目标是产生一组墨点使其平均灰度与原图像相应区域的灰度相当，以保证人眼在一定距离观察时几乎不能分辨出来，产生连续灰度级的错觉。 -Goal is to produce a set of dots to the original image corresponding average gray gray area equivalent to the guarantor when viewed from a distance the eye can hardly tell the differen