Self-Verifying Visual Secret Sharing Using Error Diffusion and Interpolation Techniques

In this paper, we propose a novel scheme called a self-verifying visual secret sharing scheme, which can be applied to both grayscale and color images. This scheme uses two halftone images. The first, considered to be the host image, is created by directly applying a halftoning technique to the original secret image. The other, regarded as the logo, is generated from the host image by exploiting the interpolation and error diffusion techniques. Because the set of shadows and the reconstructed secret image are generated by simple Boolean operations, no computational complexity and no pixel expansion occur in our scheme. Experimental results confirm that each shadow generated by our scheme is a noise-like image and eight times smaller than the secret image. Moreover, the peak signal-to-noise ratio value of the reconstructed secret image is larger than 33 dB. Based on the extracted halftone logo, the proposed scheme provides an effective solution for verifying the reliability of the set of collected shadows as well as the reconstructed secret image. Furthermore, the reconstructed secret image can be established completely if and only if k out of n valid shadows have been collected. To achieve our objectives, four techniques were adopted: error diffusion, image clustering, interpolation, and inverse halftoning-based edge detection.