Inverse Halftoning Method Using Pattern Substitution Based Data Hiding Scheme.

The objective of inverse halftoning is to reconstruct high quality grayscale images from bi-level halftone images. Different from the previous inverse halftoning approaches, our algorithm computes the difference image between the predicted image using Gaussian filtering from a halftone image and the original grayscale one. The difference image is then compressed and embedded into the halftone image using a reversible data hiding method. In the image reconstruction process, the marked halftone image is scanned to extract the embedded data. Finally, a better quality of reconstructed image can be generated by adding the extracted difference image to the predicted image. Experimental results show that the proposed approach can efficiently improve the quality of reconstructed images for inverse halftoning when compared to the previous approaches. [ABSTRACT FROM AUTHOR]