Prediction image generating apparatus using mask and apparatus for coding, transmitting and decoding a binary image using the same

Abstract

A prediction image generating apparatus using a plurality of masks and an apparatus for coding, transmitting and decoding a binary image using the same. The prediction image generating apparatus includes a maximum value searching unit, a minimum value searching unit, a mean calculation unit, a binarization unit and a comparing unit. The maximum value searching unit searches a maximum value of element values of one of the masks corresponding to a pixel having one binary level among a plurality of pixels located in front of the pixel having the current binary level to be predicted in a window of a predetermined size. The minimum value searching unit searches a minimum value of element values of the one mask corresponding to a pixel having the other binary level among a plurality of pixels located in front of the pixel having the current binary level to be predicted in the window of the predetermined size. The mean calculation unit takes an average of the maximum value and the minimum value searched from the maximum value searching unit and the minimum value searching unit. The binarization unit binarizes the average determined in the mean calculation unit. The comparing unit compares the binarized average with the binary level of the current pixel and outputs prediction image data indicating a successful or a failed prediction. Accordingly, when an image obtained by binarizing a document of pictures as well as text documents is transmitted, good picture quality and high coding efficiency are realized.