SU673840A1 - Device for measuring coordinates of pattern elements - Google Patents

Description

(54) DEVICE FOR MEASURING THE COORDINATES OF THE FIGURE ELEMENTS

the input to the pulse driver output, the second pulse driver, connected by the input to the digital filter output, the delay unit associated with the output of the second pulse driver, and the output to the second trigger input, the And element, the connected inputs to the trigger output and the second pulse generator , output - to razren1u1tsemu input of the register, and the output of the unit generating counting pulses connected to the clock inputs of the analog-digital converter and digital filter.

FIG. I shows a block diagram of the device; in fig. 2 shows a signal diagram, as shown in Figure 1, and the operation of the device.

The device consists of an illuminator 1, a stage 2 on which the object 3 is measured, an electric drive 4, a displacement transducer 5, a counting pulse generation unit 6, a counter 7, a register 8, a lens 9, an analyzing diaphragm 10, a photon receiver 11, an analog-to-digital converter 12, digital filter 13, threshold element 14, drivers 15 and 16 pulses, delay block 17, trigger 18, and element 19. The following symbols are given in the diagram: 20 - signal at the output of digital filter 13, 21 - zero crossing point of signal 20, 2 2 - normal operation of the element 14, 23 - output signal of the threshold element 14, 24 - output signal of the imaging unit 15, 25 - signal from the output of the sign bit qi (:) of the left filter 13, 26 - signal at the output of the imaging unit 16.

The device works as follows

The object 3 of measurements is set on the stage 2, which is driven by the electric drive 4. When the subject is moving, the first item is transmitted by the photodetector 11. The metering is that the object’s image is re-parsed: diaphorivMii 10. At the same time, the signal at the photodetection output (the cheek will correspond to the change in transparency according to the element of the drawing. At the same time, the transducer 5 translates 1U produces an e.: | electric signal, supplied to the input of the output unit 6 even pulses formiruyuishy counting pulses over a certain time peremen1eny object table.

The counting emulsions1 1 are fed to the input of the count 7. The contents of the counter 7, T, are the current coordinate of the table at a given time. The origin is the point at which counter 7 is reset to zero. Measuring the coordinates of the elements of the drawing consists of two processes: measuring the current coordinate of the stage and generating a reference pulse at the moment when the optical axis of the device intersects the drawing element. Count pulse

is generated at the output of the AND 1 element at this m. the coordinate of the counter 7 is not registered in register 8, where it is saved until the next reference pulse arrives from the next e: 1 pattern, then this coordinate can be output to the registration. The generation of counting pulses is as follows.

The continuous output signal of the photodetector 11 is fed to the input of the analog-digital converter 12, where it is subjected to sampling and queuing by level. The output signal of the analog-to-digital converter is supplied as a code to the information input of the digital filter 13. The clock inputs of the analog-digital converter 12 and the digital filter 13 are given a signal from the output of the counting impulse generation unit 6, as a result of which the code V output is received. to certain positions of the stage, its value depends only on the coordinate of the nx,

gdep - is a sequence of natural numbers;

X is the discreteness of generation of counting pulses. Digital filter 13 is a specialized digital computing device having an impulse response corresponding to a particular slush of the elements of the figure, the coordinates of which are measured.

The counting of the coordinates of the stroke is digital (The filter has a 1-pulse peak:

G + 1, with O p NI

1, with N (

h

PC |}. I

O, with n 2N |, where X is the sampling interval (discretization of output 1P x pulses);

n - a sequence of naTypa.nbmjix numbers (n 0,1,2,3 ...);

The NI is the CCO number that determines the length of the impulse response for the transponder.

When counting the coordinates of the edge of an e-memeite pattern, the digital filter has a pulse response:

4-1, iipn O p ;. Na b.n (nx) fiP Mg, n, 3Nj,

Kjj -f 1, with ZHg. h; n Oh, when p. where X is the interval.

p - after. negotiation of the stalemate of the first numbers (p 0,1,2,3 ...);

NZ is an integer specifying the length of the impulse response of the d.h edge.

Digital filter 13 operates in such a way that its output signal 20 (see Fig. 2), when photometric, a prism differs from zero only near the elements of the pattern and changes its sign at a single point 21 rigidly attached to the number of the pattern element. At the same time, its output signal W depends only on the coordinate nx and does not depend on the speed of movement of the table.