草圖繪製是創意產業最早期的一個工序。研究發現，草圖不但表達了畫家的想法，在繪製的過程，草圖也能為畫家帶來新靈感，所以草圖繪製是不可缺少的工序。然而，原始的草圖包含許多不必要的筆觸，所以進行後期製作前，必須用線重新勾畫。傳統上，這個過程是費時和繁瑣的，畫家必須人手把每一條需要的線都重新勾畫出來。當應用到動畫創作的時候，由於涉及的草圖數量龐大，情況會變得更壊，所以有必要把整個過程自動化。現有的研究都視草圖勾勒為一個線條分組和曲線擬合的過程，他們會把相近而順暢的筆觸組合在一起，形成單一線條。然而，他們都忽略了視覺感知上的一個重要法則──格式塔理論中的閉合原理。格式塔理論是一個知名的心理學理論，解釋人類如何透過整合理解各種視覺元素。根據格式塔理論中的閉合原理，我們往往把各種分隔的視覺元素整合為一個封閉的形狀。在這篇論文中，我提出閉合原理比格式塔理論中的其他原理更能幫助我們理解草圖，從而提出了一種基於區域的方法來勾勒草圖。實驗結果發現，我的方法在保有草圖上封閉形狀的能力上比現有的方法更優勝。 / Sketching is the earliest stage of production in art and design. Sketches are useful in conveying and developing ideas. However, raw sketches contain unnecessary strokes and must be converted to neat and tidy drawings before moving onto later stage of production. Traditionally, this conversion process is time-consuming and tedious since it is performed stroke by stroke manually. The situation is even worse when it comes to animation production which involves a huge number of sketches, so there is a strong motivation to automate the conversion process. Existing works formulate the conversion process as stroke grouping and curve fitting processes, in which close and continuous strokes are grouped together to form single strokes in the resulting image. Nevertheless, previous works overlooked an important law of visual perception: the law of closure in Gestalt principles. Gestalt principles concluded from early visual perception studies demonstrate how human perceive visual elements as different groups of lines and shapes. It states that we tend to group elements into closed shape even when a gap exists. In this thesis, we utilize the idea of law of closure and propose a region-based approach to refine sketches. Experiment result shows that this method outperforms the existing methods in terms of the capability of preserving salient regions in sketches. / Detailed summary in vernacular field only. / Wong, Ka Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 59-61). / Abstracts also in Chinese. / Chapter 1 --- Introduction --- p.6 / Chapter 2 --- Background --- p.8 / Chapter 2.1 --- Role of Sketch in Art and Design --- p.8 / Chapter 2.2 --- Characteristics of Raw Sketches --- p.10 / Chapter 2.3 --- Related Works --- p.11 / Chapter 2.3.1 --- Methods for Raster Image --- p.12 / Chapter 2.3.2 --- Methods for Vector Image --- p.14 / Chapter 2.3.3 --- Deficiency --- p.17 / Chapter 3 --- Gestalt Principles and Its Application --- p.18 / Chapter 3.1 --- Introduction to Gestalt Principles --- p.18 / Chapter 3.2 --- Existing Computational Model of Gestalt Principles --- p.20 / Chapter 3.3 --- Gestalt Principles for Outline Tracing --- p.22 / Chapter 3.3.1 --- Similarity --- p.23 / Chapter 3.3.2 --- Proximity --- p.23 / Chapter 3.3.3 --- Continuity --- p.24 / Chapter 3.3.4 --- Regularity --- p.25 / Chapter 3.3.5 --- Closure --- p.25 / Chapter 4 --- Proposed Method --- p.27 / Chapter 4.1 --- Multi-scale Region Retrieval --- p.28 / Chapter 4.1.1 --- Construction of Region Hierarchy --- p.29 / Chapter 4.1.2 --- Region Refinement --- p.31 / Chapter 4.2 --- Salient Region Retrieval --- p.32 / Chapter 4.2.1 --- Flattening of Region Hierarchy --- p.32 / Chapter 4.2.2 --- Region Merging --- p.33 / Chapter 4.2.3 --- Region Pruning --- p.37 / Chapter 4.2.4 --- Region Merging by User --- p.41 / Chapter 4.3 --- Outline Synthesis --- p.43 / Chapter 4.3.1 --- Outline Synthesis of Region-boundary Strokes --- p.44 / Chapter 4.3.2 --- Smoothing of Region-boundary Strokes --- p.45 / Chapter 4.3.3 --- Outline Synthesis of Feature Strokes --- p.48 / Chapter 4.4 --- Curve Fitting --- p.50 / Chapter 5 --- Result and Discussion --- p.52 / Chapter 6 --- Conclusion --- p.58 / Chapter 7 --- Reference --- p.59
| Identifer | oai:union.ndltd.org:cuhk.edu.hk/oai:cuhk-dr:cuhk_328736 |
| Date | January 2012 |
| Contributors | Wong, Ka Wing., Chinese University of Hong Kong Graduate School. Division of Computer Science and Engineering. |
| Source Sets | The Chinese University of Hong Kong |
| Language | English, Chinese |
| Detected Language | English |
| Type | Text, bibliography |
| Format | electronic resource, electronic resource, remote, 1 online resource (iv, 6-61 leaves) : ill. (some col.) |
| Rights | Use of this resource is governed by the terms and conditions of the Creative Commons “Attribution-NonCommercial-NoDerivatives 4.0 International” License (http://creativecommons.org/licenses/by-nc-nd/4.0/) |
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