1. A hand held bar code reading apparatus for reading a bar code on a substrate, the apparatus comprising: (a) an image frame memory being configured to simultaneously retain pixel values making up a frame of image data; (b) an image sensing and processing circuit for outputting image data for capture into said image frame memory, the image sensing and processing circuit including an image sensor array having a plurality of pixels formed in a plurality of rows and columns, the image sensing and processing circuit being configured to read out image signals from said image sensor array and to digitize such signals, the image sensing and processing circuit processing image data and further being configured to contemporaneously output for capture into said image frame memory (i) a raw frame of image data comprising raw pixel values and (ii) a filtered frame of image data comprising filtered pixel values; (c) a microprocessor integrated circuit being configured to address image data of said image frame memory in accordance with instructions of an indicia decoding program.