In this paper, a new technique for image feature extraction and representation-gait energy image and principal component
analysis (PCA)—was developed. Gait energy image and PCA has many advantages over conventional PCA. In the first place, since gait energy image and PCA is based on mean and evaluation of covariance matrix, it is simpler and more straightforward to use for image feature extraction. Second, gait energy image and PCA is better than PCA in terms of recognition accuracy in all experiments. Although this trend seems to be consistent for different databases and conditions, in some experiments the differences in performance were not statistically significant.