Dispersed Data Hiding Using Hamming Code with Recovery Capability

Hamming codes can improve the embedding efficiency by hiding messages in a block-by-block manner with pixel-flipping. But since each pixel in the block is not dispersed in the image, it can only be flipped individually thus introducing undesirable visual distortion for halftone images. Also, since the errors caused by tamper are usually more than one bit in a block, the tampered region cannot be recovered by error correction of Hamming code. This paper proposes a dispersed block generating scheme through Space-filling curve decomposition to hide data using Hamming coding into these dispersed blocks. Each block consists of pixels randomly and uniformly distributed all over the cover halftone image, and the relation between pixels in the adjacent blocks is the adjacent pixels along the Space-filling curve. Experimental results show that the proposed method significantly improves the visual quality of marked halftone images and can recover local tamper.