DBN-based structural learning and optimisation for automated handwritten character recognition

Pattern recognition using Dynamic Bayesian Networks (DBNs) is currently a growing area of study. The classification performance greatly relies on the choice of a DBN model that will best describe the dependencies in each class of data. In this paper, we present DBN models trained for the classification of handwritten digit. Two approaches to improve the suitability of the models are presented. One uses a fixed DBN structure, and is based on an Evolutionary Algorithm optimisation of the selection and of the layout of the observations for each class of data. The second approach is about learning part of the structure of the models from the training set of each class. Parameter learning is then performed for each DBN. Classification results are presented for the described models, and compared with previously published results. Both approaches were found to improve the recognition rate compared to previous results.

► DBN models trained for the classification of handwritten digit (two approaches).
► Approach 1: sequence and layout of observations optimised via Evolutionary Algorithm.
► Approach 2: hybrid approach to structure learning.
► Comparison to previously published results obtained with similar kinds of DBNs.
► Second approach gave the best results. First approach can be faster and more robust.