304 research outputs found

    A Survey of Morphing Techniques

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    Image morphing provides the tool to generate the flexible and powerful visual effect. Morphing depicts the transformation of one image into another image. The process of image morphing starts with the feature specification phase and then proceeds to warp generation phase, followed by the transition control phase. This paper surveys the various techniques available for all three stages of image morphing

    2D and 3D surface image processing algorithms and their applications

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    This doctoral dissertation work aims to develop algorithms for 2D image segmentation application of solar filament disappearance detection, 3D mesh simplification, and 3D image warping in pre-surgery simulation. Filament area detection in solar images is an image segmentation problem. A thresholding and region growing combined method is proposed and applied in this application. Based on the filament area detection results, filament disappearances are reported in real time. The solar images in 1999 are processed with this proposed system and three statistical results of filaments are presented. 3D images can be obtained by passive and active range sensing. An image registration process finds the transformation between each pair of range views. To model an object, a common reference frame in which all views can be transformed must be defined. After the registration, the range views should be integrated into a non-redundant model. Optimization is necessary to obtain a complete 3D model. One single surface representation can better fit to the data. It may be further simplified for rendering, storing and transmitting efficiently, or the representation can be converted to some other formats. This work proposes an efficient algorithm for solving the mesh simplification problem, approximating an arbitrary mesh by a simplified mesh. The algorithm uses Root Mean Square distance error metric to decide the facet curvature. Two vertices of one edge and the surrounding vertices decide the average plane. The simplification results are excellent and the computation speed is fast. The algorithm is compared with six other major simplification algorithms. Image morphing is used for all methods that gradually and continuously deform a source image into a target image, while producing the in-between models. Image warping is a continuous deformation of a: graphical object. A morphing process is usually composed of warping and interpolation. This work develops a direct-manipulation-of-free-form-deformation-based method and application for pre-surgical planning. The developed user interface provides a friendly interactive tool in the plastic surgery. Nose augmentation surgery is presented as an example. Displacement vector and lattices resulting in different resolution are used to obtain various deformation results. During the deformation, the volume change of the model is also considered based on a simplified skin-muscle model

    Comparison of Three Different Image Forces for Active Contours on Abdominal Image Boundary Detection

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    Active contour, or snake, is an energy minimizing spline that is useful in image boundary detection. Active contours are stimulated by internal forces, image forces and external forces which maintain the shape of the contours while attract the contours to some desired features, usually edges. Problems in implementing active contours such as convergence and initialization have motivated researchers to modify image forces of the active contours. This paper presents a comparative study among three different image forces: traditional snakes, balloon and gradient vector flow (GVF). The study is validated by experiments on abdominal image boundaries detection. These lead to the conclusion that GVF gives the most appropriate results among the other approaches

    Image Morphing

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    Morphing is also used in the gaming industry to add engaging animation to video games and computer games. However, morphing techniques are not limited only to entertainment purposes. Morphing is a powerful tool that can enhance many multimedia projects such as presentations, education, electronic book illustrations, and computer-based training

    Animating facial images with drawings

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    Ankara : Bilkent Univ., 1996.Thesis (Master's) -- Bilkent University, 1996.Includes bibliographical references leaves 54-56.The work presented here describes the power of 2D animation with texture mai^ping controlled by line drawings. Animation is specifically intended for facial animation and not restricted by the human face. We initially have a sequence of facial images which are taken from a video sequence of the same face and an image of another face to be animated. The aim is to animate the face image with the same expressions as those of the given video sequence. To realize the animation, a set of frames are taken from a video sequence. Key features of the first frame are I’otoscoped and the other frames are automatically rotoscoped using the first frame. Similarly, the corresponding features of the image which will be animated are rotoscoped. The key features of the first frame of the sequence and the image to be animated are mapped and using cross-synthesis procedure, other drawings for the given image are produced. Using these animated line drawings and the original image, the corresponding frame sequence is produced by image warping. The resulting sequence has the same expressions as those of the video sequence. This work encourages the reuse of animated motion by gathering facial motion sequences into a database. Furthermore, by using motion sequences of a human face, non-human characters can be animated realistically or complex characters can be animated by the help of motion sequences of simpler characters.Tunali, Gamze DilekM.S

    Isosurfaces and level-set surface models

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    technical reportThis paper is a set of notes that present the basic geometry of isosurfaces and the basic methods for using level sets to model deformable surfaces. It begins with a short introduction to isosurface geometry, including curvature. It continues with a short explanation of the level-set partial differential equations. It also presents some practical details for how to solve these equations using up-wind scheme and sparse calculation methods. This paper presents a series of examples of how level-set surface models are used to solve problems in graphics and vision. Finally, it presents some examples of implementations using VISPack, an object oriented, C++ library for doing volume processing and level-set surface modeling

    Modal matching : a method for describing, comparing, and manipulating digital signals

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    Thesis (Ph. D.)--Massachusetts Institute of Technology, Program in Media Arts & Sciences, 1995.Includes bibliographical references (leaves 134-144).by Stanley Edward Sclaroff.Ph.D

    Three-dimensional morphanalysis of the face.

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    The aim of the work reported in this thesis was to determine the extent to which orthogonal two-dimensional morphanalytic (universally relatable) craniofacial imaging methods can be extended into the realm of computer-based three-dimensional imaging. New methods are presented for capturing universally relatable laser-video surface data, for inter-relating facial surface scans and for constructing probabilistic facial averages. Universally relatable surface scans are captured using the fixed relations principle com- bined with a new laser-video scanner calibration method. Inter- subject comparison of facial surface scans is achieved using inter- active feature labelling and warping methods. These methods have been extended to groups of subjects to allow the construction of three-dimensional probabilistic facial averages. The potential of universally relatable facial surface data for applications such as growth studies and patient assessment is demonstrated. In addition, new methods for scattered data interpolation, for controlling overlap in image warping and a fast, high-resolution method for simulating craniofacial surgery are described. The results demonstrate that it is not only possible to extend universally relatable imaging into three dimensions, but that the extension also enhances the established methods, providing a wide range of new applications
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