The LIMSI handwriting recognition system for the HTRtS 2014 contest
Théodore Bluche, Hermann Ney, Christopher Kermorvant · 2015
In this paper we present the handwriting recognition systems submitted by the LIMSI to the HTRtS 2014 contest. The systems for both the restricted and unrestricted tracks consisted of combination of several optical models. We extracted handcrafted features as well as pixels values with a sliding window. We trained Deep Neural Networks (DNNs) and Bidirectional Long Short-Term Memory Recurrent Neural Networks (BLSTM-RNNs), which where plugged as the optical model in Hidden Markov Models (HMMs). We propose a novel method to build language models that can cope with hyphenation in the text. The combination was performed from lattices generated from the different systems. We were the only team participating in both tracks and ranked second in each. The final Word Error Rates were 15.0% and 11.0% for the restricted (resp. unrestricted) track. We studied the impact of adding data for optical and language modeling. After the evaluation, we also used the same corpus for the language model as the winning team and obtained comparable results.