| 摘要 |
The digital values, Bij, of the brightness of points in the i<th> line undergo differential coding with, as reference, the brightness values, Bi-1,j, Bi-1,j-1 or Bi-1,j+1, of the points in the (i-1)<th> line. They are coded by blocks of consecutive values such that the difference in brightness of each point with respect to its point of reference is identical to within a tolerance 2e. The values, Bij, of a block are all coded with respect to the value Bi-1,j or the values Bi-1,j-1 or the values Bi-1,j+1, chosen in order to minimise the difference in brightness. Each block is coded by its brightness difference value, its length and a binary word indicating whether the respective references are Bi-1,j, Bi-1,j-1 or Bi-1,j+1. |
