Hand Modeling and Tracking for Video-Based Sign Language Recognition by Robust Principal Component Analysis

Abstract

Hand modeling and tracking are essential in video-based sign language recognition. The high reformability and the large number of degrees of freedom of hands render the problem difficult. To tackle these challenges, a novel approach based on robust principal component analysis (PCA) is proposed. The robust PCA incorporates an L ₁ norm objective function to deal with background clutter, and a projection pursuit strategy to deal with the lack of alignment due to the deformation of hands. The learning algorithm of the robust PCA is very simple, involving only a search for the solutions in a finite set constructed from the training data, which leads to the learning of much more representative and interpretable bases. The incorporation of the L ₁ regularization in the fitting of the learned robust PCA models results in cleaner reconstructions and more stable fitting. Based on the robust PCA, a hand tracking system is developed that contains a skin-color region segmentation based on graph cuts and template matching in the framework of particle filtering. Experiments on a publicly available sign-language video database demonstrates the strength of the method.