Apparatus for simultaneously convolving multiple digital binary images using a single convolver with a binary mask to determine pixel densities

Claim 1

An apparatus for locating a machine readable symbol, comprising: (A) an electro-optical scanner for generating an input image containing a digital representation of said machine readable symbol; (B) means for providing first and second digital binary images representative of edges in said input image; (C) a window selector for selecting a first window from said first digital binary image and a second window from said second digital binary image for processing; (D) a pixel selector for selecting a first pixel from said first window and a second pixel from said second window; (E) a shifter for bit shifting said first pixel and concatenating a plurality of trailing zero bits to said first pixel; (F) bit merging means for forming a multi-bit input pixel by combining said bit shifted first pixel and said second pixel; (G) a convolver for generating a single multi-bit output value by simultaneously applying a plurality of multi-bit input pixels to said convolver; (H) a word separator for forming a first convolution result from only the least significant bits of said output value and a second convolution result from only the most significant bits of said output value; wherein said first and second convolution results respectively represent the results of sequentially applying said convolver to said first and second windows; and (I) means for locating said machine readable symbol within said input image in accordance with said first and second convolution results.

Claim 2

An apparatus for locating a machine readable symbol, comprising: (A) an electro-optical scanner for generating an input image containing a digital representation of said machine readable symbol; (B) means for providing first and second digital binary images representative of edges in said input image; (C) a window selector for selecting a first window from said first digital binary image and a second window from said second digital binary image for processing; (D) a pixel selector for selecting a first pixel from said first window and a second pixel from said second window; (E) a shifter for bit shifting said first pixel and concatenating a plurality of trailing zero bits to said first pixel; (F) bit merging means for forming a multi-bit input pixel by combining said bit shifted first pixel and said second pixel; (G) a convolver for generating a single multi-bit output value by simultaneously applying a plurality of multi-bit input pixels to said convolver; (H) a word separator for forming a first convolution result from only the least significant bits of said output value and a second convolution result from only the most significant bits of said output value; wherein said first and second convolution results respectively represent the results of sequentially applying said convolver to said first and second windows; and (I) means for locating said machine readable symbol within said input image in accordance with said first and second convolution results.