298 research outputs found

    Drawing from calculators.

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    NPR Lenses:Interactive Tools for Non-photorealistic Line Drawings

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    Video based dynamic scene analysis and multi-style abstraction.

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    Tao, Chenjun.Thesis (M.Phil.)--Chinese University of Hong Kong, 2008.Includes bibliographical references (leaves 89-97).Abstracts in English and Chinese.Abstract --- p.iAcknowledgements --- p.iiiChapter 1 --- Introduction --- p.1Chapter 1.1 --- Window-oriented Retargeting --- p.1Chapter 1.2 --- Abstraction Rendering --- p.4Chapter 1.3 --- Thesis Outline --- p.6Chapter 2 --- Related Work --- p.7Chapter 2.1 --- Video Migration --- p.8Chapter 2.2 --- Video Synopsis --- p.9Chapter 2.3 --- Periodic Motion --- p.14Chapter 2.4 --- Video Tracking --- p.14Chapter 2.5 --- Video Stabilization --- p.15Chapter 2.6 --- Video Completion --- p.20Chapter 3 --- Active Window Oriented Video Retargeting --- p.21Chapter 3.1 --- System Model --- p.21Chapter 3.1.1 --- Foreground Extraction --- p.23Chapter 3.1.2 --- Optimizing Active Windows --- p.27Chapter 3.1.3 --- Initialization --- p.29Chapter 3.2 --- Experiments --- p.32Chapter 3.3 --- Summary --- p.37Chapter 4 --- Multi-Style Abstract Image Rendering --- p.39Chapter 4.1 --- Abstract Images --- p.39Chapter 4.2 --- Multi-Style Abstract Image Rendering --- p.42Chapter 4.2.1 --- Multi-style Processing --- p.45Chapter 4.2.2 --- Layer-based Rendering --- p.46Chapter 4.2.3 --- Abstraction --- p.47Chapter 4.3 --- Experimental Results --- p.49Chapter 4.4 --- Summary --- p.56Chapter 5 --- Interactive Abstract Videos --- p.58Chapter 5.1 --- Abstract Videos --- p.58Chapter 5.2 --- Multi-Style Abstract Video --- p.59Chapter 5.2.1 --- Abstract Images --- p.60Chapter 5.2.2 --- Video Morphing --- p.65Chapter 5.2.3 --- Interactive System --- p.69Chapter 5.3 --- Interactive Videos --- p.76Chapter 5.4 --- Summary --- p.77Chapter 6 --- Conclusions --- p.81Chapter A --- List of Publications --- p.83Chapter B --- Optical flow --- p.84Chapter C --- Belief Propagation --- p.86Bibliography --- p.8

    Designing Digital Art and Communication Tools Inspired by Traditional Craft

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    Ph.DDOCTOR OF PHILOSOPH

    Wholetoning: Synthesizing Abstract Black-and-White Illustrations

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    Black-and-white imagery is a popular and interesting depiction technique in the visual arts, in which varying tints and shades of a single colour are used. Within the realm of black-and-white images, there is a set of black-and-white illustrations that only depict salient features by ignoring details, and reduce colour to pure black and white, with no intermediate tones. These illustrations hold tremendous potential to enrich decoration, human communication and entertainment. Producing abstract black-and-white illustrations by hand relies on a time consuming and difficult process that requires both artistic talent and technical expertise. Previous work has not explored this style of illustration in much depth, and simple approaches such as thresholding are insufficient for stylization and artistic control. I use the word wholetoning to refer to illustrations that feature a high degree of shape and tone abstraction. In this thesis, I explore computer algorithms for generating wholetoned illustrations. First, I offer a general-purpose framework, “artistic thresholding”, to control the generation of wholetoned illustrations in an intuitive way. The basic artistic thresholding algorithm is an optimization framework based on simulated annealing to get the final bi-level result. I design an extensible objective function from our observations of a lot of wholetoned images. The objective function is a weighted sum over terms that encode features common to wholetoned illustrations. Based on the framework, I then explore two specific wholetoned styles: papercutting and representational calligraphy. I define a paper-cut design as a wholetoned image with connectivity constraints that ensure that it can be cut out from only one piece of paper. My computer generated papercutting technique can convert an original wholetoned image into a paper-cut design. It can also synthesize stylized and geometric patterns often found in traditional designs. Representational calligraphy is defined as a wholetoned image with the constraint that all depiction elements must be letters. The procedure of generating representational calligraphy designs is formalized as a “calligraphic packing” problem. I provide a semi-automatic technique that can warp a sequence of letters to fit a shape while preserving their readability

    Walking The Line: Examining an Illustration of A.L. 288-1 for Anatomical Accuracy and Its Implications for Studying Australopithecine Locomotion

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    After over 45 years, since Dr. Donald Johanson’s famed discovery of “Lucy” (A.L. 288-1), a debate in the scientific community still endures over the nature of her bipedal gait. Did Australopithecus afarensis walk upright more as a great ape, with significant hip and knee flexion (the Bent-Hip Bent-Knee [BHBK] walking hypothesis), or was her gait closer to a modern human’s? At the heart of this debate is a single pen-and-ink line drawing, first published in an article by Drs. J. Stern and R. Susman on australopithecine locomotion (Stern and Susman, 1983). Despite the decades of arguments that have followed, this lone two-dimensional fossil reconstruction has never been tested. This project compares the with a contemporary 3D model of A.L. 288-1, and deciding if the Stern and Susman (1983) figure, which has been crucial to BHBK proponents, is indeed anatomically accurate. To test the drawing’s accuracy, casts of A.L. 288-1’s innominate and sacrum were scanned using high-resolution computed tomography (UHR CT). This produced a 3D mesh which was compared to the original illustration. In the end, it was not possible to match the drawing to the model. Though it demonstrates nothing about australopithecine gait in itself, it undermines the BHBK hypothesis which is derived from the drawing, since it contains flawed anatomy. The flaws are likely due to the source material provided to the artist, demonstrating the importance of the collaboration between scientists and illustrators, and their ability to understand one another. Kurt Esenwein Chairpersons of the Advisory Committee Adam D. Sylvester, PhD, Associate Professor, Center for Functional Anatomy and Evolution Timothy H. Phelps, MS, FAMI, Professor (Faculty Advisor), Art as Applied to Medicine [email protected]

    Stylised procedural animation

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    This thesis develops a stylised procedural paradigm for computer graphics animation. Cartoon effects animations - stylised representations of natural phenomena - have presented a long-standing, difficult challenge to computer animators. We propose a framework for achieving the intricacy of effects motion with minimal animator intervention.Our approach is to construct cartoon effects by simulating the hand-drawing process through synthetic, computational means. We create a system which emulates the stylish appearance, movements of cartoon effects in both 2D and 3D environments. Our computational models achieve this by capturing the essential characteristics common to all cartoon effects: structure modelling, dynamic controlling and stylised rendering.To validate our framework, we have implemented a cartoon effects system for a range of effects including water effects, fire, smoke, rain and snow. Each effect model has its own static structure such as how the different parts are related temporarily. The flexibility of our approach is suggested most evidently by the high-level controls on shape, colour, timing and rendering on the effects. Like their hand-drawn counterparts, they move consistently while retaining the hand-crafted look.Since the movements of cartoon effects are animated procedurally, their detailed motions need not be keyframed. This thesis therefore demonstrates a powerful approach to computer animation in which the animator plays the role of a high level controller, rather than the more conventional hand-drawing slave. Our work not only achieves cartoon effects animation of un-precedented complexity, but it also provides an interesting experimental domain for related research disciplines toward more creative and expressive image synthesis in animation

    Hybrid sketching : a new middle ground between 2- and 3-D

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Architecture, 2005.Includes bibliographical references (leaves 124-133).This thesis investigates the geometric representation of ideas during the early stages of design. When a designer's ideas are still in gestation, the exploration of form is more important than its precise specification. Digital modelers facilitate such exploration, but only for forms built with discrete collections of high-level geometric primitives; we introduce techniques that operate on designers' medium of choice, 2-D sketches. Designers' explorations also shift between 2-D and 3-D, yet 3-D form must also be specified with these high-level primitives, requiring an entirely different mindset from 2-D sketching. We introduce a new approach to transform existing 2-D sketches directly into a new kind of sketch-like 3-D model. Finally, we present a novel sketching technique that removes the distinction between 2-D and 3-D altogether. This thesis makes five contributions: point-dragging and curve-drawing techniques for editing sketches; two techniques to help designers bring 2-D sketches to 3-D; and a sketching interface that dissolves the boundaries between 2-D and 3-D representation. The first two contributions of this thesis introduce smooth exploration techniques that work on sketched form composed of strokes, in 2-D or 3-D. First, we present a technique, inspired by classical painting practices, whereby the designer can explore a range of curves with a single stroke. As the user draws near an existing curve, our technique automatically and interactively replaces sections of the old curve with the new one. Second, we present a method to enable smooth exploration of sketched form by point-dragging. The user constructs a high-level "proxy" description that can be used, somewhat like a skeleton, to deform a sketch independent of(cont.) the internal stroke description. Next, we leverage the proxy deformation capability to help the designer move directly from existing 2-D sketches to 3-D models. Our reconstruction techniques generate a novel kind of 3-D model which maintains the appearance and stroke structure of the original 2-D sketch. One technique transforms a single sketch with help from annotations by the designer; the other combines two sketches. Since these interfaces are user-guided, they can operate on ambiguous sketches, relying on the designer to choose an interpretation. Finally, we present an interface to build an even sparser, more suggestive, type of 3-D model, either from existing sketches or from scratch. "Camera planes" provide a complex 3-D scaffolding on which to hang sketches, which can still be drawn as rapidly and freely as before. A sparse set of 2-D sketches placed on planes provides a novel visualization of 3-D form, with enough information present to suggest 3-D shape, but enough missing that the designer can 'read into' the form, seeing multiple possibilities. This unspecified information--this empty space--can spur the designer on to new ideas.by John Alex.Ph.D

    Chinese Ink-and-Brush Painting with Film Lighting Aesthetics in 3D Computer Graphics

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    This thesis explores the topic of recreating Chinese ink-and-brush painting in 3D computer graphics and introducing film lighting aesthetics into the result. The method is primarily based on non-photorealistic shader development and digital compositing. The goal of this research is to study how to bing the visual aesthetics of Chinese ink-and-brush painting into 3D computer graphics as well as explore the artistic possibility of using film lighting principles in Chinese painting for visual story telling by using 3D computer graphics. In this research, we use the Jiangnan water country paintings by renowned contemporary Chinese artist Yang Ming-Yi as our primary visual reference. An analysis of the paintings is performed to study the visual characteristics of Yang's paintings. These include how the artist expresses shading, forms, shadow, reflection and compositing principles, which will be used as the guidelines for recreating the painting in computer graphics. 3D meshes are used to represent the subjects in the painting like houses, boats and water. Then procedural non-photorealistic shaders are developed and applied on 3D meshes to give the models an ink-look. Additionally, different types of 3D data are organized and rendered into different layers, which include shading, depth, and geometric information. Those layers are then composed together by using 2D image processing algorithms with custom artistic controls to achieve a more natural-looking ink-painting result. As a result, a short animation of Chinese ink-and-brush painting in 3D computer graphics will be created in which the same environment is rendered with different lighting designs to demonstrate the artistic intention
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