SU1739244A1 - Device for automatic inspection of geometric dimensions of the object - Google Patents

Abstract

This invention relates to a measurement technique. The aim of the invention is to increase the reliability of measurement results. The device contains a sensor 1 connected in series with a charge-coupled device, a video amplifier 2, a filter 3, a delay unit 4, a clock generator 11 tor 5, a unit 6 controlled signal subtraction, a reference source 7, a comparator 8, a counter 9, an illuminator 10 illuminating the object under study 11. The image sensor 1 is periodically polled by the generator 5. During the first, third, etc. the measurement cycles of the illuminator 10 is off, and during the second, fourth, etc. measurement cycles included. In the unit 6 of the controlled signal subtraction, the video signal obtained by the background radiation of the object 11, with the illuminator 10 off, is subtracted from the video signal obtained when the illuminator 10 is turned on and the background radiation of the object 11. One of the signals is delayed for one measurement cycle when passing through block 4 delay. At the output of block 6, the background component is almost completely excluded from the video signal envelope, and it comes through a comparator 8 to the first input of counter 9, to the second input of which fill pulses come from the fifth output of the clock generator 5. 5 Il. CO with VI CJ Che yu N N

Description

1

The invention relates to a measurement technique and can be used for non-contact measurement of the dimensions of an object, for example, during mechanical tests at high temperatures.

An opto-electronic device is known comprising a controlled oscillator and a source of pulses of optical radiation, a series-connected optical receiver, an amplifier, an analog switch, a storage capacitor, a differential amplifier, and a comparator.

The disadvantage of this device is as follows.

It excludes the influence of external optical interference on the information pulse, and this is true for pulses whose duration is determined by the discharge time of the storage capacitor. However, it is devoid of means that would exclude the influence of the background radiation on the envelope shape of the video signal from the output of the image sensor, since the background radiation affects differently the individual cells of the image sensor. Therefore, this device does not provide reliable results under mechanical tests at high temperatures.

The closest in technical essence and the achieved result to the proposed is a device for automatic control of the geometric dimensions of objects, containing series-connected image sensor on a photosensitive device with charge coupling, video amplifier, filter and clock generator, the first output of which is connected to the image sensor input, and the second output is with the second input of the video amplifier, and the reference voltage source, a comparator and a counter in series. The device is further provided with a clock frequency control unit.

A disadvantage of the known device is the lack of accuracy of the measurement results in terms of the temperature of the luminous objects, caused by the fact that changing the frequency of the clock generator only stabilizes the amplitude of the video signal from the sensor output that contains the linear FPSR, but does not exclude the influence of the background radiation on the shape of the video signal. . The magnitude of the error is multiplicative.

The purpose of the invention is to increase the reliability of measurement results by eliminating errors from the influence of background radiation on the envelope shape.

video signal from the output of the image sensor.

This goal is achieved by the fact that a device for automatically controlling the geometrical dimensions of an object, containing a series-connected image sensor on a device with charge coupling, a video amplifier, a filter and a clock generator, the first output of which is connected to the input of the image sensor, and the second output is from the second input of the video amplifier, and the series-connected reference voltage source, comparator and counter, are complemented by an illuminator, a delay unit, and a control unit for subtracting signals, the first and second whose inputs are connected respectively to the outputs of the filter and delay unit, and the output is connected to the second input of the comparator, the first and second inputs of the signal delay unit are connected respectively to the first and second outputs of the clock generator, to the third output of which the illuminator is connected, the fourth output of the clock generator is connected to the third entrance

0 of the controllable subtraction unit, fifth to the second input of the counter, and the output of the image sensor is connected to the third input of the delay unit.

Fig. 1 shows the structural scheme of the device; figure 2 - timing charts of signals; FIG. 3 is a block diagram of a delay unit; figure 4 - block diagram of the delay unit, option; figure 5 - block diagram of the control unit

0 subtract signals.

The device for automatic control of the geometrical dimensions of the object (Fig. 1) contains a series-connected sensor 1 on the device with charge

5 by means of video amplifier 2 and filter 3. The device includes a delay unit 4, a clock generator 5, a unit 6 of controllable signal subtraction, a reference voltage source 7, a comparator 8, a counter 9, an illuminator 10 illuminating the object under study 11. The first the output of the clock generator 5 is connected to the first input of the block 4 delay and the input of the sensor 1, the second output of the generator 5 is connected to the second

5 inputs of a video amplifier 2 and a delay unit 4, the third output of the generator 5 is connected to the illuminator 10, the fourth output of the generator 5 is connected to the third input of the block 6 of the controlled signal subtraction, and its fifth output is connected to the second input of the counter 9,

the first input of which through the comparator 8 is connected to the output of the block 6 of the controlled signal subtraction, the first and second inputs of which are connected respectively to the outputs of the filter 3 and the block 4 of the delay. The output of sensor 1 is also connected to the third input of block 4 delay.

The delay unit 4 (Fig. 3) contains a sensor 12 connected on a device with charge coupling, a video amplifier 13 and a filter 14. In this case, the first input of block 4 is the first input of image sensor 12, the second input of block 4 is the second input video amplifier 13, the third input of block 4 is the second input of image sensor 12, and the output of block 4 is the output of filter 14.

An embodiment of the delay unit 4 (Fig. 4) comprises a series-connected video amplifier 15, a filter 16 and a controllable delay line 17. The first input of block 4 is the second input of controllable delay line 17, the second and third inputs of block 4 are the second and first inputs of video amplifier 15, respectively, and the output of block 4 is the output of controllable delay line 17.

The circuit of the controlled signal subtraction unit 6 (FIG. 5) contains a series-connected element HE 18, a switch 19 and a differential amplifier 20, as well as a switch 21, the output of which is connected to the second input of the amplifier 20. At the same time, the first input of the block 6 is connected to the second input the key 21 and the third input of the key 19, the second input of the block b is connected to the second input of the key 19 and the third input of the key 21, the third input of the block 6 is the first input of the key 21, which is connected to the first input of the element HE 18, and the output of the differential amplifier 20 is The output of block 6.

The device works as follows.

The image sensor 1 (Fig. 1) is periodically polled by the clock generator 5 based on signals from its first output. Each measurement cycle consists of the accumulation time Tn (Fig. 2a) and the output time Tv.

During the time of Tn of the first, third, p of that, etc. measurement cycles (Fig. 2b), the illuminator 10 is turned off, and during the time Tn of the second, fourth, etc. change cycles the illuminator 10 is on. During the time Tv, the output of sensor 1 periodically generates a sequence of pulses, the amplitude of which reflects the distribution of illumination in the plane

linear FPSS sensor 1, which is projected image of object 11. The output of sensor 1 is connected to one side through

video amplifier 2 and filter 3 with the first input of the block 6 of the controlled subtraction of signals, and on the other side through the block 4 of the delay with its second input. Video amplifier 2 amplifies and transforms the pulse sequence from the output of sensor 1 into a step signal, for example, using a sampling-storage device (not shown), which is controlled by signals from the second output of the clock generator 5.

Filter 3 forms a video signal, the envelope of which characterizes the distribution of the image illumination in the FZPS plane. Therefore during

0 tv time first, third, etc. the measurement cycles (illuminator 10 is turned off) at the output of filter 3 (Fig. 2b) will be a video signal, the envelope shape of which is determined by the intensity of the background radiation of the heated object (sample), and during the time Tv of the second, fourth, etc. measurement cycles (illuminator 10 on) at the output of filter 3 (fig. 2b) will be a video signal whose envelope shape is determined by the total effect of radiation from the illuminator 10 and background radiation of the heated object 11. Delay unit 4 (figure 1) performs a time delay of pulses from the output of sensor 1 to the time of one measurement cycle and

5 also forms a video signal (FIG. 2 d). Thus, during the time of tv of the second, fourth, etc. The cycles (fig. 2b, d) of the measurement at the first input of the unit 6 of the controlled signal subtraction will be the video signal, the formation conditions of which are determined by the illuminator 10 and the radiation of the heated object 11, and at its second input the video signal generated only by the radiation of the heated object 11 . During

5 times tv third, p that, etc. measurement cycles (Fig. 2c, d) - vice versa. In block 6, the controlled subtraction of signals by the signal from the fourth output of the clock generator 5 in each measurement cycle

0 subtracts the video signal obtained by the background radiation of the object 11 from the video signal obtained by the radiation of the illuminator 10 and the heated object 11.

5 Thus, the influence of the background radiation on the shape of the envelope of the video signal is almost completely eliminated (Figure 2d). The video signal from the output of block b is fed to the second input of the comparator 8, to the first input of which the reference voltage is supplied from the output of the source 7 of the reference voltage.

The video pulse formed by the comparator 8 (Fig. 2e) is fed to the first input of counter 9, to the second input of which are filling pulses from the fifth output of the clock generator 5. From the output of counter 6, a code proportional to the size of the object 11 is fed to the output of the device.

Block 4 delay (fig.Z) can be performed on a linear FPSS 12, the light-sensitive elements of which are shaded. In this case, the pulses from the output of the image sensor 1 during the time Tv, for example, of the first measurement cycle, arrive at the second input of FPSS 12, the first input of which receives control signals from the first output of the clock generator 5. The cells of FPSS 12 are charged the distribution of the magnitudes of which is proportional to the amplitudes of the sequence of pulses from the output of sensor 1. During the time Tv of the next second cycle, these charges are converted into a sequence of pulses and output from FPSS 12 synchronously with the output of pulses from the output sensor 1.

At the same time, the charges of the linear FPZS 12 are charged, the value of which is proportional to the amplitudes of the pulses coming from the output of sensor 1 during the time Tv of the second measurement cycle.

Thus, the delay of pulses from sensor 1 will always be equal to the time of one measurement cycle, i.e. T3 Tn + TV.

Video amplifier 13 amplifies the output pulses of FPSS 12 and converts them into a step signal using, for example, a sampling-storage device, which is controlled by signals from the second output of the clock generator 5 supplied to the second input of video amplifier 13. A video signal is generated using a filter 14 which enters the output of block 4.

The delay unit 4 can also be implemented using a controllable delay line (FIG. 4). In this case, the pulses from the sensor 1 are fed to the second input of the video amplifier 15, where they are amplified and converted into a step signal, for example, using a sampling-storage device controlled by signals from the second output of the clock generator 5 fed to the first input of the video amplifier 15. The filter 16 forms the envelope of the video signal, which, through the guided delay line 16, arrives at the output of block 4. The delay time of line 17 is related to the time of measurement cycle T3 Tn + TV of sensor 1 and, as it changes, changes according to the signal received to the second input of the controlled delay line 17 from the first output of the clock generator 5.

Controlled signal subtraction unit 6 (Fig. 5) operates as follows. The control signal from the fourth output of the clock generator 5 is fed to the first input of the key 21 directly, and to the first input of the key 19 through the HE element 18. In

for the time of TV, for example, an odd measurement cycle, the output of the key 21 passes the signal from the third input of the key, which is the second input of block b, and the output of the key 19 at this time receives a signal from

of the third input, which is the first input of block 6. During the time of the TV, an even measurement cycle is vice versa. Therefore, to the second input of the differential amplifier 20 in each measurement cycle

enters the total video signal generated by the sensor 1 (Fig. 1) with the illuminator 10 turned on and the background radiation of the object 11, and its first input is the background video signal. In the differential amplifier 20 (Fig. 5), the signal arriving at its first input is subtracted from the signal arriving at its second input. Difference signal, the shape of the envelope which does not depend on the background radiation

object 11, is fed to the output of block 6.

Claims (1)

Invention Formula A device for automatically monitoring the geometrical dimensions of an object, containing a series-connected image sensor on a charge-coupled device, a video amplifier, a filter and a clock generator, the first input of which is connected to the input of the image sensor, and the second output is connected to the second input of the video amplifier, and the reference voltage source, a comparator and a counter in series, characterized in that In order to improve the reliability of measurement results, by eliminating errors from the background radiation effect on the envelope shape of the video signal from the output of the image sensor, it is equipped with an illuminator, a delay unit and a controllable subtraction unit, the first and second inputs of which are connected respectively to the outputs of the filter and the delay unit and the output is connected to the second input the comparator, the first and second inputs of the signal delay unit are connected respectively to the first and second outputs of the clock generator, to the third output of which the illuminator is connected, the fourth output of the clock generator is connected to the third the input of the controllable subtraction unit, the p-image sensor is connected to the third one - to the second input of the counter, and the output is connected to the input of the delay unit. ET 15 L. Rig.Z sixteen 17 - . Fig.Chrig .5