Patent ID: 7116835

Claim:
An image processing apparatus for converting image data coded at a first bit rate into image data coded at a second bit rate, said image processing apparatus comprising: first quantization scale code calculating means for calculating a first quantization scale code required to code said image data at said first bit rate on the basis of said image data coded at said first bit rate; second quantization scale code calculating means for calculating a second quantization scale code obtained by subjecting said first quantization scale code to adaptive quantization according to visual characteristics on the basis of said image data coded at said first bit rate; normalized activity calculating means for calculating a normalized activity on the basis of said first quantization scale code and said second quantization scale code; third quantization scale code calculating means for calculating a third quantization scale code required to code said image data at said second bit rate; fourth quantization scale code calculating means for calculating a fourth quantization scale code obtained by subjecting said third quantization scale code to adaptive quantization according to visual characteristics on the basis of said third quantization scale code and said normalized activity; means for providing a determined quantization scale code from the second quantization scale code and the fourth quantization scale code; and means for using the determined quantization scale code to provide image data coded at the second bit rate.