Electro-optical mouse with improved resolution for compensation of optical distortion

申请公布号:
US4857903(A)
申请号:
US19860860231
申请日期:
1986.05.06
申请公布日期:
1989.08.15
申请人:
SUMMAGRAPHICS CORPORATION
发明人:
ZALENSKI, THOMAS
分类号:
G06F3/03;G06F3/033;G06F3/038;G06F3/039
主分类号:
G06F3/03
摘要:
An electro-optical mouse has a four-quadrant photodetector, each quadrant producing a voltage proportional to the amount of light impinging thereon. The mouse slides over a surface having optically contrasting, i.e. reflecting and nonreflecting, indicia thereon. The position of the mouse relative to a coordinate system in the plane of the surface is determined by projecting light onto the surface and then detecting the amount of light reflected from the surface onto the respective quadrants. The mouse is able to detect within which of four ranges the amount of light impinging on each quadrant lies. A two-bit code indicating the range is generated for each quadrant, thereby forming an eight-bit detector code. In the case where the eight-bit detector code is the same, i.e., ambiguous, for two different positions of the mouse relative to an indicium being optically detected, the true position at a current instant in time is identified by interpolating between the position at a previous instant in time and the position at a subsequent instant in time. This look-ahead routine is performed after the predetermined ambiguous detector code has been recognized and after a determination has been made that the position at the previous instant in time was not at or in the vicinity of one of the two positions corresponding to the ambiguous detector code.
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