A REVERSIBLE DATA HIDING SCHEME TO INVERSE HALFTONING

A new inverse halftoning algorithm based on reversible data hiding techniques for halfton images is proposed in this research. The proposed scheme has the advantages of two commonly used methods, the look-up table (LUT) and Gaussian filtering methods. We embed a part of important LUT templates into a halfton image and restore the image lossless after these templates been extracted. Then a hybrid method is performed to reconstruct a gray-scale image from the halfton image. In the image reconstruction process, the halfton image is scanned pixel by pixel. If the scanned pattern surrounding a pixel appeared in the LUT templates, a gray value is directly predicted using the LUT value, otherwise, it is predicted using Gaussian filtering. Experimental results show that the reconstructed gray-scale images using the proposed scheme own better quality than both the LUT and Gaussian filtering methods.