| 摘要 |
<p>PURPOSE:To enhance the compression efficiency of multigradation picture data by obtaining the generating frequency of the gradation value of respective picture elements for prescribed screen unit and assigning a code low in the number of bits to the higher generating frequency to encode. CONSTITUTION:The gradation of m bits is supplied to the picture of MXN dots for every dot and the gradation values at the arbitrary picture elements (i), (j) are defined to be Pi, j. In case of the gradation of m bits, since the gradation value is 2<m>, the Pi, j take values to a maximum 2<m>. Actually, the Pi, j has many same values of the adjacent picture elements, so that the generating frequency for every gradation value is obtained from the values of the respective Pi, j on the screen. The code low in the number of bits is assigned to the gradation value higher in the generating frequency to encode the respective Pi, j, and then, the picture data can be efficiently compressed.</p> |
