QUANTIZER OPTIMIZED FOR DCT AC COEFFICIENT AND METHOD THEREOF

摘要

PURPOSE: A quantizer optimized for DCT(Discrete Cosine Transform) AC(Alternating Current) coefficient is provided to decrease the time for quantization by simplifying the calculation and realizing the quantizer easily. CONSTITUTION: A quantizer optimized for DCT AC coefficient Construction comprises a step-quantity determining unit determining the step size according to the quantized bit number allocated to DCT AC coefficient, a searching unit searching for the decision level interval belonging to the value of DCT AC coefficient, and a restoration level generating unit connected to the signal output unit connected to the output terminal of the searching unit outputting the restoration level Xq that is the intermediate value of decision level located at the searcher. The method comprises steps of determining the step size of the quantized bit number allocated DCT AC coefficient transformed by DCT and set the dispersion to 1(S1), searching a decision level range including the DCT AC coefficient(S2), and searching the quantized restoration level which is the intermediate value of the decision level range(S3).