Laser scanning and multiple detection for video image processing
AssigneeWestern Electric Company, Inc.
InventorDonald P. Jablonowski
Life of this patent
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Abstract
An object (12) is raster scanned with a small, localized beam of laser light (22) and the backscattered radiation therefrom is monitored by a plurality of detectors (44). Each of the detectors (44) monitors a different characteristic of the backscattered radiation and an arithmetic operation is performed on the output of the detectors to provide a single composite video signal with enhanced contrast.
Claims6
A method for obtaining an enhanced video signal, representing a ceramic substrate having a metallic pattern thereon, the method comprising the steps of:
- raster scanning a narrow beam of illumination over the surface of the patterned substrate;
- monitoring radiation scattered by the scattered substrate with a plurality of detectors wherein a first detector detects radiation scattered at low angles by the surface of the patterned substrate while a second detector detects the radiation scattered at high angles by said surface;
- generating a video signal at the output of each detector, each video signal representing the scattered radiation impinging thereon;
- and
- subtracting the video output of the second detector from the first detector to form a composite video signal having enhanced contrast.
A method for obtaining an enhanced video signal, representing a printed wiring board having a metallic pattern thereon, the method comprising the steps of:
- raster scanning a narrow beam of illumination over the surface of the printed wiring board;
- monitoring radiation scattered by the surface of the printed wiring board with a plurality of detectors wherein a first detector detects radiation scattered at low angles by the surface while a second detector detects the radiation scattered at high angles by said board surface;
- generating a video signal at the output of each detector, each video signal representing the scattered radiation impinging thereon;
- and
- subtracting the video output of the second detector from the first detector to form a composite video signal having enhanced contrast.
A method for obtaining an enhanced video signal representing a polished semiconductor wafer having diffusive portions on the surface thereof, the method comprising the steps of:
- raster scanning a narrow beam of illumination over the surface of the wafer;
- monitoring radiation scattered by the surface of the wafer with a plurality of detectors wherein a first detector detects radiation scattered at low angles by the surface of the wafer while a second detector detects the radiation scattered at high angles by said surface;
- generating a video signal at the output of each detector, each video signal representing the scattered radiation impinging thereon;
- and
- subtracting the video output of the second detector from the first detector to form a composite video signal having enhanced contrast.
A method for obtaining an enhanced video signal representing a ceramic substrate having a metallic pattern thereon, the method comprising the steps of:
- raster scanning a narrow beam of polarized illumination over the surface of the patterned substrate;
- monitoring the radiation scattered by the surface of the patterned substrate with a plurality of detectors wherein a first detector detects a parallel component of the radiation scattered at low angles by the surface while a second detector detects an orthogonal component of the radiation scattered at high angles by said surface;
- generating a video signal at the output of each detector, each video signal representing the scattered radiation impinging thereon;
- and
- substracting the video output of the second detector from the first detector to form a composite video signal having enhanced contrast.
A method for obtaining an enhanced video signal representing a printed wiring board having a metallic pattern thereon, the method comprising the steps of:
- raster scanning a narrow beam of polarized illumination over the surface of the printed wiring board;
- monitoring the radiation scattered by the surface of the board with a plurality of detectors wherein a first detector detects a parallel component of the radiation scattered at low angles by the surface while a second detector detects an orthogonal component of the radiation scattered at high angles by said surface;
- generating a video signal at the output of each detector, each video signal representing the scattered radiation impinging thereon;
- and
- subtracting the video output of the second detector from the first detector to form a composite video signal having enhanced contrast.
A method for obtaining an enhanced video signal representing a polished semiconductor wafer having diffusive portions on the surface thereof, the method comprising the steps of:
- raster scanning a narrow beam of polarized illumination over the surface of the wafer;
- monitoring the radiation scattered by the surface of the wafer with a plurality of detectors wherein a first detector detects a parallel component of the radiation scattered at low angles by the surface while a second detector detects an orthogonal component of the radiation scattered at high angles by said surface;
- generating a video signal at the output of each detector, each video signal representing the scattered radiation impinging thereon;
- and
- subtracting the video output of the second detector from the first detector to form a composite video signal having enhanced contrast.
Dependencies are inferred from the claim text.