A robust image watermarking scheme using simplified significant wavelet tree quantization

In this present work a wavelet based watermarking technique is discussed. The proposed method transforms the image into wavelet coefficients by using DWT. A Simplified Significant Wavelet Tree (SSWT) is formed with wavelet coefficients (other than at lowest level) at higher level subband descending towards lower levels. The proposed scheme quantizes the SSWT coefficients to embed a bit of watermark into the frequency part of the image. In the watermark extraction the wavelet trees are formed on the received image to retrieve the watermark bits. The proposed scheme uses adaptive casting energy at different levels and hence achieves high robustness. Various attacks were performed to test the performance and the proposed method has shown high robustness against these attacks.