SU1411690A1 - Method of measuring ratio of television signal to fluciuation noise - Google Patents

Abstract

The invention relates to electrical measurements and can be used in the development of technical vision systems and television automation. The purpose of the invention is to increase measurement accuracy by providing measurements over the entire frequency range of a video signal by equalizing the levels of video pulses and operating noise and simplifying the measurement process. The device that implements the method includes a transmitting tube, a comparator 2, a source 3 of the reference voltage, a measuring unit 4 and a video monitoring unit 5. The essence of the method is to create on the screen a comparison field installed on the border or inside any part of the image with the observed interference. To do this, convert the analog signals into two-level, which are observed on the screen. At the same time, the level of transformation is smoothly changed and fixed both at the moment of the appearance of the contours of the selected image area on the screen, and at the time of the appearance of noise bursts on these contours. 1il i С /)

Description

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The invention relates to the field of electrical measurements and can be used in the development of technical vision systems and television automation.

The aim of the invention is to improve the measurement accuracy by providing measurements in the entire frequency range of a video signal due to higher levels of video pulses and fluctuation interference and simplifying the measurement process.

The drawing shows the block diagram of the device for implementing the method

The device contains a transmitting tube 1, to the output of which a comparator 2 is connected, to the second input of which the source 3 of the reference voltage and measuring unit 4 are connected, the output of the comparator is connected to the input of the video monitoring unit 5.

The essence of the method is to create on the screen a field of comparison established at the boundary or B1 of any part of the image of the 1-t with the observed interference. To do this, convert the analog signals into two-level, which are observed on the screen. At the same time, the level of transformation is smoothly changed and fixed both at the time of the appearance of the contours of the selected image area on the screen, and at the time of the appearance of ground bursts on these contours.

The method is carried out as follows.

The voltage of the source 3 is set so that it is obviously greater than the amplitude of the video signal of the transmitting tube 1. With this output 1

The signal of comparator 2 corresponds to one of two stable states, such as white level, and, therefore, a raster is observed on the screen of video control unit 5. Then, the reference voltage smoothly decreases and at the time when this voltage equals the video signal amplitude of the selected image area, the comparator outputs a signal corresponding to the black level, as a result of which sharp contours of the selected image area are observed on the screen of the video monitoring unit 5. moment register block 4, thereby determining

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amplitude value of the video signal. Then, the reference voltage is gradually reduced, and at the time of appearance on the sharp contours of the previously generated image of noise bursts, the value of the reference voltage is recorded in the manner described. If the image of the television test table is then read, then by working with the comparator the table strokes corresponding to a certain frequency band of the video signal estimate the signal-to-noise ratio in any frequency spectrum of the studied television sensor. In addition, by the simultaneity of the appearance on the screen of different sections of the readable table, it is possible to reliably estimate the aperture-frequency characteristics of the video path of the sensor under study under given illumination conditions of the readable object.

Claims (1)

Invention Formula The method of measuring the ratio of the television signal to the fluctuation noise in the television image, concludes with 1X, in that a comparison field is created on the receiving screen, which is set on the border or inside any part of the image with the observed interference, and the amplitudes of the video pulses of the comparison field and interference are measured according to which calculates the signal-to-noise ratio, characterized in that, in order to increase the accuracy and simplify the measurement process, analog signals are converted into two-level signals with a variable threshold These signals are observed on the receiving screen, and when measuring the amplitudes of the video signal and interference, the maximum conversion threshold is set, which is then reduced to occur on the receiving screen of the selected image section, and at this moment the conversion threshold value, which is proportional to the amplitude of the video signal, is recorded. reduce the conversion threshold until the noise signals appear on the selected image area, then record the threshold value, which is prop is rational to the amplitude of the fluctuation disturbance. Subscription