Fine-Tunning a MAP Error Corrections Algorithm for Five-Key Chording Keyboards

Different typing devices lead to different typing error patterns. In addition, different persons using the same device have different error patterns. Considering this, we propose and evaluate a spelling algorithm specifically designed for a five-key chording keyboard. It uses the maximum a posteriori probability rule, the probabilities that one character is typed for another, named confusion probabilities, and a dictionary model. Our study shows that the proposed algorithm reduces the substitution error rate from 7.60% to 1.25%. In comparison, MsWord and iSpell reduce the substitution error rates to 3.12% and 3.94%, respectively. The error rate can be further reduced to 1.15% by using individual confusion matrices for each user

Error Correction Mechanism for Five-Key Chording Keyboards

Abstract—As different text input devices lead to different typing error patterns, considering the device characteristics when designing an error correction mechanism can lead to significantly improved results. In this paper, we propose and evaluate a spelling algorithm specifically designed for a five-key chording keyboard. It is based on the maximum a posteriori probability criterion, taking into account a dictionary model and the probabilities that one character is typed for another. These probabilities are determined experimentally. In our experiment, the proposed method reduced the substitution error rate from 7.60 % to 1.59%. As comparison, MsWord and iSpell reduced the substitution error rates to 3.12 % and 3.94%, respectively. Keywords—error correction; confusion matrix; maximum a posteriori probability; chording keyboard I