Patent ID: 6812466
Filing Date: 2004-11-02
Classification: E05F,E05Y,G01J,G01S,G01V

Abstract:
An optical object sensing apparatus having ambient light cancellation capabilities comprising:an optical source and optical detector optically coupled for monitoring a target area that reflects at least a portion of an optical signal for detection as a received optical signal, said optical signal having temporal characteristics allowing said optical signal to be distinguished from ambient light, said optical detector providing a detector output signal indicative of the characteristics of said received optical signal; a conditioning circuit for outputting a conditioned output indicative of one characteristic of said detector output signal and a level output indicative of a second characteristic of said detector output signal; a sensing apparatus for using said conditioned output to sense the presence of an object in said target area; and a controller for receiving said level output from said conditioning circuit, converting said level output to a digital output, determining the magnitude of an ambient light-induced signal in said digital level output and outputting a control signal to a second input of said conditioning circuit, wherein said control signal is used by said conditioning circuit as an error compensating offset.