JPH0827186B2 - Distance distribution measuring method and congestion matching mechanism used therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to distance distribution measurement, and more particularly to a method for optically measuring the distribution of distance to an object in the surrounding environment and a congestion matching mechanism used therefor. Such distance distribution measurement is effectively used, for example, as a visual means for environment recognition of the autonomous mobile robot.

[Prior Art] There is a so-called stereo method as a method of optically measuring a distance to an object. In this method, two objective lenses having the same focal length are maintained in parallel with the optical axis kept parallel and at a predetermined distance from each other, and illuminance distribution measuring means is arranged behind each objective lens, and these two measurement lenses are measured. The distance to the object can be calculated from the positional relationship of the same illuminance distribution pattern measured by the means.

9 (a) and 9 (b) are diagrams for explaining the principle of the stereo method. In the figure, 101 and 102 are light-focusing objective lenses having the same focal length, and 101A and 102A are their optical axes. Lens 101 and 102 are optical axes 101A and 102A
A straight line (baseline) connecting the lens centers so that they are parallel to each other
Are arranged so as to be orthogonal to the optical axes 101A and 102A. A measuring means 103 is arranged behind the lens 101 at a position separated by the focal length F of the lens, and a measuring means 104 is arranged behind the lens 102 at a position separated by the distance F. These measuring means are arranged on one straight line in a direction parallel to the base line direction of the lenses 101 and 102.

In FIG. 9A, the object 105 exists at infinity on the optical axis 101A. In this case, the image 106 of the object 105 on the measuring means 103 by the lens 101 is on the optical axis 101A, and similarly the object 105 on the measuring means 104 by the lens 102.
Image 107 of is present on the optical axis 102A.

In FIG. 9B, the object 105 exists at a position separated by a finite distance X on the optical axis 101A. In this case, the image 106 of the object 105 on the measuring means 103 by the lens 101
Exists on the optical axis 101A, but the measuring means 1 by the lens 102
An image 107 of the object 105 on 04 exists at a position separated from the optical axis 102A by a distance D.

Therefore, by detecting the deviation amount D of the image 107 from the optical axis 102A by the measuring means, the lenses 101, 102 and the measuring means
From the distance F between 03 and 104 and the base line length L, the distance X to be measured can be calculated by the following equation.

X = FL / D By the way, generally, an image is formed over the entire measuring means, and it is difficult to specify an image of the same object point on the same object. Therefore, in the above stereo method, in order to obtain the positions of the images 106, 107 by the measuring means 103, 104, the illuminance distribution in one measuring means 103 and the illuminance distribution in the other measuring means 104 are correlated. .

FIGS. 10 (a), (b) and (c) are diagrams for explaining the principle of such a correlation method.

As the measuring means 103 and 104, for example, a CCD array which is a self-scanning sensor is used.

In FIG. 10 (a), a CCD array 103, which is a measuring means corresponding to the lens 101, has n light receiving elements,
The CCD array, which is the measuring means corresponding to 102, has m light receiving elements (m> n). That is, if the distance to the object on the optical axis 101A is measured, the image 106 by the lens 101 exists on the optical axis 101A regardless of the distance to the object.
Since the position of the image 107 by the image 102 changes according to the distance to the object, the CCD array 104 is provided with more light receiving elements than the CCD array 103. With this arrangement, the CCD
The array 103 is referred to as a standard field of view, and the CCD array 104 is referred to as a reference field of view.

Illuminance distributions in the standard visual field and the reference visual field as shown in FIG. 10 (a) are as shown in FIG. 10 (b). That is,
The image formation relationship of the object 105 and the image 106 with respect to the lens 101 in the optical axis direction is equal to the image formation relationship of the object 105 and the image 107 with respect to the lens 102 in the optical axis direction (that is, the magnifications are equal).
The illuminance distribution of 6 and the illuminance distribution of the image 107 differ only in that they are displaced from the optical axis by a distance D.

Therefore, the CCD arrays 103 and 104 provide outputs corresponding to the respective light receiving elements as shown in FIG. 10 (c).

Therefore, in order to correlate the outputs of the two CCD arrays,
First, the outputs S of the first to nth light receiving elements in the reference field of view
(1) to S (n) and the sum of the differences between the outputs corresponding to the outputs R (1) to R (n) of the first to nth light receiving elements in the reference field of view. Ask for. Next, similarly, the first to nth points in the reference visual field
Outputs S (1) to S (n) of the second light receiving element and outputs R (2) of the second to (n + 1) th light receiving elements in the reference field of view.
~ R (n + 1) sum of the difference between corresponding outputs Ask for. And so on Ask up to.

Of the (m-n + 1) values obtained in this way, the COR number with the smallest value (ideally 0) is selected,
The value of D can be obtained by multiplying the number by the width of one light receiving element of the CCD array.

[Problems to be Solved by the Invention] In the correlation method as described above, for example, in the case of a repetitive pattern image or the like, it may be determined that there is a correspondence even at an incorrect position when the correlation is obtained. However, there is a problem that the accuracy of measurement is not yet sufficient. Also, when trying to obtain the distance distribution to the object in the surrounding environment by performing the distance measurement based on the above correlation method in each direction,
There is also a problem that the number of calculations for obtaining the correlation becomes extremely large and the processing circuit of the measuring device becomes complicated. Further, the correlation method has a problem that the number of decompositions in the direction cannot be sufficiently increased.

Therefore, an object of the present invention is to provide an optical distance distribution measuring device that solves the problems of the conventional technique and can easily perform measurement with high accuracy and a high number of directional decompositions.

[Means for Solving the Problems] According to the present invention, in order to achieve the above object, two optical systems having substantially the same focal length are arranged so that their optical axes are parallel to each other. Illuminance distribution measuring means is arranged in the rear of each optical system at the same distance and perpendicular to the optical axis, and the ratio between the distance between the optical system and the illuminance distribution measuring means and the distance between the two illuminance distribution measuring means is made substantially constant. While maintaining the distance between the optical system and the illuminance distribution measuring means and the distance between the two illuminance distribution measuring means, the illuminance distribution is measured by each illuminance distribution measuring means, and the two illuminance distributions are respectively differentiated with respect to the position,
Corresponding signals whose absolute values are greater than or equal to a predetermined value are extracted from the two differential signals, and the positions of these corresponding signals, the focal length of the optical system, and the positional relationship between the two optical systems and the two illuminance distribution measuring means at that time are extracted. A distance distribution measuring method is provided, which is characterized in that a distance to an object is calculated for the corresponding symbol position.

Further, according to the present invention, it is preferable to use such a distance distribution measuring method as described above. Two optical elements having substantially the same focal length and juxtaposed such that their optical axes are parallel to each other are provided. System and illuminance distribution measuring means juxtaposed corresponding to the optical system, the distance between the optical systems is relatively variable with respect to the distance between the illuminance distribution measuring means, and the illuminance distribution measuring means is It is movable in the optical axis direction relative to the optical system, and the direction between the two optical systems and the illuminance distribution measuring means is perpendicular to the plane formed by the optical axes of the two optical systems. Directly or indirectly connected by a crank lever that can rotate as a shaft,
At least one of the two optical systems and the illuminance distribution measuring means is moved so as to change the relative positional relationship between the optical system and the illuminance distribution measuring means with the rotation of the crank lever. In this movement, the convergence adjustment mechanism is characterized in that the ratio of the distance between the optical system and the illuminance distribution measuring means and the distance between the two illuminance distribution measuring means is maintained substantially constant. Embodiments Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram showing an embodiment of a congestion matching mechanism of the present invention used for implementing the distance distribution measuring method of the present invention.

In FIG. 1, 11 is a lens barrel of the lens 1, and 1 A is an optical axis of the lens 1. 12 is a lens barrel of the lens 2, 2A
Is the optical axis of the lens 2. The optical axis 2A is parallel to the optical axis 1A of the lens 1. An attachment member 13 extending in the direction of the optical axis 2A is attached to the lens barrel 12. Guide elongated holes 14a and 14b extending in the optical axis direction are formed in the accessory members, respectively. Reference numerals 15a and 15b are guide pins fixed to a frame (not shown).
It is fitted to 14a and 14b. The auxiliary member 13 also has a guide pin projecting in a direction (hereinafter, referred to as P direction) orthogonal to both the optical axis direction and the base line direction of the two lenses 1 and 2.
16 are attached.

 The focal lengths of the lenses 1 and 2 are F.

On the other hand, the lens barrels 11 and 12 are connected by a connecting member 17. A drive means for reciprocating the connecting member and the lens barrels 11 and 12 in the optical axis direction is attached to the connecting member. The driving means is composed of a pulse motor 18, a male screw member 19 attached to a driving rotary shaft of the motor, and a female screw formed on the connecting member 17 so as to be engaged with the male screw member.

Reference numeral 20 denotes a crank lever, which has two arms 20a and 20b that are substantially orthogonal to each other. The arm 20a extends substantially in the base line direction, and the arm 20b extends substantially in the optical axis direction. These two
A rotating shaft 20c in the P direction is provided at the connecting portion of the two arms. The rotating shaft is rotatably connected to a frame (not shown). A guide slot 21a extending in a direction toward the center of the rotary shaft 20c is formed at the tip of the arm 20a, while a direction toward the center of the rotary shaft 20c is formed at the tip of the arm 20b. An elongated guide hole 21b extending in the direction of is formed. Then, the guide pin attached to the above-mentioned accessory member 13
16 is fitted in the guide elongated hole 21a.

Reference numerals 3 and 4 are CCD arrays having the same number of light receiving elements arranged corresponding to the lenses 1 and 2, respectively, and the CCD arrays are fixed to the supports 22 and 23 along the base line direction, respectively.
One support 22 is fixed to a frame (not shown).
In addition, the other support 23 has a guide pin projecting in the P direction.
24 are attached. The guide pin is fitted in the guide elongated hole 21b. In addition, guide elongated holes 25a and 25b extending in the base line direction are formed in the support body 23. 26
Reference numerals a and 26b are guide pins fixed to a frame (not shown).
It is fitted to a and 25b.

In FIG. 1, the center of the lens 1 and the center of the lens 2 are located at a distance L in the base line direction, and similarly CC
The center of the D array 3 and the center of the CCD array 4 are separated by a distance L in the base line direction, and the lenses 1 and 2 and the CCD array are arranged.
The lenses 3 and 4 are separated from each other by the focal length F of the lenses 1 and 2.

2 shows the crank lever 20 from the state shown in FIG.
It shows a state of being rotated clockwise by an angle θ around 20c in the figure. Due to this rotation, the lens barrels 11 and 12 move in the optical axis direction upwards in the figure by a distance ΔF. On the other hand, this rotation causes the support body 23 to move in the base line direction to the left in the drawing by the distance ΔL. And in FIG. 2, the CCD array 3
And the CCD array 4 is L '(= L + ΔL), and the distance between the lenses 1 and 2 and the CCD arrays 3 and 4 is F' (=
F + ΔF).

Here, when the arm 20a of the crank lever 20 is in the base line direction, the distance from the center of the rotary shaft 20c of the crank lever 20 to the center of the guide pin 16 attached to the accessory member 13 is A · F. The distance from the center of 20c to the center of the guide pin 24 attached to the support 23 is set to A · L (where A is a proportional constant). In this case, ΔL = A · L · tan θ ΔF = A・ F ・ tanθ, so L '/ F' = (L + A ・ L ・ tanθ) / (F + A ・ F ・ tan
θ) = L (1 + A · tan θ) / F (1 + A · tan θ) = L / F.

FIG. 3 is a block diagram showing an embodiment of an apparatus for carrying out the distance distribution measuring method according to the present invention using the congestion matching mechanism shown in FIGS.

In FIG. 3, the CCD arrays 3 and 4 are simultaneously read and driven by the same drive circuit 31, and the pulse motor 22 is driven by the drive circuit 32.

Pixel signals from the light receiving elements are sequentially output from the CCD arrays 3 and 4 in chronological order, and a differentiating circuit as an image information signal.
Input to 33,34. The differential circuit obtains a differential signal of the image information signal. The differentiated signal means a time-series signal of an increment with respect to a pixel signal preceding the pixel signal of each pixel signal input in time-series, and the image information signal is latched for one pixel. It can be obtained by subtracting the pixel signal input by the following.

The outputs of the differentiating circuits 33 and 34 are input to the difference circuit 35,
Here, the difference signal of the two differential signals is obtained.

The output of the difference circuit 35 is input to the A / D converter 36, where the difference signal is digitized.

The output of the A / D converter 36 is subsequently input to the delay circuit 37, the difference circuit 38 and the comparison circuit 39.

The delay circuit 37 uses a means such as BBD for holding the image information signal of one screen and delaying it in time. Therefore, the signal that is the output of the A / D converter 36 and the output of the A / D converter one screen before are simultaneously input to the difference circuit 38. Then, the difference circuit 38 obtains a difference signal of these two signals.

The output of the difference circuit 38 is input to the comparison circuit 40. The comparison circuit 40 compares the absolute value of the input signal with a predetermined first threshold value, and outputs a signal only when the absolute value of the input signal is larger than the threshold value.

On the other hand, the comparison circuit 39 compares the absolute value of the input signal from the A / D converter 36 with a predetermined second threshold value, and the absolute value of the input signal is higher than the second threshold value. The signal is output only when it becomes small.

The output of the comparison circuit 39 and the output of the comparison circuit 40 are ANDed.
It is input to the circuit 41, where an AND signal of both input signals is obtained.

 The output of the AND circuit 41 is input to the CPU 42.

On the other hand, a signal of the rotation angle of the motor (the rotation angle corresponds to the position of the CCD arrays 3 and 4 in the optical axis direction) is output from the motor drive circuit 32, and the signal is input to the distance calculation circuit 43. .

The distance calculation circuit 43 calculates the distance. The calculation result is stored in the memory 44 via the CPU 42.

Reference numeral 45 is a clock generation circuit that generates a clock for the operation of each block of the device.

The operation of the apparatus of this embodiment, that is, one embodiment of the method of the present invention will be described below with reference to FIGS.

4 (a) and 4 (b) are optical diagrams for explaining the details of the measurement in this example.

It is assumed that the object 5 exists at a position separated by a finite distance X along the optical axes 1A and 2A and has a predetermined length in the base line direction.

First, as shown in FIG. 4 (a), the distance between the CCD arrays 3 and 4 is set to the same L as the distance between the lenses, and the lenses 1 and 2 are
The focal length F of the lens is the distance between the CCD array and the CCD arrays 3 and 4. This corresponds to the state shown in FIG.

In this state, the image on the CCD array 3 by the lens 1 is as shown in FIG. 5A, and the image of the object 5 is formed in the center in a blurred state. On the other hand, the image on the CCD array 4 by the lens 2 is as shown in FIG. 5 (b), and the image of the object 5 is formed at a position deviated from the center to the left in a blurred state. The image on the CCD array 4 is an image obtained by moving the image on the CCD array 3 leftward by a predetermined distance.
Incidentally, FIGS. 5A and 5B correspond to the image information signals output from the CCD arrays 3 and 4, respectively.

Therefore, the differential signals output from the differentiating circuits 33 and 34 are as shown in FIGS. 5 (c) and 5 (d), respectively. Since the image information signal is a gentle signal due to the blurring of the image on the CCD array, the absolute value of the differential signal is small.

The difference circuit 35 forms a signal train of the difference between the corresponding pixel signals in the outputs of the differentiating circuits 33 and 34, and the difference signal is as shown in FIG. 5 (e). The output signal has a small absolute value due to the small absolute value of the differential signal.

The output signal from the difference circuit 35 is digitized by the A / D converter 36, and the subsequent signal processing is digitally performed.

The difference circuit 38 outputs a signal of the difference between the output signal of the A / D converter 36 and the output signal of the delay circuit 37. In the initial state, since the delay circuit 37 does not output the signal of the previous screen, the difference circuit 38 subtracts the input signal from the A / D converter 36 as a dummy of the input signal from the delay circuit. Therefore, the output signal of the difference circuit 38 becomes a signal of 0 as a whole.

Therefore, since the absolute value of the input signal to the comparison circuit 40 is smaller than the threshold value set in the comparison circuit, the output signal of the comparison circuit is as shown in FIG. 5 (f). It becomes 0 as a whole.

On the other hand, the absolute value of the input signal to the comparator circuit 39 is smaller than the threshold value set in the comparator circuit, so that the output signal of the comparator circuit as a whole is as shown in FIG. 5 (g). Will be 1.

Therefore, the output of the AND circuit 41 becomes 0 as a whole as shown in FIG.

Since the output of the AND circuit 41 is input to the CPU 42 and 1 is not included in the signal, the CPU does not issue a distance calculation command to the distance calculation circuit 43 at this time.

However, the motor drive circuit 32 outputs a motor rotation angle signal to the distance calculation circuit 43.

Then, the motor drive circuit 32 rotates the pulse motor 22 by an appropriate angle to move the support 18 by a predetermined distance in the optical axis direction, and thus the lens barrel 12 is moved by a predetermined distance in the base line direction.

Signal processing is performed on the new screen formed in this state in the same manner as above. In this state, the image on the CCD arrays 3 and 4 has a pattern substantially similar to the above case and is slightly closer to the in-focus state. However, CCD array 4
In the image above, the image of the object 5 is slightly closer to the center than in the above case.

Also in the signal processing in this state, a signal that is slightly different or the same as the above can be obtained.

In the same manner, driving of the motor 22 and signal processing are repeated.

FIG. 4B shows a state in which the distance between the CCD arrays 3 and 4 is L'and the distance between the lenses 1 and 2 and the CCD arrays 3 and 4 is F '. This state is realized by repeating the driving of the motor 18. This corresponds to the state shown in FIG.

In the present embodiment, when the crank lever 20 rotates, the relationship L '/ F' = L / F is maintained as described above, and ΔL is maintained.
And ΔF change, the images 6 and 7 of the object 5 are CCD, respectively.
It will be positioned in the center of the arrays 3 and 4 in a focused state.

That is, as described above, in FIGS. 4 (a) and 4 (b),
Since L '/ F' = L / F, L / F = (L + ΔL) / (F + ΔF) holds. Further, from the similarity relationship in FIG. 4 (b), L / [X− (F + ΔF)] = (L + ΔL) / X holds. From these equations, 1 / F = 1 / [X− (F + ΔF)] + 1 / (F + ΔF) is derived. From this, it can be seen that the object 5 and the images 6 and 7 in FIG. 4 (b) satisfy the focusing image formation formulas for the lenses 1 and 2, respectively.

In the state immediately before reaching the focused state (one screen before), the image on the CCD array 3 by the lens 1 becomes as shown in FIG. 6 (a), and the image of the object 5 is almost in the focused state. It is formed in the center in a blurred state. On the other hand, the image on the CCD array 4 by the lens 2 is as shown in FIG. 6 (b), and the image of the object 5 is slightly defocused to the left from the center while the image of the object 5 is slightly blurred near the in-focus state. Has been formed. The image on the CCD array 4 is an image obtained by moving the image on the CCD array 3 leftward by a slight distance.
6 (a) and 6 (b) correspond to the image information signals output from the CCD arrays 3 and 4, respectively.

Therefore, the differential signals output from the differentiating circuits 33 and 34 are as shown in FIGS. 6 (c) and 6 (d), respectively. Since the image information signal is a signal whose edge portion has a fairly steep slope because the image on the CCD array is almost in focus, the differential signal has a relatively large absolute value portion at the edge portion.

Therefore, the difference signal output from the difference circuit 35 is as shown in FIG. In FIG. 6 (e), the dotted line shows the difference signal one screen before, that is, the output of the delay circuit 37.

Along with this, the output signal of the difference circuit 38 becomes as shown in FIG. 6 (e ').

Therefore, since the absolute value of the input signal to the comparison circuit 40 is smaller than the threshold value set in the comparison circuit, the output signal of the comparison circuit is the whole as shown in FIG. 6 (f). Will be 0.

On the other hand, since the input signal to the comparator circuit 39 has a portion whose absolute value is larger than the threshold value set in the comparator circuit, the output signal of the comparator circuit is as shown in FIG. 6 (g). Partially becomes 1.

Therefore, the output of the AND circuit 41 becomes 0 as a whole as shown in FIG. 6 (h).

Since the output of the AND circuit 41 is input to the CPU 42 and 1 is not included in the signal, the CPU does not issue a distance calculation command to the distance calculation circuit 43 at this time.

Then, by driving the motor 18, the focused state shown in FIG. 4 (b) is obtained. In this focused state, the image on the CCD array 3 by the lens 1 is as shown in FIG. 7 (a). The image of the object 5 is formed in the center in a sufficiently focused state. On the other hand, CCD array 4 with lens 2
The upper image is as shown in FIG. 7B, and the image of the object 5 is formed in the center in a sufficiently focused state. The image on the CCD array 4 is the same as the image on the CCD array 3. 7 (a) and 7 (b) are CCD arrays 3 and 4, respectively.
Corresponds to the image information signal output from.

Therefore, the differential signals output from the differentiating circuits 33 and 34 are as shown in FIGS. 7 (c) and 7 (d), respectively. Since the image information signal has a very steep edge portion E because the image on the CCD array is in a sufficiently focused state, the edge portion E has a sufficiently large absolute value in the differential signal. .

As described above, since the outputs of the CCD arrays 3 and 4 are the same, the differential signals output from the differentiating circuits 33 and 34 are also the same, so that the difference signal output from the difference circuit 35 is shown in FIG. ), It becomes 0 as a whole. Incidentally, in FIG. 7 (e), the dotted line shows the difference signal one screen before, that is, the output of the delay circuit 37.

Along with this, the output signal of the difference circuit 38 becomes as shown in FIG. 7 (e ').

Therefore, since the input signal to the comparison circuit 40 includes a portion whose absolute value is larger than the threshold value set in the comparison circuit, the output signal of the comparison circuit is shown in FIG. 7 (f). It becomes 1 partly as shown.

On the other hand, the absolute value of the input signal to the comparator circuit 39 is smaller than the threshold value set in the comparator circuit, so that the output signal of the comparator circuit as a whole is as shown in FIG. 7 (g). Will be 1.

Therefore, the output of the AND circuit 41 is partially 1 as shown in FIG. 7 (h).

The output of the AND circuit 41 is input to the CPU 42, and since 1 is included in the signal, the CPU issues a distance calculation command to the distance calculation circuit 43 at this point, and the distance calculation circuit drives the motor. Based on the moving distance ΔL of the CCD array 4 obtained through the information on the moving distance ΔF of the lenses 1 and 2 input from the circuit 32, the following relational expression X = L ′ · F ′ / ΔL = L · F / ΔL Is used to calculate the distance X to the object 5.

The value of the calculated distance X is input to the CPU 42, and the AND
The distance is stored in the memory 44 as the distance corresponding to the portion 1 included in the output signal of the circuit 41. Incidentally, FIG. 7 (f),
In (h), two 1's are shown in the signal corresponding to the respective edge portions E, but it is possible to remove the portions other than the portions exactly corresponding to the edge portions by appropriate processing.

FIG. 8 shows the change of the absolute value of the output signal of the difference circuit 35 with respect to the change of the distance between the CCD arrays 3 and 4 when focusing on the edge portion E of the image shown in FIG. 7 in the above embodiment. It is a figure which shows schematically.

In the present embodiment, the distance between the CCD arrays is detected while the output of the difference circuit 35 suddenly becomes 0 while changing the distance between the CCD arrays. Therefore, it is easy to detect the focus state and the detection accuracy is high. Is high enough.

In the above embodiment, an example in which the edge portions of the object are equidistant at two places is shown, but in general, there are many such object edge portions at various distances in the surrounding environment. , The movement of the lens and the CCD array from the state of focusing at infinity as shown in FIG. 4 (a) to the state of further focusing at a close distance through the state as shown in FIG. 4 (b). By performing the above, the distance measurement is executed for each edge portion, and the distance distribution is measured.

In the above embodiments, the distance between the lenses at the time of sequentially reading and outputting the image signals, that is, the distance between the lenses at the time of sequentially reading the image signals can be appropriately set according to desired specifications to improve the measurement accuracy. Further, the first threshold value in the comparison circuit 40 and the second threshold value in the comparison circuit 39 are such that the first threshold value is a relatively large value and the second threshold value is almost zero. As a relatively small value, it can be appropriately set according to desired specifications.

In the above embodiment, the output of the difference circuit 35 is digitized by the A / D converter 36, but the digitization of the signal is not limited to this stage, and for example, the outputs of the CCD arrays 3 and 4 are immediately digitized. Alternatively, it may be digitized at any other suitable stage.

In the above embodiment, the lenses 1 and 2 and the CCD array 4 are moved while maintaining a predetermined relationship by using the mechanism shown in FIGS. 1 and 2, but the movement of the lenses and the CCD array is independent. It is also possible to drive with a driving means such as a pulse motor and maintain a predetermined relationship during this movement by a control signal from the CPU 42.

In the above embodiment, the pulse motor is used to drive the convergence adjusting mechanism, but in the present invention, another servo motor is used to drive the mechanism and a sensor for detecting the distance between the two illuminance distribution measuring means is used. You may arrange separately.

In the above-described embodiment, the movement of the lens barrels 11 and 12 is directly driven by the drive motor, and the CCD array 4 is driven based on the driving force. However, in the present invention, the movement of the illuminance distribution measuring means is directly driven to drive the driving force. Based on the above, the movement of the optical system may be driven.

Further, although only one of the two CCD arrays is moved in the above-mentioned embodiment, two illuminance distribution measuring means can be moved in the present invention.

Although the illuminance distribution measuring means is a CCD array in the above embodiment, the illuminance distribution measuring means may be other means in the present invention, particularly a two-dimensional image sensor. . In the case of a two-dimensional sensor, the direction of the main scanning line is set as the base line direction, and the processing as shown in the above embodiment may be executed for each line, whereby the distance distribution in a predetermined visual field range is measured. It

[Effects of the Invention] According to the distance distribution measuring method of the present invention as described above, the in-focus state is detected based on the differential signal of the illuminance distribution measured by the illuminance distribution measuring means, and then the in-focus state is detected. Since the distance to the state portion is calculated based on the arrangement of the optical system or the like, it is possible to prevent measurement errors due to pseudo correspondence that may occur in the correlation method, and the measurement accuracy is greatly improved.
Further, according to the method of the present invention, the number of decompositions in the direction of distance measurement can be increased to about the light receiving element of the illuminance distribution measuring means. Further, according to the method of the present invention, the arithmetic processing is easier than the correlation method.

Further, according to the congestion adjusting mechanism of the present invention as described above,
With one driving source, both the optical system and the illuminance distribution measuring means can be moved while maintaining a predetermined relationship to realize convergence adjustment in the distance distribution measurement, thus simplifying control in the distance distribution measurement and measurement. The accuracy can be improved.

[Brief description of drawings]

1 and 2 are schematic configuration diagrams of the mechanism of the present invention for carrying out the method of the present invention. FIG. 3 is a block diagram showing the configuration of an apparatus for carrying out the method of the present invention. 4 (a) and 4 (b) are optical diagrams in an apparatus for carrying out the method of the present invention. 5, 6 and 7 are diagrams showing signals in an apparatus for carrying out the method of the present invention. FIG. 8 shows a CCD in a device for carrying out the method of the present invention.
It is a figure which shows the signal change at the time of a distance change between arrays. 9 (a) and 9 (b) are diagrams for explaining the principle of the stereo method. 10 (a), (b) and (c) are diagrams for explaining the principle of the correlation method. 1,2: Lens, 1A, 2A: Optical axis, 3,4: CCD array, 5: Object, 6,
7: image, 11, 12: lens barrel, 20: crank lever, 22, 23: support.

Claims (4)

[Claims] 1. Two optical systems having substantially the same focal length are arranged such that their optical axes are parallel to each other, and an illuminance distribution measuring means is arranged behind each optical system at the same distance and perpendicular to the optical axis. Then
While maintaining the ratio of the distance between the optical system and the illuminance distribution measuring means and the distance between the two illuminance distribution measuring means substantially constant, the distance between the optical system and the illuminance distribution measuring means and the distance between the two illuminance distribution measuring means are set. The illuminance distribution is measured by each illuminance distribution measuring means while changing, the two illuminance distributions are respectively differentiated with respect to the position, and corresponding signals whose absolute values are equal to or more than a predetermined value are extracted from the two differentiated signals. And the focal length of the optical system and the positional relationship between the two optical systems and the two illuminance distribution measuring means at that time, the distance to the object is calculated for the corresponding signal position.
Distance distribution measurement method. 2. When extracting a corresponding signal whose absolute value is equal to or more than a predetermined value from the two differential signals, the differential signal is intermittently obtained while changing the interval between the optical system and the illuminance distribution measuring means. A difference between the signals is created, a difference between the difference and the previous difference is obtained, and it is determined whether or not the absolute value of the difference has transitioned from a state of being larger than a predetermined value to a state of being smaller. The distance distribution measuring method according to claim 1. 3. The distance distribution measuring method according to claim 1, wherein the two illuminance distribution measuring means are substantially equivalent. 4. An optical system having two optical systems having substantially the same focal length and juxtaposed such that their optical axes are parallel to each other, and an illuminance distribution measuring means juxtaposed corresponding to the optical systems. The distance between the optical systems is relatively variable with respect to the distance between the illuminance distribution measuring means, and the illuminance distribution measuring means is movable in the optical axis direction relative to the optical system. The system and the illuminance distribution measuring means are directly or indirectly connected by a crank lever which is rotatable about a direction perpendicular to a plane formed by the optical axes of the two optical systems as an axis. At least one of the two optical systems and the illuminance distribution measuring means is moved so that the relative positional relationship between the optical system and the illuminance distribution measuring means is changed with the rotation of the crank lever. During this movement, the optical system Wherein the ratio of the distance between the distribution measurement means and the distance between the two illuminance distribution measuring means is given as approximately is kept constant, the congestion combined mechanism.