Adaptive scaling for decoding spatially periodic self-clocking glyph shape codes
Convolution filtering for decoding self-clocking glyph shape codes
Methods and means for reducing bit error rates in reading self-clocking glyph codes
Self-clocking glyph code for encoding dual bit digital values robustly Patent #: 5245165
AbstractA self-clocking glyph code is composed of data glyphs which encode logically ordered data values, together with one or more multi-glyph synchronization code patterns. Each of the synchronization code patterns is distinguishable from the data glyphs, but the synchronization code pattern or patterns provide an explicit spatial reference for the data glyphs. To this end, the glyphs of the synchronization code pattern or patterns are written on the recording medium in accordance with the same spatial formatting rule as the data glyphs, plus at least one additional formatting rule that establishes a predetermined geometric relationship between the glyphs of the synchronization code pattern or patterns and corresponding ones of the spatially formatted data glyphs, such that the logical order of at least a significant number (>>1) of the data glyphs is inferable from the synchronization code pattern or patterns. Preferably, each of the synchronization code patterns is composed of glyphs that are selected from the same finite symbol set as the data glyphs, so the synchronization code pattern or patterns typically are defined by glyph patterns that have a suitably high statistical probability of being unique with respect to any pattern of data glyphs.