DEVICE AND METHOD FOR ENCODING IMAGE

摘要

PROBLEM TO BE SOLVED: To provide an image encoder having saved power consumption and improved processing speed. SOLUTION: This image encoder is provided with a quantized DCT coefficient output means for quantizing and outputting a DCT coefficient obtained by DCT-transforming the difference signal of an image signal and its predictive image signal, a non-zero coefficient judging means for judging whether a non- zero coefficient is included in a quantized DCT coefficient outputted by the quantized DCT coefficient output means, and a decoded signal output means which outputs a decoded signal obtained by decoding the output of the quantized DCT coefficient when the non-zero coefficient judging means judges that the quantized DCT coefficient includes the non-zero coefficient and which outputs all the signal components of the decoded signal without decoding the output of the quantized DCT coefficient in the case of judging that the quantized DCT coefficient never includes the non-zero coefficient.