ESTscan is a program that can detect coding regions in DNA sequences, even if they are of low quality. It will also detect and correct sequencing errors that lead to frameshifts.

Similarly to genscan, ESTscan uses a Markov model to represent the bias in hexanucleotide usage found in coding regions relative to non-coding regions. Additionally, ESTscan allows insertions and deletions when these improve the coding region statistics.

References:
Lottaz C, Iseli C, Jongeneel CV, Bucher P. (2003) Modeling sequencing errors by combining Hidden Markov models Bioinformatics 19, ii 103-ii112. Iseli C, Jongeneel CV, Bucher P. (1999) ESTScan: a program for detecting, evaluating, and reconstructing potential coding regions in EST sequences. Proc Int Conf Intell Syst Mol Biol.138-48.