JPS62134516A - Range finding method - Google Patents

Abstract

PURPOSE:To make it possible to simply and easily measure the distance up to a body to be measured by one image pickup means, by mounting a camera to the other end part of a rotary arm rotating around one end part thereof and calculating the distance from one end part of the arm to the body to be measured on the basis of movement quantity from a center line by an operation means. CONSTITUTION:An arm 3 is rotated so that the image of a body to be measured moves from such a state that said image is positioned on the center line in a vertical direction passing the center of the picture of a TV camera 4 to the lateral direction of the picture and the movement quantity from the center line of the image due to the rotation of the arm 3 is calculated to calculate the distance up to the body to be measured. That is, the arm 3 is set so that the camera 4 is positioned at the intersecting point P1 of a circle C and the straight line OT connecting points O, T and the image of the body 5 to be measured and held to such a state that the image of the body 5 to be measured is positioned at the center of the light receiving surface being the picture of the camera 4. When the arm 3 is rotated by a minute angle DELTAtheta from this state and the camera 4 is moved to the point P2 on the circle C, the body 5 to be measured relatively moves to a direction shifted by the angle alpha, which is formed by the optical axis of the camera 4, that is, the straight line OP2 connecting points O, P2 and the straight line P2T connecting points P2, T, with respect to the optical axis of said camera, that is, said straight line OP2. Therefore, the angle alpha is calculated from the picked-up image by the camera 4 to easily calculate a distance D.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a distance measuring method for measuring the distance to a measured object.

[Conventional technology]

Generally, when measuring the distance to an object to be measured, ultrasonic waves are used to measure the time it takes for the ultrasonic waves from an ultrasonic oscillator to be reflected by the object to be measured and return. A method of measuring the distance to the object to be measured based on the speed was used, and two imaging means such as a television camera or a COD image sensor were used. A method of measuring distance using the so-called triangulation method, or an image obtained by irradiating the object to be measured with light from a light source such as a laser in the form of a spot or band, and capturing the irradiated area with a single imaging device. Based on this, methods for measuring distance have been applied.

[Problem that the invention seeks to solve]

However, in the case of methods that use ultrasound, it is necessary to identify whether the reflected ultrasound is coming from the object to be measured.
There are problems in that the identification process is time-consuming and the ultrasonic oscillators and sensors are very expensive.

In addition, in the case of methods that use imaging means, the object to be measured can be observed on the screen, so there is no need for identification processing as in the case of ultrasound, but on the other hand, two imaging means are required, and on the other hand, There is a problem that the light source is required and is also expensive.

Therefore, a technical object of the present invention is to easily measure the distance to the object to be measured using a simple and inexpensive configuration.

[Failure to solve the problem]

This invention was made with the above points in mind,
An imaging means is attached to the other end of a rotary arm that rotates around one end, and the image of the object to be measured is positioned on the vertical center line passing through the center of the screen of the imaging means, and the horizontal direction of the screen is The arm is rotated so that the image moves, the amount of movement of the image from the center line due to the rotation of the arm is determined, and based on the amount of movement, a calculating means is used to move the object from one end of the arm to the object to be measured. This distance measurement method is characterized by calculating the stop layer up to.

[Function] 1.7 Therefore, in the present invention, the object to be measured is imaged by the imaging means attached to the other end of the rotating arm, and the object is positioned on the vertical center line passing through the center of the screen of the imaging means. From the position of the image of the object to be measured, the amount of movement of the image of the object to be measured in the lateral direction of the screen due to the rotation of the arm is calculated, and based on this amount of movement, the calculation means calculates the amount of movement of the image of the object to be measured. The distance to the object to be measured is calculated, and the distance to the object to be measured can be easily measured without using two imaging devices, light sources, or expensive ultra-Miyagi sensors as in the past. .

Also, each time the arm is rotated by a certain minute angle,
By repeating the distance measurement operation described above, the distance to each object to be measured existing around the imaging means and the position of each object to be measured can be determined.

〔Example〕

Next, the present invention will be described in detail with reference to drawings showing one embodiment thereof.

First, in Figure 1 showing the overall configuration, (1) is the base, (2) is the pillar installed in the center of the base (1), and (3) is the base.
(4) is a rotary arm whose one end is attached to the rotating shaft of a pulse motor provided at the upper end of the support column (2) and rotates in a horizontal plane; (5) is a television camera as an imaging means that takes an image and outputs an imaging signal; (6) is a television receiver for a monitor that displays an image of the object to be measured (5) based on the imaging signal from the camera (4); It is a machine.

Roughly speaking, in Fig. 2 which shows a processing circuit that processes the image of the object to be measured (5) from the camera (4), (7) controls the arm (3) by a pulse signal as a drive control signal from a computer, which will be described later. A pulse motor that rotates the
In (8), the switching piece (8a) is connected to the camera (4), and the switching piece (8a) is connected to the camera (4) by the switching control signal from the computer.
is the first. The input terminals of the changeover switches (9a) and (9b) that switch to the second contacts (8b) and (8C) are the first and second contacts, respectively. It is connected to the second contacts (8b) and (8C), and the image based on the video signal from the camera (4) via the switch (8) is converted into 8-bit brightness of each pixel by the storage control signal from the computer. The first and second image memories, which store grayscale information, are computers, which output the above-mentioned control signals to control each part, and both memories (
9a), (based on the memory data of 91), the arm (3
) has a function as an arithmetic device that calculates the distance from one end of the object (5) to the object to be measured (5).

Next, the operation of the above embodiment will be explained.

Now, as shown in Figure 3, the center of rotation of the arm (3) is set at O.
, the length of arm (3) is r, and the object to be measured (5) is point T.
Assume that the camera (4) is located on a circle C with a radius r, and the object to be measured (5) is located in a horizontal plane containing the circle C.

Then, circle C and 2 points 0. Set the arm (3) so that the camera (4) is located at the intersection P1 with the straight line π connecting If the arm (3) is rotated by Δθ from this state and the camera (4) is moved to a point P2 on the circle C, the optical axis of the camera (4),
That is, with respect to the straight line OP2 connecting points 0 and P2, the object to be measured (5) is connected to the straight line P2 connecting the straight line and points P2 and T.
It will move relatively in a direction shifted by the angle α formed with T.

At this time, the distance the camera (4) moves due to the rotation of the arm (3) is 4. In other words, the length of the arc between points PL and P2 is Δ
θ.

1 = 2 r 5lnT-; rΔθ
It can be approximated as °°゛■, and on the other hand, the angle βI between the straight line OT and the straight line P2T, and the angle βI between the straight line OT and the straight line P2T, and the angle between the straight line P2T and the point PI
, the angle β2 formed with the straight line PIP2 connecting P2 is, respectively,
βl=α−Δθ ・・・■π
It can be expressed as Δθ...■β2sarT-".

Furthermore, if the distance between points P+ and T is m1, and the distance between points P2 and T is d, then l = d sinβl
...0m = d sinβ2
Since it is expressed as ...■, from the above formulas ■ and ■, we get the relationship yu = 2 ...■ sinβr sinβ2, and when we expand this 0 formula, we get m = l engineering L ...■sinβl, where If we assume that both Δθ and α in equations (1) and (2) are very small and close to zero, then smβ1α−Δθ.

Since Sinβ2=1, the above equation 0 becomes the above 0
Using the formula, ゛ ′ Once...α, α−Δθ α
−Δθ, the length r of arm (3) and fff
The point 0. which is the sum of imm. The distance between T is according to the above formula %
Formula % Therefore, in the above formula (■), the length r of arm (3)
is already known, and the rotation angle Δθ of the arm (3) can also be determined from the number of pulses to the pulse motor (7), so if the angle α is found from the image captured by the camera (4), the distance can be easily calculated. Next, the procedure for determining the angle α from the image captured by the camera (4) will be explained.

Now, as shown in FIG. 4, when the imaging direction of the object to be measured (5) is shifted by a small angle α with respect to the optical axis R of the camera (4), the angle on the light receiving surface S of the camera (4) is The light receiving surface S
The amount of positional deviation i from the center point M of , 1=b−α ... [phase]
Since the angle α is very small, the above [
The amount of positional deviation 1 expressed by the formula [phase] can be approximated as Mei = IJ MeIa & - (il), and if the image of the object to be measured (5) is processed to find the amount of positional deviation i, the distance Therefore,
The angle α can be easily calculated from the above equation 0.

When the camera (4) is at the position of point PI in Fig. 3, the switching control signal from the computer aO switches the switching piece (8a) of the switch (8) to the first contact (8b) side. , an image of the object to be measured (5) in a state where the image of the object to be measured (5) is located at the center of the light receiving surface of the camera (4) is stored in the first image memory (9a) by a storage control signal from the computer aO. At the same time, the arm (3) rotates Δθ and the camera (4) moves to point P2 in Figure 3.
When the computer αG is transferred to
The switching control signal from switch (8) switches month 1 (
8a) to the second contact (8C) side, the object to be measured (
The image of the object to be measured (5) after moving in the lateral direction of the light receiving surface from the state where the image of the camera (4) is located at the center of the light receiving surface of the camera (4).
5) is stored in the first image memory J (9b).

At this time, the image data stored in both memories (9a) and (9b) is the shading information of each pixel when the light-receiving surface S is divided into NXN pixels, as shown in FIG. The data of the X-th and y-th pixels in the X direction, which is the horizontal direction of S, and the Y direction, which is the vertical direction, respectively, are L(X,)')
In addition, each pixel data of the first image memory (98) is expressed as I, + (x, y), and the second image memo 11 (98) is expressed as
If each pixel data of b) is expressed as L2 (x, y), the positional shift amount i is calculated from the difference between each pixel data of both memos IJ (9a), (91)).

That is, the evaluation amount A (X) shown by the following formula can be calculated by the computer < 10, and (1 line margin) the point (g
, the degree of similarity of images near the station) is examined using the evaluation amount A(x) shown by the above formula 0, and the coordinate in the X direction of the light receiving surface S when this evaluation #A(x) is the minimum The value X is derived by computer GO, and the derived coordinate value The angle α is calculated by the computer (10), and the calculated angle α is
The distance is calculated by the computer Qf], and the distance to the object to be measured (5) is measured.

By the way, so far we have explained the case where the arm (3) rotates in a plane parallel to the horizontal plane, but let's make the arm (3) rotate in a plane perpendicular to the horizontal plane and follow the same procedure as described in E+1. , from a state where the image of the object to be measured (5) is located at the center of the light receiving surface of the camera (4), the distance to the object to be measured (5) is determined by moving the image in the vertical direction of the light receiving surface. Of course, measurement is also possible.

As noted in m1, the object to be measured (5) is still attached to the arm (3).
The object to be measured (5
) is outside the horizontal plane that includes the arm (3), the distance can be measured based on the procedure described above, and the procedure will be explained next.

As shown in FIG. 6, as in the case of FIG. 3 described above, the rotation center of arm (3) is O, the length of arm (3) is r, and the object to be measured (5) is at point ′ and the camera (
4) is on a circle C centered on point O and parallel to a horizontal plane of radius r, and the object to be measured (5) is above the horizontal plane ■ that includes the circle C, and the object to be measured (5) is The image is from the camera (4
) Set the arm (3) and camera (4) so that they are located on the vertical center line passing through the center of the light receiving surface of the camera.

Then, the position of the camera (4) at this time is a point P on the circle C.
3 and assuming a plane parallel to the light-receiving surface of the camera (4) and including point T', the straight line E corresponding to the center line on the assumed plane is the horizontal plane V and the optical axis of the camera (4). It is perpendicular to the straight line OPg connecting points 0 and Pa and passes through point T', and from this state arm (3)
When rotated by Δθ and move the camera (4) to point P4 on circle C, the optical axis of the camera (4) after movement is point 0.
, For the straight line connecting P4, the object to be measured (5)'f;
, tIJ Line OP4 point P4. T' (!: wo connection) Direct Pa Moves relatively in the direction shifted by the angle δ formed with P4T'.

By the way, when this situation is viewed from a direction perpendicular to the horizontal plane V, the point T' is the intersection point T? of the horizontal plane ■ and the straight line E? By the rotation of the arm (3) by Δθ, the object to be measured (5) moves within the horizontal plane V in the same way as in the case of FIG. 3 described above.

Therefore, the point ゛r which is the actual position of the measured object (5)
′ is regarded as the point r, and by performing the above calculation t1 using the computer GO, the distance m between the points Pa and T″ can be calculated.
', even the distance D' between points O1T' (= r 10 m'
) is calculated.

However, the actual distance from the center of rotation of the arm (3) to the object to be measured (5) is the distance between points 0 and T', and the distance D'' is the distance between points Pa and T' by m'2. Point P3.
The angle φ between the straight line PaT' connecting T' and the straight door connecting points Pa and T'' is expressed as, and the distance m is 171' = m'/roφ...
・Since it is expressed as □□□, if the angle φ is known, the above [phase]
The distance D' can be calculated from the formula and formula (2).

At this time, when an image of an object is formed on a vertical center line passing through the center of the light receiving surface S of the camera (4), each distance from the center to the image and the optical axis of the camera (4) are calculated. The relationship between the angle formed by the imaging direction of the object is determined in advance, and the image of the object to be measured (5) indicated by point T taken by the camera (4) located at point P3 is stored in the first image memory (9a). Then, when the image is processed by the computer 0, the distance j on the light receiving surface S from the center point (y,, y) of the light receiving surface S shown in FIG. 5 to the image of the object to be measured (5) is calculated. From the relationship between the derived and previously determined distance and angle, the straight line P a
It is possible to derive the angle φ between 'I' and the stone line P a 'I''', and the angle φ thus derived is substituted into the above-mentioned (knot hole, Calculation is performed and the distance to the object to be measured (5) is measured.

In addition, when deriving the mJ recording distance J, each pixel data Ls(x ,
y) and each pixel data, zL4(x,y) of the image of the object to be measured (5) stored in the second image memo IJ (9b) with the camera (4) located at point P4, N = 51
2, find out the coordinate value y of the light receiving surface S in the Y direction when the @formula becomes the minimum, and use the following formula expressed in the same way as the above formula 0, 1=y--H...0 as shown above. By substituting the derived coordinate value y, the distance, 1
．． That is, the amount of positional deviation J of the image of the object to be measured (5) on the light receiving surface S from the center of the light receiving surface S can be derived.

However, in Fig. 6, point B on the straight line E, the intersection of the B'i dimension line E and the vertical limit line of the field of view of the camera (4), and the straight line P3B connecting the points P3 and B and the point P3.
The angle φ' with the straight line PaB' connecting ゜B' is the angle φ' of the camera (4
) is the vertical viewing angle.

Also, the angle φ and the distance m derived as described above
By using the angle of elevation when looking at the point T' indicating the object to be measured (5) from the point O, that is, the straight line -δP connecting the point O1T' and the point 0. The angle ξ formed with the straight line 7 connecting T' is m♂nφ ξ=jan-' /F r-4-m curve φ... [Yes]
is the rotation angle θ of the arm (3) from the reference position.

Using the distance D' from point O to the object to be measured (5) and the angle of elevation ξ, the position of the object to be measured (5) is determined by polar drift (θ) with point O as the origin.
.

Therefore, as shown in Fig. 7, by repeating the above operation each time the arm (3) is rotated by a certain minute angle Δθ', the camera (4) can be displayed as It is possible to measure the distance to each object to be measured in the surrounding area, and at the same time, the position of each object to be measured can be determined from a point O.
can be displayed and recognized as polar coordinates with the origin as
For example, when applied to a robot's visual sensor, it becomes possible to easily recognize the position of objects around the robot.

Note that although a television camera (4) is used as the imaging means, the present invention is not limited to this, and it goes without saying that a COD image sensor, an infrared camera, or the like may be used.

〔Effect of the invention〕

As described above, according to the distance measuring method of the present invention, there is no need to use two imaging means, a light source such as a laser, or an expensive ultrasonic sensor as in the conventional method, and only one television camera ( Since only an imaging means such as 4) is required, the distance to the object to be measured (5) can be easily measured with a simple and inexpensive configuration, which is very advantageous as a distance measuring method for robots and the like.

In addition, by repeating the distance measurement operation every time the arm (3) is rotated by a certain minute angle, the camera (4)
It becomes possible to know the distance to each object to be measured that exists around the imaging means such as, and also the position of each object to be measured.

[Brief explanation of drawings]

The drawings show one embodiment of the distance measuring method of the present invention, in which Fig. 1 is a perspective view of the external appearance of the device, Fig. 2 is a block diagram of the image processing circuit, and Figs. 3 and 4 are operation explanatory diagrams. ,
FIG. 5 is an explanatory diagram of the image data stored in the image memory of FIG. 2, and FIGS. 6 and 7 are explanatory diagrams of operations in different states. (3)... Rotating arm, (4)... Television camera, (5)... Measured object, αQ... Computer.

Claims (1)

[Claims] (1) From a state in which an imaging means is attached to the other end of a rotary arm that rotates around one end, and the image of the object to be measured is located on a vertical center line passing through the center of the screen of the imaging means,
The arm is rotated so that the image moves in the lateral direction of the screen, the amount of movement of the image from the center line due to the rotation of the arm is determined, and one end of the arm is calculated by a calculation means based on the amount of movement. A distance measuring method characterized by calculating a distance from to the object to be measured.