JPS6031383B

PURPOSE:To restore an image of high quality from a low gradation sampling signal, by predicting a density level of a remarkable picture element in the specific picture element area by a density level of each picture element around the former. CONSTITUTION:The image input side A scans an image and performs a low gradation sampling for the density information of each picture element by use of a quantizer 1. Each smapling signal is encoded by an encoder 2 and is transmitted to the output side B. The output side B decodes the encoded signal which has been received by a decoder 3, stores the contents in the memory 4, and makes it store a density level of each picture element in the specific picture element area. Based upon the contents which have been stored, a density level of a remarkable picture element is predicted by the arithmetic unit 5. A specific threshold pattern is called from ROM6, it is compared with a predictive level by the comparator 7, and white or black is decided. Thus, the low gradation sampling signal is able to restore an image of high quality.