Improvements on the Pixel-tracing Filter: Reflection/Refraction, Shadows, and Jittering

Pixel-trace filtering is an efficient anti-aliasing technique for sequence animation because its computation cost is constant regardless of scene complexity. Although it works well in simple cases, it has shortcomings with steady objects, moving shadows, reflective/refractive objects, and deforming objects. This paper significantly improves pixel-trace filtering and eliminates all these restrictions. Jittered sampling is introduced to eliminate the aliasing experienced with steady objects. Beam/pencil tracing techniques are applied to reflective/refractive objects. The G-buffer scheme is adopted to deal with moving shadows and deforming objects. Several experiments demonstrate that our improvements successfully eliminate the restrictions. It is also shown that the temporal-filtering feature of pixel-trace filtering is advantageous for flicker reduction, and an appropriate filter size is suggested based on human flicker perception. With these improvements, pixel-trace filtering becomes a powerful anti-aliasing method, and we believe that it can be a standard anti-aliasing technique for computer animation.