| 摘要 |
PURPOSE:To compress a memory required for data storage nearly to 1/2 of original data by concentrating the distribution of errors between forecast values and true values and the density of each picture element onto nearly zero to bring the word length of the original data into a length of 1/2. CONSTITUTION:The compressed data is inputted on by one byte. When the content of the inputted 1 byte is not (11111111), i.e., -128, the data is restored as a forecast error eij. If the content (11111111) appears, the succeeding two bytes are read as one data and restored as the eij. When the eij is obtained, the adjacent picture elements restored already are used to calculate a forecast value xij to a true value xij thereby restoring the true value of the picture element (i, j). The operation is applied to all picture elements to restore the original picture data from the compressed data.
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