1. A method in a computing system for identifying a sequence of glyphs, the method comprising: receiving an image of a sequence of glyphs; for each of a subset of glyphs of the sequence: determining whether the glyph matches a retained glyph; when the glyph matches a retained glyph, assigning to the glyph a character identity associated with the retained glyph; when the glyph does not match a retained glyph: retaining the glyph; selecting a character identity for the unmatched glyph; and assigning the selected character identity to the unmatched glyph; generating a representation of the image of the sequence of glyphs with the assigned character identities; and identifying the sequence of glyphs using the generated representation.