SU1348644A1 - Method of measuring object position - Google Patents

Abstract

The invention relates to a measurement technique and can be applied when measuring the movements of objects. The aim of the invention is to increase the measurement accuracy by increasing the information content of the method by restoring the envelope of a discrete video signal obtained from a linear-matrix photodetector, and calculating the coordinate of the energy center of the envelope sampled at a frequency greater than the sampling rate of the primary video signal. The device implementing the method comprises a light source 1, aperture 2, a diaphragm imaging unit 3, a linear-matrix photodetector A, a photodetector control unit 5, a sampling unit 6, a video envelope recovery unit 7, analog-to-digital converter 8, a generator 9, a unit 10 coordinate calculations, the recorder 11. The coordinate calculation is performed in block 10 in accordance with .1 hours with the formula RN - ZI and, -, J - 1 1 1, m where u5 are discrete values of the video signal envelope, R is the coordinate position of the object vfazhenna in amount ve processing cycles; N is the duration of the processing cycle, expressed in the number of processing cycles; k - the number of processing cycles in the envelope. 1 il. (L o :) 4 00 Oi 4 4

Description

one

The invention relates to a measurement technique and can be applied when measuring the movements of objects.

The purpose of the invention is to increase the measurement accuracy by increasing the information content of the method by restoring the envelope of a discrete video signal obtained from a linear-matrix photodetector, and calculating the coordinates of the energy center of the envelope sampled at a frequency higher than the sampling rate of the primary video signal.

The drawing shows a diagram of the device that implements the proposed method.

The device contains optically coupled light source 1, diaphragm 2, diaphragm imaging unit 3 and linear matrix photodetector 4, photodetector control unit 5, the first output of which is connected to the control input of the photodetector, and the second output from the control input of unit 6 sampling, the information input is connected to the output of the photodetector 4, and the output is connected to the input of the envelope recovery unit 7 connected in series with the analog-to-digital converter 8, the generator 9, the synchronization input of which is n with the third output of the photodetector control unit 5, and the output with the clock input of the coordinate calculation unit 10, the information input of which is connected to the output of the analog-digital converter 8, and the input of the linear-matrix photodetector to the discrete video signal with a period

sampling T ,, restore

ten

20

discrete video envelope, sampling an envelope with a sampling period T T,, transform discrete values of U; the binary envelope, the time interval N is measured with discrete T, the beginning of which coincides with the beginning of the photodetector survey, and the end with the last pulse of the discrete video signal, the coordinate R of the energy 15 of the envelope center is calculated relative to the beginning of the time interval N according to formula J

2 C - -% -: where k - number of pulses

tization envelope. The device that implements the method works as follows.

The light source 1 illuminates the aperture 2, the image of which is reflected from the object 12, is transferred by the aperture imaging unit 3 with the help of the beam-splitting element 1 30 and the lens 2 to the surface of the photodetector 4. When the position of the object changes, the image of the photodetector 4 moves. At the beginning of the survey cycle of the photodetector 4, the photodetector control unit 5 generates a reset signal, which from the third output of the photodetector control unit 5 is fed to the reset inputs of the first 10.1 and second noy installation - a third output d of 10.2 accumulator Bloch control unit 5 a photodetector 10 ka calculating coordinates to the inputs

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the information output of the block 10 is connected to the information input of the recorder 11, the recording input of which is connected to the control output of the coordinate calculation block 10. The coordinate calculation unit 10 comprises the first adder 10.1, the second adder 10.2, the division unit 10.3, the subtraction unit 10.4, the discriminator 10.5, the adder control unit 10.6, the counter control unit 10.7, the counter 10.8, the first delay element 10.9, the second delay element 10.10, the driver 10.11. The method of measuring the position of an object is that they form an optical signal, spatially associated with the position of the object, convert it using

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linear matrix photodetector to a discrete video signal with a period

sampling T ,, restore

five

0

five

the initial installation of the counter 10.8 and block 10.7 of the counter control and the clock input of the generator 9. The first 10.1 and second 10.2 accumulating adders are zeroed, one is recorded in the counter 10.8, the generator 9 is synchronized and produces pulses whose period is less than the period of the photodetector polling. These pulses arrive at the clock inputs of the adder control unit 10.6 and the counter control unit 10.7. The counter control unit 10.7 permits the passage of pulses arriving at its clock input to the counter input of the counter 10.8.

The photodetector control unit 5 periodically polls the photodetector.

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4, at the output of which the wines are formed

deosignals, the envelope of which is proportional to the distribution of illumination in the image of the diaphragm 2.

The signals taken from the photodetector 4 are fed to the input of sampling unit 6, which performs a synchronous sampling of video pulses taken from the photodetector. The sampling rate is equal to the survey frequency of the photodetector.

The signals from the output of sampling unit 6 are fed to the input of the envelope recovery unit 7 of the video signal, from the output of which the video signal is fed to the input of the analog-digital converter 8. From the outputs of the analog-digital converter 8, the codes corresponding to the instantaneous values of the video signal level are fed to the information inputs of the first accumulator adder 10.1 and discriminator 10.5. When the instantaneous value of the video signal exceeds a certain threshold at the output

thirty

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The discriminator 10.5 is formed before the -25 enters the input of the splitter unit 10.3 of the scientific research institute the pulse front. The magnitude of the trigger threshold of the discriminator is established based on a priori information about the level of interference in the device.

The pulse from the output of the discriminator 10.5 is fed to the control input of the adder control unit 10.6 and the driver input 10.11. On the leading edge of this pulse, the adder control unit 10.6 permits the passage of pulses arriving at its clock input from the output of the generator 9 to the clock input of the first accumulating adder 10.1 and to the input of the second delay element 10.10, from the output of which the delayed pulses arrive at the clock input of the second accumulating adder 10.2. Elements 10.9 and 10.10 delay are used to compensate for the time shifts in the nodes of the device.

The information inputs of the first accumulating adder 10.1 are supplied with codes of instantaneous values of the video signal level. At the moment of arrival of the pulse to the clock inputs the accumulating adders add to the previously accumulated sums the codes arriving at their information inputs, therefore, after the arrival of n pulses in the first and second accumulative adders the sums will accumulate, respectively

50

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division, and the code of the sum accumulated by the second accumulating adder 10.2, is fed to the input of the divisible block 10.3 division. In this case, at the output of block 10.3, a private code is formed.

On the trailing edge of the pulse formed by the discriminator 10.5, the shaper 10.11 forms a nm pulse arriving at the input of the first delay element 10.9 and controlling the input of the counter control unit 10.7, which prohibits the passage of pulses arriving at its clock input to the counter input of the counter 10.8. A code corresponding to the number of pulses counted by the counter 10.8 is fed to the inputs of the decrementing subtraction unit 10.4, the inputs from which the subtraction inputs the codes from the output of the division unit 10.3. The code of the result of the subtraction enters the information inputs of the recorder 11, which registers it on the leading edge of the pulse arriving at its recording input from the output of the first delay element.

During one survey cycle of the photodetector 4, the result code corresponding to the coordinate of the envelope energy center to J will be registered in the recorder 11

rilTU;

R N -,

and;

but) and, and)) and-, where and. - code

1.1 J 11 1 -1

the instantaneous value of the video pulse level at the moment when the first accumulating adder of the i-th pulse arrives at the clock input. If, after the arrival of the k-ro pulse, the instantaneous value of the video signal level becomes less than the response threshold, the discriminator 10.5 generates a falling edge at the output, the adder control block 10.6 prohibits the passage of pulses at its clock input to the clock inputs of accumulating adders. In the first and second accumulating adders, the results will be accumulated, respectively} 7 U;

j);

and)) U. Code of the amount accumulated

j ri; and

the first accumulating adder 10.1,

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5 arrives at the input of the divider unit 10.3

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division, and the code of the sum accumulated by the second accumulating adder 10.2, is fed to the input of the divisible block 10.3 division. In this case, at the output of block 10.3, a private code is formed.

On the trailing edge of the pulse formed by the discriminator 10.5, the shaper 10.11 forms a nm pulse arriving at the input of the first delay element 10.9 and controlling the input of the counter control unit 10.7, which prohibits the passage of pulses arriving at its clock input to the counter input of the counter 10.8. A code corresponding to the number of pulses counted by the counter 10.8 is fed to the inputs of the decrementing subtraction unit 10.4, the inputs from which the subtraction inputs the codes from the output of the division unit 10.3. The code of the result of the subtraction enters the information inputs of the recorder 11, which registers it on the leading edge of the pulse arriving at its recording input from the output of the first delay element.

During one survey cycle of the photodetector 4, the result code corresponding to the coordinate of the envelope energy center to J will be registered in the recorder 11

rilTU;

R N -,

and;

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where R is the code registered by the video signal, is carried out by the sampler; envelope with a period of discrete; N is the number of pulses, the accumulation of T T, the total values of U transform by the counter during the cycle; the envelope in the binary code. The code is measured with a discrete T time interval N, the beginning of which the invention formula falls with the beginning of the interrogation of the photodetector, and the end with the last pulse

The method of measuring the position of an object, io a discrete video signal, and the position lies in the fact that an object is determined by the R coordinate spatially related to the position of the energy center of the envelope of the object, the optical signal, predominantly the beginning of the time interval using the linear-matrix N, which is calculated by the formula of a photodetector in a discrete video 5) U;

signal with sampling period T, R N

characterized in that, with U;

the purpose of increasing the measurement accuracy, where k is the number of pulses, and the discrete-decoupling envelope of the envelope is restored.

Claims (1)

Claim A method for measuring the position of an object, which consists in generating an optical signal spatially related to the position of the object, converting it using a linear-matrix photodetector into a discrete video signal with a sampling period T, characterized in that, in order to increase the measurement accuracy, restore the envelope of the discrete. of the video signal, the envelope is sampled with a sampling period of T ₂ <T ,, convert the discrete values of the U envelope into a binary code, the time interval N is measured with the T ₂ sample, the beginning of which coincides with the start of the photodetector polling, and the end with the last pulse of the discrete video signal , and the position of the object is determined by the coordinate R of the energy center of the envelope relative to the beginning of the time interval N, which is calculated by the formula R = N ------- " ΣΖ U; where k is the number of envelope sampling pulses.