JPH0129117B2 - - 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.

Television cameras have traditionally used multiple image pickup tubes with different spectral sensitivity characteristics, and synthesized the video signals from these tubes to obtain a color video signal. is 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 it is divided into various forms based on various causes. Of these, corrections for deflection size and deflection linearity have traditionally been based on the overall registration of the screen. A registration correction method that captures the tendency of registration deviation and supplies a correction signal to the deflection coil for correction over the entire horizontal period and vertical period in response to the trend has been mainly adopted.

However, although this method can achieve relatively accurate registration at most positions, including the center of the image plane, it is possible to achieve relatively accurate registration at most positions, including the center of the image plane. Regarding the registration at the periphery of the image, which is easily affected, it is difficult to correct these independently according to each case, and there is a drawback that large registration errors in this area tend to remain. .

An object of the present invention is to eliminate the above-mentioned drawbacks of the prior art, and to enable correction of registration at the periphery of the image plane, independently of the overall registration correction including the center area of the image plane, and to make it possible to correct the registration over the entire image plane. An object of the present invention is to provide a peripheral registration correction method capable of performing sufficient correction.

In order to achieve this object, the present invention extracts the vicinity of the maximum value and the vicinity of the minimum value of the sawtooth wave voltage synchronized with each of the horizontal and vertical deflection operations, and uses the extracted voltages as correction signals for each of the horizontal and vertical deflection operations. The present invention is characterized in that registration is performed at the periphery of the image plane by superimposing the correction signals on the deflection current and adjusting the polarity and level of these correction signals.

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. For television cameras, a system with three or more image pickup tubes is usually used, but the principle of registration is to sequentially register between images from two image pickup tubes. Therefore, this embodiment can be applied in exactly the same way to a system having three or more image pickup tubes, so in order to simplify the explanation and make it easier to understand, in this embodiment,
A system with two image pickup tubes is shown.

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

The horizontal deflection circuits 3A, 3B generate horizontal deflection outputs in response to horizontal drive pulses from the input terminal 8, and supply horizontal deflection currents to the horizontal deflection coils 2A, 2B.

Further, the vertical deflection circuits 10A and 10B generate vertical deflection outputs in response to vertical drive pulses from the input terminal 15, and supply vertical deflection currents to the vertical deflection coils 9A and 9B.

On the other hand, the horizontal sawtooth wave generation circuit 7 has an input terminal 8
It operates in accordance with horizontal drive pulses from 1 to 3, and outputs a sawtooth voltage a having a period of 1H (one horizontal scanning period, including a blanking period) as shown in FIG. 2A, and supplies it to the horizontal clip circuit 6.

Therefore, this clip circuit 6 clips and extracts the portion _p1H from the maximum value of the sawtooth wave voltage a to a predetermined voltage and the portion _p2H from the minimum value to a predetermined voltage, as shown in FIG. 2B. The voltages b ₁ and b ₂ are extracted in this manner and supplied to the horizontal correction voltage amplification circuit 5. The amplifier circuit 5 inputs voltages b ₁ and b ₂ and amplifies them to produce positive and negative polarity voltages +b ₁ and -b ₁ as well as voltage +
generate b ₂ and −b ₂ respectively.

Then, the horizontal peripheral registration adjustment circuits 4A and 4B adjust these voltages +b ₁ , -b ₁ , +
b ₂ and −b ₂ as inputs, and generate correction signals c ₁ and c ₂ whose amplitudes can be arbitrarily adjusted across positive and negative polarities, as shown in FIG. Apply voltage to horizontal deflection circuits 3A and 3B to horizontal deflection coil 2
A, 2B have correction signals c ₁ , c ₂ as shown in FIG. 2E.
horizontal deflection current d superimposed on the horizontal deflection current d is supplied.

Similarly, the vertical sawtooth voltage generating circuit 14 is operated by a vertical drive pulse from the input terminal 15, and is 1V (one vertical scanning period,
However _, a sawtooth voltage e _with a period of
The voltages f _{1 and f 2} as shown _in FIG. ₂ , vertical peripheral registration adjustment circuit 11A, 11
Supply to B.

Therefore, these adjustment circuits 11A and 11B generate correction signals _g1 and _g2 as shown in FIG.
0B, and the vertical deflection current h superimposed with correction signals g ₁ and g ₂ as shown in FIG. 3E is supplied to the vertical deflection coils 9A and 9B, respectively.

Therefore, we now adjust the peripheral registration adjustment circuit (hereinafter simply referred to as adjustment circuit) 4A,
Assume that the polarity and amplitude of the correction signal _c1 shown in FIG. 2D are changed.

Then, the horizontal deflection coil 2A of the image pickup tube 1A
The waveform of the maximum value portion of the horizontal deflection current d flowing in the horizontal deflection current d shown as A in FIG. 2E changes over the range indicated by the arrow.

As a result, on the image surface reproduced by the image pickup tube 1A, only a predetermined range around the right side of the screen can be arbitrarily expanded or contracted, and the size and linearity of this area alone can be adjusted. Adjustments can be made arbitrarily.

Similarly, by changing the polarity and amplitude of the correction signal _c2 shown in FIG. 2D using the adjustment circuit 4A, it is possible to change only the waveform of the horizontal deflection current d in the portion B in FIG. 2E. As a result, as shown in FIG. 4, only a predetermined range around the left side of the reproduced image plane can be stretched or contracted arbitrarily, and the size and linearity can be arbitrarily adjusted only in this area. can.

On the other hand, if the adjustment circuit 11A is operated to change the polarity and amplitude of the correction signal _g1 shown in FIG. 3D, the vertical deflection flowing to the vertical deflection coil 9A of the image pickup tube 1A will be Since the maximum value part A of the current h can be changed as shown by the arrow, only a predetermined range of the lower peripheral part of the image plane reproduced by the image pickup tube 1A can be changed by the arrow A, as shown by the arrow A in FIG. As shown in the figure, the size and linearity of this part can be adjusted arbitrarily by stretching or contracting it arbitrarily over a certain range.
By adjusting the polarity and amplitude of the correction signal _g2 in Figure D, only a predetermined range at the upper periphery of the reproduced image surface can be expanded or contracted as shown by the arrow B in Figure 5, and the size and size of this area can be adjusted. The linearity can be adjusted as desired.

The same applies to the image pickup tube 1B, and by adjusting the adjustment circuits 4B and 11B, the image pickup tube 1B can be adjusted.
Adjust the size and linearity of the reproduced image from B in A and B in Figure 4, and A and I in Figure 5.
As shown in (b), each can be performed independently and arbitrarily.

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 5 is determined.
Since it is determined by the widths of p _1V and p _2V , the correction range at the periphery can be arbitrarily set by changing the clip levels by the horizontal and vertical sawtooth clip circuits 6 and 13.

Therefore, according to the embodiment shown in FIG.
In addition to performing overall registration of the reproduced images from each image pickup tube 1A, 1B,
Furthermore, since the size and linearity of each reproduced image can be adjusted independently in the necessary range around the image plane, it is possible to fully absorb variations in characteristics that exist between the image pickup tubes and deflection coils used. Thus, sufficient registration over the entire image plane can be achieved.

In the above embodiment, the horizontal correction voltage amplification circuit 5 and the vertical correction voltage amplification circuit 12 generate the correction voltages ±b ₁ and ±b ₂ of positive polarity and negative polarity, respectively, and the correction voltage ±
f ₁ and ±f ₂ are generated and supplied to the adjustment circuits 4A, 4B, and 11A, 11B, but these adjustment circuits 4A to 11B use direct current that can be arbitrarily changed from positive polarity to negative polarity. It is also possible to use a multiplication circuit in which one input is the control voltage of , and one of the correction voltages b ₁ , b ₂ , f ₁ , and f ₂ is supplied to the other input.

According to this, the configuration of each amplifier circuit 5, 12 can be simplified.

As explained above, according to the present invention, the size adjustment and linearity adjustment of only the peripheral portion of the reproduced image plane by each image pickup tube can be performed independently, thereby eliminating the drawbacks of the conventional technology.
Even if there are variations in the characteristics of individual image pickup tubes or deflection coils, it is possible to sufficiently compensate for them and achieve correct registration across the entire image plane, making it possible to obtain television signals of excellent image quality. It is possible to provide a registration correction method for a television camera.

[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... Horizontal deflection circuit, 4A,
4B...Horizontal peripheral registration adjustment circuit, 5...Horizontal correction voltage amplification circuit, 6...Horizontal sawtooth wave clip circuit, 7...Horizontal sawtooth wave generation circuit, 8...Horizontal drive pulse input terminal, 9
A, 9B... Vertical deflection coil, 10A, 10B...
... Vertical deflection circuit, 11A, 11B ... Vertical peripheral registration adjustment circuit, 12 ... Vertical correction voltage amplification circuit, 13 ... Vertical sawtooth wave clip circuit, 14 ... Vertical sawtooth wave generation circuit, 1
5... 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 supplying correction signals to each deflection coil, the first and second
a first and a second generating sawtooth voltage, respectively;
a sawtooth wave voltage generating means, and these first and second
first and second clips for extracting first and second correction voltages by respectively extracting a portion from the maximum value of the sawtooth wave voltage to a predetermined voltage range and a portion from the minimum value to a predetermined voltage range; means and
First and second level adjustment means are provided for generating first and second correction signals by adjusting the levels of the first and second correction voltages over predetermined positive and negative amplitude ranges, respectively. , the first correction signal is supplied to the horizontal deflection coil, and the second correction signal is supplied to the vertical deflection coil, thereby correcting the registration in the periphery of the reproduced image plane. Characteristic peripheral registration correction method.