Deformation analysis and its application in image editing.

Jiang, Lei.Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.Includes bibliographical references (p. 68-75).Abstracts in English and Chinese.Chapter 1 --- Introduction --- p.1Chapter 2 --- Background and Motivation --- p.5Chapter 2.1 --- Foreshortening --- p.5Chapter 2.1.1 --- Vanishing Point --- p.6Chapter 2.1.2 --- Metric Rectification --- p.8Chapter 2.2 --- Content Aware Image Resizing --- p.11Chapter 2.3 --- Texture Deformation --- p.15Chapter 2.3.1 --- Shape from texture --- p.16Chapter 2.3.2 --- Shape from lattice --- p.18Chapter 3 --- Resizing on Facade --- p.21Chapter 3.1 --- Introduction --- p.21Chapter 3.2 --- Related Work --- p.23Chapter 3.3 --- Algorithm --- p.24Chapter 3.3.1 --- Facade Detection --- p.25Chapter 3.3.2 --- Facade Resizing --- p.32Chapter 3.4 --- Results --- p.34Chapter 4 --- Cell Texture Editing --- p.42Chapter 4.1 --- Introduction --- p.42Chapter 4.2 --- Related Work --- p.44Chapter 4.3 --- Our Approach --- p.46Chapter 4.3.1 --- Cell Detection --- p.47Chapter 4.3.2 --- Local Affine Estimation --- p.49Chapter 4.3.3 --- Affine Transformation Field --- p.52Chapter 4.4 --- Photo Editing Applications --- p.55Chapter 4.5 --- Discussion --- p.58Chapter 5 --- Conclusion --- p.65Bibliography --- p.6

Graph Spectral Image Processing

Recent advent of graph signal processing (GSP) has spurred intensive studies of signals that live naturally on irregular data kernels described by graphs (e.g., social networks, wireless sensor networks). Though a digital image contains pixels that reside on a regularly sampled 2D grid, if one can design an appropriate underlying graph connecting pixels with weights that reflect the image structure, then one can interpret the image (or image patch) as a signal on a graph, and apply GSP tools for processing and analysis of the signal in graph spectral domain. In this article, we overview recent graph spectral techniques in GSP specifically for image / video processing. The topics covered include image compression, image restoration, image filtering and image segmentation

Constrained parameterization with applications to graphics and image processing.

Surface parameterization is to establish a transformation that maps the points on a surface to a specified parametric domain. It has been widely applied to computer graphics and image processing fields. The challenging issue is that the usual positional constraints always result in triangle flipping in parameterizations (also called foldovers). Additionally, distortion is inevitable in parameterizations. Thus the rigid constraint is always taken into account. In general, the constraints are application-dependent. This thesis thus focuses on the various constraints depended on applications and investigates the foldover-free constrained parameterization approaches individually. Such constraints usually include, simple positional constraints, tradeoff of positional constraints and rigid constraint, and rigid constraint. From the perspective of applications, we aim at the foldover-free parameterization methods with positional constraints, the as-rigid-as-possible parameterization with positional constraints, and the well-shaped well-spaced pre-processing procedure for low-distortion parameterizations in this thesis. The first contribution of this thesis is the development of a RBF-based re-parameterization algorithm for the application of the foldover-free constrained texture mapping. The basic idea is to split the usual parameterization procedure into two steps, 2D parameterization with the constraints of convex boundaries and 2D re-parameterization with the interior positional constraints. Moreover, we further extend the 2D re-parameterization approach with the interior positional constraints to high dimensional datasets, such as, volume data and polyhedrons. The second contribution is the development of a vector field based deformation algorithm for 2D mesh deformation and image warping. Many presented deformation approaches are used to employ the basis functions (including our proposed RBF-based re-parameterization algorithm here). The main problem is that such algorithms have infinite support, that is, any local deformation always leads to small changes over the whole domain. Our presented vector field based algorithm can effectively carry on the local deformation while reducing distortion as much as possible. The third contribution is the development of a pre-processing for surface parameterization. Except the developable surfaces, the current parameterization approaches inevitably incur large distortion. To reduce distortion, we proposed a pre-processing procedure in this thesis, including mesh partition and mesh smoothing. As a result, the resulting meshes are partitioned into a set of small patches with rectangle-like boundaries. Moreover, they are well-shaped and well-spaced. This pre-processing procedure can evidently improve the quality of meshes for low-distortion parameterizations

WorldBrush: Interactive Example-based Synthesis of Procedural Virtual Worlds

International audienceWe present a novel approach for the interactive synthesis and editing of virtual worlds. Our method is inspired by painting operations and uses methods for statistical example-based synthesis to automate content synthesis and deformation. Our real-time approach takes a form of local inverse procedural modeling based on intermediate statistical models: selected regions of procedurally and manually constructed example scenes are analyzed, and their parameters are stored as distributions in a palette, similar to colors on a painter’s palette. These distributions can then be interactively applied with brushes and combined in various ways, like in painting systems. Selected regions can also be moved or stretched while maintaining the consistency of their content. Our method captures both distributions of elements and structured objects, and models their interactions. Results range from the interactive editing of 2D artwork maps to the design of 3D virtual worlds, where constraints set by the terrain’s slope are also taken into account