Patent ID: 6298175
Filing Date: 2001-10-02
Classification: G06K

Abstract:
A system for sensing the presence of an object, said system comprising:an optical reader including an imaging assembly for generating image information and a controller in communication with a memory space for controlling said imaging assembly;a light source controlled by said controller positioned to emit light in a field of view of said imaging assembly, wherein said controller controls an illumination level of said light source by controlling electrical current supplied to a light emitting element of said light source,wherein said controller is configured to capture frames of image data representing scenes defined by said field of view, wherein said controller controls said light source to define a predetermined light sequence characterized by said light source emitting light at different illumination levels during successive frame capture periods of said controller, wherein said controller is adapted to analyze image information developed during said successive frame capture periods to detect whether said predetermined light sequence is represented in said image information, and wherein an operating state of said reader depends on whether said controller detects said predetermined light sequence in said image information.