Offset Alignment by Signal Processing Techniques I : Church, 1993
Church argues that length-based methods work well on clean text but may break down in real-world situations (noisy OCR or unknown markup conventions)
Church’s method is to induce an alignment by using cognates (words that are similar across languages) at the level of character sequences.
The method consists of building a dot-plot, i.e., the source and translated text are concatenated and then a square graph is made with this text on both axes. A dot is placed at (x,y) when there is a match. [Unit=4-grams].