JPH0879598A - Adjusting method for phase compensation characteristic of phase compensator and camera-shake correction device capable of application of the method - Google Patents

Abstract

PURPOSE: To easily adjust the phase compensation characteristic to accurately compensate the camera-shake. CONSTITUTION: The camera-shake is detected by a sensor 11 to supply a signal SAV to a terminal (1) of a switch 21 through filters 12 to 14. A signal DSI is supplied from a sine wave output part 22 to a terminal (b) and a detection part 24. In the production line, the terminal (b) is selected, and the signal DSI has the gain and the phase compensated by a compensation filter 15a and is supplied to a control part 17 through a D/A 16. A prism 1 is driven by this signal and a signal SP of a sensor 7. The signal SP is supplied to the detection part 24 through an A/D 23, and the phase deviation from the signal DSI is calculated, and data PD is supplied to a filter control part 25 to generate data FC. Data FC is supplied to the compensation filter 15a through a switch 26 to change the compensation characteristic. Thereafter, the switch 21 is switched to the side of the terminal (a), and the switch 26 is turned off, and the prism 1 is driven based on the signal SAV of the sensor 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of adjusting a phase compensation characteristic of a phase compensator and an image stabilization apparatus to which the method can be applied.

[0002]

2. Description of the Related Art Conventionally, in a camera shake correction apparatus for correcting a camera shake state, for example, a prism is used for camera shake correction. In the shake correction device using this prism, the fluctuation of the incident light caused by the shake is corrected by refracting the incident light in an arbitrary direction by the prism.

Now, a conventional image stabilizing apparatus using a prism will be described with reference to FIG. Note that FIG. 3 is an example in which the image stabilizing apparatus is applied to a video camera.

In FIG. 3, reference numeral 1 is a prism. This prism 1 is, for example, as shown in FIG.
A and 2b are connected by a film 3 so that they can expand and contract.
A liquid 4 having the same refractive index as the glass is injected between the two plate glasses 2a and 2b.

Further, the plate glass 2a is provided with a horizontal axis 5a for tilting the plate glass 2a in the vertical direction, and the plate glass 2b is provided with a vertical axis 5 for tilting the plate glass 2b in the horizontal direction.
b is provided. Furthermore, the horizontal axis 5a and the vertical axis 5b
Is connected to the drive coil unit 6, and by supplying a drive signal RD to be described later to the drive coil unit 6, the horizontal axis 5a and the vertical axis 5b are rotationally driven, and incident light is refracted in a predetermined direction. .

The incident light refracted by the prism 1 is condensed by a lens 8 and is formed as an optical image of a subject on an image pickup surface of an image pickup device (eg CCD) 9. This optical image is converted into an image pickup signal which is an electric signal by the image pickup element 9. The image pickup signal is supplied to a signal processing circuit (not shown) and converted into a video signal.

Next, 11 is an angular velocity sensor. The angular velocity sensor 11 detects the angular velocities of horizontal and vertical shaking due to camera shake of the camera body. The angular velocity signal SAV indicating the detected angular velocity is supplied to the high-pass filter 12 and band-limited, and then supplied to the A / D converter 13 to be converted into the angular velocity data signal DAV. The angular velocity data signal DAV is supplied to the integration filter 14 and integrated. The angular displacement data signal DAD, which is the integral data of the angular velocity data signal DAV, is supplied to the characteristic compensation filter 15. In the characteristic compensation filter 15, the gain and phase of the angular displacement data signal DAD are compensated with the characteristic shown in (Equation 1), for example.

[0008]

[Equation 1]

In the equation (1), K1, K2, K3
Is a preset coefficient.

The angular displacement data signal DAD whose gain and phase have been compensated is supplied to the D / A converter 16 as a compensated angular displacement data signal DADC and converted into an analog compensated angular displacement signal SADC. This compensation angle displacement signal SA
DC is supplied to the prism controller 17.

In the prism controller 17, the drive signal RD is generated based on the compensation angular displacement signal SADC. The drive signal RD is supplied to the drive coil unit 6 of the prism 1 to rotationally drive the horizontal axis 5a and the vertical axis 5b of the prism 1 to control the refraction direction of incident light.

The prism 1 is provided with an apex angle sensor 7 for detecting the inclination of the prism 1 in the vertical and horizontal directions, and the inclination signal SP indicating the inclination of the plate glasses 2a and 2b of the prism 1 is used for prism control. By being supplied to the section 17, the prism 1 is stably driven.

As described above, the horizontal vibration and the vertical vibration due to the hand shake are detected by the angular velocity sensor, and the prism is controlled based on the obtained angular velocity signal and the tilt signal indicating the state of the prism. For this reason, the light beam of the subject incident on the video camera is refracted in a predetermined direction by the prism, so that even when the video camera shakes, the subject's light beam is fixed at a certain position on the imaging surface of the image sensor. An optical image is formed,
Image blurring is prevented.

[0014]

By the way, the frequency characteristics of the prisms are not constant but vary from prism to prism. Therefore, assuming that the characteristic compensation filter uniformly compensates the gain and phase of the angular displacement data signal to perform the camera shake correction, as shown in FIG. 5 showing the phase characteristic of the conventional camera shake correction apparatus, it is detected by the angular velocity sensor. The phase of the tilt signal indicating the tilt of the prism driven with respect to the angular velocity signal varies as shown by lines a to c. If the line a has a phase delay and the line b has the optimum phase,
Line c shows the case of phase lead. As described above, since the phase shift occurs due to the difference in the characteristics of the prism, the camera shake correction may not be properly performed.

Further, if the characteristic of the characteristic compensation filter is manually adjusted for each prism, the adjustment work becomes very complicated.

Therefore, according to the present invention, the phase compensation characteristic can be easily adjusted so that the camera shake correction can be performed accurately.

[0017]

According to a first aspect of the present invention, there is provided a phase compensation characteristic adjusting method for a phase compensator, comprising: a camera shake detecting means for detecting a camera shake state; and an image moving section for moving image information vertically or horizontally. In a camera shake correction device having a calculation unit that calculates image movement information necessary to prevent image shake based on a detection signal from the camera shake detection unit, and a phase compensator that compensates for the tracking delay of the image moving unit, The reference signal is used as the movement information, the tracking delay of the image moving unit at this time is detected, and the compensation characteristic of the phase compensator is adjusted based on the information of the tracking delay.

According to a second aspect of the present invention, there is provided a camera shake correction device which detects a camera shake state, an image moving section which moves image information vertically or horizontally, and an image based on a detection signal from the camera shake detecting means. An arithmetic unit that calculates the movement information of the image necessary to prevent shaking, a phase compensator that compensates the tracking delay of the image movement unit, and a compensation signal of the phase compensator is adjusted by using the reference signal as the movement information. It has a phase compensation characteristic adjusting means.

[0019]

According to the present invention, the reference signal is used as the movement information, the tracking delay of the image moving unit at this time is detected, and the compensation characteristic of the phase compensator is adjusted based on the information of the tracking delay. It Therefore, the compensation characteristic of the phase compensator for compensating the tracking delay of the image moving unit is optimally adjusted including the variation of the image moving unit. Therefore, for example, the phase compensation of the phase compensator according to the invention of claim 1 is performed. If the camera-shake correction device adjusted by the characteristic adjustment method is applied to a video camera, it is possible to appropriately correct the camera-shake.

According to the second aspect of the invention, there is provided a phase compensation characteristic adjusting means for adjusting the compensation characteristic of the phase compensator by using the reference signal as the movement information. The delay is detected, and the compensation characteristic of the phase compensator is adjusted based on the information of the tracking delay. For this reason, the compensation characteristic of the phase compensator is automatically and optimally adjusted by the phase compensation characteristic adjusting means including the variation of the image moving unit. Therefore, for example, the image stabilization apparatus according to the invention of claim 2 is applied to a video camera. If so, it becomes possible to automatically adjust the compensation characteristic of the phase compensator to an optimum state in the production line of the video camera.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the image stabilization apparatus according to the present invention will be described below with reference to FIG. Note that FIG. 1 is also an example in which the image stabilizing apparatus is applied to a video camera as in FIG. 3, and portions corresponding to FIG. 3 are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, reference numeral 20 denotes a camera shake correction signal processing unit, which is constituted by, for example, a microcomputer. The angular displacement data signal DAD output from the integration filter 14 of the camera shake correction signal processing unit 20 is supplied to the terminal a of the changeover switch 21. The sine wave data signal DSI is supplied from the sine wave output unit 22 to the terminal b of the changeover switch 21. The movable terminal of the changeover switch 21 is connected to the characteristic compensation filter 15a, and the angular displacement data signal D
Either the AD or the sine wave data signal DSI is selected and supplied. The characteristic compensation filter 15a corresponds to the characteristic compensation filter 15 of FIG.

The tilt signal SP output from the apex angle sensor 7 of the prism 1 is supplied to the prism controller 17 and A /
It is supplied to the D converter 23. The slope signal SP supplied to the A / D converter 23 is converted into a slope data signal DSP and supplied to the phase difference detection unit 24. In addition, the phase difference detector 24
Is supplied with a sine wave data signal DSI from the sine wave output unit 22.
The phase shift of SP is calculated. The phase difference data PD is supplied to the characteristic compensation filter controller 25.

The characteristic compensation filter control unit 25 generates the filter coefficient data FC based on the phase difference data PD. The filter coefficient data FC based on the phase difference data PD is easily generated by referring to a table based on the phase difference data PD, for example.

The generated filter coefficient data FC is supplied from the characteristic compensation filter controller 25 to one terminal of the switch 26. The other terminal of the switch 26 is connected to the characteristic compensation filter 15a, and the filter coefficient data FC is supplied to the characteristic compensation filter 15a when the switch 26 is on. In the characteristic compensation filter 15a, the characteristic is changed by changing the filter coefficient according to the filter coefficient data FC.

The present embodiment is configured as described above,
Next, the operation will be described. For example, in a video camera production line, the movable terminal of the changeover switch 21 is switched to the terminal b side so that the sine wave data signal DSI (for example, a sine wave data signal having a frequency of 10 Hz indicating a constant continuous shake state) is received by the characteristic compensation filter 15a. Is supplied to. The characteristic compensation filter 15a compensates the gain and phase of the sine wave data signal DSI supplied with the filter characteristic based on a preset coefficient. The compensated sine wave data signal DSI is supplied to the D / A converter 16 as a compensated sine wave data signal DSIC and converted into an analog compensated sine wave signal SSIC. The compensating sine wave signal SSIC is supplied to the prism controller 17 to drive the prism 1.

A tilt signal SP is supplied from the apex angle sensor 7 of the prism 1 to the prism controller 17 and the A / D converter 23. The slope signal SP is converted into a slope data signal DSP by the A / D converter 23 and then supplied to the phase difference detection unit 24, and the phase difference detection unit 24 calculates the phase shift from the sine wave data signal DSI.

Here, referring to FIG. 2, the phase difference detecting section 24
The operation of will be described. In FIG. 2, FIG. 2A shows the sine wave data signal DSI which is digital data as an analog signal, and FIG. 2B shows the tilt data signal DSP which is digital data as an analog signal.

First, when the signal level of the sine wave data signal DSI exceeds the average value level at time t1, the measurement of the time interval from time t1 is started. After that, the measurement of the time interval is ended at the time point t2 when the signal level of the inclination data signal DSP exceeds the average value level and becomes large. Based on the measured time data Tp, the phase difference data PD is calculated by (Equation 2).

[0030]

[Equation 2]

The calculated phase difference data PD is supplied to the characteristic compensation filter controller 25. In the characteristic compensation filter control unit 25, the filter coefficient data FC is generated based on the phase difference data PD and is supplied to the characteristic compensation filter 15a via the switch 26 which is turned on.

In the characteristic compensation filter 15a, the coefficients K1 and K2 are changed based on the filter coefficient data FC to change the filter characteristics. After that, the movable terminal of the selector switch 21 is switched to the terminal a side to select the angular displacement data signal DAD, and the switch 26 is turned off to change the coefficients K1 and K2 of the characteristic compensation filter 15a. prohibited.

As described above, according to this example, in the video camera production line, the image stabilization signal processing unit 20 constituted by the microcomputer uses the sine wave data signal DSI to determine the filter characteristic of the characteristic compensation filter 15a. Since the coefficients K1 and K2 to be determined are automatically adjusted to the optimum state, the adjustment work can be facilitated.

After the adjustment is completed, the movable terminal of the changeover switch 21 is automatically changed over to the terminal a side and the switch 26 is turned off, so that the angular displacement data signal DAD is selected and the camera shake correction is performed. Together with the coefficient K
1, K2 is fixed to the optimum value. Therefore, when the video camera is used, camera shake of the video camera can be properly corrected in a wide frequency band.

It is needless to say that the phase compensation characteristic adjusting method of the phase compensator according to the present invention and the image stabilizing apparatus to which the method can be applied are not applicable only to the video camera.

[0036]

According to the first aspect of the present invention, the reference signal is used as the movement information, the tracking delay of the image moving portion at this time is detected, and the compensation characteristic of the phase compensator is based on the tracking delay information. Is adjusted. Therefore, the compensation characteristic of the phase compensator for compensating the tracking delay of the image moving unit is optimally adjusted including the variation of the image moving unit. Therefore, for example, the phase compensation of the phase compensator according to the invention of claim 1 is performed. If the camera shake correction device adjusted by the characteristic adjustment method is applied to a video camera, the camera shake of the camera body can be corrected appropriately.

According to the second aspect of the invention, there is provided the phase compensation characteristic adjusting means for adjusting the compensation characteristic of the phase compensator by using the reference signal as the movement information. Following delay is detected,
The compensation characteristic of the phase compensator is adjusted based on the information on the tracking delay. For this reason, the compensation characteristic of the phase compensator is automatically and optimally adjusted by the phase compensation characteristic adjusting means including the variation of the image moving unit. Therefore, for example, the image stabilization apparatus according to the invention of claim 2 is applied to a video camera. If so, the compensation characteristics of the phase compensator can be automatically adjusted to the optimum state in the production line of the video camera.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of an image stabilization apparatus according to the present invention.

FIG. 2 is a diagram showing an operation of a phase difference detection unit.

FIG. 3 is a diagram showing a configuration of a conventional camera shake correction device.

FIG. 4 is a diagram showing a configuration of a prism.

FIG. 5 is a diagram showing phase characteristics of a conventional camera shake correction device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 prism 2a, 2b plate glass 3 film 4 liquid 5a horizontal axis 5b vertical axis 6 drive coil section 7 apex angle sensor 8 lens 9 image sensor 11 angular velocity sensor 12 high-pass filter 13,23 A / D converter 14 integration filter 15,15a Characteristic compensation filter 16 D / A converter 17 Prism control section 21 Changeover switch 22 Sine wave output section 24 Phase difference detection section 25 Characteristic compensation filter control section 26 Switch

Claims (2)

[Claims] 1. A camera shake detection unit for detecting a camera shake state, an image moving unit for moving image information up and down or left and right, and an image necessary for preventing image shake based on a detection signal from the camera shake detection unit. In a camera shake correction device having a calculation unit for calculating movement information and a phase compensator for compensating for the tracking delay of the image moving unit, a reference signal is used as the movement information and the tracking delay of the image moving unit at this time is detected. And adjusting the compensation characteristic of the phase compensator based on the information of the tracking delay. 2. A camera shake detecting means for detecting a camera shake state, an image moving section for moving image information up and down or left and right, and an image necessary for preventing image shake based on a detection signal from the camera shake detecting means. A calculation unit for calculating movement information, a phase compensator for compensating for the tracking delay of the image movement unit, and a phase compensation characteristic adjusting means for adjusting the compensation characteristic of the phase compensator by using a reference signal as the movement information. A camera shake correction device having.