| abstract |
A hand-supportable digital imaging-based bar code symbol reading device comprises: an automatic object presence detection subsystem; a multi-mode area-type image formation and detection subsystem having a field of view (FOV), and narrow-area and wide area image capture modes of operation; a multi-mode LED-based illumination subsystem having narrow-area and wide area illumination modes of operation; 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. In the digital imaging-based bar code reading device of the present invention, the automatic illumination and exposure control subsystem continuously measures the light exposure incident upon a central portion of the FOV, and automatically controls the operation of the LED-based multi-mode illumination subsystem so that the detected object is sufficiently illuminated and the multi-mode image formation and detection subsystem enabled to form and detect good quality digital images of the automatically detected object during illumination and imaging operations. |