Robust image hashing via colour vector angles and discrete wavelet transform. Issue 3 (1st March 2014)

• Record Type: Journal Article
• Authors: Tang, Zhenjun; Dai, Yumin; Zhang, Xianquan; Huang, Liyan; Yang, Fan
• Is Part Of: IET image processing. Volume 8:Issue 3(2014)
• Page Start: 142
• Page End: 149
• Publication Date: 2014-03-01
• Subjects: cryptography -- discrete wavelet transforms -- Gaussian processes -- image coding -- image colour analysis -- interpolation -- low‐pass filters -- matrix algebra -- image watermarking; robust image hashing -- colour vector angle -- discrete wavelet transform -- DWT -- bicubic interpolation -- Gaussian low‐pass filter -- nonoverlapping blocks -- feature matrix -- LL subband -- JPEG compression -- watermarking embedding -- receiver operating characteristic curve; Image processing -- Periodicals; 621.36705
• DOI: 10.1049/iet-ipr.2013.0332
• Languages: English
• ISSNs: 1751-9659

Abstract

Abstract : Colour vector angle has been widely used in edge detection and image retrieval, but its investigation in image hashing is still limited. In this study, the authors investigate the use of colour vector angle in image hashing and propose a robust hashing algorithm combining colour vector angles with discrete wavelet transform (DWT). Specifically, the input image is firstly resized to a normalised size by bi‐cubic interpolation and blurred by a Gaussian low‐pass filter. Colour vector angles are then calculated and divided into non‐overlapping blocks. Next, block means of colour vector angles are extracted to form a feature matrix, which is further compressed by DWT. Image hash is finally formed by those DWT coefficients in the LL sub‐band. Experiments show that the proposed hashing is robust against normal digital operations, such as JPEG compression, watermarking embedding and rotation within 5°. Receiver operating characteristics curve comparisons are conducted and the results show that the proposed hashing is better than some well‐known algorithms.