Parameterization of the Quality Factor for the High Throughput JPEG 2000

Abstract

High Throughput JPEG 2000 (HTJ2K, JPEG 2000 Part 15) is a new part of the JPEG 2000 family of standards. HTJ2K provides an alternate block coding algorithm that can be used in place of the EBCOT algorithm, which is used in the JPEG 2000 Part 1. Similar to JPEG and HEVC-Intra mode, a desired option for the proposed HTJ2K (which is not available in the previous versions of the JPEG 2000) is to have a simplified Quality Factor (QF) to steer the compression process. This way the user can modify the compression level by simply increasing or decreasing the value of the QF without knowing the exact underlying compression ratio or the utilized bit-depth. In this paper, we report the results of a subjective experiment, which was designed and implemented to test a proposed QF function for the new HTJ2K encoder, according to the Q factors of the JPEG encoder. A new test methodology for this purpose is utilized and a new formulation of the Q-factor is derived for HTJ2K based on the experimental results. The statistical analysis of the experimental results beside the procedure for deriving the QF range are provided. The derived QF range in this experiment is planned to be integrated in the implementations of the High Throughput JPEG 2000.