SU799717A1 - Apparatus for demonstrating "m.goldman's" test - Google Patents

Description

The invention relates to a meaicin technique, namely to devices for the examination of vision functions. A Mira Holtzmann test demonstration device is known, containing a projector that allows you to project several figures formed on a moving base by moving their components using a button with push contacts. J The disadvantage of this device is the limited number of gradations of sizes of test objects and the impossibility of changing type of test. It is also known a device for testing the Mira Goldman test, comprising a synchronizer, a video signal conditioning unit, a channel unit, and a television receiver 2 j. A disadvantage of this device is the low consistency of checking visual acuity. The purpose of the invention is to increase the reliability of visual acuity checks by forming an arbitrary study program. This goal is achieved in that the automatic control unit, the row and column shaping units, the two chessboard formation units, the mask filling unit, the input unit, the unit registration and the console are entered into the device containing the synchro generator, video signal shaping unit, channel unit and television receiver. input answers, the output of which is connected to the input of the automatic control unit, the other input of which is connected to the outputs of the input unit 1. The output of the automatic control unit is connected to the input of the switch, the second input of which is connected to the second output of the input block, and the outputs of the switch are connected respectively to the first inputs of the row and column shaping units and the formation of the chess floor, the second inputs of which are connected to the output of the synchronizer generator, and the outputs of the blocks formed; rows and columns and two blocks of the formation; The inputs of the registering unit are connected to the output of the automatic control unit- Q

laziness. The chessboard formation unit contains a raster pulse counter, a string pulse counter, two coincidence circuits,. two triggers, two AND circuits and an OR circuit, the fault inputs of the counters of raster and lowercase pulses are connected to the outputs of the first and second coincidence circuits, the first inputs of which are connected to the outputs of the raster impulse counter and the horizontal pulse counter, respectively. The outputs of the matching circuits are connected to the first inputs of the flip-flops, the first output of the first trigger is connected to the first input of the first AND circuit, the second input of which is connected to the first output of the second trigger, the first input of the second And circuit is connected to the second input and the second output of the first trigger, the second input of the second circuit AND is connected to the second input

the house and the second output of the second trigger, and the outputs of the two AND circuits are connected to the inputs of the OR circuit.

On .4 1G. 1 shows a block diagram of a device for demonstrating the Mira Goldman test; in fig. 2 — mask configuration.

The device for demonstrating the Mira Goldman test contains an I input block, an automatic control block 2, a recording block 3, a test response input 4, test switch 5, a row formation block 6, a column shaping block 7, a chess board forming blocks 8 and 9, a synchro-generator 10, a mask filling unit 11, a video signal conditioning unit 12, a channel unit 13 and a television receiver 14 with an antenna input 15 and a video amplifier 16 input.

The chessboard formation unit contains a raster pulse counter 17, a lowercase pulse counter 18, coincidence circuit .19 and 20, triggers 21 and 22, logic AND 23 and 24 logic elements and OR.

The device for demonstrating Mira Goldman's test works as follows. five

This control is fed to the inputs of the switch 5, from the outputs of which the code of the optometric scale number is fed to the input of the block 8 forming a chessboard floor. To the input of block 9 of the formation of a chess floor, the construction of which is completely identical to block 8, the OOO1 code of the optometric scale number corresponding to the sharpness is constantly supplied

vision 2.0. The inputs of the blocks forming the chess floor are received from the synchronous generator by raster pulses of 6 MHz and lower pulses of 15625 Hz. These pulses are counted in binary

These circuits ARE reset signals for counters 17 and 18 and are fed to the corresponding inputs. The same impulses come to counting

The JJ inputs of the flip-flops 21 and 22 operating in the counting mode and giving the incoming pulses the coincidence of the codes form a square wave.

Then on the logic elements 23,

40 24 and 25 the logical equation of the cryphosignal of the chess floor Сш-t and Сш2 is realized:

,

where o t

Oh t

212

22

1 through j corresponding trigger states 21 and 22 j

Sc |, Sc | 2-sync chess floor, test and background, respectively.

Four higher bits of the horizontal beam coordinate code are received from the synchro generator to the inputs of the column formation unit 7, resulting from continuous counting f3 with 6 MHz code of the raster pulses of the master oscillator of the synchronous generator 1 With the I input unit in the 2 automatic control unit the order data is presented phenomena testobjects. The automatic control unit 2 forms the control bars; Numbers of the optometric scale and the direction of the position of the mask element that differs from the others by the pitch of the chessboard floor. The control codes from the outputs of block 2 are automatic four-way counters 17 and 18, the outputs of which are connected to the inputs of the circuits 19 and 20 coincidence. Optometric scale number codes are supplied to other inputs of the matching circuits. The codes match pulses are generated 5 10, i.e. the duration of the raster and pulse -jTp is equal to - The device for forming the columns forms the pulses C (, C. Srt, corresponding to the logical equations fni pp pp pp pp VppSpSp m2-6pp pSpV4Vpppp yy.-Sp.pp pT; 4Vpp4V where 5рр, brr, 7рр, 8рр - combination of the outputs of the binary counter of raster pulses (horizontal beam coordinate). These pulses have a duration of 32 T (10.2% of the width of the line pulses) and are offset from the beginning of the line pulse by 128 17, 160 tr and 196 T i.e. the vertical axis of symmetry of the mask is offset from the beginning of the line impulse 56%. From the synchro-generator, 0, the vertical coordinate of the beam, which is the result of continuous counting in the binary code of the horizontal pulses of 15625 Hz, enters the inputs of the block of the vertical coordinate of the beam, and generates impulse 1, Suu, p2, Su and RZ corresponding to the logical equations :, pi- “Pcpc4 pJ4VcSAc wp 2 uir. C where 5p 6 pp. 7 pf. 8 PC are combinations of the states of the binary counter of horizontal pulses (vertical Beam Coordinates). These pulses have a duration equal to 10% of the half-frame pulse duration, and are offset from the beginning of the half-pulse, respectively, by 112, 144 and 176 lines, i.e. symmetrically about the horizontal axis of the television screen. 76 Outputs. blocks of formation of rows 6, columns 7 and a chess field 8 and 9 are connected to the inputs of the mask formation block 11, in which the logical equation of the Worlds of Oldman is implemented: g / M / t rupi jnpiv n,) tr: mp (l wa) vr ,, pii (C, .-, 2 (), (5) where C, is the information signal of the Mira Goldman test. „.„ ..., .. are the directions of the test square. The information signal from the output of block 11 of the mask is received To the input of the video signal generation unit 12, to the other inputs of which television synchromesh1010 receives television syn; photo signals. The unit 11 generates a video signal, Corresponding to the requirements of GOST 7845-72. The output of the video signal shaping unit 12 is connected to the input of the channel unit 13, which modulates the frequency corresponding to the frequency of one of the television channels. the television receiver has a video amplifier input, the channel unit is not: required, and the output of the video signal conditioning unit is connected to the input. video amplifier 16 of the television receiver 14. The image of the test volume that the screen Itelevizionnogo receiver pred is the subject, and he enters his responses to the automatic control unit 2 through the control input 4 of the test responses. In accordance with a given program, the subject is presented with the next test object for recognition, or a conclusion is made about the state of view of the subject. The result of the tests and the necessary information are recorded using the device 3. Thus, the proposed device due to the possibility of presenting an arbitrary number of optometric scales of the test 4 Worlds Goldman, discrete formation of test objects increases the accuracy and reliability of checks

visual acuity reduces the influence of subjective error factors.

The presentation of tests on the screen in an arbitrary order and according to the program eliminates the possibility of memorizing the test table by heart and reduces the time of the study.

Claims (2)

Invention Formula I. The Mira Holtzmann test demonstration unit, which contains a synchronous generator, a video signal conditioning unit, a channel unit and a television receiver, which are different from the fact that, in order to increase the reliability of visual acuity checks, by forming an arbitrary study program, an automatic control unit, forming units are entered into it rows and columns, two units for forming a chess floor, a mask filling unit, an input unit, a recording unit and an answer input console, the output of which is connected to the input of the auto block Mathematical control, the other inputs of which are connected to the outputs of the input block, the output of the automatic control block is connected to the input of the switch, the second input of which is connected to the second output of the input block, and the switch inputs of the switch are respectively connected to the first inputs of the row and column shaping blocks and the mine floor the entrances of the cohorts are connected to the output of the synchro-generator, and the outputs of the blocks for forming rows and columns and two blocks for forming the chess floor are connected to the inputs of the block for filling the masks and whose output connected via a video signal forming unit to the input of a channel unit, the output of which is connected to a television receiver, the second input of which connected to the output of the signal conditioning unit, and the inputs of the recording unit are connected to the output of the automatic control unit. 2. The device according to p. I, that is, so that the block of formation of a chess floor contains a raster pulse counter, a lower pulse count, two coincidence circuits, the trigger color, two AND schemes, and the OR the inputs of the counters of the raster and line pulses are connected to the outputs of the first and second coincidence circuits, the first inputs of which are connected to the outputs of the counter of the raster pulses, respectively, and the line pulse counter, the outputs of the coincidence circuit are connected to the first inputs of two triggers, the first output of the first one, the trigger is connected to the first input of the first circuit, And, the second input of which connected to the first output of the second trigger, the first input of the second circuit AND is connected to the second input and the second output of the first trigger, the second input of the second AND circuit is connected to the second input and the second P output of the second trigger, and the outputs of the two AND circuits are connected to the inputs of the OR circuit. Sources of information taken into account in the examination 1.Patent of France No. 2287200, cl. A 61 B 3/00, published 1976. 2. Topuri, Mass Examination Acuity Television. - ;, Bulletin of Ophthalmology 197O, No. 3 (prototype).