Patent ID: 7148972

Claim:
A position recognizing device for receiving light from a plurality of light sources and recognizing a position of each of the light sources, comprising: light sources including generating circuits for generating pseudorandom number sequences unique to the respective light source and a plurality of light emitting units for emitting light having light intensity change corresponding to said pseudorandom number sequences, respectively; at least two light receiving devices for receiving the light from said plurality of light source; and a processing device for calculating a two-dimensional position or a three-dimensional position of each of a plurality of said light sources from incident position information obtained by each of the two said light receiving devices; wherein each of the two said light receiving devices includes: a position detecting element for receiving incident light from the plurality of said light sources, generating photocurrents corresponding to intensity of the light at incident positions, said photocurrents flowing into a resistance from said incident positions, and thereby providing a plurality of output signals corresponding to said incident positions; a correlation operation unit for subjecting the plurality of output signals of said position detecting element and said pseudorandom number sequences to a correlation operation, and separating and extracting signals corresponding to said plurality of output signals using a result of the correlation operation; and a decoding unit for determining said incident positions by subjecting the signals corresponding to said plurality of output signals from said correlation operation unit to an operation.