全域照明之光子映射演算法加速：多解析度分類光線內插法

Acceleration of Photon Mapping: Adaptive Sampling of Irradiance Cache by Components

陸可凡(Ko-fan Lu)

指導教授 ： 張鈞法 ； 楊舜仁

國立清華大學/電機資訊學院/資訊工程學系/碩士(2011年)

https://doi.org/10.6843/NTHU.2011.00483

摘要

在模擬真實環境中的場景時，必須追蹤全域照明中的所有光線，包括多次反射與折射等，以增加場景的真實性，同時必須耗費龐大的計算。
光子映射演算法分兩階段追蹤光線，以加快在焦散曲面的多次折射或多次反射的柔軟表面上的計算速度。除此之外，照度內插演算法能更進一步加速光線追蹤法在間接照明上的運算。

在本篇論文中，我們展示了一個演算法其概念來自於照度內插演算法並修改成以不同解析度的場景實作照度內插運算，並將其套用在光子映射演算法中對不同類別光線的運算。我們的實作能有效加速光子映射演算法在模擬全域照明的運算，並且保留場景中的細節，確實達到模擬全域照明的效果

關鍵字

全域照明 ； 光子映射 ； 分類光線 ； 照度暫存 ； 光線追蹤演算法

並列摘要

For simulating the scene with global illumination, ray tracing, which includes the rendering of multi-bounce reflection and refraction, demands heavy computation.

Photon mapping provides a two-pass method for efficiently simulating global illumination with ray tracing, which makes the computation of caustics and soft indirect illumination relatively fast. Besides, irradiance cache is a method to further speed up the computation of indirect illumination in a Monte Carlo ray tracer.

This paper presents a method that uses the concept of irradiance cache in multi-resolution to cache the irradiance of each light component in photon maps. The presented method not only can make the computation more efficient but also can preserve the details of scene.

並列關鍵字

Global Illumination ； Photon Mapping ； Light Component ； Irradiance Cache ； Ray Tracing

參考文獻

Bala, K., Dorsey, J., & Teller, S. (1999, July). Radiance interpolants for accelerated bounded-error ray tracing. ACM Transactions on Graphics (TOG) , v.18 (n.3), pp. 213-256.

Christensen, P. H. (1999). Faster photon map global illumination. Journal of Graphics Tools , n.3, pp. 1-10.

Collins, S. (1994, June). Adaptive splatting for specular to diffuse light transport. In Fifth Eurographics Workshop on Rendering , pp. 119-135.

Cook, R. L. (1986, January). Stochastic sampling in computer graphics. ACM Transactions on Graphics (TOG) , n.1, pp. 51-72.

James, A., & Kirk, D. (1990). Partical Transport and Image Synthesis. Computer Graphics , n.4, pp. 53-66.