Abstract—In this research, we introduce an efficient blind watermarking method for gray image based on wavelet tree quantization using adaptive threshold in extraction process. Based on difference value between two largest coefficients, each scrambled binary watermark bit is embedded into each block which created by four LH3 coefficients and one LH4 coefficient. In extraction process, we compare difference value in each block to adaptive threshold to recover watermark bit. The quality of extracted watermark depends on the threshold which is determined by the Weighted Within-Class Variance algorithm. Performance of proposed method is represented through experimental results under various attacks such as, Histogram Equalization, Cropping, Low-pass Filtering, Gaussian noise, Salt & Pepper noise and JPEG compression. 

Index Terms—blind watermarking, 3-level DWT, significant difference, adaptive threshold, within-class
variance

Cite: Thien Huynh The and Thuong Le Tien, "An Efficient Blind Watermarking Method based on Significant Difference of Wavelet Tree Quantization using Adaptive Threshold," International Journal of Electronics and Electrical Engineering, Vol. 1, No. 2, pp. 98-103, June 2013. doi: 10.12720/ijeee.1.2.98-103