Detection and Removal of Hidden Data in Images Embedded with Quantization Index Modulation

Methods of attack on watermarks embedded with quantization index modulation and block DCT are introduced in this paper. The proposed method can detect the presence of hidden data by analyzing the histogram or spectrum of the transform coefficients, and prevent their extraction without further degrading the image. It is shown that, in some cases, the embedding-induced distortion can even be reduced in terms of peak-signal-to-noise ratio. Experimental results are given to show the effectiveness of the method.