关键词: 离散余弦变换, 位平面, 主成份分析（PCA）

Abstract: In order to improve robust performance of illumination and greatly reduce the dimension of original face images，this paper proposes a face recognition algorithm based on bit-planes in compressed domain. The method can take the advantages of face feature directly extracted in compressed domain and bit-planes of image，and the reconstructed expression of face image.The experi-mental results indicate that the proposed approach not only increases the recognition rate，but also needs fewer projection vectors.

Key words: Discrete Cosine Transform（DCT）, bit-plane, Principal Components Analysis（PCA）