13996299
Action video retrieval based on atomic action vocabulary
We propose an efficient action retrieval system that is based on a novel action representation and an effective video matching method. We represent actions with a hierarchical encoding scheme that at low-level measures local body parts motions, which then evolves into encoding of instantaneous global body motions and finally high-level description of actions through atomic action vocabulary. Atomic action vocabulary extends the notion of keyframe-based indexing techniques, where a long action video is decomposed into a sequence of atomic sub-actions matched from the vocabulary. Efficient video matching is achieved by exploiting precomputed inter-vocabulary distances so that global video distance between video sequences can be computed in a very efficient manner that is equivalent to index lookup operations with minimal additional computational loads. Combined with atomic action vocabulary, this can provide flexible video matching schemes of finding compound action sequences of arbitrary lengths. The proposed approach is evaluated on surveillance video and a public video dataset.
5884426
Validation of an optical flow method for tag displacement estimation
Presents a validation study of an optical-flow method for the rapid estimation of myocardial displacement in magnetic resonance tagged cardiac images. This registration and change visualization (RCV) software uses a hierarchical estimation technique to compute the flow field that describes the warping of an image of one cardiac phase into alignment with the next. This method overcomes the requirement of constant pixel intensity in standard optical-flow methods by preprocessing the input images to reduce any intensity bias which results from the reduction in stripe contrast throughout the cardiac cycle. To validate the method, SPAMM-tagged images were acquired of a silicon gel phantom with simulated rotational motion. The pixel displacement was estimated with the RCV method and the error in pixel tracking was <4% 1000 ms after application of the tags, and after 30/spl deg/ of rotation. An additional study was performed using a SPAMM-tagged multiphase slice of a canine left ventricle. The true displacement was determined using a previously validated active contour model (snakes). The error between methods was 6.7% at end systole. The RCV method has the advantage of tracking all pixels in the image in a substantially shorter period than the snakes method.
13502244
Object Tracking with Bayesian Estimation of Dynamic Layer Representations
Decomposing video frames into coherent 2D motion layers is a powerful method for representing videos. Such a representation provides an intermediate description that enables applications such as object tracking, video summarization and visualization, video insertion, and sprite-based video compression. Previous work on motion layer analysis has largely concentrated on two-frame or multi-frame batch formulations. The temporal coherency of motion layers and the domain constraints on shapes have not been exploited. This paper introduces a complete dynamic motion layer representation in which spatial and temporal constraints on shape, motion and layer appearance are modeled and estimated in a maximum a-posteriori (MAP) framework using the generalized expectation-maximization (EM) algorithm. In order to limit the computational complexity of tracking arbitrarily shaped layer ownership, we propose a shape prior that parameterizes the representation of shape and prevents motion layers from evolving into arbitrary shapes. In this work, a Gaussian shape prior is chosen to specifically develop a near-real-time tracker for vehicle tracking in aerial videos. However, the general idea of using a parametric shape representation as part of the state of a tracker is a powerful one that can be extended to other domains as well. Based on the dynamic layer representation, an iterative algorithm is developed for continuous object tracking over time. The proposed method has been successfully applied in an airborne vehicle tracking system. Its performance is compared with that of a correlation-based tracker and a motion change-based tracker to demonstrate the advantages of the new method. Examples of tracking when the backgrounds are cluttered and the vehicles undergo various rigid motions and complex interactions such as passing, turning, and stop-and-go demonstrate the strength of the complete dynamic layer representation.
8291379
Video Flashlights: Real Time Rendering of Multiple Videosfor Immersive Model Visualization
Videos and 3D models have traditionally existed in separate worlds and as distinct representations. Although texture maps for 3D models have been traditionally derived from multiple still images, real-time mapping of live videos as textures on 3D models has not been attempted. This paper presents a system for rendering multiple live videos in real-time over a 3D model as a novel and demonstrative application of the power of commodity graphics hardware. The system, metaphorically called the Video Flashlight system, "illuminates" a static 3D model with live video textures from static and moving cameras in the same way as a flashlight (torch) illuminates an environment. The Video Flashlight system is also an augmented reality solution for security and monitoring systems that deploy numerous cameras to monitor a large scale campus or an urban site. Current video monitoring systems are highly limited in providing global awareness since they typically display numerous camera videos on a grid of 2D displays. In contrast, the Video Flashlight system exploits the real-time rendering capabilities of current graphics hardware and renders live videos from various parts of an environment co-registered with the model. The user gets a global view of the model and is also able to visualize the dynamic videos simultaneously in the context of the model. In particular, the location of pixels and objects seen in the videos are precisely overlaid on the model while the user navigates through the model. The paper presents an overview of the system, details of the real-time rendering and demonstrates the efficacy of the augmented reality application.
6548026
Automated Mosaics via Topology Inference
The authors present a complete approach for the automated construction of mosaics from images and video using topology inference, local and global alignment, and compositing.
39247721
True Multi-Image Alignment and Its Application to Mosaicing and Lens Distortion Correction
Multiple images of a scene are related through 2D/3D view transformations and linear and nonlinear camera transformations. We present an algorithm for true multi-image alignment that does not rely on the measurements of a reference image being distortion free. The algorithm is developed to specifically align and mosaic images using parametric transformations in the presence of lens distortion. When lens distortion is present, none of the images can be assumed to be ideal. In our formulation, all the images are modeled as intensity measurements represented in their respective coordinate systems, each of which is related to an ideal coordinate system through an interior camera transformation and an exterior view transformation. The goal of the accompanying algorithm is to compute an image in the ideal coordinate system while solving for the transformations that relate the ideal system with each of the data images. Key advantages of the technique presented in this paper are: (i) no reliance on one distortion free image, (ii) ability to register images and compute coordinate transformations even when the multiple images are of an extended scene with no overlap between the first and last frame of the sequence, and (iii) ability to handle linear and nonlinear transformations within the same framework. Results of applying the algorithm are presented for the correction of lens distortion, and creation of video mosaics.
14410544
Fluid modeling of pollution proliferation in P2P networks
P2P systems are highly vulnerable to pollution attacks in which attackers inject multiple versions of corrupted content into the system, which is then further proliferated by unsuspecting users. However, to our knowledge, there are no closed-form solutions that describe this phenomenon, nor are there models that describe how the injection of multiple versions of corrupted content impacts a clients' ability to receive a valid copy. In this paper we develop a suite of fluid models that model pollution proliferation in P2P systems. These fluid models lead to systems of non-linear differential equations. We obtain closed-form solutions for the differential equations; for the remaining models, we efficiently solve the differential equations numerically. The models capture a variety of user behaviors, including propensity for popular versions, abandonment after repeated failure to obtain a good version, freeloading, and local version blacklisting. Our analysis reveals intelligent strategies for attackers as well as strategies for clients seeking to recover non-polluted content within large-scale P2P networks.
9616848
Core architecture optimization for heterogeneous chip multiprocessors
Previous studies have demonstrated the advantages of single-ISA heterogeneous multi-core architectures for power and performance. However, none of those studies examined how to design such a processor; instead, they started with an assumed combination of pre-existing cores. This work assumes the flexibility to design a multi-core architecture from the ground up and seeks to address the following question: what should be the characteristics of the cores for a heterogeneous multi-processor for the highest area or power efficiency? The study is done for varying degrees of thread-level parallelism and for different area and power budgets. The most efficient chip multiprocessors are shown to be heterogeneous, with each core customized to a different subset of application characteristics — no single core is necessarily well suited to all applications. The performance ordering of cores on such processors is different for different applications; there is only a partial ordering among cores in terms of resources and complexity. This methodology produces performance gains as high as 40%. The performance improvements come with the added cost of customization.
15134584
Replication of Biomolecular Techniques for Implementing Intelligent Systems
In this paper, it has been shown that computational jobs, such as encoding of input data and AND, OR operation, can work on the computers (by using computer databases and algorithms for the purpose of speeding up and enhancing biological research). By combining more complex functions, more complex molecular programs for gene analysis can be constructed. It is expected an in vivo (i.e. inside cellular life forms) computer will be realized from this technology, which detects the cell state through gene expression patterns, and controls the cell conditions with output RNA (ribose nucleic acid). The replication of biomolecular techniques based upon DNA (deoxyribose nucleic acid) architecture has been proposed. It may provide a powerful tool for both research and clinical applications. To develop functional supra-molecular systems, where sequence-programmable and evolvable molecular systems have been constructed as cell-free chemical systems using biomolecules such as DNA and proteins based on the integration of electronics, computer science, IT (information technology), mathematical and statistical tools. This paper is organised into four parts: part I describes the functioning and encoding processes of DNA computers, which are implemented using a traveling salesman problem (as in artificial intelligent systems) and single shortest path routing approach (as in computer networks) using object-oriented approach of software development, part II presents database integration with DNA using client-server technologies of Web design, part III discusses the implications of DNA for computer and network security, and part IV investigates and shows the results with the use of above mentioned approaches.
752417
Single-ISA Heterogeneous Multi-Core Architectures: The Potential for Processor Power Reduction
This paper proposes and evaluates single-ISA heterogeneousmulti-core architectures as a mechanism to reduceprocessor power dissipation. Our design incorporatesheterogeneous cores representing different points inthe power/performance design space; during an application'sexecution, system software dynamically chooses themost appropriate core to meet specific performance andpower requirements.Our evaluation of this architecture shows significant energybenefits. For an objective function that optimizes forenergy efficiency with a tight performance threshold, for 14SPEC benchmarks, our results indicate a 39% average energyreduction while only sacrificing 3% in performance.An objective function that optimizes for energy-delay withlooser performance bounds achieves, on average, nearly afactor of three improvement in energy-delay product whilesacrificing only 22% in performance. Energy savings aresubstantially more than chip-wide voltage/frequency scaling.
113025
Distributed peak power management for many-core architectures
Recently proposed techniques for peak power management involve centralized decision-making and assume quick evaluation of the various power management states. These techniques do not prevent instantaneous power from exceeding the peak power budget, but instead trigger corrective action when the budget has been exceeded. Similarly, they are not suitable for many-core architectures (processors with tens or possibly hundreds of cores on the same die) due to an exponential explosion in the number of global power management states. In this paper, we look at a hierarchical and a gradient ascent-based technique for decentralized peak power management for many-core architectures. The proposed techniques prevent power from exceeding the peak power budget and enable the placement of several more cores on a die than what the power budget would normally allow. We show up to 47% (33% on average) improvements in throughput for a given power budget. Our techniques outperform the static oracle by 22%.