Quasi-continuously Controllable Dot Position Error Diffusion

概要

論文の詳細を見る
Digital halftoning, which is a technology used to reproduce continuous-tone images approximately on physically bi-level printing devices, has been studied extensively, and several techniques, such as error diffusion, have been proposed. Previously, the size and pitch of each dot has been assumed to be equal. In the case of ink-jet printers, however, the dot position can be controlled, for example by electrostatic deflection, to a greater precision than the dot size, even though the dot size is fixed. This enables the image quality to be improved without changing the dot size, since dots can be more uniformly spaced. A number of algorithms have already been proposed in which the position of each dot is continuously variable. However, the present paper introduces another solution, in which the position of each black dot is digital, but can be controlled to a greater precision than the dot size. The algorithm is an extension of conventional error diffusion. In order to obtain better halftone images, a scalable error filter has also been proposed, in which an error filter of arbitrary size can be generated by simply supplying a parameter. Through subjective evaluation image quality was shown to be considerably improved. This is thought to be a result of the increased freedom of dot position.
The Imaging Society of Japanの論文