Device and method for determining the position of a point

• US 6,279,246 B1
• Filed: 10/21/1999
• Issued: 08/28/2001
• Est. Priority Date: 04/21/1997
• Status: Expired due to Term

• Current Assignee: 3D Scanners Ltd. (Nikon Corporation)
• Original Assignee: Krypton Electronic Engineering NV
• Inventors: van den Bossche, Alex
• Primary Examiner(s): Fulton, Christopher W.
• Application Number:
  US09/403,386
• Time in Patent Office: 677 Days
• Field of Search: 335/56, 33/1.CC, 335/03, 335/04, 335/57, 335/58, 335/59, 335/60, 335/61, 33/1.MP, 332/86, 332/88, 356/375
• US Class Current: 33/556
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques
• CPC Class Codes: G01B 11/002 for measuring two or more coordinates
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01C 15/00 Surveying instruments or accessories not provided for in groups G01C1/00 - G01C13/00
• CPC Class Codes: G01S 5/163 Determination of attitude using inertial means G01C9/00; control of attitude G05D1/49

Abstract

The invention concerns a method for determining the position of a point, in which use is made of a holder (1) with a measuring point (6) and at least three reference points (2, 3, 4), where said measuring point (6) is placed against the point which it is wished to measure, the position of said reference points (2, 3, 4) is measured and the position of said point is calculated, in which use is made of a holder (1) on which the position of said measuring point (6) is determined by holding the latter at a fixed point, rotating the holder (1) in various relative positions, then measuring the positions of the reference points (2, 3, 4) for at least two different positions of the holder (1), and calculating the relative position of the measuring point (6) with respect to the reference points (2, 3, 4).

Claims

1. Method for determining the position of a point, in which use is made of a holder (1) with a measuring point (6) and at least three reference points (2, 3, 4) not in a straight line, where said measuring point (6) is placed against the point which is to be measured, the position of said reference points (2, 3, 4) is then measured, and on the basis of the position of said reference points (2, 3, 4), the position of said point is calculated, whereby the position of said measuring point (6) is determined by holding the latter at a fixed point, rotating the holder (1) in various positions, then measuring the positions of the reference points (2, 3, 4) for at least two different positions of the holder (1), and calculating the relative position of the measuring point (6) with respect to the reference points (2, 3, 4) from the measured positions of said reference points (2, 3, 4).

2. Method according to claim 1, characterised in that said holder (1) is rotated in different positions with respect to said measuring point (6).

3. Method according to claim 1, characterised in that said holder (1) is rotated in different positions with respect to a rotation point (8), at a known distance (r) from said measuring point (6), where the relative position of said rotation point (8) with respect to the measuring point (6) is determined from the direction of movement of said holder (1) when said measuring point (6) is placed against the point whose position is to be determined.

4. Method according to claim 1, characterised in that the position of said reference points (2, 3, 4) is measured several times for the same position of the holder (1), where an average position is determined for at least three reference points (2, 3, 4), and the relative position of the measuring point (6) or of said point is calculated from the average position of at least three reference points (2, 3, 4).

5. Method according to claim 1, characterised in that the position of a point on an object is determined by measuring the position of said reference point (2, 3, 4) for at least one position of the holder (1) where the measuring point (6) is placed against said point, and the position of said point, which essentially corresponds with the position of the measuring point, is then calculated from the positions of said reference points (2, 3, 4).

6. Method according to claim 1, characterised in that light points such as light-emitting diodes (LEDs) are used for said reference points (2, 3, 4).

7. Method according to claim 1, characterised in that said reference points (2, 3, 4) are observed from at least two different positions by a preferably addressable camera.

8. Method according to claim 1, characterised in that it is sensed when said detector (1) is essentially stationary, and the position of the reference points (2, 3, 4) is measured when said detector (1) is essentially stationary.

9. Method according to claim 1, wherein said holder (1) is used with an interchangeable measuring pin (5) whose free end forms the above-mentioned measuring point (6).

10. Device for applying the method as defined in claim 1, said device comprising:

a holder (1) provided with at least three reference points (2, 3, 4) and a measuring point (6); and

detectors which operate with a calculating mechanism to determine the position of said reference points (2, 3, 4), wherein said device further comprises a measuring pin (5) detachably mounted on said holder (1) and defining said measuring point.

11. Device according to claim 10, characterised in that said detectors comprise at least two addressable optical cameras.

12. Device according to claim 10 or 11, characterized in that said reference points (2, 3, 4) consist of light points, more specifically light-emitting diodes (LEDs).

13. Device according to claim 10 or 11, characterised in that at least some of said reference points (2, 3, 4) are located on a circle which encloses said holder (1), such that the position of at least three reference points (2, 3, 4) can be observed and measured by said detectors, independently of the position of said holder (1).

14. Device according to claim 10 or 11, characterised in that it comprises a switch that enables a signal to be given whenever the holder (1) is stationary or the measuring point (6) is placed against a point to be measured, where this signal determines when the position of said measuring point (6) has to be measured.

15. Device according to claim 14, characterised in that said switch is provided on the holder (1).

16. Method for calibrating a holder (1) with a measuring point (6) and at least three reference points (2, 3, 4) not in a straight line, characterised in that said measuring point (6) of the holder (1) is kept at a fixed position, then the holder (1) is rotated in various positions, the positions of the reference point (2, 3, 4) are measured for at least two different positions of the holder (1), and the relative position of the measuring point (6) with respect to the reference points (2, 3, 4) is calculated from the relative positions of the reference points (2, 3, 4).