RU1793419C - Automatic distance-finder device - Google Patents

Abstract

Usage: in instrumentation. The invention consists in that the device comprises optical systems 1,2, a light source 3, a photodetector 4 in the form of a line of N photoconverters, N threshold elements 5.3N t1 elements AND 6,7,10,12, N elements OR 9. N RS-flip-flops, recorder 11. D-flip-flops 13, 14, 15, pulse generator 16. 2 ill.

Description

The invention relates to instrumentation and can be used in various automation devices designed to measure the distance to objects of observation, for example, as a range finder for cameras. h

Devices for measuring the distance to the object of observation are widely known and can be classified as active and passive, the most promising are devices that implement the basic operating principle. In passive basic auto-ranging, the parallactic angle of the object is measured with a known basis between the two input optical channels. The measurement of the parallactic angle can be made by the angle of rotation of the swivel mirror installed in one of the input optical channels or by using a video signal storage unit in one of the input optical channels and determining its position with respect to the video signal from the other optical channel. The video signals of the two optical channels are compared by correlation or the like. Active devices use an active emitter and a multi-element receiver placed in a corresponding input optical channel. The principle of action of active devices consists either in comparing the video signals of adjacent photodetectors and controlling a rotary mirror, or in highlighting a photocell with a maximum video signal.

The closest to the claimed device in technical essence is an automatic rangefinder / which can be selected as a prototype. The prototype contains a light emitter and a receiver mounted in parallel optical channels spaced apart at a base distance. The emitter contains a light source and an optical system that provides the formation of a beam of light illuminating the subject. The receiving part includes an optical system collecting the light reflected by the object at the receiving area of the photodetector. The photodetector comprises several, for example, photoconverters located along the direction of the base distance. Brightness

Yu

WITH

3

00

and

ho

the light emitter should provide a significant excess of the illumination of the light spot at the object of observation over the natural Illumination and light intensity of sources, possibly located at the object of observation; The distance between adjacent photoconverters should correspond to the projections of the light spot constructed by the second optical system in the plane of the photodetector. The output of each photoconverter through the corresponding threshold element is connected to the input of the electronic recorder. The response level of the element is selected so that the photoconverter illuminated by a light spot produces, for example; th &,. It is enough for the triggering of the Corresponding Threshold element, while it is natural: the illumination did not cause the threshold element to trigger. The electronic recorder determines the distance to the object, iy t V; : -i l:,.

The range of the known active intra-base rangefinder, at which a given measurement accuracy is ensured, is limited due to the fact that it is usual. Different objects reflect light diffusely. This means that only a part of the light flux sent to the object is returned to the range finder window, decreasing inversely with the square of the distance to the object. Therefore, the disadvantage of the known device is to reduce the measurement accuracy with increasing range due to the increase in the possibility of false measurement at the maximums of natural obscurity, for example bl.kam ;; light and artificial light sources - possibly available at the object of observation.

The purpose of the invention is to increase the accuracy of the range measurement by eliminating the field measurements associated with optical interference, i ;;;; .-....

The goal is achieved by the fact that in an automatic rangefinder device containing receiving and transmitting channels, respectively comprising receiving and transmitting optical systems, the optical axes of which are spaced apart by a base distance, as well as a light source mounted in the focal plane of the transmitting optical system, a photodetector located in the focal plane of the receiving optical system and made in the form of a ruler of N photoconverters oriented along the base distance, N threshold elements, each input about of which the range recorder is connected to the output of the corresponding photoconverter, the first, second and third groups of N logical elements AND, (3N + 1) -u logical element AND, N logical elements OR, N RS-triggers, pulse generator and three D-flip-flops, wherein the light source is controllable, the output of each of the N threshold elements is connected to the R-input of the corresponding

An RS-trigger through a series-connected corresponding logical element AND of the first group of logical elements AND and a logical element OR AND to the S-input of the corresponding RS-trigger through the corresponding logical element AND of the second group of logical elements AND, the output of the first D-trigger is connected to the input of the second D -trigger, with the control input of the light source, with second inputs of logic elements AND the second logical group

elements And and with the first input (3N + 1) -rO

logical element AND, the output of which

connected to the second logical inputs

Elements OR, output of the second b-trigger

connected to the input of the Third D-trigger and to the second inputs of the lot elements AND of the first group of logical elements AND, the output of the Third-trigger is connected to the first inputs of the logical elements AND of the third group

logic elements And and with the input of the first D-trigger, the output of the pulse generator is connected to the second input (3N + i) -ro of the logic element And and the clock inputs of the first, second and third D-triggers,

the output of each of the N RS triggers is connected

with the second input of the corresponding logical element AND of the third group of logical elements AND, and the outputs of each of the logical elements AND of the third group of logical: elements are connected to the corresponding inputs of the range recorder.

In the device, the light source is switched to pulsed mode of operation, a pulse generator is introduced, the output connected to

control input ka; some of the three co. single ring of D-flip-flops, due to which the cycle of the device includes three cycles. At the first clock, when the first D-trigger is in a single state,

the source emits light flux towards the object of observation. Photoconverters convert the luminous flux from the object of observation into an electrical signal, which is compared with a threshold in the threshold

element corresponding to the converter. If the threshold is exceeded in one or more threshold elements, the corresponding of the second elements And opens, so that the corresponding RS-trigger is brought into a single state. The number of one or more RS flip-flops thrown into a single state during the first clock cycle is determined by the areas of the object under observation that are artificial from the light source of the device or whose natural illumination exceeds a predetermined threshold. In the second, also, the first D-flip-flop transitions to the zero state, and the second D-flip-flop assumes a single state. Therefore, the light source is turned off and exceeding the threshold illumination does not depend on this source. Those portions of the surface of the object under observation whose natural illumination is higher than the threshold trigger the corresponding first elements And, which reset the corresponding RS triggers. By the end of the second clock, only the RS-trigger, which is controlled by a photocell, onto which the light flux from the light source in the first clock, has fallen into a single state. During the third cycle, the third D-flip-flop is thrown into a single state, therefore only that of the third AND elements is opened, the second input of which receives a single signal from the RS-flip-flop. In the third step, the registrar registers the desired range from the number of the third elements from the number of the included element AND. When the third clock transitions again to the first one, the first D-flip-flop is thrown, which on the leading edge of its switching pulse resets all RS-flip-flops, and the operation cycle repeats.

The block diagram of the device is shown in FIG. 1. The device contains two optical systems 1 and 2. A light source 3 is located in the rear focal plane of the optical system 1, 2 times in the rear focal plane of the optical system. A line of N number of photoconverters is placed 4. The orientation of the photoconverter line 4 coincides with the separation direction to the base distance In optical systems 1 and 2. Photoconverters 4 are designed to convert the light flux into an electrical signal. The output of each photoconverter 4 is connected to the input of the corresponding threshold element 5. The threshold element can be made in the form of, for example, a comparator. The output of each threshold element 5 is connected to the first input of the corresponding element And 6 of the N number of first elements And to the first input of the corresponding element And 7 of the second elements And, The output of each first element And b is connected to the R-input of the corresponding RS-trigger 8 through the corresponding element OR 9, and the output of each element And 7 is connected to the S-input of the corresponding RS-trigger 8 directly. The output of each RS-flip-flop 8 through the corresponding element And 10 from N of the number of third elements And is connected to the corresponding input of the recorder 11. The registrar 11 is designed to fix the distance to the object and can be performed, for example, in the form of a linear scale consisting of a set of light emitting diodes. The control input of the light source 3, the second input of each of the second elements And 7, the first input of the fourth element And 12 are connected to the output of the first D-trigger 13, connected through the second D-trigger 14 to the input of the third D-trigger 15. The control input of each The D-trigger 13, 14, 15 is connected to the output of the pulse generator 16 and the second input of the fourth element And 12. The output of the third D-trigger is connected to the input of the first D-trigger 13, whereby the connection of the D-triggers 13, 14, 15 is three-bit circular shift register. The output of the second D-trigger T4 is connected to the second input of each first element And 6. The output of the third D-trigger 15 is connected to the first input of every third element And 10. Elements AND 6,7,10.12, elements OR 9, RS-triggers 8 and D -triggers 13, 14, 15 are standard elements of binary logic and have no features; G..:. .. g.

The device operates as follows;

The pulse generator 16 continuously generates a pulse sequence (Fig. 2a) with a frequency F. Under the influence of this sequence, the D-flip-flops 13, 14, 15 connected in a ring go sequentially in time one at a time into a single state (Fig. 2b, .c, d) accordingly, In the time interval when the first D-flip-flop 13 is in a single state, the light source 3 emits light (Fig. 26). This light is focused by the Optical system 1 in the form of a narrow beam on an observable. day to which the distance is measured. The luminous flux reflected from the object, containing components from natural illumination, illumination of the light source 3, and radiation from sources that may be present on the surface of the object, is projected by the optical system 2 onto the photoconverter system 4, where it is converted to proportional voltages. The size of the photosensitive surface of the photoconverter 4 is selected commensurate with the size of the light spot from the source 3. In FIG. Figures 2e and 2e show the output voltages for photoconverters n (, N) and the position of the object under observation at point A for the time interval ti ... t2 (Fig. 2e) and for the interval t2 t ta (Fig. 2e). FIG. Figure 2g shows similar voltages for the position of the object to be observed at point A. The video signals at time instants tj., T3 depend only on the natural illumination of the object under observation (Fig. 2e, and). At time ti ... ta, a spot of light from the light source 3 is observed on the object, which causes a sharp increase in the voltage at the output of one of the photoconverters 4, for example, the first (Fig. 2d) or the latter (Fig. 2g). These voltages vary in time according to the law of light emission by source 3 (Fig. 26). For example, for the position of the object at point A, the voltage at the output of the first phi transformer (Fig. 2 k) and the voltage at the output of an arbitrary nth photoconverter (Fig. 2l) differ sharply in the presence of a pulse from the light source 3 above the level of natural illumination of the first and p photoconverters, respectively. The threshold element 5 detects the excess of the voltage at the output of the photoconverter over a predetermined threshold. Therefore, neither the output of the first of the threshold elements 5 at the moment of exceeding the threshold is affected by a pulse of duration t2-ti with a repetition period F / 3 of a given amplitude U (Fig. 2 m). If the level of natural illumination of the nth element exceeds a threshold, then at the output of the corresponding threshold Element 5, a continuous voltage (Fig. 2 n) of the amplitude O acts. Therefore, the signal Via, the output of an arbitrary second element And 7 pb, appears only if the thresholds are exceeded in the corresponding element 5 at times ti ... t2 of switching on the SOURCE of light. This signal acts on the S-input of the corresponding RS-flip-flop 8 and transfers it to a single state. At the moment of the transfer of the single-state from the first D-flip-flop .13 to the second D-flip-flop 14 (moment t2) all the second elements And 7 are closed according to the second the entrance. A single signal from the output of the second D-trigger 14 is fed to the second input of each of the first elements of IB. The signal at the output of any of these elements And 6 appears only at the moment t2 ... t2 of the action of this pulse in the presence of a signal from the output of the corresponding threshold element 5 (Fig. 2 l), i.e. when the corresponding photoconverter is illuminated above the threshold by the natural illumination of the object, and not by source 3. The signal from the output of the And 6 element, corresponding to exceeding the threshold by natural illumination and therefore classified as a noise, is fed through the OR 9 element to the R-input of the corresponding RS-trigger 8 and translates it to the zero state. Accordingly, by the time moment t2, only that RS-flip-flop 8, whose converter was equipped with a light source 3, will remain in a single state. At time t2, the D-flip-flop 14 is reset, and the D-flip-flop 15

is transferred to a single state, which goes to the first input of all third elements And 10, However, only one of these elements opens, namely the one that is switched by its second input with

the output of the RS-flip-flop 8, which is in a single output; ; v

Therefore, in the time interval t2l ..t3, information is received from the number of the photoconverter 4 illuminated from the light source 3 at the input of the recorder 11. The registrar 11 pb to the number of the photoconverter 4 determines the desired distance to the object. On the

FIG. 2 n The waveform of the signal at the output of the first RS-trigger 8 at

jugging objects at point A. In FIG. 2 p

The waveform of the signal on

the output of n-th trigger 8 (mn, 1) with the same

the position of the object and the condition that the p-th photoconverter 4 is illuminated above the threshold of natural illumination. When the next impulse is postponed at the time ta from the generator 16 along its leading edge, the D-flip-flop 13 is reset to a single state, and the flip-flop 15 is reset. D-trigger 13 turns on the light source 3 and opens the fourth element And 12 for the duration of the signal at its second input (at the time

the duration of the pulse gi from the output of the generator is 16 pulses (gi t2 - ti). The signal with a duration of about the duration of the gi passes through the OR 9 elements to the R-input of each RS-f of the trigger 8 and puts it in the zero state. The device returns to its initial state and the measurement cycle is repeated. -; Jy. ; :. ::, l. -; h.

The technical and economic effect of the application of the proposed device is to improve the accuracy of range measurement

by eliminating false measurements caused by the natural illumination of the observation object and other interference. This makes it possible to reduce the brightness requirements of the light source, providing a predetermined accuracy of range measurement. Therefore, the power and energy intensity of the power sources used to ensure the operation of the device can be reduced. Considering the fact that this proposal can be used as an automatic rangefinder in professional and amateur cameras, for example, Zenit / 35 type, the decrease

wearable equipment allows you to improve the commercial properties of the camera while improving the quality of the resulting photographs due to the best NEVOD

the energy intensity of sources, and hence the weight of 5 ki, for sharpness in automatic mode.

Claims (1)

SUMMARY OF THE INVENTION An automatic ranging device comprising receiving and transmitting channels, including respectively receiving and transmitting optical systems, the optical axes of which are spaced apart by a base distance, as well as a light source mounted in the focal plane of the transmitting optical system, a photodetector located in the focal plane of the receiving optical system and made in the form of a ruler of N photoconverters oriented along the base distance, N threshold elements, the input of each of which is connected to the output of the corresponding photoconverter, and a range recorder, characterized in that, in order to increase the accuracy of determining the distance to the object by eliminating false measurements associated with optical interference, the first, second and third groups of N logical elements And are introduced into the device (3N + +1) -th logical element AND, N logical elements OR, N RS-flip-flops, a pulse generator and three D-flip-flops, and the light source is controllable, the output of each of the N threshold elements is connected to the R-input, respectively RS-flip-flop through sequentially connected corresponding logical element AND the first group of logical elements AND and the logical element OR to the S-input of the corresponding RS-trigger through the corresponding logical element AND of the second group of logical elements AND, the output of the first D-trigger is connected to the input of the second D-trigger, with the control input of the light source, with second logical inputs AND elements of the second group of logical elements AND and with the first input (3 N + 1) -ro of the logical element AND, the output of which is connected to the second inputs of the logical elements OR, the output of the second D-trigger connected to the input of the third D-trigger and to the second inputs of logical elements AND of the first group of logical elements AND, the output of the third D-trigger - to the first inputs of logical elements AND the third groups of logic elements And and with the input of the first D-trigger, the output of the pulse generator is connected to the second input of the (3N + 1) -th logical element And and with the clock inputs of the first, second and third D triggers, the output of each of the N RS-triggers is connected to the second input of the corresponding logical element AND of the third group of logical elements AND, and the outputs of each of the logical elements And the third group of logical elements AND are connected to the corresponding inputs of the range recorder. Figure 1