LSB Image Watermarking - Watermark Extraction

This technique replaces the Least Significant Bits (LSB) in the spatial domain of an image, inserting watermark information, digital watermark digests, or pseudo-random sequences derived from watermarks as the replacement data for the LSB sequence. The implementation typically involves iterating through image pixels and modifying the least significant bit of each color channel using bitwise operations. For grayscale images, this can be achieved by using bit manipulation functions to clear the LSB (using AND operations with 0xFE) and then setting it to the watermark bit value (using OR operations). This method enables intellectual property protection, image integrity verification, and image source tracking by embedding watermarks directly into the image data. The approach maintains original image quality while adding information hiding and protection capabilities, as LSB modifications introduce minimal visual distortion due to the low sensitivity of human vision to minor changes in the least significant bits of pixel values.