| 摘要 |
<p>PURPOSE:To improve a compression rate by obtaining a dynamic range (difference between maximum level and minimum level) and the minimum level with respect to plural picture elements and using the compressed quantized bit number so as to divide the dynamic range thereby encoding each picture element in a block to a code having the nearest level. CONSTITUTION:A dynamic range DR detected by a dynamic range calculation circuit 3 is fed to a quantization width (DELTA) deciding circuit 5, which divides the dynamic range DR in a step number corresponding to the quantization bit number to calculate a 4-bit quantization width DELTA and generates an 8-bit representative minimum level L0. A picture element data DT 1 after the quantized width DELTA and the minimum level are eliminated is fed to a quantization circuit 6. The quantization circuit 6 discriminates in which region divided the picture element data DT 1 after the minimum level is eliminated and generates the coded code DT in 4-bit specifying the region. one block 9 being the unit of coding consists of two-dimension regions 9A, 9B, 9C and 9D belonging to each field of two frames (4-field).</p> |
