Device and method for determining movement of a surface
First Claim
1. A device for determining movement of a surface relative to a detector, the detector comprising a source of radiation directed at the surface and a plurality of radiation sensors arranged to detect an intensity pattern due to interference in the radiation reflected back from the surface, the device also comprising means for repeatedly or continuously monitoring the outputs from the sensors, and comparison means for calculating a combination of the product of the interstitial spatial and temporal intensity gradients between adjacent sensors and using said gradients to yield a result indicative of the movement of the surface relative to the detector.
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Abstract
A device for determining movement of a surface relative to a detector, the detector comprising a source of radiation directed at the surface and a plurality of radiation sensors arranged to detect an intensity pattern due to interference in the radiation reflected back from the surface, the device also comprising mechanism for repeatedly or continuously monitoring the outputs from the sensors, and comparison mechanism for calculating the combination of the product of the interstitial spatial and temporal intensity gradients between adjacent sensors and using the gradients to yield a result indicative of the movement of the surface relative to the detector.
78 Citations
24 Claims
- 1. A device for determining movement of a surface relative to a detector, the detector comprising a source of radiation directed at the surface and a plurality of radiation sensors arranged to detect an intensity pattern due to interference in the radiation reflected back from the surface, the device also comprising means for repeatedly or continuously monitoring the outputs from the sensors, and comparison means for calculating a combination of the product of the interstitial spatial and temporal intensity gradients between adjacent sensors and using said gradients to yield a result indicative of the movement of the surface relative to the detector.
- 15. A method of determining movement of a surface relative to a radiation detector, comprising directing radiation at the surface and detecting by the radiation detector an intensity pattern due to interference in the radiation reflected from the surface, the detector comprising a plurality of radiation sensors, repeatedly or continuously monitoring the outputs from the sensors, and calculating a combination of the product of the interstitial spatial and temporal intensity gradients between adjacent sensors and using said gradients to yield a result indicative of the movement of the surface relative to the detector.
Specification