Digitizer using intensity gradient to image features of three-dimensional objects

• US 6,639,684 B1
• Filed: 09/13/2000
• Issued: 10/28/2003
• Est. Priority Date: 09/13/2000
• Status: Expired due to Term

• Current Assignee: NextPat Limited
• Original Assignee: NextEngine, Inc.
• Inventors: Vuong, Kevin H., Sidney, Kent E., Tandon, Amit, Diaconescu, Peter L., Drobnis, David D., Agabra, David S., McKinley, William D., Knighton, Mark S., Logan, J. Douglas, Zheng, John Z., Bahhour, Basel F., Haynie, Jill E.
• Primary Examiner(s): Stafira, Michael P.
• Assistant Examiner(s): Barth, Vincent P.
• Application Number:
  US09/660,809
• Time in Patent Office: 1,140 Days
• Field of Search: 356/601, 356/604, 356/613, 348/26, 348/128, 382/154
• US Class Current: 356/601
• CPC Class Codes: G01B 11/2518 Projection by scanning of the object
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light
• CPC Class Codes: G06T 7/55 from multiple images

Abstract

A method and apparatus to digitize three-dimensional objects. A projection assembly is retained in fixed relation to an imaging assembly. The projection assembly projects a fixed gradient light pattern into a focal zone of the imaging assembly. The imaging assembly integrates the illumination over time such that the fixed gradient reveals the features of the three dimensional object.

Claims

1. A method comprising:

varying illumination within a focal zone over time and location to create a spatially distributed gradient of light intensity;

projecting the gradient onto an object;

capturing a measurement for a light intensity at a point on the object, which relates to location of the point along the gradient;

deriving dimensional data for the point based on the measurement; and

assembling the dimensional data along with dimensional data similarly captured for a set of other points on the object into a three-dimensional model of at least a portion of the object.

2. The method of claim 1 wherein projecting comprises:

forming a stripe of light having a width, the stripe to illuminate the object; and

moving the stripe of light across a focal zone at least until a portion of the stripe has traversed the entire focal zone.

3. The method of claim 1 wherein capturing comprises:

integrating the illumination intensity within the focal zone during one capture period.

4. A method comprising:

projecting a spatially distributed gradient of light intensity onto an object;

capturing a measurement for a light intensity at a point on the object, which relates to location of the point along the gradient;

creating a ratio of measurements for the point corresponding to intensity at the point under a plurality of lighting conditions to derive dimensional data for the point; and

assembling the dimensional data along with dimensional data similarly captured for a set of other points on the object into a three-dimensional model of at least a portion of the object.

5. A method comprising:

projecting a spatially distributed gradient of light intensity onto an object;

capturing a measurement for a light intensity at a point on the object, which relates to location of the point along the gradient;

deriving dimensional data for the point based on the measurement; and

assembling the dimensional data along with dimensional data similarly captured for a set of other points on the object into a three-dimensional model of at least a portion of the object; and

wherein the capturing is performed by a linear image sensing array and a focal zone is a single line of points on the object.

6. An apparatus comprising:

a projection unit to project a spatially distributed gradient of light intensity onto an object including a curved reflector mounted radially asymmetrically on a rotatable shaft and a light source disposed to be in a focal line of the curved reflector while rotated; and

a capture unit that measure light intensity at a plurality of points on the object, the light intensity at each point indicative of a location of that point along the gradient.

7. The apparatus of claim 6 further comprising:

a light spreader interposed between the curved reflector and a focal zone.

12. The apparatus of claim 6 wherein the projection unit and the capture unit are retained in fixed relation to each other.

8. An apparatus comprising:

a projection unit to project a spatially distributed gradient of light intensity onto an object including a reflector, a light source to illuminate at least a portion of the reflector and a drive unit coupled to the reflector to drive the reflector to sweep incident light from the light source through a focal zone; and

a capture unit that measures light intensity at a plurality of points on the object, the light intensity at each point indicative of a location of that point along the gradient.

9. The apparatus of claim 8 wherein the projection unit further comprises:

a light spreader interposed between the reflector and the focal zone.

10. The apparatus of claim 8 wherein the reflector is curved to cause light from the light source to form a light stripe.

11. An apparatus comprising:

a projection unit to project a spatially distributed gradient of light intensity onto an object including a light source and a variable shutter to prevent a first percentage to a second percentage of light from the light source from illuminating a focal zone during a capture period; and

a capture unit that measures light intensity at a plurality of points on the object, the light intensity at each point indicative of a location of that point along the gradient.

13. A method comprising:

rotating an element in an optical path relative to an object to sweep a focal zone of an image sensing array (ISA) over a portion of the object independent of motion of the object; and

capturing data in the ISA which can be used to determine three-dimensional data for the object within the portion over which the focal zone sweeps.

14. The method of claim 13 further comprising:

repeating the rotating and capturing for a plurality of aspects of the object.

15. The method of claim 13 further comprising:

assembling from the data captured a three-dimensional model of at least a portion of the object.

16. The method of claim 13 wherein the ISA is a linear image sensor.

17. A method comprising:

moving an element in an optical path relative to an object to sweep a focal zone of a linear image sensor over a portion of the object;

capturing in the linear image sensor successive lines of data as the focal zone sweeps, which can be used to determine three-dimensional data for the object within the portion of the object over which the focal zone sweeps.

18. The method of claim 17 further comprising:

repeating the moving and capturing for a plurality of aspects of the object.

19. The method of claim 17 further comprising:

assembling from the data captured a three-dimensional model of at least a portion of the object.