SU1688456A1 - Device for conversion of video signal - Google Patents

Abstract

The invention relates to television and can be used as a time-frequency converter, variable parameters of a video signal. The purpose of the invention is to enhance the functionality by converting a video signal with an arbitrary number of lines. The principle of operation is based on an adaptive change in the conversion factor n, then it ensures that the number of rows of the output standard accumulates when the number of rows in the input standard changes arbitrarily. The video signal from the output of the analog-digital converter 1 is fed to the input of the multiplier 2, in which (L

Description

m

V

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the rum is multiplied by the coefficients determined by the accumulation law and formed by the divider 12 and the calculator 11, which calculates the conversion factor n. From the output of the multiplier 2, the signal goes to the first input of the adder 3, to the second input of which a signal from the storage unit enters the second input (ZB) k or ZB b, delaying the length of the string

The invention relates to television and can be used in television surveillance systems as a converter of frequency-time parameters of a video signal.

The purpose of the invention is to expand the functional capabilities by converting a video signal with an arbitrary number of lines.

FIG. Figure 1 shows the electrical structure of a video signal conversion device; in fig. 2 is a structural electrical circuit of the control unit.

The video signal conversion device (Fig. 1) contains an analog-to-digital converter (ADC) 1, multiplier 2, adder 3, first storage unit (BZ) C, fourth storage unit 5, multiplexer 6, And 7, the second and third storage units 8 and 9, a digital-to-analog converter (D / A converter) 10, a calculator 11, a divider 12 and a control unit 13 The control unit 13 (FIG. 2) contains a read address driver 14, a write address driver 15, a control unit multiplexer 16 and logic circuit 17.

The video signal conversion device operates as follows.

The principle of operation of the device is based on an adaptive change in the conversion factor, which ensures that the number of information lines accumulated during the period of the active part of the output standard field remains unchanged with an arbitrary change in the number of lines arriving at the input. The number of lines arriving during the active part of the output standard field determines the span

In ST 8, a signal is recorded corresponding to the result of the accumulation of n lines in ST 4 or ST 5. During the return stroke, the information from P8 8 is copied to PZ 9. At the same time, the accumulation of information in P8 8 takes place at the recording frequency, and overwriting from P8 to ST 9 - with a reading frequency. The signal from ST 9 is fed to a digital-to-analog converter 10. 2 Il.

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the area of space (scale) observed on a video monitor. The number of lines will vary depending on the change in the speed of the object on which the optical sensor is mounted, or on the change in the frequency of reading the signal from the optical sensor. As a result, with a constant conversion factor, the length of the portion of space observed on the VKU screen will change in proportion to the change in the number of rows, which causes geometric distortions of the observed image. In order to maintain a given image scale unchanged on the VKU screen, it is necessary to provide an adaptive change in the conversion factor depending on the number of input lines. The dependence of the conversion factor (p) on the scale (m), current values of speed (V), object motion and frequency (FCTp) of the signal readout from the optical sensor is determined by the expression

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P

M-FCTP

V-K

cip

(ABOUT

where K is the number of active lines in the racquet raster corresponding to the output standard.

Adaptive change of the conversion factor necessitates the need for adaptive filtering of the input signal, which is accomplished by accumulating the video signal during the period equal to -

PAGE with expression

according

P

W5x

ex;

(2)

where you are, the amplitude of the signal at the X output

de storage unit;

I is the amplitude of the signal of the i-th row at the input of the ADC (multiplier input);

a - coefficients defining the accumulation law, which are defined as a function of the number

one

n or 1, for example a-- n

or where q is const.

Thus, with adaptive measurement of the conversion factor and adaptive filtering, the scale of the area of space observed on the VCC remains unchanged without degrading the image quality with an arbitrary change in the number of rows of the input signal.

The input of the ADC (Fig. 1) receives a signal from a single-line optical sensor in the form of a sequence of lines. From the output of the A / D converter 1, the signal converted into digital form is fed to the first input of multiplier 2. A signal from the second output of the controlled frequency divider 12 is fed to its second input. This signal determines the coefficients a; (see expression (2)).

The multiplier 2 can be implemented on the basis of permanent memory blocks, in which the results of the paired products a-b i are recorded; for all possible values of a- and i. Magnitude b b i

Well, the division factor n of the controlled frequency divider 12 sets the signal coming from the output of the calculator 11. The latter performs calculations in accordance with the expression (1) At the same time, the signals corresponding to the given scale value M and the current value of speed V are fed to the buses M and V The calculator 11 can also be implemented on the basis of permanent storage units, in which the results of calculations are written using the formula (1) for the entire range of values of M and V.

From the output of the multiplier 2, the signal arrives at the first input of the adder 3. At the same time, its second input through the element 7 and multiplexer 6 receives a signal from BZ D or BZ 5, delaying the signal for a time equal to the length of the line 2p, and accumulation of summation results. ZB k and ZB 5 work alternately through the line on the record and on

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If there is a PI li bb in the p-mime of the record and it records the results of the summation of dm-i od of the elements of the current and previous lines of the same name, then bz 5 is in the read mode. In this case, the amplitude bars of the elements of the previous line to the second input of the adder 3 are received through multiplexer 6 and element 7 of ST 5. As a result, by the end of the accumulation period, the signal accumulated from the previous rows is recorded in one of these STs according to the expression

()

The signal determining the keriod, the flow of which accumulates. The accumulation, equal to - -,, is extracted.

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WITH

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divider 12 depending on the desired scale M and the current value of the speed V. This signal from the first output of the divider 12 is fed to the second input of the And 7 element and the first input of the control unit 13. It is a sequence of pulses with a duration equal to the duration of one

pn

line and period equal to -. With

the arrival of this pulse element

And 7 prohibits the passage of the signal from the output of multiplexer 6 and sets a zero value at the second input of the adder 3, thereby determining a new accumulation cycle. At the same time, the control unit 13, under the influence of this pulse, generates a write enable command in ST 8 and the signal from the output of multiplexer 6 is recorded in ST 8.

Thus, in ST 8, a signal is recorded that corresponds to the result of accumulating n lines in ST z or 5. Since the number of accumulated rows and n is inversely proportional to velocity V (see expression (O), the number of information lines in ST 8 is constant for a given the scale of M and the current value of V, which ultimately keeps unchanged on the screen of the ICS, the length of the portion of the space specified for observation at different values of V. Because the coefficients a ;, determined by divider 1 2, can be a function of awns V, the amplitude of the signal storage mode in the ST or ST 5 k maintained optimal for all speed ranges. Recording information lines in the ST 8 is carried out during the active portion of the output television standard floor.

The address space of an ST 8, defined by the shaper 15 of the write addresses of the control unit 13 (FIG. 2), is divided into two identical areas for even and odd lines, respectively. At the end of the active part of the field, during the return period, a census is taken from ST 8 (one of the areas) to ST 9. The address space of the ST 9, determined by the shaper 11 of the reading addresses of the control unit 13, is also divided into two areas corresponding to even and odd fields. Thus, in each of the fields of S8 8, information is accumulated during one frame and rewritten in the period of each extinguishing impulse of fields from the corresponding area of ST 8 to the corresponding area of ST 9 (even-odd) alternately. The operation of ST 8 and ST 9 is controlled by control unit 13. Shaper And reading addresses and shaper 15 al, - Rec records provide the formation of address and control signals. In turn, their operation is controlled by a logic circuit 17. It receives synchronizing pulses for the write and read modes, as well as the write enable signal from the first output of the divider 12.

The logic of the logic circuit 17 is based on the observance of a set of conditions for changing the operating modes of ST 8 and ST 9, which are necessary for the correct functioning of the device.

Conditions for switching the ST 8 from the write mode to the read mode and the ST 9 from the read mode to the write mode (transition to the overwrite mode) readout of the active part of the field from the ST 9 must be completed (the presence of a sync pulse of the output TV standard); the recording of the next line n of the ST 8 must be completed (no recording permission signal); the transition to the rewrite mode should be carried out synchronously with the beginning of the active part of the line of the output standard (the presence of the line sync pulse of the output TV standard).

Conditions for switching ST 8 from read mode to write mode and ST 9 from write mode to read mode

(transition to information accumulation mode in ST 8): the census from ST 8 to ST 9 should be completed; the transition to the accumulation mode should be carried out synchronously with the beginning of the active part of the input signal line (presence of the input signal line sync pulse)

Logic circuit 17 generating control signals in accordance with the specified conditions can be implemented based on coincidence circuits (e.g., a group of I elements) and memory elements (e.g., D-flip-flops).

As a result of logical operations on these variables, the times for switching the ST-8 to the write mode, as well as the overwriting mode in the ST-9, determine the signals that control the operation of the drivers 15 and 1C of the write and read addresses and the multiplexer 16, which multiplex the clock pulses. write - read to the shaper 15 write addresses. In this case, the accumulation of information in ST 8 takes place at a write frequency, and overwriting from ST 8 to ST 9, with a read frequency, and later, ST 9, with the same frequency. From the output of ST 9, the signal goes to the DAC 10 and further to the internal control unit. The read mode is synchronized with the sync signals F2 of the output TV standard, and the write mode is synchronized with the sync pulses F, corresponding to the decomposition parameters of the original image.

 The proposed converter provides an additional opportunity to conduct visual observations without geometric distortions on moving objects with an arbitrary change in the speed of movement.

Claims (1)

Invention Formula A video signal conversion device comprising an analog-to-digital converter, the first input of which is an input for a device video signal, a multiplier, an adder, first, second and third storage units, a multiplexer and a digital-analog converter, the output of which is an output of the device, characterized in that , in order to expand the functional capabilities by converting a video signal with an arbitrary number of lines, a fourth storage unit, calculator, divider, And element and control unit are introduced, with than the first and second inputs of the calculator are respectively inputs for signals of scale and speed, and the output is connected to the first input of the divider, the output of the analog-digital converter is connected to the first input of the multiplier, the output of which is connected to the first input of the adder and the fourth storage units, the first and second inputs of the multiplexer are connected respectively to the outputs of the first and fourth storage units, and the output to the first input of the second storage unit and to ne vomu input AND gate whose output is connected to a second input of the adder, the output of the second storage unit is connected to F2 / 7 the first input of the third storage unit, the first output of the divider is connected to the second input of the And element and to the first input of the control unit, and the second output of the divider to the second input of the multiplier, the first and second outputs of the control unit are connected respectively to the second inputs of the second and The third storage unit and the output of the third storage unit are connected to the first input of the D / A converter, the third input of the multiplexer and the second inputs of the analog-to-digital converter, divider, control unit, the first and fourth storage units are the input for the synchronization signal of the original video signal, and the third input The control unit and the second input of the digital-to-analogue conversion is the input for the CHI synchronization of the converted video signal. /five