A Study On Inverse Halftoning Of Scanned Images

When the scanned halftoning images are needed to be processed or analyzed, they should be inverse halftoned close to the original images.The factors of affecting printing and scanning have been studied and analyzed to make a foundation for modeling the printer and scanner. Focused on the influences of dot gains in printing, a halftoning model is developed. Considering the printing and scanning process, the integrated model is constructed by the mapping vector between halftone patterns and their scanning values using the experimental method. The models of printer and scanner have made a foundation to build the new method of inverse halftoning for scanned images.After studying and analyzing the existent inverse halftoning methods, a new algorithm based on partial differential equation is proposed for error-diffusion halftoning. Combining with the modeling of printer and scanner, an inverse halftoning method for scanned images is constructed. And the experimental results show that the method has better effects on denoising of scanned images.