Method and apparatus for decoding bar code symbols using independent bar and space analysis

Abstract From the Canadian patent

A bar code reader decodes a bar code symbol one character at a time, by, analyzing the spaces of each character independently from the bars of each character. The reader determines the widths of each space and each bar. The reader then determines a space-width threshold based on the widths of the spaces and a bar-width threshold based on the widths of the bars. The reader then classifies each space as being either narrow or wide by comparing each space to the space-width threshold. The reader also classifies each bar as being either narrow or wide by comparing each bar to the bar-width threshold. The reader then decodes the character according to the narrow/wide classifications.