Integrated range and luminance camera

• US 4,687,326 A
• Filed: 11/12/1985
• Issued: 08/18/1987
• Est. Priority Date: 11/12/1985
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Corby, Nelson R. Jr.
• Primary Examiner(s): Buczinski, Stephen C.
• Assistant Examiner(s): Wallace, Linda J.
• Application Number:
  US06/797,361
• Time in Patent Office: 644 Days
• Field of Search: 356/1, 356/2, 356/5, 356/141, 356/152, 358/108, 358/125
• US Class Current: 356/5.01
• CPC Class Codes: G01B 11/2536 using several gratings with variable grating pitch, projected on the object with the same angle of incidence

Abstract

A three-dimensional range camera, which produces a range map of the distances from a reference to each of M×N points in a scene, is modified to generate registered luminance and range images. The same sensor detects range and luminance variations. A planar pattern projector generates sequential presentations of time/space coded light rays which are projected onto the object. A linear array camera images the points of light on the object surface, and a processor analyzes one-dimensional scan signals to determine range. To detect luminance there is an additional presentation, either constant illumination or no artificial illumination, and the other scan signal yields luminance along the same strip of the scene.

Claims

1. An integrated range and luminance camera comprising:

a planar pattern projector to generate a 1×

N array of time and space coded light rays and to project P sequential presentations of modulated light patterns and an unmodulated pattern onto the surface of a three-dimensional object at the same place, where P=1+log_b N, b is the number of brightness levels and N is the number of rays;

a linear array sensor which detects, at an angle to projected rays, light incident on the object and generates P one-dimensional scan signals having peaks at locations corresponding to the intersections of said light rays with the object surface, and an additional scan signal corresponding to brightness; and

a processor to analyze said P scan signals to uniquely identify all rays and determine range to the object surface at N points along a line, and to analyze said additional scan signal to determine luminance along that line, and to provide registered range and luminance images.

2. The integrated camera of claim 1 and means for scanning said coded light rays and unmodulated pattern by steps over a rectangular plane, whereby successive strips of said object are imaged by said linear array sensor and registered area range and luminance images are produced.

3. The integrated camera of claim 2 wherein said pattern generator includes a sheet light source and a rotating code disk which has at least one group pattern comprised of one pattern per presentation having discrete regions whose light transmission coefficients are selected to spatially modulate the light sheet into said coded light rays, said group pattern including an additional uniform pattern with a selected light transmission coefficient.

4. The integrated camera of claim 3 wherein said pattern generator also includes a reduction lens to project said modulated and unmodulated light patterns onto the entrance of a coherent fiber optic bundle, and a projection lens to reimage said light patterns on the object surface.

5. The integrated camera of claim 2 wherein said pattern projector includes a sheet light source and a rotating code disk which has at least one group comprised of one pattern per presentation having clear and opaque regions to spatially modulate the light sheet into said coded light rays, said group pattern having an additional uniformly clear or opaque pattern.

6. The integrated camera of claim 1 wherein said pattern generator includes a narrow laser beam source, a modulator to programmably vary the intensity of said laser beam, a beam deflector to sweep the modulated beam along a straight line, and an incrementally rotatable mirror system to scan said modulated beam over a plane and project it onto the surface of a three-dimensional object.

7. An integrated range and luminance camera comprising:

a planar pattern projector to generate a 1×

N array of time and space coded light rays and to project P sequential presentations of modulated light patterns and an additional unmodulated pattern onto the surface of an object, where P=1+log₂ N and N is the number of light rays;

means for scanning said coded light rays and unmodulated pattern by steps over a rectangular plane;

a linear array camera which detects, at an angle to projected rays, points of light and light incident on the object and generates P one-dimensional scan signals having peaks at locations corresponding to imaged points of light where said coded rays are incident on the surface of said object, and an additional scan signal corresponding to brightness, said linear array camera generating a set of said scan signals at every step; and

a processor to analyze said scan signals, set by set, to uniquely identify all rays and to determine range at points along a line on said object, and to determine luminance along that strip, and to output registered area range and luminance images.

8. The integrated camera of claim 7 wherein said pattern generator includes a collimated light sheet source, a rotating code disk which has sector-shaped group patterns each comprised of one pattern per presentation of clear and opaque regions to spatially modulate the light sheet into said coded light rays, and an additional clear or opaque pattern, said patterns being illuminated one at a time in sequence.

9. The integrated camera of claim 8 further including a reduction lens which projects said coded light rays and unmodulated pattern onto the entrance of a coherent fiber optic bundle, and a projection lens to reimage the same on the object surface.

10. An integrated range and luminance camera comprising:

a narrow laser beam source;

a modulator to programmably vary the intensity of said laser beam;

a beam deflector to sweep the modulated beam along a straight line;

said modulator and beam deflector generating a 1×

N array of time and space coded light rays and sequential presentations of different subsets of said light rays during P modulated sweeps followed by an unmodulated sweep during which said laser beam is completely blanked or unblanked, where P=1+log_bN, b is the number of brightness levels and N is the number of light rays;

means for scanning said modulated beam by steps over a rectangular plane and project it onto the surface of a three-dimensional object;

a linear array camera to detect points of light where said light rays intersect the surface of said object, and other incident light, and generate at every step P one-dimensional scan signals and an additional scan signal corresponding to brightness; and

a processor to analyze said scan signals to uniquely identify all rays, determine range at N points along a line and luminance along that strip, and produce registered area range and luminance images.

11. The integrated camera of claim 10 wherein said modulator and beam deflector are controlled by said processor.