Halftoning by multiscale dot distribution

We propose a new halftoning approach that ensures the average graylevels in a grayscale image to be equal to that of a halftone over corresponding local neighborhoods, where the neighborhoods are taken with respect to a quad-tree structure. The halftoning algorithm first determines the total number of black and white dots in the entire halftone using a global mean requirement. It then distributes the dots to various local neighborhoods of the halftone using a multiscale dot distribution technique over the nodes of a quad-tree. We show that such a halftoning method produces high quality halftones particularly in the rendering of details.