Patent ID: 7293714

Claim:
A hand-supportable digital imaging-based bar code symbol reading system, comprising: a hand-supportable housing; an image formation and detection subsystem having image formation optics for producing a field of view (FOV) upon an object to be imaged and an area-type image sensing array for detecting imaged light reflected off the object during illumination operations in an image-capture mode in which substantially all rows of said area-type image sensing array are enabled; a LED-based illumination subsystem having an LED illumination array for producing a field of narrow-band illumination within said FOV during said image-capture mode; an image capturing and buffering subsystem for capturing and buffering a digital image of the object detected by said image formation and detection subsystem; an image-processing based bar code symbol reading subsystem for processing said digital image by a method of reading 1D or 2D bar code symbols graphically represented in said captured digital image, wherein said method comprises the steps of: (1) processing said captured digital image along a set of parallel virtual scan lines spaced-apart by a number of pixel-offset distances, said processing involving (i) determining a region of interest (ROI) in said digital image containing a bar code symbol, and (ii) determining the maximum pixel height of said ROI, and (iii) computing the number of pixel-offset distances that is proportional to the maximum pixel height of said ROI; (2) detecting and examining the zero-crossings along the virtual scan lines; (3) creating bar and space patterns from detected zero-crossings; and (4) decoding the bar and space patterns using one or more decoding algorithms; and a system control subsystem for controlling and coordinating said subsystems.