Optimal threshold selection in hierarchical coders for images and video

A hierarchical coder (HC) is constructed from a number of simple coders for image blocks arranged in order of increasing bit rate and reproduction quality. This paper discusses several aspects of hierarchical coders, including: a general description of the structure of a HC, its advantages and important design considerations, a discussion of how threshold selection can affect the performance of the coder through a simple example, and an introduction of a simple procedure for selecting optimal (in the rate distortion sense) decision thresholds which control the levels of the hierarchy