JPH0129118B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a registration correction method for a television camera that allows registration at the periphery of an image plane to be easily corrected independently.

Color television imaging devices traditionally use multiple image pickup tubes with different spectral sensitivity characteristics, and the video signals from these tubes are combined to obtain a color video signal. Cameras are often used.

Therefore, in an imaging device such as a color television camera that obtains a final video signal by combining video signals from multiple image pickup tubes, the final video signal is obtained from each of the multiple image pickup tubes. It is necessary to ensure that the respective images based on the video signals are accurately superimposed.

This type of superimposition of images is called registration, and can be divided into various forms based on various causes. Of these, correction of the tilt of the entire image plane (rotation correction) has traditionally been performed by centering the horizontal deflection. This was done by superimposing a sawtooth wave correction voltage synchronized with the vertical deflection on the current, and a sawtooth wave correction voltage synchronized with the horizontal deflection on the vertical deflection centering current, and changing the polarity and amplitude of these correction voltages. .

Therefore, although these conventional methods can sufficiently correct the tilt of the entire image plane, they cannot individually correct partial tilts and curvatures. It is not possible to sufficiently absorb the variations in characteristics that exist in the image plane, and to perform correct registration over all parts of the image plane.

From a practical point of view, the above-mentioned variations in characteristics have a large effect on the periphery of the image plane, so in the end, in the conventional method described above, corrections at the periphery of the image plane are carried out depending on each case. This has the disadvantage that registration errors are likely to remain in this area, resulting in deterioration of image quality.

An object of the present invention is to eliminate the drawbacks of the prior art described above, to arbitrarily correct only the tilt (curvature) at the periphery of the image plane independently of the correction of the tilt of the entire image plane, and to provide a color image with excellent image quality. An object of the present invention is to provide a peripheral registration correction method capable of obtaining a television signal.

To achieve this objective, the present invention extracts the vicinity of the maximum value and the vicinity of the minimum value of the sawtooth wave voltage synchronized with the horizontal and vertical deflection operations, respectively, and uses the extracted voltages as correction signals to control the vertical centering current and the horizontal centering current. The present invention is characterized in that by superimposing each of the currents and adjusting the polarity and level of these correction signals, it is possible to partially correct the inclination at the periphery of the image plane.

Embodiments of the peripheral registration correction method according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention, and shows an imaging system using two imaging tubes. Note that for color television, a system using three or more image pickup tubes is usually employed, and the method according to the present invention is also mainly applied to such a system.
The principle of registration is to sequentially perform registration between images from two image pickup tubes, and can be applied in exactly the same way to systems with three or more image pickup tubes. In the example, in order to simplify the explanation and make it easier to understand, a system having two image pickup tubes will be explained.

In Fig. 1, 1A and 1B are image pickup tubes, 2A,
2B is a horizontal deflection coil, 3A, 3B are vertical deflection coils, 4A, 4B are horizontal deflection circuits, 5A, 5B are vertical deflection circuits, 6A, 6B are horizontal deflection centering circuits, 7A, 7B are vertical deflection centering circuits, 8A, 8B is a horizontal peripheral registration adjustment circuit, 9A and 9B are vertical peripheral registration adjustment circuits, 10 is a vertical correction voltage amplification circuit, 11
12 is a horizontal sawtooth wave generation circuit, 13 is a horizontal drive pulse input terminal, 14 is a horizontal correction voltage amplifier circuit, 15 is a vertical sawtooth clip circuit, 16 is a vertical sawtooth wave generation circuit, and 17 is a vertical sawtooth wave generation circuit. This is a drive pulse input terminal.

The horizontal deflection circuits 4A and 4B generate horizontal deflection outputs in response to horizontal drive pulses from the input terminal 13,
A horizontal deflection current is supplied to the horizontal deflection coils 2A and 2B. At this time, the horizontal deflection centering circuit 6A,
A current for horizontal centering is supplied from 6B to horizontal deflection circuits 4A and 4B, and is superimposed on the horizontal deflection current to perform centering correction.

Similarly, vertical deflection circuits 5A and 5B have input terminal 1
A vertical deflection output is generated by the vertical drive pulse from 7, and a vertical deflection current is supplied to the vertical deflection coils 3A and 3B. At this time, vertical centering currents are supplied from the vertical centering circuits 7A, 7B to the vertical deflection coils 3A, 3B via the vertical deflection circuits 5A, 5B, and are superimposed on the vertical deflection currents to perform vertical centering correction.

Similar to the horizontal deflection circuits 4A and 4B, the horizontal sawtooth wave generation circuit 12 is operated by horizontal drive pulses from the input terminal 13, and has a period of 1H (one horizontal scanning period, however, as shown in FIG. 2A). generates a sawtooth voltage α (including the ranking period).

The clip circuit 11 clips and extracts a portion p _1H from the maximum value of the sawtooth wave voltage α to a predetermined voltage, and a portion p _2H from the maximum value to a predetermined voltage, respectively, and outputs the voltage b ₁ , shown in FIG. 2B, Extract b ₂ respectively.

These voltages b ₁ and b ₂ are applied to the horizontal correction voltage amplification circuit 1
After being amplified to a predetermined level, positive and negative voltages +b ₁ , as shown in FIG.
Converted to −b ₁ , +b ₂ , −b ₂ .

Vertical peripheral registration adjustment circuit 9A, 9
B inputs the correction voltages ±b ₁ and ±b ₂ and outputs correction signals c ₁ and c 2 whose amplitudes can be arbitrarily adjusted between positive and negative polarities, as shown in FIG. _2D . occurs,
These are supplied to vertical centering circuits 7A and 7B.

Therefore, the vertical deflection circuits 5A and 5B have the structure shown in FIG.
As shown in FIG. 2, a vertical centering current d on which a correction signal e is superimposed is supplied.

Further, the vertical sawtooth wave generating circuit 16 is operated by a vertical drive pulse from the input terminal 17, and has a cycle of 1V (one vertical scanning period, including a blanking period) as shown in FIG. 3A. A vertical sawtooth voltage f is generated, and a vertical clip circuit 15 clips and extracts a portion _p1V from the maximum value to a predetermined voltage and a portion _p2V from the minimum value to a predetermined voltage, resulting in the voltage shown in FIG. 3B. Extract g ₁ and g ₂ .

The vertical correction voltage amplification circuit 14 receives these voltages g ₁ ,
g ₂ as an input, and generates positive and negative polarity correction voltages +g ₁ , -g ₁ , +g ₂ , -g ₂ at predetermined levels as shown in FIG.
Supply to A and 8B.

Therefore, these horizontal peripheral registration adjustment circuits 8A and 8B can arbitrarily adjust the amplitude across positive and negative polarities as shown in FIG. 3D by inputting the voltages ±g ₁ and ±g ₂ . correction signal
h ₁ and h ₂ are generated and supplied to horizontal centering circuits 6A and 6B.

Therefore, the horizontal deflection circuits 4A and 4B are
As shown in , a horizontal centering current i on which a correction signal j is superimposed is supplied.

Therefore, we will now adjust the peripheral registration adjustment circuit 8A (hereinafter referred to as adjustment circuits 8A, 8B, 9A, and 9B) to change the polarity and amplitude of the correction signal _h1 shown in FIG. 3D. do.

Then, the horizontal deflection coil 2A of the image pickup tube 1A
The waveform of the portion of the correction signal j superimposed on the horizontal centering current i flowing in the horizontal centering current i shown as A in FIG. 3E changes over the range indicated by the arrow.

As a result, on the image plane reproduced by the image pickup tube 1A, only a predetermined range around the right side of the screen can be tilted in any vertical direction at any desired ratio, as shown by A in FIG.

Similarly, by changing the polarity and amplitude of the correction signal _h2 shown in FIG. 3D using the adjustment circuit 8A, the correction signal j superimposed on the horizontal centering current i shown in FIG. 2E can be changed. The waveform of the part changes over the range of the arrow, and on the reproduced image plane of the image pickup tube 1A, the waveform of the fourth
As shown by arrow B in the figure, only a predetermined range around the left side of the screen can be tilted in any direction up or down at any ratio.

Moreover, if the polarity and amplitude of the correction signal _c1 shown in FIG. 2D are changed by the adjustment circuit 9A, the image pickup tube 1
The waveform of part A of the waveform of the correction signal e superimposed on the vertical centering current d flowing through the vertical deflection coil 3A of A changes within the range of the arrow in FIG. A predetermined range around the lower side of the surface is tilted in any right or left direction at any ratio as shown by arrow A in FIG. By changing the polarity and amplitude of the correction signal _c2 , it is possible to tilt only a predetermined range around the upper side of the image plane in any left or right direction at any ratio, as shown by arrow B in Figure 5. .

At this time, the predetermined portion p _1H of FIG. 2A
Depending on the size of p _2H and p 2H, the predetermined range p _1H and
The width of p _2H is determined, and the specified part of Figure 3 A is similarly
Depending on the magnitude of p _1V and p _2V , the predetermined range in Figure 4 is determined.
Since the widths of p _1V and p _2V are determined, the correction range at the periphery can be arbitrarily set by changing the clip levels by the horizontal and vertical sawtooth clip circuits 11 and 15.

On the other hand, the same is true for the image reproduced by the image pickup tube 1B, and by adjusting the adjustment circuits 8B and 9B, as shown in FIGS. The slope of the range can be adjusted in any direction and at any rate.

Therefore, according to the embodiment shown in FIG.
In addition to adjusting the registration by adjusting the tilt of the entire screen, it is also possible to adjust the tilt of only a predetermined area around the screen independently, so it is possible to adjust the tilt of only a predetermined range around the screen independently, so it is possible to adjust the tilt of each image pickup tube and deflection coil. It is possible to perform sufficient registration alignment over the entire image plane by sufficiently absorbing variations.

In addition, instead of the above embodiment, adjustment circuits 8A, 8
One input is a DC control voltage that can be arbitrarily changed from positive polarity to negative polarity as B, 9A, and 9B, and each correction voltage is input to the other input.
Multiplication circuits each supplied with one of b ₁ , b ₂ , g _{1 ,} and g 2 may be used.

According to this, the configuration of each amplifier circuit 10, 14 can be simplified.

As explained above, according to the present invention, it is possible to independently adjust only the inclination of the peripheral portion of the image reproduced by each image pickup tube. The tilt that remains in the peripheral areas of the image due to differences in the characteristics of each deflection coil can be sufficiently corrected, and a television signal of excellent image quality with sufficient registration maintained over the entire image can be obtained. A registration correction method for color television cameras and the like can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of the peripheral registration correction method according to the present invention, and FIG.
~E, and FIGS. 3A to 3E are waveform diagrams for explaining the operation,
FIGS. 4 and 5 are explanatory diagrams showing the effects of the above embodiment. 1A, 1B... Image pickup tube, 2A, 2B... Horizontal deflection coil, 3A, 3B... Vertical deflection coil, 4
A, 4B...Horizontal deflection circuit, 5A, 5B...Vertical deflection circuit, 6A, 6B...Horizontal deflection centering circuit, 7A, 7B...Vertical centering circuit, 8
A, 8B...Horizontal peripheral registration adjustment circuit, 9A, 9B...Vertical peripheral registration adjustment circuit, 10...Vertical correction voltage amplification circuit, 11
...Horizontal sawtooth wave clip circuit, 12...Horizontal sawtooth wave generation circuit, 13...Horizontal drive pulse input terminal, 14...Horizontal correction voltage amplification circuit, 15...
...Vertical sawtooth wave clip circuit, 16... Vertical sawtooth wave generation circuit, 17... Vertical drive pulse input terminal.

Claims (1)

[Claims] 1 In a television camera that is equipped with multiple image pickup tubes and performs registration by superimposing a correction signal on the centering current supplied to each deflection coil, First and second sawtooth voltage generation circuits that generate first and second sawtooth voltages, respectively, and a portion from the maximum value of each of the first and second sawtooth voltages to a predetermined voltage range; first and second clipping means each extracting a portion from the minimum value to a predetermined voltage range to take out first and second correction voltages; first and second level adjustment means for producing first and second correction signals by adjusting the level over a predetermined amplitude range of the vertical centering current; A peripheral registration correction method characterized in that the second correction signal is superimposed on the horizontal centering current to perform registration correction in the peripheral part of the image.