Topographical object detection system
AssigneeImedge Technology, Inc.
InventorsMichael Metz, Nicholas J. Phillips, Zane Coleman, Carl Flatow
Life of this patent
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Abstract
A compact system for producing high contrast and high resolution images of a topographical surface associated with an object. The system utilizes a novel holographic optical element to produce images of topographical surfaces differentiating between ridges and valleys, and providing image details of artifacts. The system of the present invention can be realized in the form of a hand-held instrument for use in in vivo imaging of fingerprint, skin tissue and the like.
Claims65
A device for producing an image of a topographic surface having ridges and valleys, said device comprising:
- light producing means for producing light rays;
- a light transmitting substrate capable of transmitting the light produced by said light producing means;
- a topographic surface illuminating region for physical placement of an object having a topographical surface;
- an image detection means for detecting an image of said topographical surface;
- an optical element affixed to a portion of said light transmitting substrate and being disposed between said topographical surface illuminating region and said image detection means, said optical element embodying a light diffracting grating;
- wherein said topographic surface illuminating region and said optical element are each disposed substantially along a common optical axis;
- and
- wherein during the operation of said device,
- (1) light rays produced by said light producing means, propagate within said light transmitting substrate towards and into said optical element and are diffracted by said light diffracting grating,
- (2) diffracted light rays produced by said light diffracting grating, propagate directly towards said topographical surface illuminating region and fall incident upon and are intensity modulated by the ridges and valleys of said topographical surface, and
- (3) at least a portion of the intensity modulated light rays produced from said ridges and valleys of said topographical surface propagate back at an angle less than the critical angle of said light transmitting substrate through said light transmitting substrate and said optical element and fall incident upon said image detection means, whereupon an image of said topographical surface is detected.
A topographical image detector comprising a light source, an object supporting light transmitting layer, a volume hologram, an index discontinuation layer interposed between said object supporting layer and said hologram, a light transmitting substrate affixed to said hologram, and image detecting means in optical communication with said light transmitting substrate, wherein
- 1) light from said light source passes through said light transmitting substrate and said volume hologram and is then reflected at the interface of said hologram and said index discontinuity layer and is then reflected back into said volume hologram at an angle satisfying the Bragg condition;
- 2) said hologram diffracts the light which passes through said index discontinuity layer and said object supporting layer to illuminate the object supported therein, and
- 3) reflected light modulated by the surface pattern of the object is then reflected back through said index discontinuously layer, said hologram, and said light transmitting medium to said image detection means.
Dependencies are inferred from the claim text.