JPH0827185B2 - Distance distribution measurement method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a distance distribution measuring method, and more particularly to a method for optically measuring a distance distribution to an object in the surrounding environment.
Such a distance distribution measuring method is effectively used, for example, as a visual means for environment recognition of an 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.

FIGS. 8A and 8B are views 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. 8A, 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. 8B, 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 amount of deviation D of the image 107 from the optical axis 102A with 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. .

9 (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. 9A, a CCD array 103, which is a measuring unit 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.

The illuminance distributions in the standard visual field and the reference visual field as shown in FIG. 9 (a) are as shown in FIG. 9 (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, from the CCD arrays 103 and 104, outputs corresponding to the respective light receiving elements as shown in FIG. 9C are obtained.

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, it is an object of the present invention to solve the above-mentioned problems of the prior art and to provide an optical distance distribution measuring method capable of easily performing 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. An illuminance distribution measuring unit is arranged behind each optical system at the same distance and perpendicular to the optical axis, and the relative positions of the two optical systems and the two illuminance distribution measuring units have a predetermined relationship. The illuminance distribution is measured by each illuminance distribution measuring means while changing the optical axis direction and the arrangement direction of the optical system perpendicular to the optical axis so that the illuminance distribution is measured.
The two illuminance distributions are differentiated with respect to each position, and it is detected that the corresponding signals in the two differentiated signals are in the arrangement relationship indicating the in-focus state, and the two optical systems and the two illuminance distributions are measured at the time of detection. A distance distribution measuring method, characterized in that the distance to the object is calculated for the corresponding signal position based on the positional relationship of the means.

[Examples] Hereinafter, specific examples of the present invention will be proved with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of an apparatus for carrying out a distance distribution measuring method according to the present invention, and FIGS. 2 (a) and 2 (b) are partial schematic views of the apparatus. .

In FIGS. 2A and 2B, 11 is a lens barrel of the lens 1, and the lens barrel is fixed to a frame (not shown).
1A is the optical axis of the lens 1. Reference numeral 12 is a lens barrel of the lens 2, and a pair of accessory members 12a extending in the base line direction are attached to the lens barrel.
12b is attached. Guide elongated holes 13a and 13b extending in the base line direction are formed in the accessory members, respectively. 1
4a and 14b are guide pins fixed to a frame (not shown), and these are the guide elongated holes 13a and 13b, respectively.
Is fitted to. The lens barrel 12 also has a direction orthogonal to both the optical axis direction and the base line direction (hereinafter referred to as P direction).
A guide pin 15 is attached so that the guide pin 15 can be projected. Above lens
The focal lengths of 1 and 2 are both F.

Reference numeral 16 is a crank lever, which has two arms 16a and 16b that are substantially orthogonal to each other. The arm 16a extends substantially in the optical axis direction, and the arm 16b extends substantially in the base line direction. These two
A rotating shaft 16c 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 17a extending in a direction toward the center of the rotating shaft 16c is formed at the tip of the arm 16a, while a direction toward the center of the rotating shaft 16c is formed at the tip of the arm 16b. A guide elongated hole 17b extending in the direction is formed. The guide pin 15 attached to the lens barrel 12 is fitted in the guide elongated hole 17a.

Reference numerals 3 and 4 denote 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 support 18 along the base line direction. A guide pin 19 projecting in the P direction is attached to the support. The guide pin is fitted in the guide elongated hole 17b. Further, a guide elongated hole 20 extending in the optical axis direction is formed in the support 18. Reference numerals 21a and 21b are guide pins aligned in the optical axis direction and fixed to a frame (not shown), and the guide pins are fitted into the guide elongated holes 20.

A drive means for reciprocating the support in the optical axis direction is connected to the support 18. The driving means comprises a pulse motor 22, a male screw member 23 attached to the drive rotating shaft of the motor, and a female screw member 24 attached to the support so as to engage with the male screw member.

In FIG. 2A, the center of the lens 1 and the lens 2
Of the CCD 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, 2 And CCD
The arrays 3 and 4 are separated from each other by the focal length F of the lenses 1 and 2.

FIG. 2 (b) shows a state in which the crank lever 16 is rotated about the rotation shaft 16c counterclockwise in the figure by an angle θ from the state of FIG. 2 (a). With this rotation,
The lens barrel 12 moves to the left in the figure by a distance ΔL in the base line direction based on the connection relationship between the guide elongated holes 17a and the guide pins 15 and the connection relationship between the guide elongated holes 13a and 13b and the guide pins 14a and 14b. On the other hand, this rotation causes the support 18 to move into the guide slot 17b.
Based on the connection relationship between the guide pin 19 and the guide pin 19 and the connection relationship between the elongated guide hole 20 and the guide pins 21a and 21b, it moves downward in the figure by a distance ΔF. Then, in FIG. 2 (b), the distance between the lens 1 and the lens 2 is L '(= L-Δ
L), and the distance between the lenses 1 and 2 and the CCD arrays 3 and 4 is F '(= F + ΔF).

Here, when the arm 16a of the crank lever 16 is in the optical axis direction, the distance from the center of the rotating shaft 16c of the crank lever 16 to the center of the guide pin 15 attached to the lens barrel 12 is A.
Let L be the distance from the center of the rotary shaft 16c to the center of the guide pin 19 attached to the support 18 (A is a constant of proportionality).

In this case, if the rotation angle θ (radian) is small, it can be approximated as ΔL = A · L · θ ΔF = A · F · θ, and therefore L ′ · F ′ = (L−A · F · θ ) · (F + a · F · θ) = a ^{L · F-a 2 LFθ 2} . When θ is small, A ² LFθ ² can be ignored, so that L ′ · F ′ = L · F can be approximated.

In FIG. 1, 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 input to the difference circuit 38 at the same time. 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, and an AND signal of both input signals is obtained here.

 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 control circuit for controlling the clock of the operation of each block of the device.

Hereinafter, the operation of the apparatus of the present embodiment, that is, one embodiment of the method of the present invention will be described with reference to FIGS. 1 and 2 and further to FIGS.

3 (a) and 3 (b) are optical diagrams for explaining the details of the measurement in the present embodiment.

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

First, as shown in FIG. 3 (a), the distance between the lenses 1 and 2 is set to the same L as the distance between the CCD arrays, 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. 4 (a), 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. 4 (b), and the image of the object 5 is formed in a position deviated from the center to the right in a blurred state. The image on the CCD array 4 is an image obtained by moving the image on the CCD array 3 rightward by a predetermined distance.
Incidentally, FIGS. 4A and 4B 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. 4 (c) and 4 (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. 4 (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. 4 (f). It becomes 0 as a whole.

On the other hand, since the absolute value of the input signal to the comparison circuit 39 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. 4 (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 almost similar to that in the above case and is slightly closer to the focused state. However, the image on the CCD array 4 is such that 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. 3 (b) shows a state in which the distance between the lenses 1 and 2 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 22. This corresponds to the state shown in FIG. 2 (b).

In the present embodiment, when the crank lever 16 rotates, ΔL and ΔF change while maintaining the relationship of L ′ · F ′ = L · F as described above, so 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. 3 (a) and 3 (b),
Since L ′ · F ′ = LF, the following holds: LF = (L−ΔL) (F + ΔF). Further, from the similarity relationship in FIG. 3 (b), (L−ΔL) / X = L / [X + (F + ΔF)] holds. From these equations, 1 / F = 1 / X + 1 / (F + ΔF) is derived. From this, it can be seen that the object 5 and the images 6 and 7 in FIG. 3 (b) satisfy the formulas for focusing images with respect to 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 is as shown in FIG. 5 (a), and the image of the object 5 is almost close to 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. 5 (b), and the image of the object 5 is slightly defocused to the right from the center while the image of the object 5 is slightly blurred near the focused state. Has been formed. The image on the CCD array 4 is an image obtained by moving the image on the CCD array 3 rightward by a slight 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 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. 5 (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. 5 (e ').

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

On the other hand, since the input signal to the comparison circuit 39 has a portion whose absolute value is larger than the threshold value set in the comparison circuit, the output signal of the comparison circuit is as shown in FIG. 5 (g). Partially becomes 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.

Then, by driving the motor 22, the in-focus state shown in FIG. 3 (b) is obtained. In this in-focus state, the image on the CCD array 3 by the lens 1 is as shown in FIG. 6 (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. 6B, 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. 6 (a) and 6 (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. 6 (c) and 6 (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 which are the outputs of the differentiating circuits 33 and 34 are also the same. Therefore, the difference signal which is the output of the difference circuit 35 is shown in FIG. ), It becomes 0 as a whole. 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 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. 6 (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. 6 (g). Will be 1.

Therefore, the output of the AND circuit 41 is partially 1 as shown in FIG. 6 (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 lens 2 obtained through the information on the moving distance ΔF of the CCD arrays 3 and 4 input from the circuit 32, the following relational expression Z = 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. 6 (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. 7 shows the change in the absolute value of the output signal of the difference circuit 35 with respect to the change in the distance between the lenses 1 and 2 when focusing on the edge portion E of the image shown in FIG. 6 in the present embodiment as described above. It is a figure which shows schematically.

In the present embodiment, the inter-lens distance at which the output of the difference circuit 35 suddenly becomes 0 is detected while changing the inter-lens distance. Therefore, it is easy to detect the in-focus state and the detection accuracy is sufficient. Very expensive.

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 CCD array from the state of focusing at infinity as shown in FIG. 3 (a) to the state of further focusing at a close distance through the state as shown in FIG. 3 (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 lens 2 and the CCD arrays 3 and 4 are moved while maintaining a predetermined relationship by using the mechanism shown in FIG. 2, but the movement of the lens and the CCD array is independently pulsed. It is also possible to drive by a driving means such as a motor and maintain a predetermined relationship during this movement by a control signal from the CPU 42.

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 present invention as described above, it is detected that an in-focus state is achieved based on the differential signal of the illuminance distribution measured by the illuminance distribution measuring means, and then the in-focus state portion is detected. Since the distance is calculated based on the arrangement of the optical system or the like, it is possible to prevent a measurement error due to a pseudo correspondence that may occur in the correlation method, and the measurement accuracy is significantly improved. Further, according to 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 present invention, the arithmetic processing is easier than the correlation method.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an apparatus for carrying out the method of the present invention. 2 (a) and 2 (b) are partial schematic views of an apparatus for carrying out the method of the present invention. 3 (a) and 3 (b) are optical diagrams in an apparatus for carrying out the method of the present invention. FIGS. 4, 5 and 6 show the signals in the device for carrying out the method according to the invention. FIG. 7 is a diagram showing a signal change when the distance between lenses is changed in the apparatus for carrying out the method of the present invention. FIGS. 8A and 8B are views for explaining the principle of the stereo method. 9 (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, 16, 26: crank lever, 18: 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 changing the positional relationship between the two optical systems and the two illuminance distribution measuring means with respect to the optical axis direction and the alignment direction of the optical system perpendicular to the optical axis such that their relative arrangements maintain a predetermined relationship. The illuminance distribution measuring unit measures the illuminance distribution, differentiates the two illuminance distributions with respect to each position, and detects that the corresponding signals of the two differentiated signals have a positional relationship indicating focusing, and at the time of this detection. Above 2
A distance distribution measuring method, characterized in that a distance to an object at the corresponding signal position is calculated based on a positional relationship between one optical system and the two illuminance distribution measuring means. 2. An absolute value of the corresponding signal is equal to or more than a predetermined value, and when detecting that the corresponding signals of the two differential signals are in a positional relationship indicating focusing, an optical system and an illuminance distribution measuring means are provided. The differential signal is intermittently obtained while changing the interval of, the difference between the two differential signals is created, the difference between the difference and the previous difference is obtained, and the absolute value of the difference is larger than the predetermined value. The distance distribution measuring method according to claim 1, wherein it is determined whether or not the state has changed to a small state. 3. When the positional relationship between the two optical systems and the two illuminance distribution measuring means is changed, the distance between the optical axes of the two optical systems is changed and the distance between the two illuminance distribution measuring means is constant. The distance distribution measuring method according to claim 1, wherein the product of the distance between the optical axes of the two optical systems and the distance between the optical system and the illuminance distribution measuring means is maintained substantially constant. 4. The distance distribution measuring method according to claim 3, wherein the two illuminance distribution measuring means are substantially equivalent.