36557391
Toward a sentient environment: real-time wide area multiple human tracking with identities
In this paper, we presented a fully integratedreal-time computer vision system that can detect and track multiple humans in a wide-area using a network of stereo cameras. Continuous human identities are achieved by fusing video tracking with different kinds of biometric devices. The system also provides immersive visualization which enables the users to conveniently navigate through space and time and query useful events. The key innovations include stereo-based multi-object detection and tracking, a unified approach for fusing multiple sensors of different modalities, visualization and user interface design.
31836660
A Global Matching Framework for Stereo Computation
This paper presents a new global matching framework f o r stereo computation. In this framework, the second view is first predicted front the reference view using the depth information. A global match measure is then defined as the similarity function between the predicted image and the actual image. Stereo coniputcction is converted into a search problem where the goal is to find the depth rnup that maximizes the global match measure. The major advantage of this framework is that the global visibility constraint is inherently enforced in the computation. This paper explores several key components of this framework including ( I ) three color segmentation based depth representations, (2) an incremental warping algorithm that dramatically reduces the computational complexity, and (3) scene constraints such as the smoothness constraint and the color sinzilarity constraint. Experimental results using different types of depth representations are presented. The quality of the computed depth maps is demonstrated through image-based rendering from new viewpoints.
6283962
Multi-view 3D analysis with applications for augmented reality and enhanced video visualization
The article presents methods for 3D scene geometry recovery/refinement and pose estimation from motion imagery in two representative scenarios. First, we present a method for pose estimation and scene geometry recovery from extended sequences without prior knowledge of the scheme. Second, we discuss how to recover camera poses when a rough scene model is provided. We show how to extend and refine the scene model using the recovered poses. Finally, we present applications of the above techniques for 3D imagery manipulation such as enhanced visualization for video and 3D insertion of synthetic objects in the imagery.
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.
9659860
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 non-linear camera transformations. In all the traditional techniques to compute these transformations, especially the ones relying on direct intensity gradients, one image and its coordinate system have been assumed to be ideal and distortion free. In this paper, we present a formulation and an algorithm for true multi-image alignment that does not rely on the measurements of a reference image being distortion free. For instance, in the presence of lens distortion, 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 non-linear transformations within the same framework. The new algorithm is evaluated in the context of two applications: (i) correction of lens distortion, and (ii) creation of video mosaics.
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.
6867265
Servo: a programming model for many-core computing
Conventional programming models were designed to be used by expert programmers for programming for large-scale multiprocessors, distributed computational clusters, or specialized parallel machines. These models, therefore, are deemed either too difficult for an "average" programmer (who will be expected to do parallel programming in the many-core world) or too inefficient to use for many-core architectures [3]. Similarly, conventional execution models were designed for performance, not scalability.
 To address the challenge of performance scalability for many-core architectures, we introduce Servo, a Service Oriented programming model that decomposes every program into a set of components (each with its own local memory, mutable state, and a program counter) that either request services or deliver services. Servo is characterized by the decoupling of logical communication mapping between program modules (or services) from physical communication mapping between modules. This allows the services to be migrated and replicated during execution. The proposed model also allows the granularity of data parallel operations to be changed dynamically. This allows runtime variation in the locking granularity which in turn enables higher write-parallelism. Finally, the models partition even data into services. This can significantly enhance locality and makes it possible to have superlinear speedups with increasing number of cores.
 Our preliminary investigations demonstrate significant performance scalability advantages for Servo.
205912378
The architecture of Efficient Multi-Core Processors: A Holistic Approach
Abstract The most straightforward methodology for designing a multi-core architecture is to replicate an off-the-shelf core design multiple times, and then connect the cores together using an interconnect mechanism. However, this methodology is “multi-core oblivious” as subsystems are designed/optimized unaware of the overall chip-multiprocessing system they would become parts of. The chapter demonstrates that this methodology is inefficient in terms of area/power. It recommends a holistic approach where the subsystems are designed from the ground up to be effective components of a complete system. The inefficiency in “multi-core oblivious” designs comes from many sources. Having multiple replicated cores results in an inability to adapt to the demands of execution workloads, and results in either underutilization or overutilization of processor resources. Single-ISA (instruction-set architecture) heterogeneous multi-core architectures host cores of varying power/performance characteristics on the die, but all cores are capable of running the same ISA. Such a processor can result in significant power savings and performance improvements if the applications are mapped to cores judiciously. The paper also presents holistic design methodologies for such architectures. Another source of inefficiency is blind replication of over-provisioned hardware structures. Conjoined-core chip multiprocessing allows adjacent cores of a multi-core architecture to share some resources. This can result in significant area savings with little performance degradation. Yet another source of inefficiency is the interconnect. The interconnection overheads can be very significant for a “multi-core oblivious” multi-core design—especially as the number of cores increases and the pipelines get deeper. The paper demonstrates the need to co-design the cores, the memory and the interconnection to address the inefficiency problem, and also makes several suggestions regarding co-design.
17431951
Analyzing Performance of Web-Based Metrics for Evaluating Reliability and Maintainability of Hypermedia Applications
This paper has been designed to identify the Web metrics for evaluating the reliability and maintainability of hypermedia applications. In the age of information and communication technology (ICT), Web and the Internet, have brought significant changes in information technology (IT) and their related scenarios. Therefore in this paper an attempt has been made to trace out the Web-based measurements towards the creation of efficient Web centric applications. The dramatic increase in Web site development and their relative usage has led to the need of Web-based metrics. These metrics will accurately assess the efforts in the Web-based applications. Here we promote the simple, but elegant approaches to estimate the efforts needed for designing Web-based applications with the help of user behavior model graph (UBMG), Web page replacement algorithms, and RS Web Application Effort Assessment (RSWAEA) method. Effort assessment of hyperdocuments is crucial for Web-based systems, where outages can result in loss of revenue and dissatisfied customers. Here we advocate a simple, but elegant approach for effort estimation for Web applications from an empirical point of view. The proposed methods and models have been designed after carrying out an empirical study with the students of an advanced university class and Web designers that used various client-server based Web technologies. Our first aim was to compare the relative importance of each Web-based metric and method. Second, we also implemented the quality of the designs obtained based by constructing the User Behavior Model Graphs (UBMGs) to capture the reliability of Web-based applications. Thirdly, we use Web page replacement algorithms for increasing the Web site usability index, maintainability, reliability, and ranking. The results obtained from the above Web-based metrics can help us to analytically identify the effort assessment and failure points in Web-based systems and makes the evaluation of reliability of these systems simple.
27580015
Register Multimapping: A technique for reducing register bank conflicts in processors with large register files
In this paper, we investigate Register Multimapping as a technique to reduce register bank conflicts for processors with large register files, but relatively slow clock speeds. Register multimapping involves mapping an architectural register to multiple physical registers belonging to different banks. Reads can proceed using any of the physical registers, thereby minimizing read bank conflicts. Write conflicts can be minimized by allowing delayed allocation of physical registers [5]. Our experiments show that register multimapping can result in performance improvements up to 15% (10% on average) over baseline processors that are port-constrained. Improvements are up to 13% (5.5% on average) over port-constrained processors that support delayed allocation of registers.
16117863
A Comparative Study of Different Sensors for Smart Car Park Management
Wireless sensor networks offer a very attractive, low cost alternative for traffic monitoring and surveillance in car parking, freeways and intersection in different environmental conditions. In such systems, robust and reliable vehicle detection is a critical step, thus it is important to carefully evaluate the different modes of operations in order to address existing issues. This paper proposes a vision of improvements to wireless sensor car parking network system by presenting valuable comparison data for different sensors using different type of software functions and hardware components. The main goal of this work is to present a simple, automated analysis and comparison of power management, communication efficiency and threshold times using different sensors and a corresponding prediction of the above features. The results show a clear difference in various parameters by using different types of sensors for vehicle detection.