DWT based robust image hashing algorithm

JPEG 2000 is a wavelet-based image compression standard and coding system. It will supersede the original JPEG standard in the future. Compared with Counterlet transform or Gabor filter, wavelet transform used in JPEG 2000 is less effective to extract robust edge features. In this paper, a novel discrete wavelet transform (DWT) based image hashing algorithm is proposed. Robust bits of HL, LH and HH sub-band in the same middle-frequency scale are extracted first. Then, they are fused to generate the hash. Experimental results show that the proposed algorithm is highly robust to content preserving operations as well as having an excellent performance on tampering localization. In addition, since robust features are extracted in the same scale, the generation of hash is only needed to decode JPEG 2000 image code stream partially.