Evaluation of a Model for Compressed Normal Maps in Graphic Objects
Kazuya Hayase, Toshihiko Yamasaki, Kiyoharu Aizawa · The Journal of The Institute of Image Information and Television Engineers · 2006
Normal maps are often used in computer rendering graphics to achieve more realistic objects. Both the number of normal maps and their data size have been increasing in recent times. Therefore, normal map compression algorithms, such as 3Dc, have been developed. However, there is no measure to evaluate the quality of lossy compressed normal maps. Therefore, the quality of graphic objects rendered with lossy compressed normal maps was evaluated by using the peak signal-to-noise ratios (PSNR) between the original normal maps and the compressed ones or by using the PSNR between rendered images, which is computationally expensive. We developed a model to evaluate their quality and to analyze the characteristics between lossy compressed normal maps and 3D images rendered with them.