14241332
Visual tracking in the presence of motion blur
We consider the problem of visual tracking of regions of interest in a sequence of motion blurred images. Traditional methods couple tracking with deblurring in order to correctly account for the effects of motion blur. Such coupling is usually appropriate, but computationally wasteful when visual tracking is the lone objective. Instead of deblurring images, we propose to match regions by blurring them. The matching score for two image regions is governed by a cost function that only involves the region deformation parameters and two motion blur vectors. We present an efficient algorithm to minimize the proposed cost function and demonstrate it on sequences of real blurred images.
6346856
Real-Time Feature Tracking and Outlier Rejection with Changes in Illumination
We develop an efficient algorithm to track point features supported by image patches undergoing aflne deformations and changes in illumination. The algorithm is based on a combined model of geonietty and photometry that is used to track features as well as to detect outliers in a hypothesis testing framework. The algorithm runs in real time on a personal computer, and is available to the public.
2927787
Real-time virtual object insertion
We present a system to insert virtual objects into real image sequences in real time. The system consists of offthe- shelf hardware (a camera connected to a Pentium PC) and software to (a) automatically select and track region features despite changes in illumination, (b) estimate threedimensional position and orientation of surface patches relative to an inertial reference frame despite individual pointfeatures appearing and disappearing, (c) insert a texturemapped virtual object into the scene so as to make it appear to be part of the scene and moving with it. This is all done in real time. The multi-thread C++ code, which is readily interfaced with a frame grabber as well as Matlab for development, will be made available to the public at the demonstration.
121904888
Shedding light on stereoscopic segmentation
We propose a variational algorithm to jointly estimate the shape, albedo, and light configuration of a Lambertian scene from a collection of images taken from different vantage points. Our work can be thought of as extending classical multi-view stereo to cases where point correspondence cannot be established, or extending classical shape from shading to the case of multiple views with unknown light sources. We show that a first naive formalization of this problem yields algorithms that are numerically unstable, no matter how close the initialization is to the true geometry. We then propose a computational scheme to overcome this problem, resulting in provably stable algorithms that converge to (local) minima of the cost functional. Although we restrict our attention to Lambertian objects with uniform albedo, extensions of our framework are conceivable.
9201508
Structure from Motion Causally Integrated Over Time
We describe an algorithm for reconstructing three-dimensional structure and motion causally, in real time from monocular sequences of images. We prove that the algorithm is minimal and stable, in the sense that the estimation error remains bounded with probability one throughout a sequence of arbitrary length. We discuss a scheme for handling occlusions (point features appearing and disappearing) and drift in the scale factor. These issues are crucial for the algorithm to operate in real time on real scenes. We describe in detail the implementation of the algorithm, which runs on a personal computer and has been made available to the community. We report the performance of our implementation on a few representative long sequences of real and synthetic images. The algorithm, which has been tested extensively over the course of the past few years, exhibits honest performance when the scene contains at least 20-40 points with high contrast, when the relative motion is "slow" compared to the sampling frequency of the frame grabber (30 Hz), and the lens aperture is "large enough" (typically more than 30/spl deg/ of visual field).
163013
A Variational Approach to Shape from Defocus
We address the problem of estimating the three-dimensional shape and radiance of a surface in space from images obtained with different focal settings. We pose the problem as an infinite-dimensional optimization and seek for the global shape of the surface by numerically solving a partial differential equation (PDE). Our method has the advantage of being global (so that regularization can be imposed explicitly), efficient (we use level set methods to solve the PDE), and geometrically correct (we do not assume a shift-invariant imaging model, and therefore are not restricted to equifocal surfaces).
20588758
Cluster computing
Cluster computing can be described as a fusion of the fields of parallel, high-performance, distributed, and high-availability computing. Cluster computing has become a hot topic of research among academic and industry community including system designers, network developers, language designers, standardizing forums, algorithm developers, graduate students and faculties. The use of clusters as computing platform is not just limited to scientific and engineering applications; there are many business applications that can benefit from the use of clusters. There are many exciting areas of development in cluster computing with new ideas as well as hybrids of old ones being deployed for production as well as research systems. The aim of this special issue is to bring together original and latest work from both academia and industry on various issues related to cluster computing. This research, and development, is being done in many areas but there are a few that are of special interest. The first one is, with no doubt, the network. Clusters are based on the communication between nodes and designing fast and low latency networks is a must for clusters to become the configuration of the future. Plenty of work being done in this are in