Efficient Inverse Halftoning of Ordered Dither Images utilizing Matrix Addresses and Flat Area Detection

Efficient inverse halftoning (IH) methods of ordered dithering images were studied by utilizing a flat-area detection and dither matrix address information, for threshold ordering types of clustered dot and dispersed dot. The methods are based on the table look-up scheme, which has been considered to be most effective and quite practical. The flat area detection mechanism is found to generally contribute to save the memory size, and the dither matrix address information is found to contribute to save the memory size in some conditions. With the proposed ideas, the memory size to provide the same SNR in the conventional method is reduced to between 1/8 and 1/32, and the designed IH methods were also found to improve the generality of IH functions