JP3346937B2 - Range finder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a range finder, and more particularly to a range for calculating the position of an irradiation point by triangulation by observing the irradiation point of a light beam on a work object in a three-dimensional space in robot operation. About the finder.

[0002]

2. Description of the Related Art Recent research on robots is mainly aimed at autonomy of the robot, and it is indispensable to measure the work environment, that is, the position of the work target object, in order for the robot to operate autonomously. . As one of the methods, there is a three-dimensional position measurement of a work target object using a laser range finder.

As shown in FIG. 7, in this three-dimensional position measurement, an operator 19 uses an image input to the TV monitor 3 from two cameras 6 and 7 that put an object to be worked in the field of view. The measurement target position is confirmed on the object, and the position is irradiated with the laser spot by the light beam 8 from the laser light source 4. The operator 19 moves the laser spot with the joystick 2 or the like while checking on the TV monitor 3. Thereafter, the position of the laser spot on the input image plane from the two cameras 6 and 7 is measured, and the three-dimensional position of the measurement target is calculated according to the principle of triangulation.

[0004]

However, even if the laser spot is continuously moved by operating the joystick 2, the work target may not be continuously tracked by the laser spot on the image plane of the TV monitor 3.

[0005] For example, as shown in FIG.
When scanning the laser spot from 1 to the bus 20 located in front of the building 21, the scanning line 23 moves from the building 21 to the bus 20 at the point where the light beam 8 is moved by the joystick 2 or the like.
Is continuously changed horizontally, but changes discontinuously on the image plane of the TV monitor 3.

[0006] Such a discontinuity is usually unavoidable as long as the work object irradiated with the laser spot has a depth.

On the other hand, due to such discontinuity, it is unexpectedly difficult to scan the light beam 8 to irradiate a laser spot to a desired position to be measured, and this imposes a considerable burden on the operator. Therefore, there has been a problem that the measurement operation time becomes long.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to designate a target point for position measurement on a work object on a monitor screen and easily irradiate the target point with a light beam. It is an object of the present invention to provide a screen instruction type range finder capable of shortening a measurement time of an irradiation point position and reducing a burden on an operator.

[0009]

In order to achieve the above object, a range finder of the screen instruction type according to the present invention comprises:
A rangefinder that irradiates a light beam emitted from a light source onto a work object, observes the irradiation point with a camera, and calculates the position of the irradiation point by triangulation, and uses a camera to measure the target area including the target point for position measurement. Monitor means for copying and monitoring the image taken by this camera on a monitor screen,
Target point designating means for designating the target point on the monitor screen, a half mirror disposed in front of the camera, and a conjugate plane at a position conjugate with the imaging plane of the camera with respect to the half mirror. Setting, the light beam can be moved to an arbitrary position on the conjugate plane by moving an emission port of the light beam in a plane parallel to the conjugate plane so that the light beam is irradiated on the conjugate plane. And a light beam moving means for moving the light beam to a conjugate point on the conjugate plane corresponding to the target point in response to an instruction from the target point indicating means.

[0010] Preferably, the light beam moving means is capable of moving the light beam to an arbitrary position on the conjugate plane so that the light beam is irradiated perpendicular to the conjugate plane. Features.

Preferably, the half mirror is disposed so as to form an angle of 45 degrees with the image forming plane of the camera.

[0012]

A conjugate plane located at a position conjugate with the imaging plane of the camera is set for a half mirror disposed in front of the camera.
Each point on this conjugate plane is one-to-one with each point on the imaging plane of the camera.
Corresponding to The target point for position measurement on the work object corresponds to an image point on the image plane, and this image point corresponds to a point on the conjugate plane. Since the image plane of the camera is monitored on the monitor screen, designating a target point on the monitor screen leads to designating a point on the conjugate plane corresponding to the target point.

In response to the instruction of the target point on the monitor screen by the target point designating means, the light beam moving means moves the light beam to a position on the conjugate plane corresponding to the designated target point.

The light beam moved to the corresponding conjugate point in this way is reflected by the half mirror and is irradiated to the target point on the work. This irradiation point is observed with a camera, and the irradiation point position is calculated by triangulation.

Here, the light beam does not necessarily need to be irradiated perpendicular to the conjugate plane. For example, when a light beam emitted from a light source is condensed and used as a point light source, and the point light source is moved on a conjugate plane, the light beam does not need to be irradiated perpendicularly to the conjugate plane. On the other hand, when irradiating a parallel light beam onto the conjugate plane, the light beam needs to be irradiated perpendicularly to the conjugate plane.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 5 shows the entire configuration of the screen-instruction type range finder according to the present embodiment. In FIG. 5, two CCD type cameras 6, 7 are arranged at predetermined intervals so as to enable triangulation. The cameras 6 and 7 are connected to the control device 1, and the control device 1 performs calculations necessary for triangulation. The images of the measurement target areas including the target point of the position measurement by the cameras 6 and 7 are observed by the operator 19 on the monitor screen of the TV monitor 3 via the control device 1.

The TV monitor 3 is connected to target point indicating means 35 such as a joystick. The target point instructing means 35 instructs the user by moving a cursor such as a cross mark to the position of the target point for position measurement on the monitor screen of the TV monitor 3.

A half mirror 5 is provided in front of the camera 6. The half mirror 5 is erected perpendicularly to a plane formed by the principal rays of the camera 6 and the camera 7, and the surface of the half mirror 5 is approximately 4
At an angle of 5 degrees. A plane conjugate with the image plane 10 with respect to the plane of the half mirror 5 is defined as a conjugate plane 14.

Light beam moving means 30 is connected to the control device 1. The light beam moving means 30 moves the light beam 8 to an arbitrary position on the conjugate plane 14 so that the light beam 8 is irradiated perpendicular to the conjugate plane 14.
In addition, when the target point is designated on the monitor screen by the target point designating means 35, the light beam moving means 30 responds to the designation by moving the light beam to a conjugate point on the conjugate plane 14 corresponding to the target point. 8 is moved.

The TV monitor 3, the laser light source 4, the cameras 6, 7 and the light beam moving means 30 are connected to the control device 1, and the control device 1 performs necessary control of a range finder of a screen instruction type.

Next, the arrangement of the half mirror 5 will be described. The half mirror 5 is arranged so as to form an optical system as shown in FIG. 3 or FIG. In FIG.
An imaging lens 9 is provided in front of the half mirror 5. The half mirror 5 is arranged in front of the camera 6 so that the reflection surface of the half mirror 5 is perpendicular to the predetermined reference plane 31. Here, the predetermined reference plane 31 is a plane formed by the imaging light beam 32 and the reflected imaging light beam 33, and the imaging light beam 32 corresponds to a target point Po and a target point Po for position measurement on the work object. The corresponding imaging point P on the imaging plane 10 of the camera 6
c, and the reflected imaging light beam 33 is a line formed by reflecting the combined light beam 32 by the half mirror 5. The half mirror 5 is arranged so as to form an angle of 45 degrees with the imaging plane 10. The conjugate surface 14 of the imaging surface 10 with respect to the half mirror 5 is the half mirrors 5 and 4
Make an angle of 5 degrees. The point conjugate of the imaging point Pc with the half mirror 5 is Pf.

Here, the light beam 8 emitted from the laser light source 4 is applied to the conjugate plane 14 so as to pass through the point Pf. If the light beam 8 is a parallel light beam, the point P
f and perpendicular to the conjugate plane 14. If the light beam 8 is not a parallel light beam on the conjugate plane 14, the light beam 8 is focused on the point Pf to form a point light source.

It should be noted that, as shown in FIG.
May be arranged before the imaging lens 9. In this case, the imaging lens 24 is disposed at a position conjugate to the half mirror 5 of the imaging lens 9, and the light beam 8 is
Then, the light is irradiated to the half mirror 5.

Next, referring to FIG.
0 etc. will be described. The light beam from the laser light source 4 is guided by an optical fiber 15.
The tip of the optical fiber 15 is connected to an optical fiber connector 16, and the optical fiber connector 16 is
It is connected to the. The optical fiber moving table 22 can be moved in a plane parallel to the conjugate plane 14 by DC motors 17 and 18 with encoders.

The end of the optical fiber connector 16 is such that the end face of the optical fiber 15 is exposed. The end face of the optical fiber 15 has a small area of about 10 μm, so that the end face of the optical fiber 15 can be regarded as forming a point light source. The position of the optical fiber connector 16 is adjusted so that the point light source formed on the end face of the optical fiber is located on the conjugate plane 14.

An imaging lens 2 is provided in front of the optical fiber end face.
4 are provided. The imaging lens 24 performs the same function as the imaging lens 9. That is, in FIG. 4, the imaging lens 24 associates the target point Po with the conjugate point Pf in the same manner as the imaging lens 9 associates the target point Po with the imaging point Pc. As a result, the light beam emitted from the point light source formed on the end face of the optical fiber is applied to the target point Po via the half mirror 5. Incidentally, as shown in FIG. 3, the imaging lens 24 can be omitted by disposing the imaging lens 9 in front of the half mirror 5.

Next, triangulation using the apparatus of this embodiment will be described. As shown in FIG.
Is formed on the image plane 10 of the camera 6 and displayed on the TV monitor screen 11 via the control device 1. Worker 1
Reference numeral 9 denotes an operation of the target point indicating means 35 such as a joystick to indicate a measurement target position of the work target 13 on the TV monitor screen 11. This measurement target position corresponds to the target point Po for position measurement. The instruction by the target point instructing means 35 is performed by moving the center of the + -shaped marker to the position to be measured and performing marking at that position, and information on the position to be measured is input to the control device 1.

The control device 1 calculates the position of the conjugate point Pf on the conjugate plane 14 corresponding to the target point Po. Based on this calculation result, a command for the amount of movement is sent to each encoder of the DC motors 17 and 18 with encoders. With this instruction,
The DC motors with encoders 17 and 18 move and drive the optical fiber moving base 22. As a result, the point light source formed on the end face of the optical fiber 15 is
Come to the position.

Next, the laser light source 4 is driven, and the light beam 8 is emitted to the work object 13 via the half mirror 5. Since the conjugate plane 14 is at a conjugate position with respect to the half mirror 14, the light beam 8 is irradiated to the target point Po on the work object 13.

In FIG. 2, the magnification between the TV monitor screen 11 and the image plane 10 of the camera 1 is m. The coordinates of an imaging point Pc having a conjugate relationship with the point Pf and points of the TV monitor screen 11 corresponding to the imaging point Pc are represented by (Xc, Yc), (X
t, Yt), the position on the imaging plane 10 is calculated by the equations (a-1) and (a-2), and the laser irradiation position is calculated. Xc = − (1 / m) · Xt (a-1) Yc = − (1 / m) · Yt (a-2) Next, a diagram of three-dimensional position measurement by two cameras based on the principle of triangulation is shown. 6 and FIG. FIG. 6 is a flowchart illustrating an algorithm of three-dimensional position measurement. As described above, the monitor screen 11
Then, the center of the + -shaped marker is moved by the target point indicating means 35 to a point Pt corresponding to the imaging point Pc of the target point Po, and marking is performed at that position, whereby information on the position to be measured is input to the control device 1. . The control device 1 calculates the position of the conjugate point Pf on the conjugate plane 14 corresponding to the target point Po. The position of the point light source formed on the end face of the optical fiber 15 is the conjugate point P
The optical fiber moving table 22 is moved by the light beam moving means 30 so as to be at the position f. Next, a laser spot is irradiated. Next, the position of the irradiation point is calculated by triangulation.

When a laser spot is irradiated on a point Po (x, y, z) in the measurement space, the position of the point P (x, y, z) is obtained according to a normal triangulation as shown in FIG. Can be In FIG. 9, two cameras 6, 7 are arranged at an interval l. The camera measurement coordinates of the position measurement system are set as shown in the figure, and the y-axis is selected to pass through the left camera optical axis direction and the x-axis is passed through the center of the right camera lens. As shown in the figure, the coordinates of the camera imaging planes having the point of intersection with the optical axis as the origin are also set on both camera imaging planes.

When a point P (x, y, z) in the measurement space is captured by the left and right cameras, the point P is expressed as P
L (xL, yL) and PR (xR) on the right camera image plane.
, YR). The position up to the point P can be known by directly using the angle when viewing the point P from the center of the left and right lenses.
The position is obtained from L (xL, yL) and PR (xR, yR). The straight lines PPL and PPR are expressed by the following equations. XL / x = f / y = yL / z (b-1) XR / (x-1) = f / y = yR / z (b-2) where f: lens focal length l: between viewpoints, (between lenses ) Distance From the equations (b-1) and (b-2), the position of the point P is yL
= YR can be obtained by the following equation. x = xL.l / (xL-xR) (c-1) y = fl / (xL-xR) (c-2) z = yL.l / (xL-xR) (c-3) According to the configuration of the present embodiment, the half mirror 5 is provided, the conjugate plane 14 of the imaging plane of the camera 6 is set, the target point Po is indicated by the target point designating means 35 on the monitor screen, and in response to this instruction. The light beam moving means 30 can move the position of the point light source formed on the end face of the optical fiber to the conjugate point Pf on the conjugate plane 14 corresponding to the target point Po. Irradiation to the point Po can be reliably and easily performed.

In the above description of the embodiment, a laser light source such as a semiconductor laser is used as the light source 4. However, the light source is not limited to a laser light source, but may be a light beam such as an LED.

The half mirror is arranged so as to form an angle of 45 degrees with the image forming plane 10 of the camera 6. However, the half mirror is not limited to 45 degrees and may be formed at another angle if the conjugate plane 14 can be provided. Good.

In the above description of the embodiment, the case where a point light source is formed on the conjugate surface 14 and the point light source is moved on the conjugate surface 14 has been described. However, the present invention is not limited to this. When a collimated light beam is used, the light beam is always radiated perpendicularly to the conjugate plane 14, and the conjugate plane 1
4 may be translated.

According to the configuration of the present invention, the light beam 8 is directed to the target point Po on the work object specified on the monitor screen.
And the position of the target point Po can be measured. Therefore, by applying the present invention, it is possible to designate a set of points on a monitor screen image, and identify the designated range with color information and shade information. Further, as described above, the distance information of the area identified by the color information and the shading information can be added by triangulation. As a result, the grayscale information and the like can be associated with the distance information, and can be used as an input device for grayscale information and distance information for image recognition.

[0037]

As described above, according to the structure of the present invention, a half mirror is provided in front of the camera to set a conjugate plane of the imaging plane of the camera, and a target point is specified on the monitor screen by the target point specifying means. In response to this instruction, the light beam moving means
Since the light beam can be moved to the conjugate point on the conjugate plane, the light beam can be reliably and easily applied to the target point on the work object. As a result, in the operation of applying the laser spot to the position to be measured, the burden on the operator can be significantly reduced, and the time required for measurement can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a configuration of an embodiment of a screen instruction type range finder according to the present invention.

FIG. 2 is a diagram showing a relationship between a TV monitor, an image forming plane of a camera, and a measurement object.

FIG. 3 is a diagram illustrating an optical system used in the present embodiment.

FIG. 4 is a diagram illustrating another optical system used in the present embodiment.

FIG. 5 is a block diagram schematically showing an embodiment of a range finder of a screen instruction type.

FIG. 6 is a flowchart showing an algorithm applied to the embodiment.

FIG. 7 is a block diagram schematically showing a conventional screen instruction type range finder.

FIG. 8 is a diagram showing an example of a conventional laser spot movement.

FIG. 9 is a principle diagram illustrating three-dimensional position measurement by triangulation with two cameras.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Control device 2 Joystick 3 TV monitor (monitor means) 4 Light source 5 Half mirror 6 CCD camera 7 CCD camera 8 Light beam 9 Imaging lens 10 Imaging surface 11 TV monitor screen 12 Image 13 Work object 14 Conjugation surface 15 Optical fiber Reference Signs List 16 optical fiber connector 17 DC motor with encoder 18 DC motor with encoder 19 worker 20 bus 21 building 22 optical fiber moving table 24 imaging lens 30 light beam moving means 35 target point indicating means

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideki Matsuzawa 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Keihin Works, Toshiba Corporation (56) References (58) Fields surveyed (Int.Cl. ⁷ , DB name) B25J 3/00-3/04 B25J 9/10-9/22 B25J 13/00-13/08 B25J 19/02-19/06 G05B 19/18-19/46 B23Q 15/00-15/28 B23Q 17/00-23/00 G01B 11/00-11/30 G01C 3/06

Claims (3)

(57) [Claims] 1. A range finder for irradiating a light beam emitted from a light source onto a work object, observing an irradiation point with a camera, and calculating an irradiation point position by triangulation, including a target point for position measurement. Shoot the target area with a camera,
Monitor means for monitoring an image taken by the camera on a monitor screen; target point designating means for designating the target point on the monitor screen; a half mirror disposed in front of the camera; A conjugate plane at a position conjugate to the image plane of the camera is set with respect to a mirror, and the light beam is irradiated on a plane parallel to the conjugate plane so that the conjugate plane is irradiated with the light beam.
The light beam can be moved to an arbitrary position on the conjugate plane by moving an emission port of the beam, and the light beam is moved to a conjugate point on the conjugate plane corresponding to the target point in response to an instruction from the target point indicating means A range finder of a screen instruction type, comprising: a light beam moving unit that moves the light beam. 2. The light beam moving means is capable of moving the light beam to an arbitrary position on the conjugate plane so that the light beam is irradiated perpendicular to the conjugate plane. Item 2. A screen instruction type range finder according to Item 1. 3. The screen pointing type range finder according to claim 1, wherein the half mirror is arranged so as to form an angle of 45 degrees with an image plane of the camera.