Pairwise facial expression classification

This paper presents a novel facial expression recognition methodology. In order to classify the expression of a test face to one of seven pre-determined facial expression classes, multiple two-class classification tasks are carried out. For each such task, a unique set of features is identified that is enhanced, in terms of its ability to help produce a proper separation between the two specific classes. The selection of these sets of features is accomplished by making use of a class separability measure that is utilized in an iterative process. Fisher´s linear discriminant is employed in order to produce the separation between each pair of classes and train each two-class classifier. In order to combine the classification results from all two-class classifiers, the `voting´ classifier-decision fusion process is employed. The standard JAFFE database is utilized in order to evaluate the performance of this algorithm. Experimental results show that the proposed methodology provides a good solution to the facial expression recognition problem.