JPS62190411A - Distance measuring instrument - Google Patents

Abstract

PURPOSE:To reduce the size and weight of a distance measuring instrument and to measure distance with high accuracy through simple constitution by varying the distance between contour parts of plural pieces of luminous flux according to the distance from a light projection position to a subject. CONSTITUTION:Pieces alpha and beta of infrared beam luminous flux from light projection parts 2a and 2b differ in section perpendicular to optical axes at a long, an intermediate, and a short distance according to their diffusion and the pieces of luminous flux overlap with each other at the long distance. Reflected luminous flux from the object is incident on the photodetection surface of a CCD line sensor 4 and its photodetection pattern corresponds to the distance to the object. The output of the sensor 4 is inputted to a mu computer 7 to generate select signals corresponding to the long, intermediate, and short distances and a focus adjusting circuit 8 and a driving motor 9 operate according to those signals. Consequently, a photographic lens 1 moves to a position corresponding to the distance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a 7III rhinoceros device, and more particularly to a distance measuring device that measures distance using an active method.

[Prior Art] Conventionally, a light beam is projected from a light emitting means toward an object to be measured, the reflected light of the projected light beam from the object to be measured is received by a light receiving means, and the distance from the base or position of this light receiving position is calculated. Active distance measuring devices that perform distance measurement based on the above generally use a single projected light beam, and to detect the light receiving position, the light emitting means or light receiving means is moved to the position where the received light level is maximized. Displace (11-formation (Unexamined Japanese Patent Publication No. 1983)
-135308, etc.) was taken.

[Problems to be Solved by the Invention] The method of detecting the light receiving position and measuring the distance by displacing (scanning) the light emitting means or the light receiving means to a position where the received light level is maximum does not require the above displacement or Since it includes a mechanical servo element for scanning, the structure becomes complicated and becomes an impediment to miniaturization and weight reduction.

The present invention has been made in view of the above points, and provides a distance measuring device that requires a mechanical servo element, is small and lightweight, and is capable of high-precision distance measurement with a simple configuration. The aim is to provide 1]

[Means and operations for solving the problem] In the distance measuring device of the present invention, the plurality of light beams projected by the light projection means have a contour of the light beam of one summer depending on the distance from the projection position to the subject. The distance between the parts is changed, and the reflected light of the projected light flux from the subject is received by the light receiving means, and the output of the light receiving means is inputted to the subject distance identifying means. IS! A signal for identifying the object distance is output according to the degree of proximity of a cold number projection pattern formed by projecting several light beams onto the object.

[Example] Hereinafter, the present invention will be explained based on illustrated embodiments.

In a camera to which an embodiment of the distance measuring device of the present invention is applied, two light projecting sections 2a and 2b are provided with a photographic lens 1 in between, as shown in FIG. These two light projecting parts 2a and 2b are composed of infrared light emitting diodes, and are arranged so that their respective optical axes are parallel to the optical axis of the photographic lens 1 and are symmetrical with respect to the optical axis of the lens. Photography lens 1
A beam splinter 3 is disposed on the optical axis 2 of the camera to form an image of the light incident from the photographing lens 1 at a position conjugate with the imaging surface (film). A CCD line sensor 4 is disposed at a position conjugate with the lAi image plane, and an 11J viewing light cut filter 5 is disposed between the line sensor 4 and the beam splitter 3.

Therefore, the infrared light projected from the two light projectors 2a and 2b, reflected by the subject, and incident on the imaging lens 1 passes through the beam splitter 3 and the visible light cut filter 5, and then passes through the CC.
The light is received by the light receiving surface 1- of the D line sensor 4.

By the way, the two luminous fluxes α2β projected from the light projectors 2a and 2b are thin infrared beams, and their optical axes are parallel to each other, but as the distance increases, the luminous fluxes α and β become smaller. It is spreading little by little. In other words, these two projected light fluxes α and β are placed at a long distance.

If we cut perpendicular to the optical axis for both medium and short distances, the cross-sectional shape will be as shown in Figure 3.
It is large at long distances, small at short distances, and intermediate in size at intermediate distances. Therefore, the two projected light fluxes α and β
The positional relationship between the contours of the cross section of is stable depending on the distance, and the contours of the two light beams α and β are completely separated at short distances, contact at medium distances, and definitely intersect at long distances. Thus, parts of the two beams of light completely overlap.

The light receiving surface of the CCD line sensor 4 receives the two projected light fluxes α and β reflected by the subject.
The light receiving pattern for this CCD line sensor 4 also corresponds to the distance to the subject. That is, when the subject is far away, as shown in FIG. 4(A), parts of the two reflected light beams are received differently at the center of the CCD line sensor 4.

Therefore, the waveform of the output 4a of the CCD line sensor 4 has a two-step shape with one step higher at the center. Also,
In the case of a medium distance, as shown in FIG. 4(B), the two reflected light beams are received by the CCD line sensor 4 in parallel, and therefore the output 4a of the CCD line sensor 4 is flat even at the center. The waveform has a one-step shape. Furthermore, in the case of a short distance, as shown in FIG. 4(C), the two reflected light beams are received by the CCD line sensor 4 in a separated state, so the waveform of the output 4a of the CCD line sensor 4 is centered It is low at the top and has a 1:6 shape at both the left and right positions. That is, when the subject distance changes from long distance to medium distance to short distance, the waveform of the output 4a of the CCD line sensor 4 also takes on a different shape. Therefore, by reading the waveform of the output of the CCD line sensor 4, the object distance can be determined.

The output of the CCD line sensor 4 is A as shown in FIG.
After being converted into a digital value by the /D converter 6, it is manually input to the microcomputer 7. The microcomputer 7 processes the digitally converted output of the CCD line sensor 4 into )
Selection signal OUT, O according to the distance 41 of “medium” and “near”
U.T.

Outputs 0UT3. This selection signal OUT, ~QUT3
When any of the above is input to the focus adjustment circuit 8, the circuit 8
sends a drive signal to the lens drive moke 9 to move the photographic lens 1 to a focus position corresponding to the distance.

The microcomputer 7 is configured to perform a signal processing function as shown in FIG.

Next, the signal processing function of the microcomputer 7 shown in FIG. 5 will be explained using the program operation flowchart 1 shown in FIG.

A light emission signal is sent from the read signal generating means 11 in the microcomputer 7 to the light projecting sections 2a and 2b.

Then, the CCD line sensor 4 receives the two light beams reflected from the subject and accumulates the signal type A::r for a certain period of time. Then, when a clock-like read signal is sent from the read signal generating means 11 to the CCD line sensor 4, the CCD
The signal of each pixel accumulated in the line sensor 4 is sequentially output from one end pixel to the other end pixel of the CCD line sensor 4 to the A/D converter 6, and the A/D signal generated from the readout signal generating means 11 is outputted to the A/D converter 6. Along with the start signal, analog values corresponding to each pixel signal of the CCD line sensor 4 are converted into digital values and taken into the microcomputer 7.

Inside the microcomputer 7, the A/D converted CC
The output of the D line sensor 4 is sequentially sent to the edge detection means 13.
is man-powered. When the digital signals corresponding to each pixel of the CCD line sensor 4 are sequentially read out from the pixels at one end and manually input to the first edge detection stage 13, first, the signal input manually to the edge detection means 13 is The signal is stored in memory M, and the next signal is stored in memory M2.

In this edge detection means 13, the memory M
A comparison is made between the value stored in memory M2 and the value stored in memory M2. The edge detection means 13 records the reference value (threshold value) set by the reference value setting means 12 as a reference signal, and as long as the value in the memory M2 does not exceed the reference value further than the value in the memory M1. , the signal in the memory M2 is sequentially updated, and when it exceeds the uF value, it is determined that the signal in the memory M2 has gone up by receiving the reflected light flux from the subject. Since the value of memory M2 exceeds the reference value than the value of memory M2, the value of memory M2 becomes 17. It is stored in the edge value storage means 14 as an upstream edge value.

On the other hand, the read signal generating means 11 operates a timer in synchronization with the start of reading from the CCD line sensor 4, and the time of this timer is T- When Te, the signal of this central pixel is converted into A/]:l by the A/D converter 6 and stored in the center value storage means 15 as a memory value Me. This memory value Me and the memory value M2 stored in the edge value storage means 14 are compared by a difference detection means 16. The output of the difference detection means 16 is manually inputted to the selection signal generation means 17, but when the difference detection means 16 detects Me −M2>0, the output 4a of the CCD line sensor 4 is
As shown in Figure (A), it is determined that the device is compatible with long distance, so at this time, the selection signal generating means 17 outputs the selection signal OUT for long distance.

is sent to the hold circuit 18 of the focus adjustment circuit 8.

Further, when the difference detection means 16 detects Mc-M2-0, the output 4a of the CCD line sensor 4 is as shown in FIG. 4(B).
As shown in the figure, it is judged to be compatible with medium distance, so
At this time, the selection (,1) generation means 17 sends out the middle distance selection signal 0UT2.Then, the difference detection means 16 or M
When e M2 < 0 is detected, it is determined that the output 4a of the CCD line sensor 4 corresponds to a short distance as shown in FIG. Send selection signal 0UT3. In the hold circuit 18, each of the above selection signals OUT, 0UT2゜0
It holds the UT3 and sends corresponding signals to the lens drive circuit 19. Thereby, the lens drive circuit 19 drives the lens drive motor 9 to a focus position corresponding to the distance.

In the A111 distance device of the above embodiment, light is emitted from the two light emitting sections 2a and 2b, and the center of the image formation of the reflected light is made to coincide with the optical axis of the imaging optical system, so that parallax occurs. There is no such thing. Further, by using the CCD line sensor 4, distance measurement can be performed with simple condition judgment.

Next, another embodiment of the present invention will be described.

FIG. 7 is a block diagram of a 7Ill+ distance device showing another embodiment of the present invention. In the distance measuring device of this embodiment, two light receiving elements 24a and 24b are used in place of the CCD line sensor 4 used in the previous embodiment. That is, as shown in FIG. 8, the optical system of the camera to which this embodiment is applied includes two light projectors 22a and 22b and two light projectors located symmetrically across the optical axis of the photographic lens 21. Optical lenses 20a and 20b are arranged, and as in the previous embodiment, the projected light beams from the light projectors 22a and 22b are reflected by the limb photographing object 26 and then enter the camera along the optical axis of the photographing lens. It has become. A first light receiving element -J'24a is arranged on the same optical path as the optical axis of the photographing lens 21 divided by the beam splitter 23,
A second light receiving element 24b is arranged slightly apart from the second light receiving element 24b. III at the front position of the two light receiving elements 24a and 24b.
A visual light cut filter 25 is arranged. The two light projectors 22a and 22b are composed of semiconductor laser diodes, and their light sources are placed at the focal positions of the projector lenses 20a and 20b, so the projected light beam becomes a narrow parallel beam that does not spread far. . The optical axes of the light projecting lenses 20a, 20b are slightly tilted in the direction t'L becomes closer to the 11 as they go farther away, so that the two light beams α projected by the light projectors 22a, 22b. ,β. The cross-sectional shape of is shown in Fig. 9, and in the case of a long distance, there are two light beams α. ,β
. For intermediate distances, the luminous flux α. and β. When the contours of are in contact with each other and at a short distance, there are two luminous fluxes α. and β
. are separated. Therefore, the light reflected from the subject 26 and returned to the vicinity of the light receiving elements 24a and 24b is reflected by the subject 26.
Figure 10 (Δ) when the position is far V11 distance, when it is l+ili distance, and when it is short distance, respectively.
As shown in , (B) and (C), the distribution pattern of the light amount 27 becomes 5゛ (.If you look at the distribution pattern of this reflection light meter 27, at a long distance, the light amount is the largest in the center, and the light amount on the left and right of it is the largest. Because the light intensity in that part is one step lower (10th
(see Figure (8)), in this case the first. Second light receiving element 2
4a and 24b both receive the reflected light, and the amount of light received by the first light receiving element 24a is twice the amount of light received by the second light receiving element 24b. In addition, at intermediate distances, the light amount at the center of the reflected light amount 27 and the light amount on the left and right sides thereof are the same (see FIG. 10 (13)), so in this case, the first light receiving element 2
The amount of light received by the second light receiving element 4a becomes equal to the amount of light received by the second light receiving element 24h. Furthermore, at a short distance, the amount of reflected light 27 does not exist at the center, but there is some light amount on the left and right sides (see FIG. 10(C)), so in this case, there is no output from the first light receiving element 24a, and there is no output from the second light receiving element 27. Only the output of the light receiving element 24b is generated.

In other words, the second light receiving element 24b always receives only one of the two reflected light fluxes and produces an output according to the amount of light received, regardless of the distance, but the first light receiving element 24b
When the object 26 is at a long distance, a is an output corresponding to the received amount of two reflected light beams, when the object 26 is at a medium distance, it is a received light output of one reflected light beam, and when the object 26 is at a short distance, the received light output is zero.

In FIG. 7, the output of the first light receiving element 24a and the output of the second light receiving element 24b are exclusively subtracted by a subtracter 28, and are also led to an adder 29 and added. The subtracter 28 subtracts the second light from the output of the first light receiving element 24a.
When the output of the light receiving element 24b is subtracted, the subtraction a: i2
8 outputs a positive signal in the case of a long distance, a zero signal in the case of a medium distance, or a negative signal in the case of a short distance.

When the output of the first light receiving element 24a and the output of the second light receiving element 24b are added in the adder 29, a larger output signal is obtained from the adder 29 as the distance increases. The output of is adjusted to an appropriate level by a level 1 regulation circuit consisting of an operational amplifier 38, a resistor 39, and a variable resistor 40, and is then given to a light emitting drive circuit 41, and is sent to the light emitting unit based on the oscillation signal from the oscillator 2g42. 22a, 22
The cane of the light emitting drive circuit 41 for blinking is automatically adjusted. Therefore, the closer the subject distance is and the greater the amount of reflected light, the lower the amount of light projected by the light projectors 22a and 22b, and As the amount of reflected light decreases, the amount of light projected by the light projectors 22a and 22b increases to compensate for the difference in amount of reflected light caused by the difference in distance.

The output of the subtracter 28 is sent to a synchronous detection circuit 30 and detected in synchronization with the signal emitted from the oscillator 42, that is, in synchronization with the light projections of the light projection sections 22a and 22b. The signal is held and amplified until it is sufficiently saturated by an amplifier 32 having an extremely large amplification factor. As a result, the output of this amplifier 32 is "+1" when the output of the 1,1-2 subtracter 28 is positive (long distance), "0" when it is zero (medium distance), and "0" when the output of the 1,1-2 subtracter 28 is positive (long distance), Sometimes it becomes "-1" and is input to the non-inverting input terminal of the comparator 33.

On the other hand, when the photographic lens 21 is moved by a lens drive means such as a motor (not shown), a lens position detector 36, which is attached to the photographic lens 21 and is made of known means such as a potentiometer or an encoder, generates a lens position signal. . This lens position signal is
This lens position i & signal is input to the inverting input terminal of the comparator 33 via a, and this lens position i & signal is "+1" when the photographing lens 21 is at the long-distance, middle-distance, and short-distance photographing positions, respectively.
",""0","-1" outputs are sent to the inverted input terminal of the comparator 33.The taking lens 21 is moved from the near side to the far side, and the lens The position signal changes from negative to 11-.Therefore, when the output of the amplifier 32 and the lens position signal become equal, that is, when the photographing lens 21 reaches the in-focus position, the output of the comparator 33 changes from positive to 11-. Flip to page.

The solenoid circuit 34 is in a de-energized state when the output of the comparator 33 is positive, and the lens F'+'+I member 35
The solenoid circuit 3
4 becomes energized, and the lens stop part shrine 35 is held by the holding frame 37.
The photographic lens 21 is stopped by engaging with the upper locking groove 37a.

In this embodiment, since a CCD line sensor is not used, the configuration is simpler and easier to fit than the previous embodiment.

In addition, in all of the above-mentioned embodiments, two
This configuration eliminates parallax by arranging two light projectors and matching the projected light flux pattern with the optical axis of the photographing lens. If the distance device is configured as an external distance measuring type, the configuration shown in FIG. 11 will be obtained. That is, in FIG. 11, the optical axis of the photographing lens 21 and the optical axis of the light-receiving lens 44 are made parallel to each other, and the light-emitting lenses 20a and 2 are connected with the light-receiving lens 44 in between.
0b is arranged with its optical axis tilted as described above, and the light projecting sections 22a and 22b are arranged so that the light source is located at the focal position of the light projecting lenses 20a and 20b. Light receiving lens 4
A first light-receiving element 24a is arranged on the optical axis 1- of the lens 4, and a second light-receiving element 24b is arranged at a distance from the light-receiving element 24a.
is located. Even when the light emitting part and the light receiving part are configured in this way, "-2 Figures 8 to 10 (A) to (C
) can act similarly to that described by ).

In addition, in each of the two examples, long distance and medium distance.

We have explained the structure in which the three-point zone at a close distance is JIIJ distance apart, or the structure is such that the distance between the two reflected light beams can be read in even finer detail using a CCD line sensor or three or more light receiving elements. For example, a highly accurate 711 that can measure distances not only from three points but from multiple points.
11 range devices can be provided.

Furthermore, the number of projection light beams is not limited to two, and more projection light beams may be used.

[Effects of the Invention] As described above, according to the present invention, distance measurement is performed by recognizing the reception pattern of the projected light beam, so that no mechanical servo element or the like is required at all. It is possible to reduce the weight, and to perform high and low range distance measurement with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a distance measuring device according to an embodiment of the present invention; FIG. Figure 3 is a cross-sectional view of the light beam projected by the light projecting unit in Figure 2, according to the distance, and Figures 4 (A) to (C) are the reflected light beams imaged on the CCD line sensor. Figure 5 is a block diagram explaining the function of the microcomputer shown in Figure 1 above, 5 is a flowchart explaining the program operation of the micro convenience store, FIG. 7 is a block diagram of a jPI range device showing another embodiment of the present invention, and FIG. Fig. 9 is a cross-sectional view corresponding to the distance of the light beam projected by the light emitting part in Fig.-1-2 Fig. 8; (A) to (C) are diagrams showing a photoelectric pattern according to each distance of a reflected light beam and the positional relationship of a light receiving element with respect to the same pattern. Figure 11 is a modification of the light projecting part and light receiving part in the d111 distance device. FIG. 2a, 2b, 22a, 22b--Light projecting section (light projecting means) 4... CCD line sensor (light receiving means)
7... Microcomputer (identification means) 24a, 24b... Light receiving element (light receiving means) 28...
...Subtractor (discrimination means) h2 figure %5 figure 7:76 figure

Claims (1)

[Scope of claims] Light projecting means for projecting a plurality of light beams such that the distance between the cross-sectional contours of the plurality of light beams has a predetermined correlation with the distance from the projection position to the subject, and this light projection means a light-receiving means for receiving reflected light from a subject of a projected light flux; and an identification means for identifying a subject distance based on the output of the light-receiving means from the degree of proximity of a plurality of projection patterns formed by projecting the plurality of light fluxes onto the subject; A distance measuring device comprising: and.