Face and iris localization using templates designed by particle swarm optimization

Abstract

Face and iris localization is one of the most active research areas in image understanding for new applications in security and theft prevention, as well as in the development of human–machine interfaces. In the past, several methods for real-time face localization have been developed using face anthropometric templates which include face features such as eyes, eyebrows, nose and mouth. It has been shown that accuracy in face and iris localization is crucial to face recognition algorithms. An error of a few pixels in face or iris localization will produce significant reduction in face recognition rates. In this paper, we present a new method based on particle swarm optimization (PSO) to generate templates for frontal face localization in real time. The PSO templates were tested for face localization on the Yale B Face Database and compared to other methods based on anthropometric templates and Adaboost. Additionally, the PSO templates were compared in iris localization to a method using combined binary edge and intensity information in two subsets of the AR face database, and to a method based on SVM classifiers in a subset of the FERET database. Results show that the PSO templates exhibit better spatial selectivity for frontal faces resulting in a better performance in face localization and face size estimation. Correct face localization reached a rate of 97.4% on Yale B which was higher than 96.2% obtained with the anthropometric templates and much better than 60.5% obtained with the Adaboost face detection method. On the AR face subsets, different disparity errors were considered and for the smallest error, a 100% correct detection was reached in the AR-63 subset and 99.7% was obtained in the AR-564 subset. On the FERET subset a detection rate of 96.6% was achieved using the same criteria. In contrast to the Adaboost method, PSO templates were able to localize faces on high-contrast or poorly illuminated environments. Additionally, in comparison with the anthropometric templates, the PSO templates have fewer pixels, resulting in a 40% reduction in processing time thus making them more appropriate for real-time applications.