Position measurement apparatus and method using laser

• US 6,697,147 B2
• Filed: 11/07/2002
• Issued: 02/24/2004
• Est. Priority Date: 06/29/2002
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Ko, Won-Jun, Yang, Soo-Sang
• Primary Examiner(s): Tarcza; Thomas H.
• Assistant Examiner(s): Andrea; Brian K
• Application Number:
  US10/289,300
• Publication Number:
  US 20040001197A1
• Time in Patent Office: 474 Days
• Field of Search: 356/152.1,139.03,152.2,4.03 348/135,136,142,140 702/159 901/47,46 382/106
• US Class Current: 356/4.03
• CPC Class Codes: G01C 3/08 Use of electric radiation detectors

Abstract

A position measurement apparatus and method using laser includes a laser generating device, an image device, and a control unit. The laser generating device generates three or more laser beams progressing in parallel with each other at regular intervals. The image device obtains a picture for three or more points formed on a target by the laser beams. The control unit calculates a position relative to the target using number of pixels between pairs of neighboring ones of the three or more points in the picture. Thus, the present invention is advantageous in that laser pointers and a CCD camera having simple constructions and low prices are used, so that the position measurement apparatus is handled conveniently and is economical.

Claims

1. A position measurement apparatus, comprising:

a laser generating unit to generate three or more laser beams progressing in parallel with each other at regular intervals;

an image unit to obtain a picture for three or more points formed on a target by the laser beams; and

a control unit to calculate a position relative to the target using numbers of pixels between pairs of neighboring ones of the three or more points in the picture.

2. The position measurement apparatus according to claim 1, wherein the laser generating unit comprises:

laser pointers installed to allow the three or more points to be positioned on a straight line.

3. The position measurement apparatus according to claim 2, wherein a point formed by a center one of the laser pointers is displayed at a center position on a screen of the position measurement apparatus.

4. The position measurement apparatus according to claim 1, wherein the image unit is configured so that a focus thereof is set to be in a same direction as an indicating direction of the laser pointers.

5. The position measurement apparatus according to claim 1, wherein the control unit detects the numbers of pixels between pairs of neighboring ones of the three or more points, and calculates an actual distance between the target and the image unit using the numbers of pixels obtained by the detection if the numbers of pixels are the same.

6. The position measurement apparatus according to claim 5, wherein the actual distance between the target and the image unit device is calculated by the following Equation:

$L=k<br><br>\frac{1}{x-b}$

where L is the actual distance between the target and the image unit device, x is a sum of the numbers of the pixels between the pairs of neighboring ones of three points in the picture, and k and b are constants.

7. The position measurement apparatus according to claim 1, further comprising:

a picture processing unit to detect position information of the points by filtering the picture, wherein the control unit measures the relative position using the position information detected by the picture processing unit.

8. The position measurement apparatus according to claim 1, wherein the position measurement apparatus is mounted on a mobile robot to measure a relative position of the mobile robot to a surrounding target.

9. A position measurement method, comprising:

generating three or more laser beams progressing in parallel with each other at regular intervals;

obtaining a picture for three or more points formed on a target by the laser beams; and

calculating an angle between each of the laser beams and the target, and a distance between an image device to obtain the picture and the target using numbers of pixels between pairs of neighboring ones of the three or more points in the picture.

10. The position measurement method according to claim 9, wherein the calculating comprises:

detecting the numbers of pixels between the pairs of neighboring ones of the three or more points; and

calculating the distance between the target and the image device using the numbers of pixels obtained by the detection if the numbers of pixels are the same.

11. The position measurement method according to claim 10, wherein the distance between the target and the image device is calculated by the following Equation:

$L=k<br><br>\frac{1}{x-b}$

where L is the distance between the image device and the target, x is a sum of the numbers of pixels between the pairs of neighboring ones of three points in the picture, and k and b are constants.

12. The position measurement method according to claim 9, wherein the calculating is performed so that position measurement is executed by detecting position information of the points by filtering the picture.

13. A position measurement method, comprising:

obtaining a picture of points provided on a target on which lasers are incident; and

measuring a position of a mobile object relative to an angle and a distance of the mobile object to the target using numbers of pixels between the points in the picture.

14. The method according to claim 13, wherein the measuring of the position of the mobile object is performed in real time.

15. An apparatus comprising:

a motor controllable to move the apparatus;

lasers to generate laser beams;

an image unit to obtain a picture of laser points formed on a target by the laser beams; and

a control unit to calculate a position of the apparatus relative to the target using numbers of pixels between the laser points shown in the picture, and to control the motor to move the apparatus in accordance with the calculated position.

16. A computer readable medium encoded with processing instructions for implementing a position measurement method performed by a computer, the method comprising:

obtaining a picture of points provided on a target on which lasers are incident; and

measuring a position of a mobile object relative to an angle and a distance of the mobile object to the target using numbers of pixels between the points in the picture.

17. An apparatus comprising:

first and second lasers to generate first and second laser beams to be incident on a target;

an image unit to obtain a picture of points formed on a target by the first and second laser beams;

a rotation correction unit which rotates the image unit such that an average path of the first and second laser beams is perpendicular to the target; and

a control unit to calculate a position relative to the target using numbers of pixels between the points in the picture.