A Fast Noniterative Visually Lossless Compression of Dental Images Using BPG Coder

Here we consider lossy compression of grayscale dental images. To preserve valuable diagnostic information, we propose to carry out visually lossless compression. For this purpose, it is proposed to apply better portable graphics (BPG) coder for which quality and compression ratio is controlled by the quality parameter Q. To provide invisibility of distortions and artifacts, visual quality metric called PSNR-HVS-M is analyzed for which the threshold of distortion invisibility is known. Experiments with image fragments are carried out for dental images produced by Morita imager. It is shown that quality of compressed images slightly depends on image acquisition mode. We give recommendations concerning Q setting to provide invisibility of distortions. These recommendations are also based on the results of analysis of dental image visual quality carried out by a group of dentistry experts. It is shown that BPG coder offers several benefits compared to several counterparts.