JPS6036906A - Photoelectric type distance measuring apparatus - Google Patents

Abstract

PURPOSE:To prevent the wrong result of measurement from being utilized and to enable selection of the most adequate result of measurement by emitting the 2nd signal indicating that the plural results of measurement exist by discriminating the same from the 1st signal indicating that the measurement is substantially infeasible. CONSTITUTION:A difference between the max. value and min. value of a video signal is taken with one or both of both signal trains and detection is made that the distance measurement is infeasible on account of excessively small contrast of the light intensity possessed by an object. Said detection is accomplished in the form of converting the video signal to the pulses having the pulse width indicating the light intensity. The 1st means emits the 1st signal by detecting that the measurement is substantially infeasible. The 2nd means which detects the existence of plural amts. of shifts to attain the max. coincidence of the two video signal trains and emits the 2nd signal indicating such existence is provided. Such detection is accomplished by feeding the read-out pulse to the shift register thereof and counting the number of the logical values outputted successively from the end of the shift register.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that can be incorporated into any optical instrument to measure the distance to an object such as a subject using a combination device of a photoelectric sensor and an electronic circuit.

[Prior art and its problems]

This measuring device has been known for quite some time, but in recent years, new devices have appeared, such as the one disclosed in Japanese Patent Publication No. 57-49884 and others, which is a so-called purely electronic device that has no moving parts within the measuring device. However, it is attracting attention as a compact, inexpensive, and highly accurate distance measuring device.

The principle of this type of device is shown in FIGS. 1 and 2.

In FIG. 1, light emitted by an object 1 whose distance d is to be measured, e.g. the reflected light of sunlight, is connected to a pair of lenses having a short focal length f installed in an optical instrument with a base distance f between them. The light enters small lenses 2 and 3 through two spatially different optical paths 4 and 5, respectively. Object 1 is 2 in the diagram
An image 7.8 of an object having a luminous intensity distribution indicated by the chevrons is imaged by the small lenses 2, 3 onto their common focal plane 6. In this figure, to make the explanation easier to understand, the center of the object 1, and therefore the center IC of its luminous intensity distribution, is shown facing directly in front of the small lens 2.
The center 7C of the image 7 on the focal plane 6 formed by the small lens 2 is located at a position 70, and this image center position 70 does not change dramatically even if the distance d to the object 1 changes. On the other hand, when the distance d to the object 1 is infinite, the center 8C of the image 8 formed by the small lens 3 is at a position 80 on the focal plane 6 directly facing the lens 3, as is easily seen,
As the distance d becomes smaller, the image center 8C shifts to the left in the figure, and when the positional relationship shown in the figure exists, the image center 8C is located at a position 81 on the focal plane 6, which is a distance X away from the original position 80.

Now, on the focal plane 6, there is an optical sensor array 1 at a position where images 7 and 8 of the object 1 are received by the small lens 2°3, respectively.
0.11 is provided. These optical sensor arrays 10
．． 11 generally consists of a mutually different number ri, n of photovoltaic elements or photosensitive resistive elements, each element in the array receiving an electrical signal related to the amount of light it receives, e.g. proportional to the amount of light. is emitted as shown in FIG. 2(a).

Now, if we can measure the distance X of the above-mentioned deviation by some means, then from the principle of simple triangulation, d = b
The distance d to the object 1 can be determined by the formula -f/x.

Now, since the signals output by each element in the optical sensor array 10.11 have analog values as shown in Figures 2(a) and (b), the distribution of output signals along each optical sensor array is as shown in the figure. It has a step-like pattern. Although this analog value may be used as it is to calculate the above-mentioned deviation distance X, it is usually converted into a digital value of 4 in order to simplify the electronic circuit and improve accuracy. The simplest quantization method is to compare the analog value with an appropriate threshold voltage Vt as shown in FIGS. 2(a) and 2(b), and
Similarly, large analog values are @1# and small analog values are 0.
# is converted into a 1-bit digital value as shown in (C) and (d) of the same figure. Next, by comparing the divisions of digital values as shown in FIGS. 2(C) and 2(d) along the sensor array 10.11 of both parties with each other using an electronic circuit, the above-mentioned deviation distance @x can be measured as a value expressed in the number of sensors. Same figure (C)
The distribution of digital values represented by the chain line corresponds to the case where the distance d to the object 1 is infinite and the amount of deviation It can be seen that the result is to calculate the distance X on the optical sensor array expressed by the number of elements.

In the example of FIG. 1, if the optical axis of the finder (not shown) for selecting the object 1 for which the distance d is to be determined coincides with the optical axis of the small lens 2, that is, as described above, the small lens 2
Although the case where the lens directly faces the object 1 has been described, of course the optical axes of the finder and the small lens generally do not coincide. Assuming that the 7-inder is located between the two small lenses 2 and 3, the image 7 on the two-party sensor array 10.11,
8 is the distance X and X! to the right and left respectively from the original position when object 1 is at infinity. The height will fall. However, even in this case, by setting x = *, +xl, the distance d to object 1 can be calculated using the exact same relational expression as above, so that the distance d can be measured using the image on both sensor arrays. There is no difference in that it boils down to calculating the amount of deviation X.

FIG. 3 is a block diagram showing an example of an electronic circuit that measures the above-mentioned deviation amount X expressed in the number of optical sensor elements. Normally, the entire electronic circuit shown including the optical sensor array section is It is integrated on one semiconductor chip. In this FIG. 3, the optical sensor array section 100 indicated by a dashed line includes a left optical sensor array 100L and a right original sensor array 100B.
A quantization circuit 20 receives the light of the image formed by the aforementioned small lens and converts the photoelectric output signal into a quantization circuit 20.
A)-log ψ digital converter (hereinafter referred to as A) on the left in 0
(referred to as DC) 300L and ADC 300L on the right as shown by the arrows in the figure.

This signal transmission serially transmits the output signal of each photosensor element to A.
Sometimes it is sent to DC, sometimes it is sent in parallel. In these ADCs 300L and 300R, the analog signal from each photosensor element is converted into a digital value of 1 bit or a desired number of bits, and then stored in the attached register 40.
Send it to 0L and 400B and store it. These registers may be, for example, shift registers, which have the same number of stages as the photosensor arrays 100L, 100R and which store the quantized digital light in the same order as the light intensity distribution in the image entering the photosensor array. If the output of the aforementioned ADC, in which the value is stored, is multi-bit, then
The above-mentioned shift register is constructed by arranging, for example, binary shift registers in parallel for the number of signal bits. At this stage, the distribution of digital values is shifted by the number of shift register stages corresponding to the shift amount X between the left and right images received by the optical sensor arrays 100L and 100R, and the shift register 40OL
, 400 liters are stored.

In order to find the number of stages of deviation in the digital value distribution in the shift register corresponding to the above-mentioned deviation Jix, the distance detection circuit 5
00 is set. Initially both left and right registers 400L,
The digital value stored in 400R is sent to the comparator circuit 600 and stored in the left and right registers for each stage of the shift register. The control pulse CP stored in both registers 400 and 400
L.

After the digital storage value in one of the 400 registers is shifted by one stage relative to the other, the comparison circuit 600 checks whether the digital values in both registers match or differ in each stage in the same manner as described above. When the number of matches is greater than the previous number of matches stored in the comparison result storage circuit 700, the number of matches stored in the comparison result storage circuit 700 is rewritten to a new number of matches, and the distance signal is calculated. A pulse is sent to a counter in circuit 800 causing it to add one to its stored value, which was initially reset to zero. Similarly, both registers 800L and 800R are controlled by the control pulse CP from the central control circuit 900.
The digital values inside are shifted by one stage and compared. However, if the new number of matches is smaller than the number of matches stored in the comparison result storage circuit 700, the stored value of the number of matches is The distance signal calculation circuit 800 is not updated and the distance signal calculation circuit 800
It is not added to the counter inside either. After the above-mentioned comparison is made a predetermined number of times in this way, the count value remaining in the counter in the distance signal calculation circuit is the one that best represents the distribution of digit values originally stored in both registers. This indicates the number of stages of deviation necessary for good matching, and the number xn of optical sensors corresponding to the amount of deviation X that can be requested is calculated.

The distance M signal calculation circuit 800 calculates the amount of deviation X or the final distance d based on the optical sensor converted deviation number xn.
is calculated based on a predetermined formula, a distance signal is sent out in response to a distance signal read pulse from the central control circuit 900, and the central control circuit 900 sends out this distance signal to the outside in response to a call from an external device. .

The distance measuring device constructed as described above, which is a purely electronic type with no moving parts, is gaining popularity due to its small size, low cost, and high distance measurement accuracy, but when you actually see the device in operation, However, it was found that there were various problems.

One of these cases is that the brightness of the object whose distance is to be measured is low, for example, when it takes a negative EY value.In this case, the optical sensor array 10.11 in FIG. , 100RK Since the amount of light coming in is small,
The output signal value from each photosensor in the array is so low that it does not reach the threshold value Vt for signal quantization shown in FIG. This means that the results of distance measurements using digital signal values that have been detected cannot be fully trusted. This issue could be solved by using an optical signal accumulation type sensor as the optical sensor, but since it takes time to accumulate the signal, it is difficult to capture images over long distances, such as in a video camera, where the field of view of the camera is moved while capturing images. If the measurement takes time, the measurement becomes meaningless and cannot be applied at all. Therefore, if an image is taken without keeping the distance measurement time within the necessary limit, the image will be taken under incorrect focusing conditions based on the wrong distance measurement result, and the taken image will be blurred.

On the other hand, even if the object is bright enough, if there is almost no contrast between light and dark within the object, it will be difficult to measure distance even from the measurement principle described above, and if there is no contrast at all, it will be difficult to measure the distance. becomes impossible. In such a case, no matter what threshold value is used to quantize the output signal of the optical sensor,
This is because the pattern of digital signal values necessary for distance measurement cannot be obtained.

On the other hand, even when the object is very bright, errors may occur in the distance measurement results. The difference between light and dark in the field of view of a camera is generally very large, and the brightness in bright areas is often 106 times the brightness in dark areas, so it is difficult to vary the threshold for quantization over such a wide range. Have difficulty. When an object is very bright, even if there is a contrast between light and dark inside it, most of the contrast exceeds the threshold for quantization, and no information about the contrast between light and dark can be obtained or the information is lost. It may become extremely small.

In either case, the digital output from the ADC 300 in Figure 3 will have insufficient pattern information of "0" and "1#," and no matter how accurately the digital circuit operates, the distance measurement results obtained will be Becomes uncertain.ADC
Attempts have been made to increase the amount of light and dark pattern information by converting the output into not only 1-bit information but also multi-bit information. No M effect.

In addition, if two or more objects at different distances enter the field of view of the optical sensor array, or if the object has a regular light and dark pattern, such as a striped or checkered pattern, the digital circuit will Distance measurement data is output by faithfully searching for the point where the pattern information from the sensor array matches the maximum, so there may be cases where there are multiple distance measurement results, and it is not possible to determine which measurement data should be the correct result. It turns out to be a problem.

[Purpose of the invention]

The purpose of the present invention is to provide a method for measuring distances even when the properties of the object to be measured are not suitable for distance measurement and sufficient measurement data cannot be obtained, or when multiple pieces of measurement data can be obtained.
The purpose is to prevent erroneous measurement results from being used and to enable the selection of the most reasonable measurement results.

[Key points of the invention]

In order to achieve the above object based on the drawbacks of the prior art described above, the present invention organizes the problems of the prior art and takes countermeasures against them.

The first is that the optical properties of the target object, such as being very dark or lacking contrast, are inherently unsuitable for distance measurement, and therefore distance measurement is virtually impossible. There are cases.

In such a case, even if distance measurement is impossible, it is necessary to at least notify the optical instrument or equipment that uses the distance measurement results. In order to detect such a situation, the present invention particularly utilizes video signal sequences emitted by a pair of optical sensor arrays that receive images of objects. The video signal sequence used for this detection may be the signal itself emitted by the optical sensor, or may be a signal obtained by quantizing the signal. In order to detect that it is virtually impossible to measure from such a signal train, it is advantageous to focus on the maximum video signal value and minimum signal value in the signal train, rather than taking the average value of the signal train. be. If the maximum video signal value in both signal trains does not reach the required predetermined value in one or both of the signal trains, measurement is essentially impossible, so it is determined that measurement is not possible from the maximum video signal value. It can be detected, and conversely, it is possible to avoid the risk of determining that measurement is not possible when measurement is possible. By taking the difference between the maximum value and the minimum value of the video signal for one or both of the signal sequences, it is possible to detect that the contrast of the light intensity of the object is too low to make distance measurement possible. Furthermore, although it is possible to easily find such maximum and minimum values by using the video signal values after digitization, it is possible to easily find the maximum and minimum values by using a pulse having a pulse width that represents each video signal in the optical intensity layer. It is advantageous to do this in a converted form. The maximum and minimum values of such pulse width can be found using a simple OR gate or AND gate. Furthermore, it is advantageous to make this pulse width especially inversely proportional so that it decreases with increasing video signal. As a result, even if there is a variation of several orders of magnitude in the light intensity distribution of an image, such variation can be contained within a relatively small pulse width range, and the logic gate described above can reduce the pulse width within a short time. This is because the length can be accurately determined. First in the present invention
The means detect that such a measurement is substantially impossible and emit a first signal.

Next, the present invention includes second means for detecting the existence of a plurality of shift amounts that maximize the coincidence of two video signal streams and issuing a second signal to that effect.

This second method deals with cases where even if the first method described above cannot detect the object, multiple distance measurement results still occur due to the optical properties of the target object, and the results are therefore uncertain. This is the case. In this case, just because the results are uncertain does not mean that they are not immediately available. Depending on the purpose of using distance measurement, it is often sufficient to select a result suitable for the purpose from a plurality of distance measurement results, for example, the shortest distance among the results. Therefore, in the present invention, a second signal indicating that a plurality of measurement results exist is issued separately from the above-mentioned first signal.

Optical instruments and users who use distance measurement results should
Since it is possible to know a plurality of measurement results together with the second signal, it is possible to select and use the result that best suits the purpose from among the plurality of measurement results based on the second signal. It is advantageous to use a shift register to detect the existence of a plurality of measurement results. Since the degree of coincidence between two video signal streams is measured for various amounts of shift, a shift register with the same number of stages as the amount of shift used to test the degree of coincidence is provided, and the shift register is set to correspond to the amount of shift for which the maximum match is obtained. A logical value indicating that the maximum match has been obtained, for example, "1#, can be stored in the stage with the number corresponding to the maximum match. Detection of the existence of multiple maximum matches can be done by sending a read pulse to this shift register. This can be done by counting the number of the above-mentioned logical values successively output from the end of the shift register.Furthermore, in this case, the plurality of maximum matching deviation amounts, that is, the plurality of measurement results are successively determined by the misalignment amount. It is advantageous to detect whether these two values are present or whether they are present discontinuously with respect to mutually spaced displacement amounts.

Optical instruments and users can select and use the result that best matches their purpose from multiple measurement results based on the signal indicating the existence of multiple measurement results and the signal indicating whether the distribution is continuous or discontinuous. can.

As described above, by emitting the second signal indicating that there are multiple measurement results separately from the first signal indicating that measurement is virtually impossible, it is possible to measure distance using only one type of signal. Even in cases where opportunities would otherwise be lost, it is possible to increase the chances that measurement results will be used.

[Embodiments of the invention]

In order to describe the embodiments of the present invention in detail below, the main points of the digital circuit according to the present invention for calculating distance measurement data will first be explained with reference to FIG.

FIG. 4 shows the portion after register 400 in FIG. 3, and in this embodiment, it is configured as a shift register through which digital values pass, rather than a register that stores digital values.

The shift register 410 in the figure corresponds to the register 400L on the left side of FIG. The digitized object turn information data from the ADC 300L in FIG. 3 is serially input. The digital values input in this way are sequentially shifted to the left in the diagram, but from stage 41m to stage 41m.
From the stages up to n (referred to as n)m), the digital values in the stages are output in parallel as shown.

As can be easily seen, the number of such parallel outputs is n-m+1. On the other hand, the other shift register 420 is composed of m stages 421 to 42m in this embodiment. The pattern information data is input serially and is successively shifted to the left stage in the diagram. The output from this shift register 420 is serially output only from the final stage 42m.

Stages 41m to 41n of the shift register 410 described above
The nm+1 parallel output data from the shift register 420 and the serial output data from the final stage 42m of the shift register 420 are sent to the comparison circuit group 600, where they are compared with each other simultaneously in parallel. This comparison circuit group 600 is n-
It consists of m+1 comparison circuits 60m to 60n, and as shown in FIG.
and a counter 630, respectively. For example, the exclusion of the comparator circuit 60 i (i=m−n)
The SIBNOOR gate 610 inputs the data from the stage 41 f (i = rn-n) of the shift register 410.
and data E2 from the stage 42m of the shift register 420 are input, and output "1" is generated only when both data match.This output passes through the OR gate 620 and increments the counter 630 by one. The operation is -3rd
The digitized image pattern data from the ADCs 300L and 300R shown in the figure is input into shift registers 410 and 420 in synchronization with each other, and from the time when the first data reaches stages 41m and 42m, respectively, is carried out sequentially until the data reaches the stage 41n of the shift register □410, and each comparator circuit 6
The counter 630 from 0m to 60n contains input data Il to the exclusive Noah circuit.

The number of times I2 matches is stored as a count value. As can be easily seen, the comparison circuit 60m compares the digital pattern data of the images received by the optical sensor arrays 100L and 100R in FIG. to the left,
A matching circuit when the right video data is compared with a deviation of O is stored.

Similarly, the counter 630 in the comparison circuit one to the left of the comparison circuits 60m is the number of matches when the left and right video data are compared with a deviation of 1, and the counter 630 in the last comparison circuit 60n is the number of matches between the left and right video data. The number of matches when the video data is compared after being shifted by n−m optical sensors is stored. According to the above, each counter 630 of the comparison circuits 60m to 60n receives left and right video data from 0 to n-m.
The number of matches of n-m+1 M pieces of data, which are compared with each other while being shifted from each other, is stored.

As described above, the comparison results in which the left and right video data are shifted by 0 to nm are obtained, and the number of shifts at which the maximum number of matches is stored in the comparison results is then found. Therefore, the read clock pulse P62 from the timing control circuit 910 in FIG. 4, which corresponds to the central control circuit 900 in FIG.
60n or gates 620 all at once. Of course, each counter 630 has a sufficient number of stages to store the maximum number of matching results of the above-mentioned comparison results, and although the above-mentioned stored contents have not reached the point where the final stage overflows, the NOR gate 62
The read clock pulse P62 passing through 0 causes the count value to overflow from the counter 630, which had stored the maximum number of matches, and the carry output terminal of the counter shown in FIG. A carry output C is generated from.

The carry output C from the counter 630 of each comparison circuit 60m to 6On is input in parallel to the stages 70m to 70n of the nm+1 stage shift register 700 in FIG. 4, which corresponds to the comparison result storage circuit 700 in FIG. 3. is recorded and memorized.

Further, the output C from each counter 630 is output from the OR gate 650.
is also input in parallel as shown in the figure, and the OR gate 650
When a carry output is generated from any one of the counters 630, the gate is opened and the timing control circuit 910 is notified of this fact. When the timing control circuit 910 learns that this carry output has been issued, it immediately stops issuing the read clock pulse P62. As a result, the increment of each counter 630 stops at 1 and no further carry output is generated, so that the shift register 7
Only the stage corresponding to the counter 630 that has stored the maximum number of matches in 00 will store a carry output of, for example, 1''.Of course, if there are two or more counters 630 that have stored the maximum number of matches, , correspondingly, a plurality of stages in the shift register 700 have a logic value of "1".
” will be memorized.

In this embodiment, the distance signal calculation circuit 800 is configured as a simple counter, and is incremented by a count clock pulse P80 from a timing control circuit 910, and a shift register 7 synchronized with the pulse P80.
By the read shift pulse P70 given to 00,
If even one logical value 1 is output from stage 70m of shift register 700, stepping is immediately stopped. As a result, the counter 800 stores the number of deviations that indicate the maximum match between the left and right video data. This stored value is read by the central control circuit 900 in FIG. 3, by the timing control circuit 910 in this embodiment, and outputted to the outside as a distance signal. However, as can be seen from the above explanation, even if the shift register 700 stores the logical value ``1#'' indicating the maximum match in the digit number stages,
The smallest number of deviations among them will be output as a distance signal.

In the circuit for calculating the distance signal as described above, the distance double voltage signal may become uncertain due to various reasons as described above. Hereinafter, embodiments of the present invention will be described in detail for each factor that makes the distance signal uncertain. In the following examples, the first means is shown in FIGS. 8 to 10, and the second means is shown in FIG. 11, and the first means is shown in FIGS. Among the signals emitted by the second means, DA, I)B, DC and DD indicate the first signal, and DE, DF and DG indicate the second signal.

FIG. 6 shows the distance measuring device according to the present invention at 7' when the power is turned on.
C is a circuit that detects uncertainty in a distance signal that occurs directly. When the power switch 951 shown in the figure is turned on, the voltage of the power source S is applied to an integrating circuit composed of a resistor 952 and a capacitor 953, and The potential V at the connection point with the capacitor 953 increases as shown by V in FIG. The potential ■ is input to the inverter 954 used as a threshold element, and the output S of the inverter 954 is
As shown in FIG. 7, the signal S remains 0 after the potential V becomes larger than the threshold value Vth of the inverter 954. Furthermore, the signal S is input to a one-shot circuit 955 that outputs a pulse at the falling edge of the input. Therefore, the output St of the one-shot circuit 955 becomes as shown in FIG. 7.Output S2
is further input to the set terminal S of the flip-flop 956, so the output DA of the flip-flop 956 becomes "1#" when the output potential V of the integrating circuit reaches the threshold voltage vth of the inverter 954. The distance measuring circuit is activated by the signal S! to start the measuring operation, and when the measuring operation is completed, the timing control circuit 910 sends a CL signal whose waveform is shown in FIG. When the signal is sent, the output DA of the 7 lip-flop 956 becomes 10#.In other words, the output DA of the 7-lip flop 956 is "1", which means that the distance measuring circuit is performing a measurement operation, but the measurement result is not reliable. This shows that.

Next, an embodiment of the present invention will be described for a case where it is practically impossible to measure the distance due to the optical conditions of the object. FIG. 8 shows a specific circuit of an embodiment of the present invention, which corresponds to one optical sensor in the optical sensor array 100 in FIG. 3 and one conversion element in the ADC 300. In this example, the optical sensor is a photodiode. 110. In the figure, a photodiode 110 converts a weak amount of incident light into a strong or weak photocurrent i. Photocurrent i is capacitor 12
0, and the output voltage VC of the capacitor 120 rises with a slope corresponding to the magnitude of the photocurrent i, as shown in FIG. The capacitor voltage VC is input to an inverter 150 used as a threshold element, and the output Q of the inverter 150 is supplied to the discharge transistor 130 by a reset pulse PIO whose waveform is shown in FIG. 9 from the timing control circuit 910. When the voltage is sent, it is 1'', and when the capacitor voltage VC reaches the threshold value vth of the inverter 150, it becomes 10''. The width tm7)f of this pulse of the output Q of the inverter group 50 is a signal representing the light intensity (tm7)
il: is almost inversely proportional to L. In other words, the optical sensor circuit shown in FIG. 8 starts measuring the light intensity upon receiving the beam set noculus PIO, and outputs a pulse Q having a pulse width tm representing the light intensity.

Of course, the output from the optical sensor is input to a signal converter 300 as shown in FIG. 3, and is converted into a digital value by an image deheater.

Now, FIG. 10 and FIG. 11 are circuits for detecting a malfunction in the output Q of such an optical sensor. Similarly, n photosensors 101R to 10mL constitute the right photosensor array 100R.
10n liters are each shown. These optical sensors start measuring the light intensity all at once upon receiving the above-mentioned reset pulse P10, and output pulses Q having a pulse width (representing the respective light intensities). The inverter groups 961L to 96 m L and the right inverter groups 961R to 96 n RK (-reso input are input.Furthermore, the outputs of the left inverter 961L to 96 mL are input to the left AND gate 97AL and the left inverter group 961R to 96 n RK. or game) is input in parallel to 970L, and similarly the right input/(
-The output of 961~96nR is the ant game on the right) 9
7AR and the right or game) are input in parallel to 970B.

As can be easily seen, the output AL of the left AND gate 97AL is the inverted waveform of the one with the longest pulse width among the output pulses Q from the left photosensor group 101L to 1QmL, and The output OL of the 970L has an inverted waveform with the shortest pulse width. Similarly, the output AR of the right AND gate 97AR is the inverted waveform of the longest pulse width among the output signals Q from the right photosensor group 101~10nR, and The output of the 970R is an inverted waveform with the shortest pulse width.

The outputs AL, AR of these AND gates and the outputs OL, OR of the OR gates are input to the circuit of FIG. 11 as shown. In the circuit of FIG. 11, the signals OL and O
R is ORed by OR gate 981 and input to timer 982 . From the above explanation, the time from when the optical sensor arrays 100L and 100R start operating by the reset pulse PIO until the output of the OR gate 981 becomes 1'' is the optical sensor arrays 101L to 10mL, 101
It will be easily understood that the response time is the same as the shortest response time within R to 10 nR, that is, the time tmO until the output Q is output. If the timer 982 is configured to start its timing operation using the reset pulse PIO described above and stop its operation based on the output of the OR gate 981, the shortest pulse width tm described above will exceed a predetermined value. timer 9
82 issues an output DB. Now, the width tm is the 8th
Since the output DB from the timer 982 is almost inversely proportional to the light intensity in the optical sensor circuit shown in the figure, the output DB from the optical sensor 101 is approximately inversely proportional to the light intensity.
This means that even the strongest light intensity received by L~10mL and l0IR~10nR is weaker than the predetermined light intensity. On the other hand, the signal AL and the signal are input to the Nantes gate 983. In the same manner as described above, this Nantes Gate 983
The time when the output is 11# is the time when the output of optical sensor 101L~10m
It is the same as the one with the longest response time among the outputs Q from L, 101R to 10nR. Furthermore, since the output of this Nant gate 983 and the output of the above-mentioned OR gate 981 are ANDed by the AND gate 984, the time when the output of this AND gate 984 is 'l#' is the time when the optical sensor l
It is equal to the difference between the longest response time and the shortest response time among the outputs Q from 0IL to 10mL and 101 to 10nR. In this embodiment, the duration of the output of the AND gate 984 is regarded as representative of the contrast of the image of the object, and the output of the AND gate 984 is converted to
When the duration of the output of the AND gate 984 is less than a predetermined value, that is, the contrast in the image of the object is less than a predetermined value, and the distance measuring operation is difficult. Sometimes, the timer 985 is caused to generate an output signal DC.

The circuit shown in the lower part of FIG. 11 is for detecting a case where there is an extreme difference in the light intensity of two objects that fall within the field of view of the optical sensor array. As shown, the signal OR is inverted by an inverter 986 and ANDed with the signal AL by an AND gate 987. The signal AL is set to 0'# by the reset pulse PIO, and the left optical sensor l0I
J, -10mL, only when the one with the longest response time responds, that is, when all the left photosensors respond, returns to ``1#'', and the inverted signal of the signal OR is reset by the reset pulse P10. “1#tonashi, right optical sensor 1
When the one with the shortest response time among 01 to 10n responds, that is, if any one of the right photosensors responds, it becomes 0'', so the AND gate 987
The output signal is output from the left optical sensor 101L to 10.
This means that none of the right photosensors 101 to 10n responded even though all of the mL responded. That is, in the output of the AND gate 987, the light intensity of the image of the object received by the left photosensor array 100L is extremely strong compared to the light intensity received by the right photosensor array 1ooR, and distance measurement operation is virtually impossible. It means something. Similarly, as shown, the signal AR and the inverter 98
The fact that the AND gate 989 which takes an AND with the inverted signal of the signal OL by 8 and outputs an output means that the light intensity received by the right photosensor array 100 is the same as that of the left original sensor array 100.
The light intensity received by L is also extremely strong, meaning that distance measurement is virtually impossible. Note that when the AND gate 987 or 989 outputs an output, the OR gate 990 opens and the slip 70 that was reset by the reset pulse PIO
Set ';'991 to output signal DD. The output of such a signal DD is generated not only when there is an extreme difference in the light intensity of two objects in the field of view of the optical sensor array as described above, but also when there is a
It is also useful for detecting cases where the optical system is accidentally covered, such as when the optical system is accidentally closed.

Next, FIG. 12 shows a circuit for detecting that a logical value indicating the maximum coincidence of left and right images is stored in a plurality of stages of the shift register 700 in the distance measuring circuit system of FIG. 4 described above. . In such a case, it means that there are multiple conclusions that the distance measurement circuit has calculated as the correct distance, and it is naturally impossible to select which one is the true one within the distance measurement circuit, but the distance measurement result It is necessary for the optical instrument and the user to make a selection based on some kind of separate judgment, such as adjusting the focus of the camera using the . but,
The fact that there are multiple measurement results requires that the optical instrument or user receiving the distance signal be at least informed of the fact that there are multiple measurement results. The longest distance among the measurement results,
Alternatively, outputting only the shortest distance as a measurement result is obviously insufficient.

The circuit shown in Figure 12 is designed to not only detect the presence of a plurality of Shoichi constant connections, but also to detect the condition of their distribution. In the figure, °100 is the shift register shown in Figure 4, and the reading is IJjL shift pulse P.
The memory contents therein are read out from the right side by 70, and the oak shown in FIG.
output to the printer 800. Figure 7 Lip Flop 100
1 receives the output from the shift register 700, and is set when the logical value "1" stored in a certain stage is output.The next shift register 70
When the output from 0 becomes the logical value “O#”, the inverter 10
If the AND condition of the AND gate 1003 is satisfied between this inverted output from 02 and the output of the flip-flop 1ooi, and the output becomes 1#, the next 7 lip 70 block 1004
Set. Thereafter, when the output of the shift V distaff 00 becomes 11" again, the AND condition of the ant game) 1005 is satisfied, and the next 7 lip-flops 1006 are further set by the output "1#. From the above, the fact that the output of the last 7 rib flop 1006 becomes "1#" means that a plurality of "1#" are stored in the shift register 700 and "0" exists between them, that is, a plurality of distances This means that measurement results exist, and they exist discontinuously. Note that in the above explanation, flip-flop 1
001.1004 and 1006 are all reset in advance before accepting the output signal from the shift register.

Furthermore, the counter 1007 in FIG. 12 calculates how many "1"s are stored in the shift register 700
This is a binary counter that counts how many distance measurement results there are. When the count value reaches 2, the output terminal Q1 becomes "l#".
Then, set the flip-flop 1008. Further, when the count value reaches 4, the output terminal Q2 of the next stage becomes "1" and the Noritsubu flop 1009 is set. The output of this 7-rib flop 1009 is a signal DG, and this signal DG means that there are four or more distance measurement results. In addition, 1010 in the figure is the above-mentioned flip 7.
Since the inverted output from the inverter 1011 of the 0tt pump 1006, the output of the flip-flop 1008, and the inverted signal of the signal DG from the inverter 1012 are input, the output signal DE of the ANDG 1010 is used for distance measurement. The result is 2
(output of 7 lip 70 tube 1008) less than 4 (output of 7 lip 70 tube 1008)
7 rip 70 knob 1009) and the distance measurement results are continuous (inverted output of flip 70 knob 1006). Similarly, and gate 101
3 takes the AND condition of the output of the flip 70 knob 1006, the output of the clip flop 1008, and the inverted output of the 7 flip 70 knob 1009, so the output DF is such that the distance measurement results are 2 or more and less than 4. This also means that the distance and line measurement results are discontinuous (output of flip 70 knob 1006).

Information indicating the existence of a plurality of distance measurement results as described above can be used in a simple manner. For example, when using distance measurement results for focusing a camera, if there are four or more measurement results, the measurement results are considered completely unreliable.
1-Attr)Pit8'n(?FrshiIm+1-SLL-L-L) The fact that the distance measurement is uncertain can be displayed in the viewfinder of the camera by known means to notify the user. If there are two or more distance measurement results but less than four, that is, two or three, it is possible to decide which signal to use for automatic focusing based on the properties of the optical instrument.For example: If there are two measurement results and they are consecutive, focus on the closest distance, and if there are three measurement results and they are consecutive, focus on the center distance of the three. In addition, if two measurement results are discontinuous, it is also possible to match the distance to the one closest to the middle of the surface measurement results. This can vary depending on the optical characteristics of the device and the user's purpose of use, and it is easy to predetermine it according to the characteristics and purpose.In addition, when there are multiple distance estimation results, It is needless to say that the method of presenting the information does not have to be in the manner described above, and can be appropriately selected and configured by those skilled in the art within the scope of the present invention.

〔Effect of the invention〕

As explained above, in the present invention, the light emitted by the object whose distance is to be measured is received via two spatially different optical paths, and the imaged image is captured by one optical sensor, each consisting of a plurality of optical sensors. producing two video signal sequences representing the light intensity distribution within the image received by the paired optical sensor array;
A photoelectric distance measuring device that sequentially compares the two video signal sequences while shifting them in a quantized state and measures the distance to the object from the amount of shift when the two video signal sequences reach a maximum match. a first means for detecting a condition in which distance measurement is virtually impossible from the video signal strings and emitting a first signal to that effect; and a plurality of shift amounts for maximally matching both video signal strings. A second means for detecting this and emitting a second signal to that effect is provided, so that erroneous measurements can be avoided when the optical properties of the object whose distance is to be measured are inherently unsuitable for distance measurement. It is possible to prevent the results from being used, and also when it is difficult to measure distances, such as when multiple measurement results are generated due to the optical properties of the object, the second method can be used.
Based on the signal, it is possible to select and use the most appropriate measurement result from a plurality of measurement results. In particular, the second signal indicating that there are multiple measurement results is emitted separately from the first signal indicating that measurement is virtually impossible, so it is difficult to measure distance with only one type of signal. This has the effect of increasing the chances that the measurement results will be used even if the opportunity is lost.

[Brief explanation of the drawing]

Figures 1 to 3 all show the conventional technology, and Figure 1 is an explanatory diagram of the principle of a photoelectric distance measuring device. Figure 2 is an explanatory diagram of the quantization method of an analog signal from an optical sensor array. FIG. 3 is a block diagram showing the overall configuration of the photoelectric distance measuring device. 4 to 12 all show embodiments of the present invention,
Internal Temperature Figure 4 is a block diagram showing the main parts of the distance measuring circuit of the photoelectric distance measuring device according to the present invention, Figure 5 is a circuit diagram showing one specific circuit of the comparison circuits 60m to 60H in Figure 4,
FIG. 6 is a circuit diagram for emitting the first signal DA immediately after power is turned on as a first means, FIG. 7 is a waveform diagram for explaining the operation of the circuit shown in FIG. 6, and FIG. One optical sensor in the optical sensor array (photosensors 101L~10mL, 101R~ shown in FIG. 10) as part of the means for
9th circuit diagram showing a specific circuit example of 10nR)
The figure is a waveform diagram for explaining the operation of the circuit shown in Figure 8.
Figure 0 is a circuit diagram of a specific circuit for detecting a condition in which distance measurement due to an image of an object is virtually impossible as the first means, and Figure 11 shows a detection signal from the circuit in Figure 10. FIG. 12 is a circuit diagram showing an example of a specific circuit that receives the signals and emits the first signals DB, DC, and DD. FIG. FIG. 2 is a circuit diagram of a specific example of a circuit that emits DF and DG. In the figure, 100:L, 10oR: optical sensor array, 10ii, -10mL, 101R~10nR
: Optical sensor, 300.300L, aoog: Analog-to-digital converter for quantizing video signals, 400L, 4
00 几, 410, 420: Shift register as a register for storing the converted video signal string, 600: Comparison circuit group for comparing two video signal strings, 60m'-6On
: Comparison circuit, 610: Exclusive no-go for detecting coincidence of video signals, 630: Counter for storing the number of coincidences of video signals in two video signal sequences, 700: 2
Shift registers 97AL, 97AR for storing the amount of shift that makes the video signal sequences match at the maximum; AND gate 970L for detecting the maximum value in the video signal. 970L: OR gate that detects the minimum value in the video signal,
1006: Flip 70 tab for storing that a plurality of measurement results exist and have occurred discontinuously; 1007: Counter for counting the number of measurement results; DA, DB;
DC, DD: first signals; DB, DF, DG: second signals. Continued from page 1 0 Inventor Takashi Nishibe Inside Yokosuka Train Board 2

Claims (1)

[Scope of Claims] An imaged image is received by a pair of optical sensor arrays each consisting of a plurality of optical sensors to produce two image signal sequences representing the light intensity distribution within the image, and both At least the two video signal trains are sequentially compared while mutually shifting the video signal trains in a quantized state, and the distance to the object is measured from the amount of shift when both video signal trains reach maximum agreement. a first means for detecting a condition in which it is virtually impossible to measure a distance from the source and emitting a first signal to that effect; and second means for emitting a second signal to that effect. 2. In the device described in claim 1, the first means detects the video signal value corresponding to the maximum light intensity in the video for each of the two video signal trains, and detects the video signal value corresponding to the maximum light intensity in the video, and On the other hand, a photoelectric distance measuring device characterized in that it is configured to emit a first signal when the video signal value does not reach a predetermined value. 3) In the device described in claim 1, the first means detects the video signal value corresponding to the maximum light intensity in the video for each of the two video signal trains, and the A photoelectric distance measuring device characterized in that it is configured to emit a first signal when none of the video signal values reach a predetermined value. 4) Percentage Allowance In the device described in claim 1, the first means detects the maximum value and minimum value of the video signal in two video signal streams, and detects the difference between the maximum value and the minimum value. A photoelectric distance measuring device characterized in that it is configured to emit a first signal when the distance does not reach a predetermined value. 5) In the device described in claim 1, the first means detects the maximum value and the minimum value of the video signal in each of the two video signal trains, and detects the maximum value and the minimum value of the video signal in each of the two video signal trains. A photoelectric distance measuring device, characterized in that it is configured to emit a first signal when the difference between the maximum value and the minimum value of the video signal does not reach a predetermined value for either one of the video signals. 6) Percentage Allowance In the device described in claim 1, the first means detects the maximum value and minimum value of the video signal in each of the two video signal trains. A photoelectric distance measuring device configured to emit a first signal when the maximum value of the video signal in one video signal train does not reach the minimum value of the video signal in the other video signal train. . 7) In the product according to any one of claims 2 to 6, each video signal in the video signal train represents light intensity and is converted into a pulse having a width of 1 Kurzi and whose starting point is synchronized. A photoelectric distance measuring device characterized in that the maximum value or the minimum value of the video signal in the video i-sequence is detected by a logic gate that detects the end point of the noculus. 8) In what is stated in claim 7. Each video signal in the video signal train is converted into a pulse whose pulse width decreases as the light intensity increases, and the earliest end of the pulse is detected by an OR gate. 1. A photoelectric distance measuring device characterized in that the minimum value of a video signal in a video signal is detected by detecting the maximum value of the video signal and detecting the latest end of the pulse using an AND gate. 9) In any one of claims 2 to 6, when each video signal in the video signal train is quantized, the maximum value of the video signal in the video signal train or A photoelectric distance measuring device characterized in that a minimum value is detected. 10) In the thing described in claim 1, the first
A photoelectric distance measuring device, characterized in that the means detects power-on to the distance measuring device and is configured to emit the first signal during at least one distance measuring operation cycle from the power-on. 11) In the thing described in claim 1, the first
A photoelectric distance measuring device characterized in that the transmission of a distance signal from the distance measuring device is stopped by the first signal emitted by the means. 12. In the thing described in claim 1. The second means is configured to detect that the amount of shift that makes the two video signal sequences match at most is greater than or equal to a first predetermined value and less than a second predetermined value, and to issue a second signal to that effect. A photoelectric distance measuring device characterized by: 13) The photoelectric distance measuring device according to claim 12, wherein the first predetermined value is two and the second predetermined value is four. 14) % allowance In the thing described in claim 1, the second
The photoelectric device is characterized in that the means is configured to detect that a plurality of shift amounts for maximally matching two video signal sequences occur discontinuously, and to issue a second signal to that effect. type distance measuring device. 15) Percentage Permissible In the thing described in claim 1. The second means is configured to detect that a plurality of shift amounts that bring the two video signal sequences to the maximum match are successively occurring, and to issue a second signal to that effect. Photoelectric distance measuring device. 16) Range of % tolerance requirement In the item described in item 1, the second
17) Claims A photoelectric distance measuring device according to item 16, characterized in that the number of predetermined values is four. 18) The photoelectric distance measuring device according to claim 16, characterized in that the sending of the distance signal from the distance measuring device is stopped by the second signal emitted by the second means. . 19) In the thing described in claim 1, both signals of a shift register have a logical value indicating that the two video signal sequences are in maximum agreement, and the number of stages corresponds to the shift amount for mutually comparing both signal sequences. The first means counts or stores the logical values that are successively applied from the shift register in response to readout pulses, and stores the logic values in a stage corresponding to the amount of shift that makes the columns coincide with each other to the maximum. A photoelectric distance measuring device characterized in that the photoelectric distance measuring device is configured to detect the existence of a plurality of displacement amounts.