Digital imaging-based bar code symbol reader employing an LED-based illumination subsystem driven by an automatic light exposure measurement and illumination control subsystem

摘要

A digital imaging-based bar code symbol reading device comprises: an automatic object presence detection subsystem; an image formation and detection subsystem employing a CMOS area-type image sensing array; an LED-based illumination subsystem; an automatic light exposure measurement and illumination control subsystem; an image capturing and buffering subsystem; an image-processing bar code symbol reading subsystem; an input/output subsystem; and a system control subsystem for controlling the subsystems. The LED-based illumination subsystem is automatically driven by the automatic light exposure measurement and control subsystem responsive to the generation of control activation signals by the image sensing array and the automatic object presence detection subsystem during object illumination and image capture operations.