METHOD FOR ESTIMATING HALFTONE PICTURE OF BINARY PICTURE

摘要

PURPOSE:To increase the picture processing speed with high reproducibility of pictures by obtaining the estimated values of a halftone picture element of the halftone picture to be estimated by means of plural types of openings and defining one of those estimated values of the picture element that satisfies the prescribed deciding conditions as the estimated value of the halftone picture element of the relevant picture. CONSTITUTION:The number of white picture elements (black picture elements) are counted within each opening while various types of openings are shifted every picture element. Then the count value of the white picture element is multiplied by the gain decided by the type of the opening to decide the estimated value of the halftone picture of the corresponding opening. For instance, 7 types of estimated values are obtained to a single picture element with use of 7 types of openings. In this respect, a large opening is used to secure the high gradation expression in a low space frequency area. While a small opening is used in a high space frequency area to reproduce a picture of high image resolution. In such a way, the quality of the halftone picture is totally improved.