Gray-level image watermarking with high capacity based on spread transform

In the present paper, we propose a gray-level image watermarking algorithm with high capacity based on bit decomposition and spread transform. To implement this algorithm, the gray-level digital watermark image is bit decompounded into a series of binary digital images, then the cover data extracted from the original cover image are projected to multiple orthogonal directions, while a binary image is embedded in each orientations. Testing results show that that watermark can be blindly extracted using this algorithm, and its the transparency and robustness are excellent.