Binary image processing for decoding self-clocking glyph shape codes

A process for decoding a bitmap image space representation of a self-clocking glyph shape code composed of glyphs having shapes that encode digital data values, such that every distinct data value that is encoded by said code is represented by the shape of a respective glyph;

• said glyphs being selected from a set of n permissible glyph shapes, with each of said glyph shapes being preassigned to the encoding of a predetermined digital data value;
• said glyphs being spatially distributed in said bitmap image space in substantial accordance with a spatial formatting rule:
• said process comprising the steps of
• locating at least three non-colinear reference points in said bitmap image space, said reference points having a predetermined nominal spatial relationship to each other;
• determining the spatial relationship of said reference points in said bitmap image space;
• calculating a skew correction factor from the spatial relationship of said reference points in said bitmap image space;
• determining an X scale correction factor and a Y scale correction factor for said bitmap image space representation of said glyph code;
• calibrating said spatial formatting rule in accordance with said skew and scale correction factors;
• identifying an approximate center position of a first of said glyphs in said bitmap image space;
• filtering said bit map image space representation of said glyph code in accordance with a finite number of shape matching discrimination filters for each of said n permissible images, thereby providing at least n filtered representations of said glyph code;
• spatially sampling all of said filtered representations of said glyph code in substantial accordance with said calibrated spatial formatting rule to obtain relative filter correlated match strength values for each glyph of said glyph code as filtered by each of said filters, said sampling starting at the approximate center position of a predetermined one of said glyphs and continuing from there, approximate glyph center position-to-approximate glyph center position, in substantial accordance with said calibrated spatial formatting rule
• comparing the filter correlated match strength values of each of said glyphs, glyph-by-glyph for all of said filters, to classify said glyphs by their shapes;
• and
• assigning decoded data values to said shape classified glyphs in accordance with the data values preassigned to said glyph shapes.