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A dynamic segment designate lossless coding (DSDC for short) method for sparse binary patterns is proposed in this paper. First of all, in order to reduce the correlation of the binary image, we carry out peculiar difference in row and column on the white/black (0/1) binary image successively, the resultant image is also binary, but commonly it is sparser than before, that is to say, the proportion of non-zero element will decrease. Afterwards we join rows of the simpler image by linking their heads and tails correspondingly into a long one-dimensional array. Scan the one-dimensional array from left to right step by step and divide the array into a number of non-all-zero segments (1 and 0 included) of fixed length and all-zero segments (only 0 included) of varying length according to a certain rule. In the algorithm, we always encode a subsection as often as we divide it from the one-dimensional array. After that, perform distinct coding method for the two kinds of segments of non-all-zero segments and all-zero segments respectively. For non-all-zero segment, we encode each non-all-zero element with its segment-relative address code and skip over the zero elements in each segment. As for all-zero segment, we designate the length of the all-zero segment with bin tree code, which represents the number of contiguous zero element contained in it. The Decoding method is the backward process of coding. Read out the bit stream from the code file and reconstruct the segment by using the corresponding method every time. Finally, if differential operation is carried out at the course of encoding, perform reverse difference on the current binary image and we will reconstruct the original binary image. The whole process is lossless. The encoding process and the decoding process are nearly balance in computational time or in computational complexity. In this paper, the eight binary images CCITT 1-8 have been tested by some methods mentioned in this paper. It has been demonstrated by the experimental result that the dynamic segment designate coding method is efficient for encoding sparse binary patterns.
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