Resolution Scalable Image Coding Through Recombining DCT Coefficients

The basic unit of image coding based on DCT was deemed as a complete entity, such as 8 × 8 code block in JPEG standard, therefore, the image coding based on DCT has large difficulty to implement resolution scalability. This paper proposed a resolution scalability scheme for image codec based on DCT. The encoder recombines the DCT coefficients according to their frequency, and the sub DCT code blocks are encoded in term of the image resolution. After decoding the coefficients form low-frequency to high-frequency, the decoder selects the IDCT models to reconstruct the image from low resolution to high resolution. Experimental results show that our method can get more flexible scalability than that of the methods of DWT base.