SU1424138A1 - Method and apparatus for scanning television image by electron beam in single-tube color tv cameras with line color filters - Google Patents

Description

(21) A087180 / 24-09

(22) 05.13.86

(46) 09/15/88. Bksh. No. FOR (72) V.N. Bezrukov, A.G.Vaniev and S.V. Novakovsky

(53) 621.397 (088.8)

(56) Samoilov V.L, and others. Fundamentals of color television. M .: Radio and communications, p. 70-72.

(54) METHOD OF TELEVISION IMAGE ELECTRONIC EXPANSION METHOD IN SINGLE-TUBE CAMERAS OF COLOR TELEVISION WITH 111 TRIQUE 1 LIGHT-MILTERS AND DEVICE FOR ITS IMPLEMENTATION

(57) The invention relates to television. The purpose of the invention is to reduce interference in the form of spatial beats by defocusing an electron beam horizontally, sweeping the TV image, and eliminating interference

in the video signal at the initial and final sections of the line .. The scanning method is carried out by the device containing a transmitting tube 1, r-r 2 line sweep, r-r 3 frame sweep, sync generator 4, block 5 power, switch 6 and strobe unit 7. In the case of significant dark currents of the electron beam of the transmitting tube, when the raster is displaced from the field to the field horizontally at the edges of the raster, noises arise at the initial and final portions of the line. They are caused by the fact that the sweeping electronic key, additionally shifting, enters the non-working portions of the target of the transmitting tube 1. The gating unit 7 suppresses the TV-line portions with these interferences, and at the output of the device a video signal is amplified interference from spatial beats and interference from the increased dark currents of the transmitting tube 1 at the initial and final sections of the line. 2 sec. and 3 z. p, 3 sp.

(/

WITH

li

N

four:

ABOUT

about

The invention relates to television and can be used in single-chamber color television cameras with dashed light filters.

The purpose of the invention is to reduce interference in the form of spatial beats by defocusing the spreading television image of the electron beam horizontally and eliminating interference in the video signal at the initial and final portions of the line.

Figure 1 shows the position of the raster on the target of the transmitting house when scanning the first and second fields of the television image; 2 shows gating of the output video signal of the transmitting tube with high dark currents; FIG. 3 is a structural electrical circuit of a device implementing the proposed method of scanning a television image by an electron beam in single-tube color television cameras with dashed light filters.

The method of scanning a television image with an electron beam in one-channel color television cameras with dashed light filters is that during the scanning of a television image with an electron beam in the transmitting tube, the electron beam is additionally shifted along the line periodically from field to field by no more than 1 / A period of the stroke filter. Such an additional displacement of the sweeping electron beam from the field to the field leads to the observer’s eye integrating into the both fields during the frame the image of moire lines from spatial beats arising from the transmission of television images of vertical stripes whose period is close to or a multiple of the period of the line filter will perceive these bands as noise, i.e. moire from spatial beats decays into noises. In order to

this did not happen much worse

nor the definition of the television image horizontally, it is advisable to set the additional displacement of the scanning electron beam not exceeding 1/4 of the period of the line filter.

This additional displacement of the scanning electron beam from field to field can be carried out by

0

5 0 5

g Q

five

0

the change from field to field constant component of the lower-case deflection voltage. In this case, one field will be counted with a shift relative to the other field by an amount of not more than 1 / A of the period of the line filter (Figure 1).

It is also possible to shift the scanning electron beam by discrete pseudo-random variation of the trigger start phase in rows. It is also advisable to set the maximum amount of displacement of the spreading electron beam from the field to the field of no more than 1 / A of the period of the line filter. According to the change in the duration of the active part of the line, when the start-up phase changes, it is necessary to change the electron beam return time in rows.

A nano-best spatial beat suppression effect is provided by a method in which a pseudo-random change in the triggering phase of an image sweep by rows is carried out according to a normal law. In this case, the moire from spatial beats is perceived by the eye of the observer as white noise.

When transmitting tubes with large dark currents are used, the additional displacement of the sweeping electron beam causes the initial and final portions of the line to interfere with t "many currents. Therefore, to eliminate this interference, it is necessary to produce video gating to separate the active part of the line (Fig. ).

A device that implements the proposed method of scanning a television image by an electron beam in single-tube color television cameras with dashed light filters contains (FIG. 3) transmission tube 1, horizontal scanning generator 2, vertical scanning generator 3, clock generator A, scanning generator power generator unit 5 , switch 6 and gating block 7

The first output of the sync generator A through the horizontal scanning generator 2 is connected to the horizontal scanning input of the transmitting tube I. The second output of the synchronizing generator A through the generator 3 of the vertical scanning is connected to the inputs of the vertical scanning of the transmission tube 1. The third output of the synchronizing generator A

connected to the control input of the switch 6. The fourth output of the synchronous generator 4 is connected to the synchronization input of the gating unit 7. The first and third outputs of the power supply unit 5 of the sweep generators are connected respectively to the first and second inputs of the switch 6. The output of the switch 6 is connected to. the power supply of the generator 2 horizontal scan. The second output of the power supply unit 5 of the scan generators is connected to the power input of the generator 3 of the frame scan. The output of the transmission tube 1 is connected to the input of the gating unit 7, the output of which is the output of the video signal.

A device that implements the proposed method of scanning a television image by an electron beam in single-tube color television cameras with ytrikh filters operates in the following way.

The synchronous generator 4 generates synchronization pulses of lines that are fed to the input of the horizontal scanning generator 2, synchronizing field pulses, which are fed to the input of the 3 frame scanning generator, pulsing control pulses

6 and gating pulses for a block

7 gates. The generator generator power supply unit 5 provides the voltage of the vertical frame generator 3 and, through the switch 6, the horizontal line generator 2. Voltage generator 2 line voltage supplied to the first and second input of the switch 6 from the unit

The 5 power generators of the ugazvertki differ by a small amount. When switching the switch 6 from the field to the field, the horizontal-scanning generator 2, when scanning the electron beam in rows in one field, is powered by one voltage, and when scanning by rows in another field, from another voltage. Thus, at the output of the horizontal scanning generator 2, the constant component of the deflection of the horizontal scanning voltage is changed, and the raster that reads the potential relief from the target of the transmitting tube 1 is shifted from

In the case of significant dark currents of the electron beam of the transmitting tube, when the raster is displaced from the field to the field horizontally, at the edges of the screen, at the initial and final sections of the line, interference will occur due to the fact that the sweeping electron beam, additionally shifted, goes to the non-working Transmitting tube mitral areas 1. Gating unit 7 suppresses portions of the television line with these interferences. At the output of the device, a video signal is formed, in which interference from spatial beats is reduced and interference is eliminated.

U

from the increased dark currents of the transmitting tube at the initial and final sections of the line.

Claims (3)

1. A method of scanning a television image by an electron beam in single-tube color television cameras with optical filters, in which the developing electron beam is moved in rows from left to right, and half a meter from top to bottom, in order to reduce interference in the form of spatial beats, by defocusing horizontally the electron beam that expands the television image and eliminates noise in the video signal on the initial and final sections of the line, which expands the electron beam when eremeschenii by rows to additionally periodically shifted from field to field along the row by an amount not greater than 1 / A filter schtrihovogo period. 2 ;, The method according to claim 1, characterized in that the additional periodical displacement of the developable electron beam from field to field is carried out by changing the apparent component of the horizontal deflecting voltage. 3. Method POP.1, characterized in that the additional periodical displacement of the spreading electron beam from field to field is carried out by discrete floor to polo horizontally. The magnitude of the pseudo-random phase change is the offset determined by the difference in supply voltage applied to the first and second INPUT of switch 6 does not exceed 1/4 of the stroke period: a new light filter lycKa, the sweeping of the electron beam in rows, and the return time in rows, respectively, reduce or increase by the amount of change in phase lycKa, the sweeping of the electron beam in rows, and the return time in rows, respectively, reduce or increase by the amount of change of the phase srig.2