NPR（Non-Photo-realistic Rendering）是近年來在影像處理範疇中發展相當快速之一項研究課題，主要目的是以電腦、演算法自動產生類似素描、水彩之類，輸出與一般照片不同類型事物。與其處於另一極端為PR（Photo-realistic Rendering），其目標是追求以電腦產生接近真實事物為最重要目的，所產生事物越成功，表示程式越成功，如Matting。NPR可進一步根據實體模型（Physical Model）之有無來細分，若有實體模型，則依據實體模型特性，以電腦程式模擬，其結果會較為良好；反之，若無實體模型，則需憑藉研究者思考與觀察，盡可能找出更多正確資訊，來模擬求得最後結果，本研究屬於NPR中Non Physical Model中一環。將藝術家對相片作素描或水彩畫之想法，轉換成電腦演算法產生。
根據畫家說法，繪畫即是光與陰影之表現，以現在科學角度而言，其實就是亮度強弱之表現。而從亮度這項資訊中，亦可分離出許多供畫家參考依據，例如繪圖區塊、繪圖方向…etc，而NPR可以說是一步步實現畫家作品之一門研究。
本研究主要步驟為：讀取及分析影像資訊，分離出灰階及色彩資訊、輪廓及方向資訊、填色資訊，繪出基本圖形，再模仿鉛筆與水彩特性，補足基本繪圖特徵不足之缺陷，以期達到較真實之繪畫影像。第一章對真實繪畫，以及之前研究作簡介；第二章參考各研究理論提出理論依據並照其方法實作；第三章描述本研究之實際使用方法及必要之修正，並且將結果呈現。

NPR (Non-Photo-Realistic Rendering) is a new and quick-developed research topic in Image Processing. The main purpose of NPR is to generate pencil sketching or watercolor, something different from photos, automatically by computer algorithms. On the other hand, there is another technique called PR (Photo-Realistic Rendering). The goal of PR is to generate real objects by computer algorithms, such as Matting.
Furthermore, NPR includes two modes: one is with physical model and the other is not. With physical model, researchers could write programs to simulate NPR by the properties of physical model. Without physical model, researchers could write programs to simulate NPR by their observation and deliberation.
This thesis belongs to the latter, NPR without physical model. In the viewpoint of artists, drawing is performance of light and shadow. Then, in scientific, drawing depends on the degree of luminance. Luminance supports artists block and direction when drawing.
In this thesis, chapter 1 is introduction of art and previous researches. Chapter 2 describes theories what we can use and present the results. Chapter 3 describes the methods what this thesis use and necessary amendment, and present the results.

第一章 簡介 1
第一節 序論 1
第二節 素描藝術創作 5
第三節 繪畫工具 7
第四節 硬筆、鋼筆素描 13
第五節 彩色理論及色彩模型 18
第六節 科技影像與藝術發展 25
第二章 理論依據 28
第一節 非真實照片式繪圖（Non-Photorealistic Rendering） 28
第二節 影像增強 33
第三節 真實筆觸生成 39
第四節 色鉛筆畫 43
第五節 水彩畫 47
第三章 實際操作方法、步驟與結果 51
第一節 前置作業 51
第二節 基本筆觸繪畫 57
第三節 鉛筆筆觸與紙張效果 58
第四節 色鉛筆轉換 59
第五節 柔和鉛筆素描 59
第六節 水彩畫 65
第四章 未來工作 70
參考書目 71

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