Patent ID: 6449395
Filing Date: 2002-09-10
Classification: H04N

Abstract:
An image encoding apparatus for generating encoded images which have encode amounts close to corresponding target encode amounts, the image encoding apparatus comprising:a relationship storage means for storing relationships, for each of one or more standard images, between a group of a plurality of quantization widths and one or more groups of a plurality of encode amounts, wherein each of the one or more groups of the plurality of encode amounts is obtained by encoding each of the one or more standard images using the plurality of quantization widths respectively; a quantization width determining means for obtaining a target encode amount and referring to the relationship storage means to obtain one or more quantization widths which correspond to one or more encode amounts which each are closest to the obtained target encode amount in each group of the one or more groups of the plurality of encode amounts; and an encoding means for obtaining an image and encoding the obtained image using the one or more quantization widths obtained by the quantization width determining means, wherein the encoding means includes: a predicted encode amount calculating means for obtaining an image, obtaining an orthogonal transformation image by performing an orthogonal transformation on the obtained image, generating one or more quantization tables using the one or more quantization widths obtained by the quantization width determining means, generating one or more quantized orthogonal transformation images by quantizing the orthogonal transformation image using the generated one or more quantization tables, and calculating one or more predicted encode amounts for the obtained image using the generated one or more quantized transformation images; an optimum quantization width determining means for reading the relationships from the relationship storage means, obtaining a quantization width corresponding to the target encode amount using the one or more predicted encode amounts and using the read relationships, and determining the obtained quantization width as the optimal quantization width; and an image encoding means for generating a quantization table using the optimal quantization width, and encoding the obtained image using the generated quantization table.