JPH05207358A - Prism reference position adjusting device and video camera - Google Patents

Abstract

PURPOSE:To greatly reduce the deterioration of a color aberration or a resolution generated due to the variation of a circuit constant at the time of a still operation by controlling a motor. CONSTITUTION:This device is equipped with a prism 15, a mechanical lock bar 12 which fixes the position of the prism l5, a motor 2 which drives the prism 15, and a microcomputer 9 which controls the drive of the prism 15. At the time of releasing the fixing of the prism 15 by the mechanical lock bar 12, the motor 2 is controlled so that a reference position at the time of fixing the prism 15 by the mechanical lock bar 12 can be obtained.

Description

Detailed Description of the Invention

[0001]

The present invention relates to, for example, VAP (Var).
The present invention relates to a prism reference position adjusting device and a video camera which are suitable for application to a video camera or the like in which a prism such as an iable Angular Prism) element is driven to correct so-called camera shake.

[0002]

2. Description of the Related Art Conventionally, VAP (Variable An)
A video camera has been proposed in which a camera shake is corrected by using a regular prism element.

This VAP element is a kind of prism in which two plate glasses are joined by a transparent spring portion which is a bellows, and a viscous liquid is filled inside the spring portion.

This prism is usually arranged in front of a lens that allows light from a subject to enter the CCD element.

The left and right portions of the front glass plate are pivotally supported inside the video camera, and the upper and lower portions of the rear glass plate are pivotally supported inside the video camera.

A position detecting element for detecting the position of the plate glass is arranged in front of the front plate glass, and a position detecting element for detecting the position of the plate glass is arranged above the rear plate glass.

The axes of the front and rear plate glass are connected to motors for vertical and horizontal driving, these motors are connected to a drive circuit, and this drive circuit is connected to a microcomputer.

Inside the video camera, an element such as an angular velocity sensor for detecting a change in angular velocity due to camera shake is arranged.

Then, based on the angular velocity data detected by the angular velocity sensor, the microcomputer drives the above-mentioned vertical and horizontal driving motors via a drive circuit to vertically and horizontally move the front and rear plate glasses. It is made to drive.

The amount of movement of the front and rear plate glass during driving in the vertical and horizontal directions corresponds to the difference between the position detection signal detected by the position detecting element and the microcomputer.

As described above, in the related art, the angular velocity caused by camera shake is detected, and the drive signal based on the detected angular velocity data and the position detection element for detecting the vertical and horizontal positions of the prism (VAP element) are detected. According to the difference signal from the position detection signal, the prism is moved in the vertical and horizontal directions to refract the optical axis, thereby correcting the image disturbance due to camera shake.

[0012]

By the way, in the above video camera, the center of the position detection signal at the so-called mechanical mounting center detected by the position detection element and the center of the control signal from the microcomputer due to the variation of the circuit constants. There is a gap in the values.

In this case, the prism is driven to move from the original center position of the mechanism, which causes the optical axis to be refracted, causing chromatic aberration and lowering the resolution.

In particular, when the prism is deformed with a fast response as in the case of a camera shake correction operation, it is almost unrecognizable to the human eye, but in the stationary state, due to such a variation in the circuit constant, this chromatic aberration is caused. The deterioration of the image quality due to will be recognizable to the human eye.

The present invention has been made in view of the above points, and in the case of performing a camera shake correction using a prism,
It is possible to significantly reduce chromatic aberration and deterioration of resolution caused by variations in circuit constants at rest, and by absorbing variations in circuit constants, it is not necessary to pay attention to how to select resistors and capacitors. Therefore, it is an object of the present invention to propose a prism reference position adjusting device and a video camera which can reduce the cost by eliminating the need for using a highly accurate element.

[0016]

A prism reference position adjusting device according to the present invention includes a prism 15 as shown in FIGS.
Fixing means 12 for fixing the position of the prism 15, driving means 1, 2 for driving the prism 15, and driving means 1,
And a control means 9 for controlling the driving of the prism 15 of No. 2 to drive the prism 15 to a reference position when the prism 15 is fixed by the fixing means 12 when the fixation of the prism 15 by the fixing means 12 is released. The means 1 and 2 are controlled.

According to the above-described video camera of the present invention, the prism 15, the optical system 16 to which the light from the subject is incident through the prism 15, and the light from the subject to be incident through the optical system 16. Imaging means 17 and imaging means 1
Signal processing means 18 for signal-processing the video signal from 7.
The fixing means 12 for fixing the position of the prism 15, the driving means 1, 2 for driving the prism 15, and the fixing means 12 when the fixation of the prism 15 by the fixing means 12 is released.
The control means 9 for controlling the driving means 1 and 2 so that the prism 15 becomes the reference position when the prism 15 is fixed, and the adjustment value obtained during the control performed on the driving means 1 and 2 by the control means 9 are The storage means 9 is stored, and the reference position of the prism 15 is controlled by the content stored in the storage means 9.

[0018]

According to the present invention described above, when the fixing of the prism 15 by the fixing means 12 is released, the driving means 1, 2 are controlled so as to be at the reference position when the prism 15 is fixed by the fixing means 12. Therefore, when applied to a video camera, for example, when performing image stabilization using a prism, it is possible to significantly reduce chromatic aberration and deterioration of resolution caused by variations in circuit constants at rest, and By absorbing the variation in the circuit constants, it is not necessary to pay attention to how to select the resistors and the capacitors, that is, it is not necessary to use a highly accurate element, so that the cost can be reduced.

Further, according to the present invention described above, the fixing means 1
The adjustment value when being controlled by the driving means 1 and 2 is stored in the storage means 9 so that the prism 15 is set to the reference position when the prism 15 is fixed by the storage means 9. Since the reference position is controlled, when performing image stabilization using a prism,
It is possible to significantly reduce chromatic aberration and deterioration of resolution caused by variations in circuit constants at rest, and by absorbing variations in circuit constants, it is not necessary to pay attention to how to select resistors and capacitors. Therefore, it is not necessary to use a highly accurate element, which can reduce the cost.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the prism reference position adjusting device and the video camera of the present invention will be described in detail below with reference to FIG. 1, but first, with reference to FIG. 2, the video camera to which the present invention is applied. An example will be described.

In FIG. 2, reference numeral 15 denotes a prism, and as shown in the figure, the plate glass 3 and the plate glass 4 are joined by a transparent spring portion 14a having a hollow inside, and the inside of the spring portion 14a is joined. For example, it is configured by filling a viscous liquid.

A prism having such a structure is generally used as a VAP.
It is called a (Variable Angular Prism) element.

The right and left sides of the plate glass 3 on the front side of the prism 15 are supported inside the video camera by the shafts 3a and 3b of the plate glass 3, and the upper and lower sides of the plate glass on the rear side of the plate of the prism 15 in FIG. Axis 4
It is axially supported inside the video camera by a and 4b.

Also, these shafts 3a and 3b, 4a and 4
Of b, shaft 3a is connected to motor 1 and shaft 4b is connected to motor 2
Connect to.

These motors 1 and 2 are driven by amplifier circuits 7 and 8, respectively.

Reference numeral 5 is a position detection circuit for detecting the vertical position of the plate glass 3, and the output of this position detection circuit 5 is supplied to the inverting input terminal (-) of the amplification circuit 7.

Further, 6 is a position detection circuit for detecting the horizontal position of the plate glass 4, and the output of this position detection circuit 6 is supplied to the inverting input terminal (-) of the amplification circuit 8 described above.

A control signal (position command signal) from the microcomputer 9 is supplied to each non-inverting input terminal (+) of each of the amplifier circuits 7 and 8.

The microcomputer 9 includes sensors 10 and 1 such as an angular velocity detecting sensor for detecting an angular velocity.
A control signal obtained by subjecting the detection signal from No. 1 to digital filtering, for example, is supplied as a position command signal to each of the amplifier circuits 7 and 8 described above.

Therefore, each amplifier circuit 7 and 8 supplies the difference between the control signal from the microcomputer 9 and the position detection signal from each position detection element 5 and 6 to each motor 1 and 2, respectively.

Thus, the image disturbance due to camera shake is corrected by changing the optical axis by the movement of the prism 15, and the corrected light from the subject is passed through the lens 16 to the CCD (charge coupled device) element ( The number of CCD elements is not limited).

The light from the subject photoelectrically converted by the CCD 17 is supplied to the video camera main circuit 18 as a video signal, and the video camera main circuit 1
After being subjected to various kinds of signal processing at 8, the signal is supplied to, for example, a television monitor (not shown) via the output terminal 19, and is displayed as an image on the tube surface thereof.

As described above, the hand shake is caused by the movement of the hand that supports or holds the video camera so that the light of the subject moves up and down or left and right on the image pickup surface of the CCD element 17, thereby causing the television. This is a phenomenon in which an image on the tube surface of a John monitor moves vertically or horizontally on this tube surface.

Therefore, as described above, if the optical axis is changed by the prism 15 before the light from the subject is incident on the CCD element 17 and the correction is performed, the light of the subject on the image pickup surface of the CCD element 17 is vertically or vertically changed. Can be prevented from moving left and right.

When the vertical correction is actually performed, the motor 1 is rotated to rotate the plate glass 3 in the vertical direction to change the refraction angle of the prism 15, and when the horizontal correction is performed, the motor 2 is rotated. Then, the plate glass 4 is rotated in the horizontal direction to change the refraction angle of the prism 15.

Further, in the figure, 12 is a mechanical lock bar, and this mechanical lock bar 12 drives a motor (not shown) by, for example, the microcomputer 9 to fix the prism 15 in a predetermined state. Is.

Now, the essential parts of the above-described video camera according to the present invention will be described with reference to FIG.

In FIG. 1, as an example, the movement of the image on the tube surface due to camera shake due to the horizontal rotation of the plate glass 4 of the prism 15, that is, the movement of the light of the object on the image pickup surface of the CCD element 17 is corrected. A case will be described.

It should be noted that although illustration and description of the correction of camera shake by the vertical rotation control of the plate glass 3 of the prism 15 are omitted, the correction is used for the camera shake correction of the prism glass 15 by the horizontal rotation control of the plate glass 4. Since the circuit configuration and the operation thereof are the same, only the shake correction by the rotation control in the horizontal direction will be described.

In FIG. 1, parts corresponding to those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In this example, as shown in FIG.
The amplifier circuit 8 shown in FIG. 2 is composed of a third-order low-pass filter 25, a summing circuit 22, and a motor drive circuit 20 having a differential structure, which are indicated by alternate long and short dash lines.

As shown in this figure, the third-order low-pass filter 25 connects the output port of the microcomputer 9 to the non-inverting input terminal (+) of the amplifier circuit 26 through resistors R8, R7 and R6, and The connection point of R7 and R6 is connected to the inverting input terminal (−) of the amplifier circuit 26 via the capacitor C2, the inverting input terminal (−) of the amplifier circuit 26 is connected to the output terminal of the amplifier circuit 26, and The non-inverting input terminal (+) of the amplifier circuit 26 is grounded via the capacitor C1.

The connection point between the resistors R7 and R8 is grounded via the capacitor C3.

As can be seen from this figure, the resistor R8 and the capacitor C3, the resistor R7 and the capacitor C2, the resistor R6 and the capacitor C1 respectively constitute a low pass filter.

The position command signal output from the microcomputer 9 is, for example, duty 50%, 47.
It is a KHz PWM (pulse width modulation) type signal.

As shown in FIG. 5, in this position command signal, the high level "1" voltage is the same as the power source 28 of the microcomputer 9, and the low level "0" voltage is the ground potential.

Therefore, when the position command signal from the microcomputer 9 is smoothed by the above-mentioned third-order low-pass filter 25, the voltage becomes 1/2 of the voltage of the power source 28 of the microcomputer 9, for example.

The adder circuit 22 is constructed as follows.

That is, the output terminal of the third-order low-pass filter 25, that is, the output terminal of the amplifier circuit 26 is connected to the inverting input terminal (-) of the amplifier circuit 23 via the resistor R5, and the inverting input of the amplifier circuit 23 is connected. Terminal (-) and this amplifier circuit 23
The output terminals of the amplifier circuit 23 are connected to each other, and the non-inverting input terminal (+) of the amplifier circuit 23 is grounded via the reference power source 24 (for example, half the voltage of the reference power source 28).

The connection point of the resistor R5 and the inverting input terminal (-) of the amplifier circuit 23 is connected to the output terminal of the position detecting element 6 via the resistor R4.

As shown in this figure, the power supply terminal of the position detecting element 6 is grounded, for example, via a reference power supply 6a which generates a voltage half that of the reference power supply 28.

Reference power source 6 connected to the position detecting element 6
Reference numeral a denotes a power supply that regulates the level of the signal output by the position detection element 6 when the plate glass 3 of the prism 15 is at the center position.

The power source of the reference power source 6a is generated by the circuit configuration shown in FIG. 4, for example.

As shown in FIG. 4, the inverting input terminal (-) and the output terminal of the amplifier circuit 30 are connected, the output terminal of the amplifier circuit 30 is connected to the power supply terminal of the position detecting element 6, and the amplifier The non-inverting input terminal (+) of the circuit 30 and the connection point of the resistors R10 and R11 are connected.

Further, one end of the resistor R10 is connected to the power source 28 of the microcomputer 9 shown in FIG.

Connecting in this way, resistors R10 and R1
By adjusting the resistance value of 1, it is possible to obtain a voltage half the voltage of the power supply 28 of the microcomputer 9, but this is not always the case in consideration of the variations in the resistors R10 and R11 and the voltage drop due to the wiring impedance. I won't.

The position detection signal (for example, angle information) from the position detection element 6 and the microcomputer 9
The position command signal supplied through the next low-pass filter 25 is mixed (a difference is taken) by the adder circuit 22 and the voltage of the reference power source 24 connected to the non-inverting input terminal (+) of the amplifier circuit 23. Is the difference between this amplifier circuit 2
It is output from 3.

The position command signal output from the amplifier circuit 23 is supplied to the motor drive circuit 20.

The structure of the motor drive circuit 20 is as follows.

That is, the output terminal of the amplifier circuit 23 is connected to the resistor R.
2 is connected to the inverting input terminal (−) of the amplifier circuit 21 via a 2 and the non-inverting input terminal (+) of the amplifier circuit 21 is connected to the non-inverting input terminal (+) of the amplifier circuit 26 of the adding circuit 22; The inverting input terminal (-) and the output terminal of the amplifier circuit 21 are connected via a resistor R1 and the motor drive coil is connected between the output terminal of the amplifier circuit 21 and the connection point of the amplifier circuit 23 and the resistor R2. Connect with L.

Therefore, the motor 2 is driven by the differential output of the amplifier circuit 21.

Reference numeral 29 is a controller separate from the video camera shown in FIG. 2, for example.
Is connected to the microcomputer 9 via a LANC terminal (not shown).

A communication format called LANC (a format for mutual communication at the cycle of the vertical synchronizing signal)
Then, the mechanical lock bar 12 is driven by a motor (not shown) by the controller 29, and the plate glasses 3 and 4 of the prism 15 are pressed to lock the prism 15.

It should be noted that the mechanical lock bar 1 is controlled by the controller 29.
It is also possible to provide a switch on, for example, a video camera without operating 2, and drive the mechanical lock bar 12 by operating this switch.

Of the voltages supplied to the adder circuit 22, the voltage from the position detecting element 6 is Vdet, the voltage from the microcomputer 9 is Vpwm, and the resistors R4 and R5 of the adder circuit 22 are respectively. The resistance value is r1,
When the resistance value of the resistor R3 is r2 and the voltage of the reference power source 24 is Vref2, the voltage Vde from the position detection element 6 is Vde.
t can be expressed by the following equation 1.

[0066]

## EQU1 ## Vdet = Vref2 + ΔV1

Similarly, the voltage Vpwm from the microcomputer 9 can be expressed by the following equation 2.

[0068]

## EQU00002 ## Vpwm = Vref2-.DELTA.V2

Therefore, from the above equations 1 and 2, the output Vput of the adder circuit 22 is represented by the following equation 3.

[0070]

## EQU00003 ## Vput = -r2 / r1 (.DELTA.V1-.DELTA.V2) = r2 / r1 (.DELTA.V2-.DELTA.V1)

The resistors R4 and R5 of the adder circuit 22 are
Although it is also affected by the variation of the resistance value r1 of the above, it is assumed here that they are the same.

In this example, ΔV2 = Δ of the above-mentioned equation 3
V1 is controlled to be "0" at the center position of the prism 15.

That is, in the present example, for example, in the factory line adjustment process, the position detecting element 6 (the position detecting element 5 shown in FIG. 2 in the vertical direction control of the plate glass 3 at the center position of the prism 15 is used. The position command signal from the microcomputer 9 is aligned with the center of the position command signal, that is, ΔV2 =
The center value of the position command signal from the microcomputer 9 is determined so as to be ΔV1.

This method will be described with reference to the flowchart of FIG.

For convenience of explanation, the processing steps under the control of the microcomputer 9 indicated by the solid line and the processing steps under the control of the human controller 29 indicated by the broken line are incorporated into one flowchart.

In step 100, the PWM duty is set to 50%. Then, the process proceeds to step 110.

That is, the prism 15 is brought to the center position by attaching the mechanical lock bar 12, but when the motor 2 is driven with a large torque, the mechanical lock bar 1 is moved.
Since the position cannot be fixed at 2, the prism 15 is electrically stopped at a substantially center position by setting the duty of the position command signal to 50%.

At step 110, the person is the controller 2
9 is operated to fix the prism 15 so that the position of the prism 15 becomes the center position. And step 12
Move to 0.

At step 120, the position data detected by the position detecting element 6 is fetched. And step 130
Move to.

In step 130, the mechanical lock bar 12
Remove. Then, the process proceeds to step 140.

That is, a person operates the controller 29,
The mechanical lock bar 12 is separated from the prism 15.

In step 140, the duty of the PWM output is adjusted so that the position data matches the previous position data. Then, the process proceeds to step 150.

That is, the duty of the position command signal is adjusted so that the position data from the position detecting element matches the stored previous position data.

When the duty of the position command signal is adjusted in the state of step 130, that is, with the mechanical lock bar 12 removed, the prism 15 is at the center position when the motor 2 is stationary (when the prism is attached). In consideration of such setting), it is possible to obtain ΔV2 such that ΔV2 = ΔV1 from the above-mentioned formula 3.

In step 150, the PWM center value at the center position of the prism 15 is adjusted from the duty of 50% to the duty obtained in the previous step.

That is, this process is a process for replacing data so that the prism 15 always operates centering on the value set in step 140 during normal operation, and the value of the position command signal when the prism 15 is at the center position is, for example, a microcomputer. 9 Non-volatile memory (EEPRO)
M, memory to be backed up, etc.), read this value during normal operation, and PWM for the deviation of the center value
Is a process for correcting and outputting.

As described above, in this example, when the fixation of the prism 15 by the mechanical lock bar 12 is released,
Since the motor 2 is controlled so as to be at the reference position when the prism 15 is fixed by the mechanical lock bar 12, the adjustment value at this time is stored, and the motor is controlled based on this adjustment value. When using a prism, it is possible to significantly reduce chromatic aberration and deterioration in resolution caused by variations in circuit constants at rest, and by absorbing variations in circuit constants,
It is not necessary to pay attention to how to select resistors and capacitors, that is, it is not necessary to use highly accurate elements,
This can reduce costs.

The above-mentioned embodiment is an example of the present invention.
Of course, various other configurations can be adopted without departing from the scope of the present invention.

[0089]

According to the present invention described above, when the fixing of the prism by the fixing means is released, the driving means is controlled so as to be at the reference position when the prism is fixed by the fixing means. For example, when applied to a video camera, when performing image stabilization using a prism, it is possible to greatly reduce chromatic aberration and deterioration of resolution caused by variations in circuit constants at rest,
Also, by absorbing the variations in circuit constants, it is not necessary to pay attention to how to select resistors and capacitors,
That is, it is not necessary to use a highly accurate element, and there is an advantage that the cost can be reduced.

Further, according to the present invention described above, the reference position when the prism is fixed by the fixing means,
The adjustment value when controlled by the drive means is stored in the storage means, and the reference position of the prism is controlled by the content stored in this storage means. Therefore, when the shake correction is performed using the prism, the adjustment is stopped. Chromatic aberration and deterioration of resolution sometimes caused by variations in circuit constants can be significantly reduced, and by absorbing variations in circuit constants, it is not necessary to pay attention to how to select resistors and capacitors. There is an advantage that it is not necessary to use a highly accurate element, and thus cost can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a main part of an embodiment of a prism reference position adjusting device and a video camera of the present invention.

FIG. 2 is a configuration diagram showing an example of a video camera to which the present invention is applied.

FIG. 3 is a flowchart for explaining an embodiment of the prism reference position adjusting device and the video camera of the present invention.

FIG. 4 is an explanatory diagram for explaining an embodiment of the prism reference position adjusting device and the video camera of the present invention.

FIG. 5 is an explanatory diagram for explaining one embodiment of the prism reference position adjusting device and the video camera of the present invention.

[Explanation of symbols]

 1, 2 Motors 3, 4 Plate glass 5, 6 Position detection element 7, 8 Amplification circuit 9 Microcomputer 10, 11 Sensor 12 Mechanical lock bar 14a Spring part 14b Liquid 15 Prism 16 Lens 17 CCD element 18 Video camera main circuit 19 Output terminal 20 21, 23, 26 Amplification circuit 22 24, 28 Reference power supply 25 29 Controller

Claims (2)

[Claims] 1. A prism, fixing means for fixing the position of the prism, driving means for driving the prism, and control means for controlling the driving of the driving means with respect to the prism. A prism reference position adjusting device, characterized in that when the prism is released, the drive means is controlled so as to reach a reference position when the prism is fixed by the fixing means. 2. A prism, an optical system into which light from a subject is incident via the prism, an image pickup unit into which light from the subject is incident via the optical system, and a video signal from the image pickup unit. Signal processing means for signal processing, fixing means for fixing the position of the prism, driving means for driving the prism, and fixing means for fixing the prism by the fixing means when the fixing means fixes the prism. It has a control means for controlling the drive means so as to be the reference position when fixed, and a storage means for storing the adjustment value obtained at the time of the control performed on the drive means by the control means. A video camera characterized in that the reference position of the prism is controlled by the contents stored in the storage means.