Various Digital Image Watermarking Techniques

This project implements various digital image watermarking techniques using MATLAB, including wavelet transform and Least Significant Bit (LSB) approaches. These methods serve to protect digital image copyrights, enable authentication, and prevent unauthorized copying and tampering. The wavelet transform watermarking technique leverages frequency domain characteristics of images by embedding watermarks into different frequency wavelet coefficients. This approach typically involves decomposing the image using wavelet transforms like 'dwt2' function, modifying specific coefficient ranges, and reconstructing the image with 'idwt2'. The algorithm provides robust watermark hiding and extraction capabilities while maintaining image quality. LSB watermarking operates by embedding watermark information into the least significant bits of image pixel values. This method exploits human visual system's insensitivity to minor changes in image details. Implementation involves using bitwise operations ('bitset', 'bitget' functions) to modify the LSB planes while preserving the overall visual appearance. The technique offers high capacity and simplicity in implementation. These digital image watermarking technologies demonstrate significant application potential in secure transmission and storage of digital media, with MATLAB providing excellent prototyping capabilities through its image processing toolbox and built-in functions for transformation and pixel manipulation.