- 學位論文
在光子映射法下可變照度估計半徑之研究
A Study of Adaptive Radiance Estimating Radius of Photon Map
摘要
光子映射法是由Jenson所提出的一種全域照度演算法，其方法的特徵即為使用一帶能量之粒子即光子，將光子射入3D虛擬場景中，記錄其碰撞位置等相關資訊，以此作為照度估計方法的依據；在光子映射法中因為光子碰撞位置的分佈並不均勻，因此在照度估計的分佈也隨之有分佈不均的現象，另外照度估計是光子映射法中最耗費時間的，若能減少在照度估計時的花費，便可加速整個演算法的運算。 本篇論文提出光子映射法下新的照度估計方法，以計算每次光子碰撞所產生的照度影響範圍，此照度影響範圍隨光子航行距離的增加而擴大，並以兩個參數Base和Rate來控制其擴大的速度，以適應各種不同的場景。 實驗結果顯示，改良的照度估計方法不僅達到演算速度上的改進，所求得的照度分佈也較為均勻。 關鍵字：光子映射法，照度估計。
並列摘要
Photonmap is a global illumination algorithm proposed by Jenson，it uses a energy carrying particle or so called photon and shoot the photons into 3D realistic scene，record the photon hit position and relative information，and use these information to estimate the radiance；because the distribution of photon hit position in photonmap method is not smooth，so the radiance distribution of photonmap is not smooth，too。Furthermore the radiance estimation is the most time consuming procedure of photonmap algorithm，if we can reduce time cost here，we can accelerate the whole photonmap algorithm's computation。 This paper present a new radiance estimating method of photonmap，we compute the radiance coverage of each photon hit，this radiance coverage increasing with the distance of the photon travels in the 3D realistic scene。We also use two parameters Base and Rate to control the increase speed of the radiance coverage in order to fit different scenes。 By the experiment result，improved radiance estimating method no only accelerate the computation of photonmap algorithm but also have the distribution of radiance more smoothly。 Keyword：photonmap，radiance estimation。
參考文獻
延伸閱讀
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