出版社：The Institute of Image Information and Television Engineers
摘要：Normal mapping is one of the most essential technologies for creating realistic three-dimensional computer graphics. In conventional normal map compression, such as 3Dc, only x and y components are encoded and z components are restored based on the normalizing condition. We describe an intuitively comprehensive error analysis algorithm for this approach that shows the conditions under which the compression error becomes larger. Non-linear quantization algorithms based on a formula for better compression performance than the conventional approaches are also described. Experimental results using 300 normal maps demonstrate that the PSNR is improved by 0.29-0.85 dB. In addition, the quality of rendered images can be improved by 0.76-1.81 dB on average. Our algorithms are compatible with random access and highly parallel processing on GPUs.
