Optimum rate allocation in pyramid vector quantizer transform coding of imagery

The optimum rate allocation is derived for pyramid vector quantization (PVQ) in transform coding of monochromatic imagery. A modification to the low-rate PVQ encoding algorithm is described, which provides improved performance. Images are encoded with both the PVQ and standard scalar quantizer transform coders, demonstrating that the PVQ coder reduces the mean-square encoding error and better preserves image edges.