SU634315A1 - Graphic information readout device - Google Patents

Description

The invention relates to the field of automation and computer technology, in particular, to semi-automatic devices for reading the coordinates of image elements from a document, based on the measurement of the propagation time of ultrasonic waves in various media.

Devices for reading graphic information Ij, 2 are known, comprising a tablet, a measuring ultrasonic emitter connected to a generator and acoustically connected to linear coordinate microphones connected to respective conversion channels, each of which consists of a series-connected receiving and amplifying unit, trigger And of the logic element and the counter and the automatic correction unit with a reference emitter and sound receiver.

The known devices have a large composition of equipment and technologically sophisticated linear coordinate sound receivers.

The closest in technical essence to the proposed device is a known device for reading graphic information 3, comprising a tablet, a measuring ultrasonic emitter connected to the output of a pulse generator, a measuring ultrasonic receiver connected via a series-connected usi, trigger and logic element the input of the counting by, reference emitter and npi cMHiiK, connected to the autocorrection unit, the output of which is connected to one of the inputs of the logical element And, vygohT, generation ora mpulsov 1 is connected to one input of setting trigger disadvantage of ycTpoikTea are 1 evysoka measurement accuracy coordinates and complex structure.

The aim of the invention is to improve the accuracy and simplify the device.

This goal is achieved by the fact that the device contains ultrasonic reflectors, one of which is orthogonal on the sides of the tablet and acoustically connected to the measured emitter and receiver, and the other acoustically connected to the reference emitter and receiver, and the first time delay unit. which is connected to the impulse generator, the second input is -7 to the output of the autocorrection unit. and the output is to another trigger setup input ... An additional difference is that in the device the time delay unit contains a series-connected trigger, an AND logic gate and a frequency divider, the output of which is connected to one of the trigger setup inputs and to the output of the block, the first and second inputs of which are connected to another the trigger input and one of the inputs of the main logic element I. The essence of the proposed solution is illustrated in the drawings. FIG. 1 shows a functional diagram of a device for inputting graphical information; in fig. 2 shows time diagrams for his work; in fig. 3 shows the design of a tablet when used as a sound-conducting medium of air; in fig. 4 shows a plate made of solid sound duct. The device contains a plan. 1, in which the working field 2, the measuring emitter 3 of ultrasound, connected to the generator 4, the measuring sound receiver 5, located in one case with the emitter 3, acoustically connected with it through reflectors 6, 7 and connected to conversion channel 8, which consists of a series-connected amplifier 9, trigger 10, one of the installation inputs connected to the generator 4, the AND 11 logic element and the counter 12, the automatic correction unit 13 with the reference radiators 14 and a receiver 15 connected acoustically through a reflector 16, and a time delay unit 17 through which generator 4 is connected to a setup input of trigger 10 and which consists of a series-connected trigger 18, an AND 19 logic element, one of the inputs associated with an output of block 13 automatic correction, and frequency divider 20, the output connected to the setup input of the trigger 18. Located on the tablet 1 within the working field 2, the coordinate remover in which the emitter 3 and the receiver 5 are located is always positioned from the reflecting Ate 6 at a distance greater than the maximum distance to the reflector 7. This allows the X and Y coordinates to be separated in time, the Generator 4 generates the starting pulses of the radiator 3 and the triggers 10, 18. It can work in the mode of generating single pulses at the moment of pressing buttons 21, located on the coordinate puller, or in the self-oscillating mode with a repetition period longer than the propagation time of the sound from the emitter 3 to the reflector 6 and back to the receiver 5, with their maximum distance from the reflector 6. Channel 8 conversion azhdy measuring cycle generates and outputs to the external device the two codes, which correspond to X and Y coordinates in the reference system of the working floor 2. Block 13 provides automatic correction codes constancy coordinates of one and the same point on the working area for various parameters of turbo-boiling medium. The time delay unit 17 determines the origin of the Y coordinate on the working field 2 and makes this count independent of the parameters of the sound-conducting medium. FIG. 2 shows voltage diagrams Ui (t) at the output of generator 4; Uj (t) - at the output of the amplifier 9; US (t) is at the output of the time delay unit 17 and 1) 4 (1) is at the output of the trigger 10. The design of the tablet shown in FIG. 1 is not always convenient since some of it is not used. In this connection, when using air as a sound duct, the tablet is made as shown in FIG. 3. In this tablet, the entire surface is working. The reflector 7 is located on the top, and the reflector 6 is located on the bottom surface of the plate 1. The acoustic path can be extended along one of the coordinates by the corner guard 22. Thus, in this tablet version, the measuring radiator 3 is connected acoustically to the sound receiver 5 through a system of reflectors 6 and 22. If, during the acquisition of coordinates, the sound propagates in the body of the tablet, the extension of the acoustic path along one of the coordinates is achieved by bending the tablet 1 shown in FIG. 1, along the edge of the working field 2, as shown in FIG. 4. Reflecting surfaces in this plate are faces 6 and 7. Opposite edges have absorbers 23 and 24 ultrasonic vibrations. The device for entering graphic information operates as follows. At the moment the device is turned on, the automatic correction unit 13 starts to operate in self-oscillating mode. It continuously probes the space between the reference head, in which the emitter 14 and the sound receiver 15, and the reflector 16 are located. The distance between the reflector and the reference head is precisely fixed, therefore during conversion to a digital code, you can always determine the error (error code) due to the deviation of the parameters of the sound-conducting medium from normal. The scheme of the automatic correction block 13 is constructed in such a way that it provides at its output a change in the frequency of clock pulses in accordance with the change in the parameters of the medium. In this case, the same measured code corresponds to the same code for different states of the sound-conducting medium. The operator combines the viewfinder with the point of the image, the coordinates

which, it is necessary to determine and presses the button 21. The generator 4 at the time ti generates a signal Ui (t) arriving at the measuring emitter 3 and the inputs of the trigger 10, 18. As a result, an ultrasonic pulse is emitted, and the trigger 10, 18 overturns, allowing the arrival of the clock pulses through the logic elements And 11, 19 at the inputs of the counter 12 and the divider frequency 20, respectively. At time tj, when the sound wave reaches the measuring sound receiver 5, having reflected from the reflector 7, at the output of the amplifier 9, a first voltage pulse U2 (t) is formed, which returns the trigger 10 to the initial state and thereby stops the flow of clock pulses into counter 12. It records the X coordinate. The possible values of the X coordinate lie in the time interval ti. At time t, a pulse U (t) at the output of frequency divider 20 (this occurs after issuing the X coordinate to external devices) appears, which returns trigger 18 to the initial state and flips trigger 10. In the conversion channel 8 The counting of the Y coordinate begins, and the time delay block 17 stops its operation. At time tj, when the sound wave from the reflector 6 reaches the sound receiver 5, a second voltage pulse U2 (t) is generated at the output of the amplifier 9, which returns the trigger 10 to its original state in. Counter 12 is fixed Possible values oordinata Y. Y coordinates lie within a time interval. During the time from the time t te until the occurrence of the next pulse Ui (t) Y coordinate is transmitted to the external device.

As can be seen from the description of the device operation, the reference and measurement channels operate on the principle of echolocation, when the medium is probed in the forward and reverse directions. In this case, the errors caused by the wind effect in the forward and reverse directions of ultrasound propagation have a different sign and are mutually compensated.

The use of block 17 of the time delay allows you to keep the origin Y always on the same geometrical place. This is because the same code corresponds to the same metric device in the device. Since the conversion factor of the frequency divider 20 is constant; the origin of the coordinates Y does not depend on time.

The use of a delay element in the device with a delay time tj const will lead to measurement errors of the coordinates Y, since the sound wave travels the same distance at different times depending on the parameters of the medium, which cannot be accounted for by the delay line with 1h const.

The proposed device has the following advantages over known devices:

the device plate is autonomous and not connected by electrical circuits to the device circuit;

- the device contains only one channel

transformations;

-the device provides high accuracy of measurement of coordinates due to the compensation of wind effects.

Claims (3)

1. A device for reading graphic information containing a tablet, measuring ultrasonic emitter connected to the output of a pulse generator, measuring ultrasonic receiver connected through an serially connected amplifier, trigger and logic element And to the input of the counter, a reference emitter and receiver connected to the autocorrection unit, the output of which is connected to one of the inputs of the logic element AND, the output of the pulse generator is connected to one of the setup inputs of the trigger, which is from m, with tsel1) Yu improve accuracy and simplify the apparatus, it comprises ultrasonic reflectors, some of which are orthogonally side .m tablet and acoustically coupled to measurement of, 1uchatelem and receiver, and the other is acoustically connected to the reference emitter and receiver, and the time delay unit, the first input of which is connected to the pulse generator, the second input to the output of the autocorrection shock circuit, and the output to another setting input of the trigger. 2. A device for reading graphic information according to claim 1, characterized in that it contains a time delay unit. sequentially connected trigger, logic element And and the divider frequency 1, 1, the output of which is connected to one of the setup inputs of the trigger and to the output of the block, the first and second inputs are connected to the other installation input of the trigger and one of the inputs of the logic element I. Sources of information taken into account with expert: 1 USSR author's certificate Luo 488231, cl. G About KI / 00, 18.10.71. 2. Authors certificate of the USSR L 517908, cl. G 06 K 11/00, 11.03.74. 3..Authorial Soviet Union Le Le 525976, cl. G 06 K 11/00. 1974. J gz