The University of Sussex

Improving generalisation in radial basis function networks for face recognition

A.Jonathan Howell, Hilary Buxton

This paper presents experiments using an adaptive learning component based on Radial Basis Function (RBF) networks to tackle the unconstrained face recognition problem using low resolution video information. Firstly, we performed preprocessing of face images to mimic the effects of receptive field functions found at various stages of the human vision system. These were then used as input representations to RBF networks that learnt to classify and generalise over different views for a standard face recognition task. Two main types of preprocessing (Difference of Gaussian filtering and Gabor wavelet analysis) are compared. Secondly we provide an alternative, `face unit' RBF network model that is suitable for large-scale implementations by decomposition of the network, which avoids the unmanagability of neural networks above a certain size. It uses small, individual networks for each class and allows the addition of new data to the database without complete re-training of the system. Finally, we show the {2-D} shift, scale and $y$-axis rotation invariance properties of the standard RBF network. Quantitative and qualitative differences in these schemes are described and conclusions drawn about the best approach for real applications to address the face recognition problem using low resolution images.

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