Digital imaging-based bar code symbol reading system employing an led-based multi-mode illumination subsystem with far-field and near-field led illumination arrays driven by an automatic light exposure measurement and illumination control subsystem responsive to control activation signals generated by an automatic object presence and range detection subsystem

摘要

A digital imaging-based bar code symbol reading system which comprises: an automatic object presence and range detection subsystem; an image formation and detection subsystem having an area-type image sensing array with a field of view (FOV); a multi-mode LED-based illumination subsystem having LED illumination arrays for producing fields of narrow-band illumination in near and far portions of the FOV; 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 illumination arrays are automatically driven by the automatic light exposure measurement and illumination control subsystem in response to the generation of control activation signals by the automatic object presence and range detection subsystem.