US 5,548,418 A · Holographic structured light generator

Abstract

The present invention is a holographic structured light generator (HSLG) for generating an array of an arbitrary number of laser beamlets from a single laser beam using a point laser light source and a hologram. In a first preferred embodiment of the present invention, a hologram having an image of four point sources in a common plane is fabricated using four point sources as the object beam, and a reference beam. A reconstruction beam, aligned identically with respect to the hologram as was the reference beam during fabrication of the hologram, is then directed at the hologram, generating the array of laser beamlets from the four point sources in the hologram. In a primary application of the HSLG, it is used to map the surface of an object in three dimensions. The HSLG is used with video cameras, computer image processing equipment and an optical spatial light modulator to yield 3-D data for use with CAD systems.

Claims93

Dependent claims

An apparatus for generating an array of electromagnetic beamlets comprising:

(a) a hologram having an image of three phase-controlled point sources;
(b) a reconstruction electromagnetic source producing a reconstruction beam;
(c) means for directing the reconstruction beam at the hologram;
and
(d) means for aligning the reconstruction beam such that three phase-controlled beams are generated from the of the three phase-controlled point sources, said three phase-controlled beams overlapping each other and interfering with each other to produce an ordered array of electromagnetic beamlets,
wherein the three point sources are located at the corners of a triangle in a common plane.

3 more elements

A three-dimensional imaging system comprising:

(a) a hologram having a virtual image of a plurality of phase-controlled point sources;
(b) a laser reconstruction source producing a reconstruction beam;
(c) means for directing the reconstruction beam towards the hologram;
(d) means for aligning the reconstruction beam with respect to the hologram such that the plurality of phase controlled beams is generated, said beams overlapping each other and interfering with each other produce an array of laser beamlets originating from the at least two sources is formed;
(e) means for directing the array of laser beamlets along a first optical axis to a spatial light modulator;
(f) means for modulating the laser beamlets in at least one spatial light modulator pattern and for directing the modulated laser beamlets at an object;
(g) a video camera directed along a second optical axis at the object, wherein said second optical axis is not parallel to the first optical axis, said video camera recording a sequence of images of the array of laser beamlets reflected by the object ordered according to the sequence of spatial light modulator patterns;
and
(h) means for calculating a three dimensional image of the object from the sequence of images of the array of laser beamlets.

6 more elements

A three-dimensional imaging system comprising:

(a) a hologram having a virtual image of a plurality of phase-controlled point sources;
(b) a reconstruction laser source producing a reconstruction beam;
(c) means for directing the reconstruction laser beam at the hologram;
(d) means for aligning the reconstruction beam with respect to the hologram such that the plurality of phase controlled beams are produced, said beams overlapping each other and interfering with each other to produce an array of laser beamlets;
(e) means for directing the array of laser beamlets along a first optical axis at an object;
(f) a video camera directed along a second optical axis at the object, wherein said second optical axis is not parallel to the first optical axis, said video camera comprising means for recording at least one coded image of the array of laser beamlets reflected by the object;
and
(g) means for calculating a three dimensional image of the object from the at least one coded image of the array of laser beamlets reflected by the object.

5 more elements

A method for obtaining a three dimensional image of an object comprising:

(a) directing a reference beam derived from a creation laser source at a holographic medium;
(b) deriving a first plurality of at least two additional phase-controlled beams from the creation laser source;
(c) directing the first plurality of additional phase-controlled beams at the holographic medium from a common plane, said first plurality of additional phase-controlled beams combining with the reference beam at the holographic medium to form a hologram comprising a virtual image of the first plurality of phase-controlled point sources;
(d) directing a reconstruction beam from a reconstruction laser source at the hologram comprising a virtual image of the first plurality of phase-controlled point sources, said reconstruction beam having the same orientation relative to the hologram as the reference beam had relative to the holographic medium, thereby generating a first plurality of phase-controlled laser beams, said phase controlled laser beams overlapping with each other and interfering with each other to produce an array of laser beamlets;
(e) directing the array of laser beamlets at a spatial light modulator, and then directing the array of laser beamlets along a first optical axis at an object;
(f) directing a video camera along a second optical axis at the object, said second optical axis being non-parallel to the first optical axis;
(g) recording at least one image of the reflection of the array of laser beamlets;
and
(h) calculating a three dimensional image of the object from the at least one image.

6 more elements

A method for obtaining a three dimensional image of an object comprising:

(a) directing a spatially coded reference beam derived from a creation laser source at a holographic medium;
(b) deriving a first plurality of at least two additional phase-controlled beams from the creation laser source;
(c) coding the first plurality of at least two additional phase-controlled beams;
(d) directing the first plurality of coded additional phase-controlled beams at the holographic medium from a common plane, said first plurality of coded additional phase-controlled beams combining with the coded reference beam at the holographic medium to form a hologram comprising a coded image of the first plurality of point sources;
(e) directing a reconstruction beam from a reconstruction laser source at the hologram comprising a coded image of the first plurality of point sources, said reconstruction beam having the same orientation relative to the hologram as the reference beam had relative to the holographic medium, thereby generating the first plurality of phase-controlled_beams, said phase-controlled beams overlapping with and interfering with each other to produce a coded array of laser beamlets;
(f) directing the coded array of laser beamlets along a first optical axis at an object;
(g) directing a video camera along a second optical axis at the object, said second optical axis being non-parallel to said first optical axis;
(h) recording at least one coded image of the reflection of the coded array of laser beamlets;
and
(i) calculating a three dimensional image of the object from the at least one coded image.

7 more elements

An apparatus for generating an array of electromagnetic beamlets comprising:

(a) a hologram having an image of a first plurality of at least two phase-controlled point sources;
(b) a reconstruction electromagnetic source producing a reconstruction beam;
(c) means for directing the reconstruction beam at the hologram;
and
(d) means for aligning the reconstruction beam such that a first plurality of phase-controlled beams is generated from the virtual image of the first plurality of at least two phase-controlled point sources, said first plurality of phase-controlled beams overlapping each other and interfering with each other to produce an ordered array of electromagnetic beamlets;
and
(e) a spatial light modulator, said spatial light modulator positioned to modulate the beams in the ordered array of electromagnetic beamlets.

4 more elements

Dependencies are inferred from the claim text.

Holographic structured light generator

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Holographic structured light generator

Life of this patent

Abstract

Claims93