A highly efficient rate control algorithm for JPEG2000 images

The JPEG2000 image compression standard is the newest still image compression standard for digital image consumer electronics, such as digital cameras. However, Tier-1 encoding in the JPEG2000 standard algorithm requires a significant amount of memory and code time. In this study, a highly efficient and low-complexity rate control algorithm for JPEG2000 is proposed to reduce the memory requirements and the computation time. A revisable threshold is developed and is used to select the passes of each code block during Tier-1 encoding. Only the selected passes are encoded during Tier-1 and Tier-2 encoding. This routine avoids the encoding of all code passes and improves the coding efficiency. The experimental results based on standard test images show that the proposed algorithm can reduce the Tier- 1 coding time by up to 86.36% and the working memory by up to 95.50% at a bit rate of 0.125 bpp in comparison to the postcompression rate distortion algorithm. The peak-signal-to-noise ratio across the images remains almost unchanged. The proposed algorithm can not only significantly improve the encoding efficiency but also maintain the image quality. Therefore, it can be applied to consumer imaging devices such as digital cameras, cameras in mobile phones and compact consumer cameras in the form of either embedded or processing software to reduce the memory and hardware requirements.