15112267
Evaluation of 3D face analysis and synthesis techniques
The reconstruction of 3D face models is mostly achieved by using 2D images. We compare the strengths and weaknesses of different image processing techniques for 3D face generation. It is anticipated that the optimal solution will be applied in the future for 3D face analysis and synthesis. As approaches to 3D face modelling, the paper presents: binocular stereo, using a stereo correspondence algorithm or manual triangulation; orthogonal views; photometric stereo. Photometric stereo and orthogonal views seem to provide the best rendering while keeping a reasonable time efficiency, implementation difficulty and cumbersomeness. However, 3D face acquisition techniques have not closed the gap between accuracy and cumbersomeness
15344875
Albedo recovery using a photometric stereo approach
This paper describes a method for the estimation of surface reflectance values using a photometric stereo approach. Evaluations show that surfaces rendered with reflectance values calculated by the proposed method have more realistic appearances than those with constant albedo.
5472476
Image Stitching - Comparisons and New Techniques
This work describes the steps involved in the generation of a panoramic image, i.e., image acquisition, image registration and image merging. Different approaches for each of these steps are discussed and compared. The resultant images from image registration and image merging are quantitatively evaluated to provide an indication to the performance of the different methods. The methods provided in this work can be used to generate panoramic images for the use of interactive panoramic viewing of images, architectural walk-through, and other applications associated with the modelling of 3D environments.
11144392
Integration of Photometric Stereo and Shape from Occluding Contours by Fusing Orientation and Depth Data
In this paper, we have investigated the fusion of surface data obtained by two different surface recovery methods. In particular, we have fused the depth data obtainable by shape from contours and local surface orientation data obtainable by photometric stereo. It has been found that the surface obtained by fusing orientation and depth data is able to yield more precision when compared with the surfaces obtained by either type of data alone.
29297649
Shape from Photometric Stereo and Contours
In this work, we propose an alternative approach to 3D shape recovery by combining photometric stereo and shape from contours methods. Surfaces recovered by photometric stereo are aligned, adjusted and merged according to a preliminary 3D model obtained by shape from contours. Comparisons are conducted to evaluate the performances of different methods. It has been found that the proposed approach provides more accurate shape recovery than the photometric stereo and shape from contours methods.
3245287
Study and Comparison of 3D Face Generation
Four techniques to generate 2.5 D face surfaces from a set of 2D images are compared using both rendering results and surface distance comparison for Orthogonal Views (OV), Photometric Stereo (PSM), Automatic and Interactive Binocular Stereo (ABS and IBS) using Dur database of 20 face surfaces. PSM obtains the best rendered surfaces.
45076304
Spatial Semantic Virtual Worlds: The Structural Duality and Beyond
18457324
On the higher-order edge toughness of a graph
For an integer c, 1?c??V(G)??1, we define the cth-order edge toughness of a graph G as tc(G)=min|X|?(G?X)?cX?E(G) & ?(G?X)>c The objective of this paper is to study this generalized concept of edge toughness. Besides giving the of the cth-order edge toughness ?c(G) of a graph G, we prove that `?c(G)?k if and only if G has k edge-disjoint spanning forests with exactly c components?. We also study the `balancity? of a graph G of order p and size q, which is defined as the smallest positive integer c such that ?c(G) = p/(p?c).
260704
An implementation of parallel dynamic load balancing for adaptive computing in VLSI device simulation
A new parallel semiconductor device simulation using the dynamic load balancing approach is presented. This semiconductor device simulation based on adaptive finite volume error estimation, and monotone iterative methods has been developed and implemented on a Linux-cluster with MPI library. Two different parallel versions of the algorithm to perform a complete device simulation are proposed. The first one is a dynamic parallel domain decomposition approach. The second version is a parallel current-voltage characteristic points simulation. The implementation shows that a well-designed load balancing simulation can reduce the execution time up to an order of magnitude. Compared with the measured data, numerical simulations on P-N diode, N-MOSFET, and DTMOS devices are presented to show the accuracy and efficiency of the method.
2319896
Range Image Registration Based on Circular Features
Range sensing technology allows the photo-realistic modeling of large-scale scenes, such as urban structures. A major bottleneck in the process of 3D scene acquisition is the automated registration of a large number of geometrically complex 3D range scans in a common frame of reference. The generated 3D representations, after automated registration, are useful for urban planning, historical preservation, or virtual reality applications. Man-made urban scenes provide an abundance of linear features that can be used for the solution of the problem. Many scenes though require the utilization of non-linear primitives. This paper provides a solution of the registration problem based on the robust detection and matching of circular features from the range data sets. We present results from experiments with complex range scans from the interior of a large-scale landmark urban structure (Grand Central Terminal, NYC), where traditional methods would fail. This work is part of a larger range registration system that is based on extracted features of multiple geometric types.
14818835
An empirical evaluation of several methods to select the best system
Simulation is an important tool for comparing the performance of several alternative systems. There is therefore significant interest in procedures that efficiently select the best system, where best is defined by the maximum or minimum expected simulation output. In this paper, we examine both two-stage and sequential procedures that represent three structurally different modeling methodologies for allocating simulation replications to identify the best system, and we evaluate them empirically with respect to several measures of effectiveness. Empirical evidence suggests that sequential procedures perform better than their two-stage counterparts, including a heuristic sequential variation on Rinott's procedure. Further, there appears to be significant benefit to using procedures based on a Bayesian, average-case analysis as opposed to the statistically-conservative indifference-zone formulation.