Method and apparatus for illuminating volume data in a rendering pipeline

摘要

An apparatus illuminates samples in a volume rendering pipeline. The apparatus includes the following units. A gradient magnitude modulation unit produces an opacity, emissive, diffuse and specular modulation factor from a gradient magnitude vector of each sample. A reflectance mapping unit produces a diffuse intensity and a specular intensity from the gradient magnitude vector of each sample and an eye vector of the volume. A first arithmetic logic unit combines an opacity of each sample with the corresponding opacity modulation factor to generate modulated opacities. A second arithmetic logic unit combines an emissive coefficient with the emissive modulation factor of each sample to generate modulated emissive coefficients. A third arithmetic logic unit combines the diffuse intensity with the diffuse modulation factor of each sample to generate modulated diffuse intensities. A fourth arithmetic logic unit combines the specular intensity with the specular modulation factor of each sample to generate modulated specular intensities, and a lighting unit applies the modulated emissive coefficient, modulated diffuse and specular intensities to color components of the samples to illuminate the volume sample. <IMAGE>