| 摘要 |
PURPOSE:To quantize or inversely quantize picture data with the quantization characteristic of proper precision in a wide range without increasing the scale of a constitution circuit by performing quantization based on the nonlinear quantization characteristic expressed with the multiplication value between the value of a power of two and its coefficient. CONSTITUTION:A quantization characteristic QUANT is obtained in accordance with a specific formula where (k) is first quantization information indicating the exponent of the power of two and i/2+j is second quantization information indicating the coefficient by which the value of the power of two should be multiplied. (j) and (k) are positive integers, and (i) is 0 or one. When quantization information consists of 5 bits and bits are denoted as Q1 to Q5 in order from the most significant bit, (k), (j), and (i) are expressed by (Q1Q2), (Q3Q4), and (Q5) respectively. In the quantization characteristic reproducing circuit shown in the figure, the value of quantization information (Q3Q4Q5) is inputted to a shifter 110, and the value of quantization information (Q1Q2) is used to shift it, and the 7-bit quantization characteristic QUANT is finally reproduced from the output obtained by conversion of quantization information (Q1Q2) in a table part 111. |
