Ranging system for three-dimensional object digitizing

• US 5,218,427 A
• Filed: 09/06/1991
• Issued: 06/08/1993
• Est. Priority Date: 09/06/1991
• Status: Expired due to Fees

• Current Assignee: Stephen K. Koch
• Original Assignee: Stephen K. Koch
• Inventors: Koch, Stephen K.
• Primary Examiner(s): EVANS, FANNIE L
• Application Number:
  US07/755,685
• Time in Patent Office: 641 Days
• Field of Search: 356/1, 356/376, 364/561
• US Class Current: 356/602
• CPC Class Codes: A61F 2/2875 Skull or cranium A61F2/2803 and A61F2/3099 take precedence
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: B33Y 50/00 Data acquisition or data processing for additive manufacturing
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G05B 19/4207 in which a model is traced or scanned and corresponding data recorded

Abstract

An apparatus for digitally representing the surface of a three-dimensional object uses a laser beam to establish a laser line-of-sight from the laser source having a predetermined position to a surface point on the three-dimensional object. The laser beam produces a reflected light beam that a reflecting surface or mirror receives along a view line-of-sight from the surface point through an aperture. By way of triangulating a laser line-of-sight, a view line-of-sight, and a base line-of-sight, it is possible to calculate the laser line of sight distance to the three-dimensional object. The laser line of sight distance is then converted into a digital representation of the surface point on the object. By associating numerous of these surface points, it is possible to form a digital representation of the surface of a three-dimensional object. The result is a high resolution and accurate digital representation of the object surface.

Claims

1. A method for digitally representing the surface of a three-dimensioned object, comprising the steps of:

directing a laser beam in a laser line-of-sight from a laser source to a surface point on the object to produce reflected light beams;

capturing a specific light beam reflecting from said surface point through an aperture at a predetermined angle from said laser line-of-sight;

receiving said captured light beam at a reflecting surface along a reflecting line-of-sight at said predetermined angle;

reflecting said captured light beam from said reflecting surface to a sensor along a sensing line-of-sight orthogonal to said laser line-of-sight, so that laser line-of-sight, said reflecting line-of-sight, and said sensing line-of-sight form a right triangle having predetermined angles;

measuring a sensing line-of-sight distance and calculating therefrom a laser line-of-sight distance;

converting said laser line-of-sight distance into a digital representation of said surface point; and

associating a plurality of said surface points to form a digital representation of the surface of the three-dimensional object.

2. The method of claim 1, further comprising the step of:

determining whether said laser beam hits the object.

3. The method of claim 2, further comprising the step of:

redirecting said laser beam on the object upon determining that said laser beam does not strike the object.

4. The method of claim 1, further comprising the step of:

positioning said aperture and reflecting surface for each illuminates along said sensing line of sight.

5. The method of claim 4, wherein said sensing line of sight distance is determined by a position of said reflecting surface.

6. The method of claim 1, further comprising the step of:

determining a positioning angle for said reflecting surface by taking range measurements of two know points along said laser line of sight.

7. A ranging system for a three dimensional object digitizing system, comprising:

a laser source for directing a laser beam along a laser line of sight to a surface point on an object in order to produce reflected light beams;

a member having an aperture for capturing a specific light beam reflecting from said surface at a predetermined angle from said laser line of sight;

a mirror coupled to said member and for receiving said captured light beam along a reflecting line of sight and directing said captured light beam along a sensor line of sight orthogonal to said laser line of sight, said laser line of sight and said reflecting line of sight and said sensor line of sight forming a right triangle having predetermined angles;

a sensor coupled to said laser source and for receiving said captured light beam along said sensor lien of sight and determining a sensor line of sight distance in response to said captured light beam; and

a processing circuit for receiving said sensor line of sight distance and determining a laser line of sight distance for said surface point therefrom, said processing circuit determining a plurality of laser line of sight distances for a plurality of surface points to form a digital representation of said object.

8. The ranging system of claim 7, further comprising:

an incidence detector for monitoring whether said laser beam strikes said object.

9. The ranging system of claim 7, further comprising:

a collecting lens for intensifying said captured light beam as said captured light beam passes through said member to said sensor.

10. The ranging system of claim 7, wherein said member and mirror cooperatively move to capture a light beam along said reflecting line of sight at said predetermined angle to provide said sensor with said captured light beam along said sensor line of sight.

11. The ranging system of claim 10, wherein said sensor controls movement of said member and said mirror in order to place a captured light beam on said sensor line of sight.

12. The ranging system of claim 11, wherein said range measurement is taken when said captured light beam is centered on said sensor.

13. The ranging system of claim 11, wherein said sensor includes two photodiodes for positioning said member and said mirror such that said captured light beam illuminates along said sensor line of sight.

14. The ranging system of claim 13, wherein said processing circuit includes a comparator for comparing signals received from said photodiodes.

15. The ranging system of claim 14, wherein said processing circuit generates a digital output in response to said comparison.

16. The ranging system of claim 7, wherein said processing circuit determines said laser line of sight distance in response to a position of said mirror.

17. A ranging system for a three dimensional object digitizing system, comprising:

circuitry for directing a laser beam in a laser line of sight on a surface point of a three dimensional object to produce reflected light beams;

an apertural member for capturing a specific reflected light beam at a predetermined angle from said laser line of sight;

a reflecting surface for directing said captured light beam along a sensing line of sight, said sensing line of sight being orthogonal to said laser line of sight;

circuitry for sensing said captured light beam along said sensing line of sight to determine a sensing line of sight distance; and

circuitry for determining a laser line of sight distance in response to said sensing line of sight distance for a plurality of surface points on said object, said determining circuitry forming a digital representation of said three dimensional object from said laser line of sight distance.

18. The ranging system of claim 17, further comprising:

circuitry for positioning said apertural member and said reflecting surface such that said captured light beam illuminates along said sensing line of sight for each desired surface point of said object.

19. The ranging system of claim 18, further comprising:

circuitry for sensing whether said laser beam strikes said object.

20. The ranging system of claim 19, wherein said sensing circuitry controls said directing circuitry to redirect said laser beam onto said object.