JPH0326768B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a distance measuring device used, for example, as a distance measuring device for a camera equipped with an automatic focusing device. The present invention relates to a distance measuring device that receives light with a pair of light-receiving element arrays arranged in a row, and calculates the distance to a measurement target from the correlation of the outputs of both light-receiving element arrays.

[Prior art]

2. Description of the Related Art As conventional distance measuring devices as described above, those shown in FIGS. 1 to 3 are known.

Figure 1 is a schematic plan view of the configuration of the device that projects an image in the ranging direction onto a pair of photodetector arrays, and Figure 2 detects the phase where the arrangement patterns of the photodetector outputs of the pair of photodetector arrays most match. FIG. 3 is a block circuit diagram for digitizing the output of the light receiving element.

In FIG. 1, images in the distance measurement direction I are projected by lenses 1 and 2, respectively, onto a pair of light-receiving element arrays 3 and 4 arranged side by side with a certain distance d between them. Here, the constant distance d is the distance between the light-receiving elements in the light-receiving element arrays 3 and 4 onto which the image of the distance-measuring object T is projected when the distance-measuring object T is at an infinite distance. Then, a distance measurement target T located at a distance l from lenses 1 and 2
When the distance x between the light-receiving element on which the image of
The distance l is determined by l=d×f/x. f is the focal length at which the lenses 1 and 2 form an infinite image on the light receiving element rows 3 and 4. However, distance x
is determined by the detection circuit shown in FIG.

In FIG. 2, 3 and 4 are light-receiving element rows similar to those in FIG. 1, and 5 and 6 are light-receiving element rows 3,
4 is a binarization circuit array that binarizes the output at a predetermined logic level; 7 and 8 are shift registers; 9 is a coincidence detection circuit array; 10 is a counter; and 11 is a judgment circuit. The analog output of each light-receiving element in the light-receiving element rows 3 and 4 is digitally converted to "0" or "1" at an appropriate threshold level by the respective binarization circuits in the binarization circuit rows 5 and 6. and written into shift registers 7 and 8. The outputs of each bit of the shift registers 7 and 8 are input to a match detection circuit array 9 and compared. Each circuit in the match detection circuit array 9 outputs "1" if the two inputs from the shift registers 7 and 8 are the same, and outputs "0" if they are different. The counter 10 counts the output "1"s from the match detection circuit array 9 and outputs the number to the determination circuit 11. The judgment circuit 11 is
After memorizing this number, shift register 7 or 8
is shifted by 1 bit, and the output number of the counter 10 after the shift is stored again. Furthermore, the judgment circuit 11
After repeating such shifting of the shift registers 7 and 8 and storage of the output number of the counter 10 a predetermined number of times, the maximum number of the stored output numbers of the counter 10 is determined. The state in which the maximum number of outputs is obtained is the state in which the arrangement patterns of the light receiving element outputs of the light receiving element rows 3 and 4 are the most consistent, and the number of shifts until this maximum number of outputs is obtained is as shown in Figure 1. Corresponds to distance x. That is, when calculating the distance l to the distance measurement target T using this number of shifts, instead of the constant distance d between the pair of light receiving element arrays 3 and 4,
A value obtained by dividing the distance d by the arrangement pitch of the light receiving elements in the light receiving element rows 3 and 4 may be used. However, in the case of a distance measuring device of an automatic focus adjustment device, it is not necessary to calculate the distance l one by one, and if the focus adjustment lens is moved in the optical axis direction corresponding to the number of shifts mentioned above, then the focus adjustment lens This means that the distance l has been found based on the axial position. Note that, as can be seen from the above explanation in FIG. 2, the registers to which the digital outputs of the binarization circuit arrays 5 and 6 are written need not both be shift registers, but at least one of them must be a shift register. Good to have. Further, a circuit as shown in FIG. 3 is used for each of the binarization circuits in the binarization circuit arrays 5 and 6.

In FIG. 3, 12 is a photodiode which is a light-receiving element constituting the light-receiving element rows 3 and 4 in FIGS. 1 and 2; 13 and 14 are switching transistors;
15 is a capacitor, 16 is an inverter, V _D is a drive voltage for photodiode 12, and G and C are operating signals for switching transistors 13 and 14, respectively. In this binarization circuit, switching transistors 13 and 14 are turned off and a driving voltage is applied to photodiode 12 to perform image projection, and then switching transistor 14 is temporarily turned off by actuation signal C. After turning on the capacitor 15 and discharging the capacitor 15, the operation signal C is further turned on.
The capacitor 15 is charged by turning off the switching transistor 14 with the activation signal G, then turning on the switching transistor 13 with the activation signal G, and after a certain period of time has passed, the switching transistor 13 is further turned on with the activation signal G. is turned off, and during that time, if the charging voltage of the capacitor 15, which is carried out by a current approximately proportional to the intensity of light received by the photodiode 12, exceeds the threshold voltage of the inverter 16, the output of the inverter 16 becomes " Reversed from “1” to “0”,
If the charging voltage has not reached the threshold voltage, the output of the inverter 16 remains "1", thereby converting the output of the photodiode 12 into a binary value. In this case, if the time from turning on to turning off the switching transistor 13 is too long, all the capacitors 15 will be charged above the threshold voltage; Since the charging voltages of all capacitors 15 do not reach the threshold voltage, and the array patterns of the binary outputs of the light receiving element arrays 3 and 4 match in all phases, the distance x information will no longer be available. Therefore, the time from when the switching transistor 13 is turned on to when it is turned off is the same as that of the light receiving element array 3,
It is necessary to set the amount of light received by the entire light receiving element No. 4 in consideration, but this type of control has the drawback that it is generally complicated.

Furthermore, in the conventional distance measuring device as described above, if relatively different noise is superimposed on the output of one or both of the light receiving element rows 3 or 4, erroneous ranging information may be obtained. There is also the disadvantage that distance measurement information may not be obtained at all. FIG. 4 shows an example of such a case.

A in Fig. 4 is a curved waveform that approximates the output array pattern when no noise is superimposed on the outputs of the light-receiving element arrays 3 and 4, or when noise is superimposed with relatively no difference even if superimposed. B shows the case where noise is superimposed on the trapezoid as shown by the relative hatching on the output of the light-receiving element array 3.
Similarly, C shows the case where noise is superimposed on the triangle. The vertical axis of the figure is the output of the constituent light receiving elements, that is, the strength of the charging current or the charging voltage of the capacitor 15 in FIG. 3, and the dashed line is the threshold level. In the case of A, the light receiving element rows 3 and 4
A conversion array pattern of approximately the same light receiving element output can be obtained for which matching phase can be obtained, but in the case of B and C,
Either no coincident phase is determined, or an incorrect coincident phase is determined.

In order to eliminate the above-mentioned drawbacks, the inventors of the present invention first developed a conversion method that shows the differential value of the output array pattern as shown in FIG. Invented a distance measuring device that uses an array pattern. The invention was patented in 1982.
No. 7275. In the distance measuring device, a conversion circuit as shown in FIG. 5 is used instead of the binarization circuit shown in FIG. 3, and a conversion circuit as shown in FIG. A conversion circuit array in which the conversion circuits shown in FIG. 5 are arranged in parallel as shown by the two-dot chain line is used.

In FIG. 5, 121 and 122 are photodiodes which are adjacent light receiving elements in one light receiving element row, 131, 132 and 141, 142 are switching transistors, 151 and 152 are capacitors, 161 and 162 are inverters, V _D is the driving voltage of the photodiode, G and C are the operating signals of the switching transistors, and the configuration up to this point is the same as that of the binary circuit shown in FIG. 2. and,
The outputs of inverters 161 and 162 are both input to NOR gates 17 and 18, respectively.
is a strobe signal that generates a "0" pulse at constant or varying time intervals, and a reset signal R that is input to the R terminals of flip-flops 22 to 24.
, the activation signal C is the switching transistor 14
At the same timing as turning on 1,142,
“0” pulse causes flip-flops 22 to 24
This is a signal that resets their Q outputs to "0" and therefore their outputs to "1".

According to this conversion circuit, the switching transistors 141 and 142 are turned on by the operation signal C, and at the same time, the flip-flops 22 to 24 are reset by the reset signal R, and the Q output is set to "0".
Then, from now on, if the outputs of the inverters 161 and 162 are inverted from "1" to "0" while inputting the "0" pulse of the strobe signal φ, the outputs of the NOR gates 17 and 18 will be Inverted from “0” to “1”. Therefore, the switching transistors 131 and 132 are turned on, and charging of the capacitors 151 and 152 is started. Now, hypothetically, between one "0" pulse of the strobe signal φ and the next "0" pulse, the capacitor 15
If only the charging voltage of 1 exceeds the threshold voltage and the output of the inverter 161 is inverted from "1" to "0", the output of the NOR gate 17 will change when the next "0" pulse of the strobe signal φ is input. The output of the NOR gate 18 is inverted from "0" to "1" and remains "0". When the output of NOR gate 17 is inverted to “1”, NOR gate 1
9 outputs a set signal of "0" to the set terminal S of the flip-flop 22. As a result, the Q output of the flip-flop 22 becomes "1",
The outputs of the NOR gates 17 and 18 are held at "0". However, the output of the NOR gate 17, which is once inverted to "1", is input as a "0" set signal to the set terminal S of the flip-flop 24 via the inverter 21, and the output of the NOR gate 17 is inverted to "1".
The Q output of 4 is inverted from "0" to "1", and the output is inverted from "1" to "0". the result,
The output q ₁ of the NOR gate 25 is the flip-flop 23
Gives "0" regardless of the Q output. Also, q ₃ of the Q output of the flip-flop 23 is the NAND gate 2
Since the output of the NOR gate 18 inputted to 0 remains at "0", it remains at "0" after being reset, and this "0" of _q3 and the "0" of the Q output of the flip-flop 24 are Noah Gate 2 being input
The output q ₂ of 6 gives "1". That is, the output of photodiode 121 is
2, and the difference is large enough that only the output of the inverter 161 is inverted between one "0" pulse and the next "0" pulse of the strobe signal φ. , output q ₁ , q ₂ , q ₃
give "0", "1", and "0", respectively.

Next, suppose that between one "0" pulse and the next "0" pulse of the strobe signal φ, the charging voltages of the capacitors 152, 152 both exceed the threshold voltage, and the inverter 16
If the outputs of 1 and 162 are both inverted from "1" to "0", both NOR gates 17 and 18 are inverted from "0" to "1" when the next "0" pulse of the strobe signal φ is input. do. This inversion is also temporary, as in the previous case, since the inversion causes a set signal of "0" to be input from the NOR gate 19 to the set terminal S of the flip-flop 22. Then, the inverted output "1" of the NOR gate 17 sets the flip-flop 24 to invert the Q output from "0" to "1".
Since the Q output is inverted from "1" to "0", the output q ₁ of the NOR gate 25 gives "0" as in the previous case. Further, the inverted outputs "1" of the NOR gates 17 and 18 input the set signal "0" to the set terminal S of the flip-flop 23 via the NOR gate 20, and the Q output _q3 is changed from the reset "0" to "0". At the same time, this output _q3 is inverted to 1, and at the same time, the output _q2 of the NOR gate 26 is inverted to the flip-flop 24.
The output is set to “0” regardless of the output. That is,
The outputs of the photodiodes 121 and 122 change from one “0” pulse of the strobe signal φ to the next “0”
Inverters 16 and 16 respectively between pulses
When the difference is in a small range such that the output of 1,162 is inverted, the outputs q ₁ , q ₂ , and q ₃ give "0", "0", and "1", respectively.

Finally, if one of the strobe signals φ is “0”
Between the pulse and the next “0” pulse,
If only the charging voltage of the capacitor 152 exceeds the threshold voltage and the output of the inverter 162 is inverted from "1" to "0", the output of the NOR gate 18 will be "0" next to the strobe signal φ.
When a pulse is input, it is inverted from "0" to "1", and the output of the NOR gate 17 remains "0". In this case as well, since the inverted output "1" of the NOR gate 18 inputs the set signal "0" to the set terminal S of the flip-flop 22 via the NOR gate 19, the "0" of the NOR gate 18 changes to "1".
The reversal to is temporary. Even if the output of the NOR gate 18 is inverted to "1", the output of the NOR gate 17 is "0", so the flip-flop 23 is not set, and the flip-flop 23 is not set.
4 is also not set. Therefore, the Q outputs of the flip-flops 23 and 24 are both "0" and the output remains "1", so the output of the NOR gate 25 is
q ₁ remains "1", output q ₂ of NOR gate 26 remains "0", and output q ₃ remains "0". In other words, the output of photodiode 1 is higher than the output of photodiode 121.
When the output of the inverter 162 is large and the difference is large enough that only the output of the inverter 162 is inverted between one "0" pulse of the strobe signal φ and the next "0" pulse, then Outputs q ₁ , q ₂ , and q ₃ give "1", "0", and "0", respectively.

As described above, the conversion circuit of FIG. 5 determines whether the output difference between adjacent light receiving elements in a row of light receiving elements decreases or increases by more than a predetermined value given by the pulse interval of the strobe signal φ, or is within a predetermined value. Thus, each provides a different signal output. Therefore, a converter array consisting of parallel converter circuits in which parts of the converter circuits are overlapped one after another can be created by differentiating the output arrangement pattern of the light receiving elements in the light receiving element array shown in FIG. , this will give a conversion pattern that looks like a ternarized differential value. That is, the conversion circuit shown in FIG. 5 can be called an output difference ternarization circuit, and a conversion circuit string consisting of such conversion circuits in parallel can be called a difference ternarization circuit string. Note that in the conversion circuit shown in FIG. 5 that converts the output difference between the light receiving elements, the switching transistors 131 and 132
can be omitted, and therefore the actuation signal G can also be omitted.

By using the above-mentioned differential ternarization circuit array in _place of the binarization circuit arrays ₅ and ₆ in FIG. ) In the conventional distance measuring device mentioned above, the complexity of controlling the time setting from on to off of the switching transistors 131, 132, etc. using the operation signal G, and the difference between the light receiving element rows. This eliminates the disadvantage that distance measurement information cannot be obtained or incorrect distance measurement information can be obtained when noise is superimposed.

However, even in a distance measuring device using such a differential ternary circuit array, if the “0” pulse interval of the strobe signal φ is too long when one conversion of the output of the light receiving element array is performed, Inverter 16
If all the outputs of 1,162, etc. are reversed and distance measurement information cannot be obtained, or conversely, if the "0" pulse interval of the strobe signal φ is too short, the differential of the output array pattern of the light receiving element will be If the output of the light-receiving element changes periodically due to a conversion array pattern in which the values are binarized, there is a problem that incorrect ranging information may be obtained. .

Figure 6 shows the strobe signal φ when the output array pattern of the light receiving element array is converted by the differential ternarization circuit array.
The relationship between the length and shortness of the "0" pulse interval and the conversion pattern is shown, A is the output array pattern before conversion, B is the conversion output array pattern when the "0" pulse interval of the strobe signal φ is too long, and C D shows the conversion output array pattern when the interval is too short, and D shows the conversion output pattern when the interval is appropriate. Note that the conversion outputs 1, 0, -1 are the combinations of the outputs q ₁ , q ₂ , q ₃ in FIG. 5, respectively [0, 1, 0],
This is when it becomes [0, 0, 1], [1, 0, 0]. If the output array pattern of A is converted like B, no ranging information will be obtained, and if it is converted like C, many coincident phases will be detected and erroneous ranging will be performed. It turns out. and,
If converted as shown in D, one matching phase will be detected and accurate distance measurement will be performed.

[Purpose of the invention]

The present invention converts the output array pattern of each of a pair of light-receiving element rows into a relative difference array pattern that determines whether the output difference between adjacent light-receiving elements increases or decreases by a predetermined value or more, and matches the pair of converted patterns. This was done in order to further eliminate the problem with the above-mentioned distance measuring device, which detects the phase of converted into a pattern,
An object of the present invention is to provide a distance measuring device that performs accurate distance measurement.

[Structure of the invention]

The present invention includes a light receiving means in which two sets of light receiving element rows each including a plurality of light receiving elements are arranged at a predetermined interval;
a plurality of comparison means provided corresponding to each of the plurality of light-receiving elements, which compares whether or not the amount of light received by the light-receiving element reaches a predetermined value, and outputs a signal when the amount of light received by the plurality of light-receiving elements reaches a predetermined value; The output of one comparison means and the output of the other comparison means of the two comparison means corresponding to two adjacent light receiving elements among the light receiving elements are detected at predetermined intervals, and it is determined which signal output is faster or equal. determining means for determining whether the plurality of light receiving elements are slow or slow for each predetermined two light receiving elements of the plurality of light receiving elements; Compare the output of the discrimination means for
and a coincidence detection means for detecting a coincidence between the two light-receiving element arrays. A counting means is provided for counting the number of outputs indicating that the light reception levels of two adjacent light receiving elements are determined to be equal, and when the number of the counted outputs and the number determined by the discrimination means match, , the predetermined period in the discriminating means is shortened, and distance measurement is performed again based on the shortened period. A distance measuring device characterized by:

〔Example〕

The present invention will be explained below with reference to embodiments shown in FIGS. 7 to 10.

FIG. 7 is a block circuit diagram showing an example of the detection circuit of the distance measuring device of the present invention, FIG. 8 is a time chart showing an example of changes in the strobe signal, FIG. 9 is an operation flowchart of the judgment control circuit, and FIG. 7 is a graph showing a relationship between an output array pattern of a light receiving element array and an array pattern of converted outputs.

In FIG. 7, 3 and 4 are the same light-receiving element arrays as in FIG. 2, 5' and 6' are differential ternarization circuit arrays consisting of parallel output difference ternarization circuits as shown in FIG. 5, and 7a
and 8a is _a shift register for output q ₁ or q ₂ in FIG.
0'' is a counter, 11' is a judgment control circuit, 27 is an AND circuit array, 28 is a comparison circuit, and 29 is a strobe signal generation circuit.In this detection circuit,
Although only one of the outputs q ₁ and q ₂ in FIG. 5 is used, one more shift register is added for each of the light-receiving element arrays 3 and 4, and the converted outputs q ₁ and q 2 are used. Of course, all the information on q ₂ and q ₃ may be used. In this detection circuit, the output arrangement pattern of the light receiving element rows 3 and 4 is determined by the differential ternarization circuit rows 5' and 6'.
As described with reference to FIG. 5, the outputs q ₁ , q ₂ , q ₃ are converted into an array pattern, and the output q ₁ or q ₂ is input to the shift registers 7a, 8a, and the output q ₃ is input to the shift registers 7b, 8a. 8b. and,
The output q ₁ or q ₂ and the output q 3 corresponding to the arrangement order of the light receiving element rows 3 _{and 4} are the coincidence detection circuit row 9a.
and 9b, and the match detection circuit arrays 9a,
9b outputs "1" when they match, and outputs "0" when they do not match. The outputs corresponding to the arrangement order of the coincidence detection circuit arrays 9a and 9b are further compared in the AND circuit array 27, and the AND circuit array 27 is for the outputs of both the coincidence detection circuit arrays 9a and 9b that are both "1". Output “1”,
The number of output "1"s is counted by the counter 10', and the judgment control circuit 11' stores the count number of the counter 10'. Next, the judgment control circuit 11'
is shift register 7a, 7b or 8a, 8b
1 bit and repeats the operation of storing the counted number of the counter 10' after the shift.
The maximum number of counts stored last is determined, and the number of shifts when the maximum number of counts is obtained is defined as the time when the object of distance measurement has been determined. This is similar to the determination circuit 11 shown in FIG. 1, or the distance measuring apparatus using the conversion circuit of FIG. 5 invented earlier. However, the point that this judgment control circuit 11' performs the above-mentioned operation is that it performs the above-mentioned operation after receiving information from the comparison circuit 28 that the array pattern of the converted output is in a state where effective matching can be detected. This is different from the determination circuit 11 shown in FIG. 2 and the previously invented distance measuring device. That is, the judgment control circuit 11' starts charging the capacitors 151, 152, etc. shown in FIG. First, a strobe signal having a "0" pulse time interval as shown by δ=4EV in FIG. 8, for example, is outputted as φ in FIG. In the example of FIG. 7, the inverters 161, 162, etc. for triggering the driving of the strobe signal generation circuit 29 described above may only be provided for the light receiving element array 3. When the "0" pulse of the strobe signal is output, at that point the output array pattern of the photodetector arrays 3 and 4 is converted into the conversion pattern of the conversion outputs q ₁ , q ₂ , and q ₃ as described above in the shift register. 7a, 7b and 8
It is input to a and 8b. Light receiving element row 3 at this time
The converted outputs q ₃ of q 3 are all "1" when the output difference between adjacent light receiving elements is 4EV or less in terms of received light intensity difference.
The counter 10'' counts "1" of the conversion output _q3 , and when the count number of the counter 10'' is equal to the number of bits of the shift register 7b, the comparison circuit 28 sends the conversion output array pattern to the judgment control circuit 11'. A signal is output to the effect that the count is flat and effective coincidence detection cannot be performed, and when the above-mentioned count number is less than the number of bits, a signal is output to the effect that effective coincidence detection is possible. This determination operation of the comparison circuit 28 is performed in the determination step "Is the converted output array pattern flat?" in the flowchart of FIG. Then, the judgment control circuit 11'
performs the above-mentioned coincidence detection operation (coincidence phase detection operation) when a signal indicating that effective coincidence detection will be performed from the comparator circuit 28, and when a signal indicating that effective coincidence detection will not be carried out, Measure the distance again as shown below. That is, once the charging of the capacitors 151, 152, etc. is started again, this time conversion is performed using a strobe signal of δ = 2EV, and a signal is input from the comparator circuit 28 to the effect that effective coincidence detection is performed. Thereby, the judgment control circuit 11' performs a coincident phase detection operation.
However, if a signal indicating that effective coincidence detection is not performed is still input from the comparison circuit 28, operations such as further conversion using a strobe signal of δ=1EV are repeated. For example, even if conversion is performed using a strobe signal of δ = 1/8EV, the difference in output between adjacent light receiving elements is 1/8EV or less, and still the comparator circuit 2
When a signal indicating that effective coincidence detection is not performed is inputted from 8, the judgment control circuit 11' outputs a signal indicating that distance measurement is not possible, and displays the signal.

FIG. 9 shows the main operations of the above-mentioned operations performed by the judgment control circuit 11'. Note that the conversion output array pattern flat in the flowchart of FIG. 9 occurs when a signal indicating that valid coincidence detection is not performed is output from the comparator circuit 28, and coincidence phase detection is determined by the count number of the counter 10'. This is an operation to memorize the number of shifts and find the number of shifts at which the maximum count number was obtained.

As the judgment control circuit 11' operates as described above, the output arrangement pattern of the light receiving element array as shown in A in FIG.
The converted output patterns B to D provide accurate distance measurement information. In addition, B
If one shift register is added to each of the photodetector arrays 3 and 4 so that all of the conversion outputs q ₁ , q ₂ , and q ₃ are used, then C is added to the shift registers 7a and 8a in FIG. When the conversion output q ₂ is input, D is the conversion output to the shift registers 7a and 8a.
This is the case when q ₁ is input.

〔Effect of the invention〕

According to the present invention, even if noise with a relative difference is superimposed between the outputs of a pair of light-receiving element arrays, it will not become impossible to measure distance or obtain erroneous distance measurement information. In addition, even if the output array pattern of the light receiving element array is periodic, if the heights of the peaks or valleys of the output of the light receiving elements are different, an excellent effect can be obtained in that accurate distance measurement can be performed.

[Brief explanation of drawings]

Figure 1 is a schematic plan view of the configuration of the device that projects an image in the ranging direction onto a pair of photodetector arrays, and Figure 2 detects the phase where the arrangement patterns of the photodetector outputs of the pair of photodetector arrays most match. Figure 3 is a binary circuit diagram of the light receiving element output, Figure 4 is an output graph showing an example where noise is superimposed on the output of the light receiving element array, and Figure 5 is an output difference ternarization circuit. , FIG. 6 is a graph showing the relationship between the output array pattern of the light receiving element array and the conversion output pattern by the differential ternarization circuit array,
FIG. 7 is a block circuit diagram showing an example of the detection circuit of the distance measuring device of the present invention, FIG. 8 is a time chart showing an example of changes in the strobe signal, FIG. 9 is an operation flowchart of the judgment control circuit, and FIG. 7 is a graph showing a relationship between an output array pattern of a light receiving element array and an array pattern of converted outputs. 1, 2... Lens, 3, 4... Light receiving element array,
5, 6...Binarization circuit array, 5', 6'...Differential ternarization circuit array, 7, 7a, 7b, 8, 8a, 8b...
Shift register, 9, 9a, 9b... Coincidence detection circuit array, 10, 10', 10''... Counter, 11...
...Judgment circuit, 11'...Judgment control circuit, 12,1
21, 122...Photodiode, 13, 13
1,132,14,141,142...Switching transistor, 15,151,152...Capacitor, 16,161,162...Inverter, 17-19,25,26...Nor gate, 2
0...Nand gate, 21...Inverter, 22
~24...Flip-flop, 27...AND circuit array, 28...Comparison circuit, 29...Strobe signal generation circuit.

Claims (1)

[Scope of Claims] 1. A light receiving means in which two sets of light receiving element rows each consisting of a plurality of light receiving elements are arranged at a predetermined interval, and a light receiving means provided corresponding to each of the plurality of light receiving elements, and an amount of light received by the light receiving element. a plurality of comparing means for comparing whether or not the value has reached a predetermined value and outputting a signal when reaching the predetermined value; and one of the two comparing means corresponding to two adjacent light receiving elements among the plurality of light receiving elements. The output of the comparison means and the output of the other comparison means are detected at predetermined intervals, and it is determined whether the output of the signal is early, equal, or slow. a discrimination means for the light-receiving elements, and a coincidence detection means for comparing the output of the discrimination means for one of the two sets of light-receiving element arrays with the output of the discrimination means for the other of the light-receiving element arrays, and detecting a match. In the distance measuring device that determines the distance to the object from the correlation between the outputs of the two sets of light receiving element arrays, two of the adjacent light receiving element arrays in the one of the light receiving element arrays in the discriminating means.
A counting means is provided for counting the number of outputs indicating that the light reception levels of the two light receiving elements are determined to be equal, and when the counted output number and the number determined by the discrimination means match, the discrimination means A distance measuring device characterized in that the predetermined period in is shortened and distance measurement is performed again based on the shortened period. 2. A counting means for counting the number of outputs indicating that the outputs of the discriminating means are determined to belong to a specific discriminating level, and a discriminating level setting means for changing the discriminating level; 2. The distance measuring device according to claim 1, wherein the distance measuring device counts the number of objects.