Abstract—Contrast enhancement operation is often used to highlight some information, weaken or remove some unwanted information in tampered images. In this paper, a tampered image detecting method is proposed based on wavelet analysis for specific fingerprints left by contrast enhancement operation in image. Firstly, the RGB color space of image was converted into YCbCr color space and the Y monochrome channel image was extracted; secondly, the normalized energy was calculated in the wavelet details sub-bands after wavelet transform of image’s pixel value histogram of the component; finally, the tampered image was identified according to the normalized energy. The results of the experiment show there is an obvious distinction between tampered and unaltered sub-blocks divided. Furthermore, the contrast experiment results about wavelet transform and Fourier transform show that the former is better than the latter in both accuracy and time complexity.
Index Terms—Contrast enhancement, fingerprints, histogram, wavelet transform
Wenqing Bu and Ning Zheng are now with the Institute of Computer Application Technology, Hangzhou Dianzi University, Hangzhou, China, 310018 (e-mail: bu_wenqing@126.com).
Ming Xu is now with the Institute of Computer Application Technology, Hangzhou Dianzi University, Hangzhou, China, 310018 (e-mail: mxu@hdu.edu.cn).
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Cite: Wenqing Bu, Ming Xu, and Ning Zheng, "A Tampered Image Detecting Method Based on Wavelet Analysis," International Journal of Information and Electronics Engineering vol. 2, no. 1, pp. 38-43, 2011.
