如何準確的描述一個物體材質帶給人的視覺感受，一直都是許多行業致力於解決的問
題，為了解決此問題，國際照明委員會定義視覺外貌(Visual appearance)名詞，來描述
每一材質所擁有的四種屬性，分別為顏色、光澤度、透明度及紋理，藉由對此四種屬
性進行定量的分析來達到描述物體材質的目的；而目前傳遞視覺感受方面，渲染為最
直接呈現的方法。因此本研究將視覺外貌中定義的屬性與目前主流的渲染流程 PBR
(Physically-Based Rendering) 建立連結關係，而目前 PBR 渲染流程中主流之一的
Metallic/Roughness 渲染流程定義了對材質進行渲染所需的基本 4 種屬性貼圖，分別
為基本色貼圖、表面法向量貼圖、粗糙度貼圖及金屬度貼圖。藉由將視覺外貌的數值
代入 PBR 中定義的不同屬性貼圖中，來對物體材質做擬真渲染。本研究使用一個多
角度陣列式 LED 取像裝置進行實驗，實驗一「材質外貌擬真渲染實驗」量測了兩種
不同種類的材質(紡織品及裝潢壁紙)共計 20 個樣品，並計算其的各屬性貼圖後進行
渲染，最後透過人因實驗結果分析量測並計算後的各屬性貼圖的可信度；實驗二「取
樣減量之材質外貌擬真渲染實驗」對實驗一結果中評價分數最高的四個樣本嘗試使用
33 盞、30 盞、18 盞、15 盞、9 盞、3 盞光源來計算其粗糙度貼圖，並和使用全部光
源計算出的結果進行互相比較，結果顯示對高粗糙度的樣本而言，光源數量減至 3 盞
時皆無明顯差異，意即 3 盞光源配置即可產生可接受的 Roughness Map；對於低粗糙
度的樣本而言，光源數量減至 9 盞時會有明顯差異，意即 15 盞光源的配置即足夠產
生可接受的 Roughness Map。

How to accurately describe the visual experience of materials has always been an issue that researchers are trying to persue. In order to solve this problem, CIE (Commission Internationale de’Eclairage) gave a clear definition for visual appearance in 2008. Visual appearance consists of the properties of color, texture, gloss, and transparency that are evaluated by quantitative analysis. According to these analysis, the rendering process of PBR (Physically Based Rendering) is introduced in this research. Those basic quantity maps, called base color, normal, roughness and metallic maps, are used in Metallic/Roughness mainstream workflows of PBR. In this research, the data with different volumetric SVBRDF (Spatially Varying Bidirectional Reflectance Distribution Function) was captured by a self-developed SVBRDF measurement system. The purpose of Experiment 1 is verifying the reality of PBR texture of our device by psychophysical experiments. There are up to 20 samples, including textiles and wall-papers, that are verified. The result of Experiment 1 is considered as the base of Experiment 2. In Experiment 2, we chose the four qualified samples to evaluate and attend to decrease the number of LED light bulbs in our system, which is important cues for roughness map estimation in SVBRDF measurement. Totally, six types of arrangement, including these cases of 33, 30, 18, 15, 9, and 3 LED light bulbs, are evaluated. The roughness maps under different number of lights were tested based on Experiment 1 by psychophysical experiment, as well. The results of Experiment 2 show that in case of 3 LED light bulbs is acceptable for the material with higher roughness. And, in case of 9 LED light bulbs is not enough for the material of lower roughness. By contrast, in case of 15 LED light bulb is just acceptable in this situation.

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