SU983731A1 - Device for reading graphic data - Google Patents

Description

one

The invention relates to automation and computing and can be used to convert, into digital form and enter graphic information into a computer. It can also be used as a standard computer input device.

A device for reading graphic information is known, comprising a tablet with a system of orthogonal coordinate buses connected via switches to a control unit, coordinate counters and a coordinate remover connected to an amplifier. In the process of measuring the coordinates, tires are alternately alternated along each of the coordinate axes with current pulses until the signal induced in the coordinate remover exceeds a predetermined level. As a result, a code proportional to the number of excited tires for the corresponding coordinate is recorded on the coarse counter.

To clarify the coordinates, the amplitude of the induced signal is successively compared with the amplitudes of the signals of the unit of formation of the reference pulses, the current input associated with the combined outputs of the coordinate tires of the tablet, and

10, the control input is with a precision counter, with the output of said block connected to one of the inputs of the comparison circuit. The unit forcing the reference pulses contains

15 a group of straight conductors laid with an exact reference step, a switch of said conductors and a reference sensor permanently fixed and inductively coupled to

20 by a group of straight conductors, wherein the reference sensor is connected via an amplifier to the output of the unit for forming reference pulses. The code for the lower bits is determined by sequentially polling the group of the straight conductors of the unit for forming reference pulses and counting them until the amplitude of the signal of the coordinate remover signal and the amplitude of the signal of the reference sensor are equal. Thus, the code of each of the coordinates corresponding to the position of the center of the puller relative to the beginning of the coordinates of the working field is added up from the code corresponding to the number of polled tires to the moment of appearance in the puller of the inductive signal (high bits) and the code corresponding to removal Nickname of the last excited coordinate bus (low bits) The disadvantages of this device are the relatively limited accuracy of the coordinate measurement caused by mechanical limitations on the packing density of straight linear conductors of the unit for forming reference pulses, mutual distortion of the magnetic field of these conductors with their dense packing, as well as a large amount of equipment for switching the specified reference conductors. Closest to the present invention is a device comprising a plan with orthogonal coordinate buses connected to switches connected to a pulse distributor, counters, a coordinate remover connected to an amplifier connected to an analog-to-digital converter, an interpolator, AND, OR, and generators. pulses, 2. However, the known device is not sufficiently accurate. The purpose of the invention is to improve the accuracy of the device. The goal is achieved by the fact that a device containing a tablet made in the form of a system of two mutually orthogonal coordinate buses connected to corresponding switches, the inputs of which are connected to the first pulse distributor, whose input is connected to the first pulse generator, and the outputs are connected to an analog-to-digital converter connected to the memory unit, and with the first and second counters, an OR element, whose inputs are connected to the second pulse generator and to the analog-digital 14 transducer, and the output is connected to the input of the third counter connected to the pulse distributor, a pulse datum connected to the first amplifier, a decoder whose input is connected to the output of the second counter, a second amplifier whose input is connected to a coordinate remover, and the output is connected to the input of the OR element and to the input of the delay element, the output of which is connected to one input of elements AND of a group, the other inputs of which are connected to the second counter, and the outputs connected to an interpolator, are connected in series to the third generator p pulses, voltage divider, another input of which is connected to the first amplifier, and a multiplier, another input of which is connected to the second amplifier, and the output is connected to the memory unit, while the interpolator inputs are pd connected to the decoder and to the delay element, and the outputs are connected with the inputs of the OR element and the second counter. FIG. 1 shows the amplitude characteristic of the measuring system of the device; in fig. 2 is a block diagram of the calculation algorithm in FIG. 3 - functional device diagram. The device includes a tablet 1 with two systems of mutually orthogonal coordinate buses, a 2-coordinate remover, switches 3 and i, a decoder 5, a sensor of 6 pulses, the first 7 and second 8 amplifiers, an amplitude correction block 9, an analog-digital block transformed. driver 11, first 12 and second 13 counters, elements AND 1t groups, control unit 15, consisting of a delay element 16, a first pulse generator 17, a pulse distributor 18, a second pulse generator 19, an OR element 20, and a third counter 21, block 13 contains a third pulse generator 22, a voltage divider 23, and a multiplier 2C. The block diagram of the device also includes an interpolator 25 containing a pulse generator 26, an AND 27 element, a trigger 28, an OR 29 element, a counter 30, decoders 31 and 32, a memory block 33, a code selection block 3, an OR 35 element, an element And 36, the counter 37, the distributor 38 pulses, element

AND 39, element AND kQ, counter k, distributor k2 of pulses, element OR 43, distributor kk of codes, element AND kS, register C6, block 7 of choice of codes, register 8, block E of transfer valves, adder 50, distributor of 51 codes, registers 52 and 53 and shear patterns 5 and 55.

The device works as follows.

After installing the sighting crossover of the puller 2 at the readable point, the operator starts the scheme for: dew of the coordinate tires of the tablet 1 with the Start signal. According to this signal, the generator 19 of pulses sets the counter 21 to one state, which permits the passage of the pulses of the generator 17 to the first output of the distributor 18 of pulses. At this time, the switch 4 is started, performing alternate switching and excitation of the coordinate buses.

These same pulses of the generator 17 are fed to the counting input of the tire counter 12, where a rough count of the coordinates is formed. The arrival of pulses occurs until the bus nearest to the puller 2 coordinates excites and the output of amplifier 8 does not receive a signal arriving through the OR 20 element at the counting input of the counter 21 and prohibiting the passage of generator pulses to the first output of the distributor. The generator pulses will then be present at the second output of the distributor, from where they arrive at the digital input of the analog-digital converter 11, as well as at the input of the counter 13- The analog signal corrected for the variation of the pulses of the bus polling current will come to the analog input of the ADC 11; puller coordinates. The correction of the latter is carried out in block 9. which has a generator 22 reference pulses, the amplitude of which is set taking into account the location of the sensor 6 pulses and accounting for the calculation of the coefficients, the divider 23 analog signals, the input of which receives signals from the amplifier 7, the sensor 6 pulses and the generator 22 reference pulses. At the output of the divider 23, a signal is generated that is proportional to the ratio. This signal is fed to the input of the multiplier 2 analog signals, the second input of which receives the signal from the amplifier 8, the signal

at the output of the multiplier is proportional to the product of two SIGNALS QnV; / Id. Thus, how many times the reference signal from the generator 22 differs from the signal from the pulse sensor 6, the signal from the coordinate remover changes by the same time, thereby eliminating the accuracy of coordinate measurements caused by the nonidentity of the excitation currents in the coordinate tires of the tablet. This signal, stored in block 10, will be present at the analog input of the ADC 11 during its conversion

digitally

At the time of comparing the analog signal with a linearly increasing signal at the input of the ADC 11, a signal is generated that arrives at the counting input

counter 21 and stopping the supply of pulses at the second output of the distributor 18 pulses. In this case, on the counter 13, the digital value of the measured

Claims (2)

signal size, And since the working part of the amplitude-spatial characteristic of the puller 2 is a non-linear function shown in FIG. 1, the true distance from the last interrogated tire to the puller center is determined in the interpolator 25 by reverse splicing. The spline-interpolation method is chosen because it can provide any predetermined accuracy of calculations with a constant calculation algorithm. The previously obtained experimental values of the coefficients and the values of the nodal points of the spline are stored in the memory block 33, where also the code of the measured signal value from the puller 2 coordinates is recorded using the AND AND group elements according to the signal from the output of the delay element 16. Further, in accordance with the algorithm shown in FIG. 2, a calculation is made corresponding to the distance. The sequence of the calculation operation is set by the counter 30 and the decoder 31. At the output of the element 27 And there appears a sequence of pulses of the generator 26, to the inputs of the elements and ST and 40. as well as to the inputs of the distributors 38 and 42 pulses. When performing an operation of addition type, the permitting signals from one of the outputs of the first group of outputs permitting the execution of the instructions. 2) the generator pulses 26 through the element AO are fed to the input of the counter A1, which defines an addition cycle consisting of five cycles. At the same time, the fifth pulse from the output of the meter A1, arriving at the input of the operation counter 30 through the element OR 29, sets it to the next state that prohibits the pulse generator to arrive at the counter A1, which is then set to the initial state. During the execution of the clock cycles of the first operation, the first signal from the output of the distributor 2 pulses is implemented using block 3, the selection from block 33, at the address determined by decoder 32, corresponding to the number, records this number to the adder 50 by the second signal. determined by the state of the decoder 32, whose state, in turn, is determined by the state of the operation decoder 31 and by the network of the decoder 5, which decrypts the state of the counter: 13. In counter 13, the number is the current number of the interval in which Oromo is made with the measurement. The third and fourth signals, similar to the first and second, select the second number from the memory and write it to the kB register. By the first signal, the contents of the kB register in the additional code are transferred through the valve Ad block to the adder 50. The result obtained the signal from the element And the AZ is recorded in the register A6, the operation of this is completed, the counter 30 is set to the next state at which the enabling signal appears on one of the outputs of the second group of outputs f (the outputs permitting ie multiply instruction). The signals of the generator 26 through the element And 27 are received at the same time at the input of the multiplication counter 37, which controls the pulse distributor 38; Following the scheme in FIG. 2, the operation is performed in two multiplication instructions. The first impulse dispenser 38 pulse-. The COB is selected from the f} 6 register using the OR element 35 and the block 3 of the corresponding code of the number X. The second signal records it in the register 8 of the multiplicand and the multiplier register 52 through. the element OR A3 and the AA code distributor, Register 52 and adder 50 have right-shift circuits 5A and 55. The sequence of operation of the circuit is then determined by the state of the least significant bit at the output of the register 52. If it contains 1, then a multiplicative is added to the sum of the partial products in the adder 50, i.e. the signal from the output of the register 52 permits the passage of a pulse from the third output of the distributor 38 through the element AND 39 to the input of the block Ad transfer valves, while a multiplicand is added to the sum of the partial products. Further, the pulse, from the fourth output of the distributor 38, is shifted to the right in the adder 50 and the register 52. If, however, in the low-order bit of the register 52 is written O, then the shift is performed without performing addition. The last pulse from the output of the counter 37 will switch the counter 30 operations to the next state and, through the element A, A5 will record the intermediate result in the register A6. During the following operations, the remaining numbers are multiplied in a similar way. After performing these operations, the pulse from the corresponding output of the operation counter 30 adds one to the contents of the counter 13, the decoder decrypts the number for sampling in subsequent operations. The sequence of the operation and their number is determined by the counter 30, and each of them is performed similarly to the described addition and multiplication operations. The sixteenth pulse of the counter 30 (since there are fifteen operations in all) sets the trigger 28 to the zero state, thereby terminating the interpolator and setting it to the initial state, and adding one to the counter 21, setting it to a new state for determine the coordinates of the point. The result of the last operation is recorded in the register 53 and represents the exact count of the coordinate of the center of the puller center (lower bits of the coordinate code), the X coordinate code of the point is determined by the sum of the contents of the counter 12 and the register 53. The exact count time of one coordinates when implementing; the proposed technical solution on 155 series chips and the number of times the code series is equal to fifteen, does not exceed 20 microseconds. The average manual tracking speed of 1 cm / s and with the maximum required device sampling step is 0.01 mm, the measurement time for one coordinate is 5 ms. Thus, the calculation of the exact reading can be carried out in the intervals between the readings at a sufficiently high tracking speed. The introduction of new units and blocks, as well as new constructive links between them, has significantly improved the accuracy of the device. The invention includes a device for reading graphic information containing a tablet made as a system of two mutually orthogonal coordinate buses connected to corresponding switches, the inputs of which are connected to the first impulse distributor, whose input is connected to the first pulse generator, and the outputs are connected to an analog-digital converter connected to the memory unit, and with the first and second counters, an OR element whose inputs are connected to the second pulse generator and to the analog-digital device The output is connected to the third input of the counter connected to the pulse distributor, the pulse sensor connected to the first amplifier, the decoder whose input is connected to the output of the second counter, the second amplifier whose input is connected to the coordinate remover, and the output connected to the input of the OR element and to the input of the delay element which is output. It is connected to one input of elements AND of a group, the other inputs of which are connected to the second counter, and the outputs are connected to an interpolator, characterized in that, in order to improve the accuracy of the device, it contains series-connected third pulse generator, voltage divider, the other input connected to the first amplifier, and a multiplier whose other input is connected to the second amplifier, and the output is connected to a memory unit, while the interpolator inputs are connected to the decoder and to the delay element, and the outputs are connected with the inputs of the OR element and the second counter. Sources of information taken into account in the examination 1. The author's certificate of the USSR K 627463, cl. G About K 11/06, 1976. 2. USSR author's certificate for application No. 2999 2b, cl. SOBKP / On, 1980 (prototype). -J