Oblivious Digital Watermarking Scheme with Blob-Oriented and Modular-Arithmetic-Based Spatial-Domain Mechanism

An oblivious and robust digital watermarking scheme with a blob-oriented and modular-arithmetic-based spatial-domain mechanism is presented. It is oblivious in the sense that no original image is required for watermark extraction. By a bloboriented and modular-arithmetic-based embedding–extracting mechanism, which slightly and unevenly perturbs the intensities of the pixels within a blob through the entire image except the exact edges and their 3 ∗ 3 neighboring pixels so that the mean intensity of the marked blob equals a preset value, the scheme achieves robustness against JPEG compression, filtering, noise, and scaling in addition to keeping the embedded watermark transparent and tamper-resistant. The uniqueness and the fusion of the watermark before embedding further increase the difficulties of collusion attack. The experimental results demonstrate that such an oblivious scheme is indeed robust and is superior to some existing oblivious schemes with respect to JPEG compression and filtering. C © 2001 Academic Press