Image coding distortion reduction apparatus and method

A moving image coding distortion reduction method comprising controlling a decoder configured to decode a coded moving image signal to obtain a decoded moving image signal, and output, as coding characteristic information, a picture type or quantization information of a field or frame of the decoded moving image signal obtained when the coded moving image signal is decoded, a motion detector configured to obtain a motion detection output indicating a motion of an image of the decoded moving image signal, a coding distortion reduction module configured to have a coding distortion reducing characteristic which reduces a coding distortion included in the decoded moving image signal, a ringing distortion reduction module configured to reduce a ringing distortion of the decoded moving image signal in accordance with the coding characteristic information and the motion detection output, and a block distortion reduction module which is configured so that an output of the ringing distortion reduction module is input thereto and which is configured to reduce a block distortion,

• wherein when a detection signal from the motion detector changes to a smaller motion detection amount and when the quantization information changes to a larger quantization step, a ringing reduction of the ringing distortion reduction module is controlled so that the ringing reduction is enhanced, and
• when a detection signal from the motion detector changes to a greater motion detection amount and when the quantization information changes to a larger quantization step, a block reduction of the block distortion reduction module is controlled so that the block reduction is enhanced.