the image from the memory smaller than the stored image, and shift the cut-out position of the image from the memory in the direction to cancel the movement of the image. Thus, the image correction means of the memory control system is configured to correct the shake, and further expand the cut-out image signal to correct the screen size and then output the image signal.

This system is characterized in that shake correction can be performed electronically without using an optical correction mechanism such as VAP.

In FIG. 8, reference numeral 100 denotes a zoom lens, 1
Reference numeral 01 is an image pickup device (CCD image sensor or the like) for converting an optical image into an electric signal, and 102 is an A / D converter. 10
An image processing circuit 3 is provided in the field memory 106 so as to reduce a shake component in the image pickup signal based on a control signal (shake signal) 108 input from the microcomputer COM2.
An angle of view for performing a so-called electronic zoom by performing a shake correction process of correcting a shake of an image by shifting a cutout position of more predetermined image information and an enlargement process of an image read from the feed memory 106, and converting to a normal screen size. It constitutes a correction processing unit and is realized by a microcomputer.

Reference numeral 104 interpolates 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 106 to a normal angle of view. It is an interpolation processing means. As this interpolation method, well-known means may be used, for example, interpolation between pixels may be performed with an average value between adjacent pixels. Further, 105 is a D / A converter, 107
Is an encoder for detecting the zoom magnification ratio of the zoom lens 100.

Next, the operation of the above configuration will be described.

The optical image that has passed through the zoom lens 100 is
It is converted into an electric 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 stored in the memory 106 via the memory control unit of the image processing circuit 103.
Write to. Here, the control signal (shake signal) 108 input from the microcomputer COM2 and the zoom information from the encoder 107 determine the cut-out position of the image signal from the field memory 106, that is, the read range and its read position.

Next, the signal read from the field memory 106 is supplied with the scanning width of the output image according to the cutout size.
That is, in order to convert the angle of view to the original size, the number of pixels to be output in a normal one pixel output period is obtained, and the interpolation processing circuit 104 performs interpolation processing for pixels without pixel information. Then, this signal is converted into an analog signal by the D / A converter 105 and output.

The specific example of the image correcting means 9 for correcting the shake has 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 flowchart of FIG.

First, in step S201, the DC component is removed through the DC cut filter 2 and the amplifier 3, and the angular velocity signal from the angular velocity detector 1 amplified to a predetermined level is converted by the A / D converter 4. It is converted into a digital signal, and the microcomputer COM2 takes in this.

Subsequently, in step S202, the panning / tilting and the photographing state are determined by the angular displacement signal obtained by integrating the angular velocity signal and a predetermined high frequency component extracted from the angular velocity signal by the HPF 10 by the integrating circuit 5. To do.

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 the panning / tilting and the shooting state are those empirically obtained.

In the next step S204, the HPF 10 is calculated using the characteristic setting coefficient to set the characteristic, and in the subsequent step S205, the HPF 10 is calculated.
The signal output by 10 is integrated by the integrating circuit 5,
It is converted into an angular displacement signal (shake signal).

Then, in step S206, A / D
The angular velocity signal output from the converter 4 is calculated to detect the center frequency of the shake, and in the next step S207, correction of the phase / gain correction circuit 11 according to the center frequency of the shake obtained in step S206. The coefficient is read in advance from a table (not shown) prepared in the microcomputer COM2.

The phase / 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. The correction coefficient is read and the phase and gain correction characteristics corresponding to the shake frequency are set.

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

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

As a means for performing frequency detection using the angular velocity signal of FIG. 1, for example, a threshold value is provided near the center of the signal, and detection can be performed by the time at which this center is crossed or the number of times of crossing in a fixed time. However, this method depends on the stability of the DC signal. In other words, when shooting with a handheld device, a lot of low frequency components are included, so
Accurate shake frequency detection becomes difficult.

Therefore, the frequency is detected by paying attention to the increase and decrease of the signal for each sampling. That is, increase in signal
One set of decrease is set as one shake, and the frequency is indexed according to 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.

Here, an example of the frequency detection method and operation in this embodiment will be described with reference to the flowchart shown in FIG. It should be noted that this process is performed once every fixed time.
It shall be repeated at a rate of once.

In step S301, reading (loading) of the frequency detection time T is performed in the next step S302.
In step S3, the counter t for the clock function is read out, that is, the counting operation of the counter is started, and the subsequent step S3
In 03, the frequency detection time T is compared with the clock counter t, and the count value t of the clock counter is equal to the predetermined time T.
If the time counter t has reached, the process proceeds to step S319, and if not, 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 flowchart of FIG. 9 is executed once.

In step S305, the increase flag 1 for checking whether the increase of the angular velocity signal has occurred up to the previous time is loaded. The increase flag 1 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 the next step S306, it is determined by the flag 1 whether or not the increase of the angular velocity signal has occurred up to the previous time. If the flag 1 = “H”, it is determined that the increase has occurred in the past. Then, the process proceeds to step S307, and if flag 1 = "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 of the angular velocity signal has occurred by the previous time, step S306
At 307, decrease flag 2 is loaded to see if the decrease has occurred by the previous time. Decrease flag 2
Is set to "H" when the decrease has occurred until the last time, and is set to "L" when the decrease has not occurred in the past. In the next step S308, it is determined by the flag 2 whether or not the decrease has occurred up to the previous time. If the flag 2 = "H", that is, if the decrease has occurred in the past, the process proceeds to step S309, and the flag 2 =
If “L”, that is, the decrease has not occurred in the past, the process proceeds to step S312.

In step S309, the shake number counter N1 for counting the number of shakes (vibrations) is loaded, and in step S310, the shake number counter N is loaded.
"1" is added to 1. In the next step S332, the absolute amount of angular displacement when increasing and decreasing (L _D −L _U ).
Is calculated and added to the shake displacement amplitude amount TA, the process proceeds to step S311, the increase flag 1 and the decrease flag 2 are reset, and the process ends.

On the other hand, in the above step S306,
When it is determined that the increase flag 1 is not "H", and when it is determined that the decrease flag 1 is not "H" in step S308, that is, when neither increase nor decrease has occurred in the past, the process proceeds to step S312. Migrate here 1
The angular velocity data 1 _-1 before sampling (previous processing) is loaded, and then the process proceeds to step S313 to load the current angular velocity data 1 detected by the angular velocity detector 1. Then, in the next step S314, the increase of the angular velocity data within one sampling period, or
A threshold level "a" for a change that determines that a decrease has occurred is loaded.

A value according to the frequency and amplitude can be set by the threshold level a and the sampling time.

In the next step S315, the absolute value of the amount of change in the angular velocity data within one sampling period is compared with the threshold level a, and if not reached, the process ends. If it has reached (if the absolute value of the change amount is equal to or higher than the threshold level a), the process proceeds to step S316, and the change amount of the angular velocity in one sampling period is positive (increase) or negative (decrease). It is determined whether there is any, and if positive, the process proceeds to step S317.

At step 317, it is judged by the flag 1 whether or not the increase has occurred up to the previous time. If the flag 1 is "H", the processing is ended. If the flag 1 is "L", that is, if the increase has not occurred in the past, step 31
8, the increase flag 1 is set to "H" here,
In the next step 319, the angular displacement amount 1 is stored in L _U , and the process ends.

When it is determined in step 316 that the amount of change in angular velocity during one sampling period is negative (decrease), the process proceeds to step 320, and flag 2 is used to determine whether the decrease has occurred up to the previous time. If the flag 2 is "H", the process is terminated. Also, flag 2
Is "L", that is, if no decrease has occurred in the past, step 3
22. Here, the decrease flag 2 is set to "H", the angular displacement amount 1 is stored in L _D in the next step 319, and the process ends.

In step S303 described above,
If the count value of the clock counter t has reached the frequency detection time T, the process proceeds to step S323, the shake number counter N1 is loaded, and the shake number (N1) is detected at the detection time T in the next step S324. Division is performed and the number of shakes (runout frequency F) per unit time (1 second) is obtained. Then, in the next step S325, the shake counter N1 is cleared, and in the following step S326, the clock counter t is cleared.

In the next step S327, the shake frequency F is stored in a predetermined storage area, and then in step 3
At 28, the shake displacement total amplitude amount TA is loaded. At step 329, the shake displacement total amplitude amount TA is divided by the detection time T, and the shake frequency F is added to obtain the shake amplitude amount A. Then, in step 330, the shake amplitude amount A
Is stored in a predetermined storage area, and in the next step 331, the shake displacement total amplitude amount TA is cleared, 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 a The influence of the noise component can be removed by setting. Further, there is an advantage that it can be easily realized by performing processing using a microcomputer.

According to this method, when a low frequency swing and a high frequency swing occur at the same time, a high swing frequency can be extracted.

FIG. 11 shows a block diagram of the frequency / amplitude detecting means 13.

Reference numeral 171 is a frequency detecting means for detecting the shake frequency by the processing according to the flow chart shown in FIG. 10 using the angular velocity signal as an input, and 172 is a frequency detecting means for detecting the frequency and the amplitude by similarly inputting the angular displacement signal.
It is an amplitude means, and the shake frequency calculation means 173 detects the shake frequency based on these signals. Reference numeral 174 is a frequency detecting means set so as to detect only the shake in the low frequency band based on the detection time T and the threshold level a.

Reference numeral 175 is a changing means for changing the detection sensitivity according to, for example, the noise level. By setting the frequency detection time T and the threshold level a, it is possible to measure a relatively arbitrary frequency band, for example, a low frequency. It is possible to detect the frequency narrowed down to the fluctuation of.

By changing the detection threshold level a depending on the disturbance and noise (motor drive noise, etc.), stable measurement becomes possible. Further, as a simple amplitude detecting means, the shake amplitude can be detected together with the detection frequency by detecting the average value of the difference between the displacement amounts when the increase and the decrease occur.

In this system, the detection accuracy can be changed 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, the resolution is 0.5 Hz. Therefore, by changing the frequency detection time T according to the detection frequency F, it is possible to achieve detection accuracy according to the detection frequency.

For example, when the previous detection frequency F is less than 10 Hz, T = 2 [sec] is set, and detection is performed with an accuracy of 0.5 Hz. When the previous detection frequency F is 10 Hz or more, T = 1.
By detecting as [sec] with an accuracy of 1 Hz, the time required for detection can be shortened.

However, due to the correlation between the shake frequency detection accuracy and the detection time, it takes a longer time to improve the detection accuracy.

Therefore, for example, the minimum unit of detection is T = 0.5.
It is conceivable that the detection result is calculated by weighting with [sec]. There can be any number of data used for averaging, but the case of using the data two times before is described below.

For example, f = F ... f = (F + F- ₁ ) / 2 ... f = (F + F- ₁ + F- ₂ ) / 3 ... F: Current detection frequency F _-1 : Detection frequency before 1 time F _-2 : Detection frequency before 2 times, etc. are prepared. When the detection result F changes abruptly, the formula is used, and the result of shake detection is focused. If so, the detection cycle is extended by increasing the detection cycle, such as using an equation or an equation.

However, in this case, the detected frequency requires a value based on the correlation with the previous time. That is, it is necessary to detect whether the value is increasing or decreasing at the time of the detection result, and consider it in calculating the average value or the weighted data.

With this configuration, it is possible to quickly respond to a sudden change in the shake frequency and improve the detection accuracy at any time when continuous shake continues to be applied. .

Normally, the correction frequency range in such a shake correction apparatus is about 1 to 15 Hz for camera shake, but depending on the shooting condition, an amplitude of about 3 to 5 Hz for still shooting, for example, is 6 to 10 Hz for a vehicle. Depending on the skill of the photographer and the shooting conditions, such as a large amplitude, a relatively large amplitude shake has a narrow frequency range (band).
It is known to be distributed in. Also, when using a tripod, I am worried about high frequency vibrations, and
It is distributed up to ~ 30 Hz.

Next, the effect of this embodiment will be described.

First, since the center frequency of shake is detected, it is effective as one item for determining the photographing state as described above.

Also, by combining with the phase and gain correcting means applied for previously, it is possible to perform the optimum correction according to the skill level of the photographer, the photographing state and the like.

Suppose that the sufficient effect of shake correction can be obtained because the residual shake component is -30 dB with respect to the added shake.
If you can do the following, it is considered to be in a sufficient state. (Because the focal length of the image pickup device has a large effect on the shake correction effect, the focal length is simply 2
If it is twice, the same effect cannot be obtained in an image obtained unless there is a double suppression effect. ) However, in the overall shake suppression effect including the shake sensor that detects shake and the image correction system, at present, the range in which the residual shake amount after shake correction can be suppressed to −30 dB against shake is as described above. Can be obtained only in a narrow range as compared to the shake range of the correction target (1 to 15 Hz).

To show a concrete example, it is assumed that the frequency characteristics obtained by the current angular velocity detector and the image correction means 9 shown in FIG. 2 are as shown in FIG.

As described above, this shows the frequency characteristic of the image correction system with respect to the input of the sinusoidal vibration applied to the current angular velocity detector. The upper diagram shows the gain characteristic and the lower diagram shows the phase characteristic. Represents a characteristic. The vertical axis represents gain (upper figure) and phase (lower figure), respectively, and the horizontal axis represents frequency (1 to 1).
00 Hz).

The characteristic 1 of FIG. 12 is obtained by expanding the range. Focusing on the phase of this characteristic 1, the phases match at 3 Hz, and the HPF 10 (here, the cutoff frequency is 0.06 Hz) or the integrator circuit 5 as the frequencies before and after the phase match toward the low frequency side.
The phase advances due to the influence of the cutoff frequency of 0.07 Hz, and the phase lags toward the high frequency side due to the influence of the angular velocity detector 1 and the image correction means 9. Note that the gain is 1 to 1
It is almost constant up to about 0 Hz.

FIG. 13 shows the damping characteristic at this time.
6 is a characteristic 6 of the above, and the 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 can be achieved at 3 Hz where the phases match, and the suppression of -30 dB is almost achieved at 2 to 4 Hz, but the suppression effect is about -18 dB at 10 Hz.

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

Here, in order to correct the phase delay of the characteristic 1, if a characteristic having a phase lead element represented by a transfer function of H (s) = a (s + b) ... Is connected in series, The phase can be corrected at a predetermined frequency. In addition, a and b are arbitrary constants, and s is a variable of Laplace transform. This is to set the frequency higher than the range of shake suppression and advance the phase. This is performed by the phase / 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, 10H
It can be corrected by advancing the 7.5 deg phase with z.

That is, the characteristic 2 is to correct the phase shift of the characteristic 1 at 10 Hz (to match the phase and also match the gain). This can be set by the expression b. Further, a is adjusted so that the gain becomes 0 dB at 10 Hz. If this is realized by the phase / gain correction circuit 11, the characteristic 1 can be changed to the characteristic 5 shown in FIG. 14, and the characteristic 7 (see FIG. 13) showing the damping 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) OUT: residual shake component after shake correction IN: shake amount.

At 20 Hz, similarly to the characteristic 1,
If the characteristic 4 is realized by the phase / compensation circuit 11 as shown in FIG. 14, the characteristic 5 is obtained. The characteristic 8 (see FIG. 13) represents the damping effect realized by the characteristic 5, and
The best damping effect is obtained near Hz.

In order to realize the characteristics of the equation in the phase / compensation circuit 11, a digital filter may be used. If a first-order IIR filter is used as 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, b1: filter coefficient 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 operation may be performed with the filter coefficient obtained from the table. .

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 distributed over a narrow range to some extent depending on the skill of the photographer and the shooting condition. To do.

Therefore, if it is constructed so as to give the best correction effect to the center band of such a shake, the skill of the photographer and the photographing condition (handheld, attached to a tripod, or from the top of the vehicle, etc.) are set. The optimum correction is possible.

(Second Embodiment) FIGS. 15 and 16 are diagrams relating to a second embodiment of the present invention, and FIG. 1 is a block diagram showing the main configuration of a shake correction apparatus.

The second embodiment is different from the first embodiment in the frequency / amplitude detecting means of 13, and the other points are the same, so that the description thereof will be omitted.

That is, in the present embodiment, in order to improve both the detection time and the detection accuracy, different detection times, for example, the detection time is A detection time 0.5 sec detection accuracy 2 Hz B detection time 1.0 sec detection accuracy 1 Hz C detection time Prepare 2.0 sec detection accuracy 0.5 Hz, and if B is included in A, the result of B is
If is contained in B, the result of C is used. This improves the detection speed.

In FIG. 15, reference numerals 41, 42 and 43 are input with an angular velocity signal, and frequency detection means for detecting a frequency according to the detection time of A, B and C, and 44, 45 and 46 are input with an angular displacement signal. , Frequency detecting means for detecting a frequency based on the detection times of A, B, and C, and the shake frequency calculating means 47 calculates the detected frequency based on these results.

By this method, both the detection time and the detection accuracy can be improved.

For example, when a 5.6 Hz sine wave is input to the frequency / amplitude detection means 13 shown in FIG. 15, the frequency detection means A finds that the frequency is 4 to 6 Hz after 0.5 [sec]. By means B 1.0
It can be seen from the frequency detecting means C that the frequency is between 5 and 6 Hz after [sec], and that the frequency is between 5.5 and 6.0 Hz after 2.0 [sec].

Frequency / amplitude detecting means 1 shown in FIG.
FIG. 16 shows an example of frequency detection by No. 3.

It can be seen that the detection time is faster than that in a single detection time, and the detection sensitivity is improved if the same frequency continues.

In the present embodiment, the main frequency band of the shake at the time of shooting is detected by the signal of the vibration gyro which is used for the shake detection, and this is used for the control so that the optimum condition according to the shooting condition and state can be obtained. Shake correction is possible. Also,
Since it is possible to maximize the correction effect in the main frequency band applied to the image pickup apparatus including the shake correction apparatus, it is possible to expect a great improvement in the effect with respect to the vibration having a specific frequency distribution.

(Correspondence between Invention and Embodiment) In this embodiment, the angular velocity detector 1 corresponds to the vibration detecting means of the present invention.
The image correction means 9 corresponds to the correction means of the present invention, the drive circuit 8 corresponds to the position control means of the present invention, the frequency / amplitude detection means 13 corresponds to the detection means of the present invention, and the phase / gain correction circuit 11 is provided. Corresponds to the characteristic changing means of the present invention. The integrator 5 corresponds to the integrating means of the present invention.

The above is the correspondence relationship between each configuration of the embodiments and each configuration of the present invention, but the present invention is not limited to the configurations of these embodiments, and a configuration capable of achieving the functions shown in the claims. It goes without saying that it may be of any type.

(Modification) In the present embodiment, the frequency and the amplitude are respectively detected, and the position control of the image correcting means 9 is performed based on these, but the present invention is not limited to this, and these are not limited thereto. It goes without saying that either one of them may be detected and the position control of the image correction means 9 may be performed by this.

Further, in the present embodiment, the example in which the angular velocity detector is used as the vibration detecting means is shown, but the present invention is not limited to this, and the displacement detector, the angular displacement detector, the acceleration detector, the angular acceleration It may be a detector or the like.

Further, although the present invention shows an example applied to an image pickup apparatus such as a silver halide camera and a video camera, it can be applied to other optical equipment.

Further, the present invention may be constructed by appropriately combining the above-described embodiments or their techniques.

[0127]

As described above, according to the present invention as set forth in claim 1, the detection means for detecting at least one of the frequency and the amplitude of the vibration from the output of the vibration detection means by two or more different detection times. , Characteristic changing means for changing the characteristic of the position control means based on the output of the detecting means,
For example, the minimum detection time is set, one detection means is operated in time series, and at least one of the frequency and amplitude used to change the characteristic is determined from the correlation of a plurality of outputs obtained by different detection times, Alternatively, at least one of the frequency and the amplitude used for changing the characteristic is determined based on the correlation of the plurality of outputs obtained by the plurality of frequency detecting means having two or more different detection times.

Therefore, it is possible to shorten the frequency detection speed, improve the detection accuracy, and perform the optimum shake correction according to the use environment.

According to the second aspect of the present invention, there are provided an integrating means for integrating the output of the vibration detecting means and a detecting means for detecting at least one of the frequency and the amplitude of the vibration from the output of the integrating means. , Signals having different frequency characteristics of angular velocity and angular displacement are used.

Therefore, by using two signals having different frequency characteristics of angular velocity and angular displacement, it is possible to set the detection sensitivity advantageous for noise while maintaining the detection accuracy.

Further, according to the present invention as set forth in claim 3, change means for changing the detection accuracy of the detection means based on the detection result of at least one of frequency and amplitude is provided, and at least one of frequency and amplitude is detected. The detection accuracy of the detection means is changed based on the result.

Therefore, depending on the shake frequency, it is possible to perform finer detection accuracy at low frequencies and faster measurement at high frequencies.

According to the present invention as defined in claim 4, two or more detection means having different detection times are provided, and the detection results of the outputs of these detection means are synchronized to detect the frequency and amplitude of vibration. At least one is detected.

Therefore, the frequency detection result can be output fastest.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram showing an example in which a VAP is used as the image correction means in FIG. 1 and a voice coil actuator is used in a drive system.

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

FIG. 4 is a diagram for explaining the configuration and operation of VAP in the same manner.

5 is a block diagram showing the drive circuit of FIG. 2. FIG.

FIG. 6 is a configuration diagram showing an example of a case where a VAP is used as the image correction means in FIG. 1 and a stepping motor is used as a drive system.

FIG. 7 is a block diagram showing the drive circuit of FIG.

8 is a block diagram showing an example of a case where a memory control method for electronic correction is used as the image correction means in FIG.

FIG. 9 is a flowchart showing a control operation in the first embodiment of the present invention.

FIG. 10 is a flowchart showing an operation at the time of detecting a shake frequency in the first embodiment of the present invention.

FIG. 11 is a block diagram showing a circuit configuration of a main part in the first embodiment of the present invention.

FIG. 12 is an enlarged view showing the range of FIG. 18.

13 is a diagram showing a suppression rate of the frequency characteristic shown in FIG.

FIG. 14 is a diagram showing how the frequency / frequency characteristics shown in FIG. 12 are changed by a phase / gain correction circuit.

FIG. 15 is a block diagram showing a circuit configuration of a main part in a second embodiment of the present invention.

FIG. 16 is a diagram showing an example of frequency characteristics in the second embodiment of the present invention.

FIG. 17 is a block diagram showing a configuration of a conventional shake correction apparatus.

FIG. 18 is a diagram showing frequency characteristics of phase and gain of a general angular velocity detector.

[Explanation of symbols]

 1 Angular velocity detector 4 A / D converter 5 Integrator circuit 8 Drive circuit 9 Image correction means 10 HPF 11 Phase / gain correction circuit 13 Frequency / amplitude detection means COM2 Microcomputer

Claims (4)

[Claims] 1. A vibration detecting means for detecting a vibration applied to the apparatus, a correcting means driven in a direction for removing the influence of the vibration, and a position of the correcting means is controlled based on an output of the vibration detecting means. In the shake correction apparatus including the position control means, the detection means for detecting at least one of the frequency and amplitude of vibration from the output of the vibration detection means at two or more different detection times, and the output of the detection means A shake detecting device, comprising: a characteristic changing means for changing the characteristic of the position control means based on the characteristic detecting means. 2. An integrating means for integrating the output of the vibration detecting means, wherein the detecting means is means for detecting at least one of the frequency and the amplitude of the vibration from the output of the integrating means. The shake correction apparatus according to claim 1. 3. The shake correction apparatus according to claim 1, further comprising a changing unit that changes the detection accuracy of the detecting unit based on the detection result of at least one of frequency and amplitude. 4. The detecting means is composed of two or more means having different detection times, and is means for detecting at least one of the frequency and the amplitude of vibration by synchronizing the detection results of the outputs of these means. The shake correction device according to claim 1 or 2, wherein