5590959
CAD for polyp detection: an invaluable tool to meet the increasing need for colon-cancer screening
Abstract Colorectal cancer is the third most common cancer in both men and women and it was estimated that in 2003 nearly 150,000 cases would be diagnosed and 57,000 people would die. Screening has been accepted as a means for early detection of the disease, yet only a portion of the eligible population undergoes colorectal cancer screening, partially due to comfort issues of undergoing a full colonoscopic examination. Virtual colonoscopy (VC) has been demonstrated to be an effective means of performing screening and given the number of people who are candidate for screening better tools, such as Computer Aided Detection (CAD), are required to fulfill this increasing need. The developed CAD system, presented in this paper, has focused on the detection of polyps of sizes up to and including 20 mm. The results have demonstrated that: the developed algorithm generalizes, the sensitivity and specificity for middle- to large-sized polyps is on the average 95% while the overall sensitivity is roughly 88% and the false positive has remained at a manageable 4 per volume.
14750394
Global models with parametric offsets as applied to cardiac motion recovery
We introduce a new solid shape model formulation that includes built-in offsets from a base global component (e.g. an ellipsoid) which are functions of the global component's parameters. The offsets provide two features. First, they help to form an expected model shape which facilitates appropriate model data correspondences. Second, they scale with the base global model to maintain the expected shape even in the presence of large global deformations. We apply this model formulation to the recovery of 3-D cardiac motion from a volunteer dataset of tagged-MR images. The model instance is a variation of the hybrid volumetric ventriculoid (HVV), a deformable thick-walled ellipsoid model resembling the left ventricle (LV) of the heart. A unique aspect of of implementation is the employment of constant volume constraints when recovering the cardiac motion. In addition, we present a novel geodesic-like prismoidal tessellation of the model which provides for more stable fits.
11252982
Segmentation of range images as the search for geometric parametric models
Segmentation of range images has long been considered in computer vision as an important but extremely difficult problem. In this paper we present a new paradigm for the segmentation of range images into piecewise continuous surfaces. Data aggregation is performed via model recovery in terms of variable-order bi-variate polynomials using iterative regression. Model recovery is initiated independently in regularly placed seed regions in the image. All the recovered models are potential candidates for the final description of the data. Selection of the models is defined as a quadratic Boolean problem, and the solution is sought by the WTA (winner-takes-all) technique, which turns out to be a good compromise between the speed of computation and the accuracy of the solution. The overall efficiency of the method is achieved by combining model recovery and model selection in an iterative way. Partial recovery of the models is followed by the selection (optimization) procedure and only the “best” models are allowed to develop further.The major novelty of the approach lies in an effective combination of simple component algorithms, which stands in contrast to methods which attempt to solve the problem in a single processing step using sophisticated means. We present the results on several real range images.
14869645
Multi-modality model-based registration in the cardiac domain
Recent advances in CT technology have made possible the acquisition of high resolution images of the heart in which important anatomical features such as the coronary vessels are visible. The state of the art in MR Imaging techniques, on the other hand, typically provides lower resolution but can facilitate the differentiation of viable (healthy) cardiac tissue from infarcted (injured) tissue. The registration of CT and MR images of the same heart permit the association of anatomy with function. As an example, given an infarcted region, the coronary vessels responsible for irrigating that region may be isolated and targeted for treatment (e.g., coronary bypass). We demonstrate a software package, PROTEUS, which is capable of registering CT and MR images. Since the manifestation of cardiac tissue in the two modalities differs so greatly we rely on features to perform the matching. Specifically, we employ a model-based approach that relies on segmented contours delineating the inner and outer borders of the left ventricle (LV). Given these contours, our technique is completely automatic.
5097328
Dynamic Programming for Detecting, Tracking, and Matching Deformable Contours
The problem of segmenting an image into separate regions and tracking them over time is one of the most significant problems in vision. Terzopoulos et al. (1987) proposed an approach to detect the contour regions of complex shapes, assuming a user selected initial contour not very far from the desired solution. We propose to further explore the information provided by the user's selected points and apply an optimal method to detect contours which allows a segmentation of the image. The method is based on dynamic programming (DP), and applies to a wide variety of shapes. It is exact and not iterative. We also consider a multiscale approach capable of speeding up the algorithm by a factor of 20, although at the expense of losing the guaranteed optimality characteristic. The problem of tracking and matching these contours is addressed. For tracking, the final contour obtained at one frame is sampled and used as initial points for the next frame. Then, the same DP process is applied. For matching, a novel strategy is proposed where the solution is a smooth displacement field in which unmatched regions are allowed while cross vectors are not. The algorithm is again based on DP and the optimal solution is guaranteed. We have demonstrated the algorithms on natural objects in a large spectrum of applications, including interactive segmentation and automatic tracking of the regions of interest in medical images. >
38069956
Introduction to the Special Issue on Innovative Applications of Computer Vision
14748622
Power Efficient Algorithms for Computing Fast Fourier Transform over Wireless Sensor Networks
Collaborative signal processing is one of the most promising applications that are currently being investigated for sensor networks. In this paper, we use FFT computation as a vehicle to highlight the issues involved in realizing distributed computations over sensor networks that have global and local communication and synchronization characteristics. We present a power efficient algorithm for computing 1-D Fast Fourier Transform (FFT) over single and multi-hop wireless sensor networks. The proposed algorithm reduces the number of transmissions, eliminates typical redundant computations in a distributed FFT algorithm and uniformly maps complex multiplications over all the sensors nodes by introducing an extra bit-complement permutation stage after first (log2N)/2 iterations. We show that the proposed algorithm improves energy consumption by 36% on the average on multi-hop sensor networks. This saving in energy consumption significantly improves the battery life of the sensor nodes thereby increasing lifetime of the sensor network.
10971639
Digital signature: use and modification to achieve success in next generational e-business processes
A US law, the electronic signatures (E-Sign) in Global and National Commerce Act (signed by then President Clinton on 30 June 2000 with an effective date of 1 October 2000), grants electronic signatures legal validity equivalent to traditional handwritten counterparts. The intention of this law is to cut costs while providing more stringent security. In the emerging e-commerce arena, electronic signatures hold great potential for facilitating secure electronic transactions. But signatures are used in many critical business processes that occur prior to or independent of final transactions. Contract development and numerous other processes entail a series of draft modifications and sign-offs. Can electronic signatures provide cost savings and security in these activities? In this paper, we (i) detail fundamentals and the current status of electronic signatures; (ii) describe the integration of electronic signatures with electronic verification and authentication technologies; (iii) explore e-commerce applications, especially document management processes, that could benefit from adopting electronic signatures; and (iv) propose modifications to the electronic signature process to enable innovative document management processes. We propose modifications using partial document ownership, soft signatures, and hard signatures.
15718873
A predictive empirical model for pricing and resource allocation decisions
We present a semi-parametric model that describes pricing behaviors in a market environment, and we show how that model can be used to guide resource allocation and pricing decisions in an autonomous trading agent. We validate our model by presenting experimental results obtained in the Trading Agent Competition for Supply Chain Management.
18669821
Managing computing resources in intranets: an electronic commerce perspective
Abstract Intra-organizational networks (intranets) are increasingly being developed for information sharing and collaborative work in geographically dispersed organizations. However, organizations are increasingly realizing that having an intranet in itself may not provide expected increase in productivity and benefits. Intranet resources have to be managed appropriately and with organizational goals in mind for intranets to be a meaningful part of organizational environment. In this paper we provide a framework to manage the resources in the intranets using the concepts of electronic commerce. Specifically, we propose the creation of an electronic organizational unit, intranet Resource Management Unit (iRMU), that manages user requests using a dynamic priority pricing approach. The iRMU integrates a dynamic priority pricing approach with the concepts of topology management, security management, and software-agents based service construction to create a comprehensive resource management environment. The contribution of this paper is to provide a framework that integrates existing technological base with economic pricing approaches to create an economics-embedded intranet resource management approach.
19327594
Mobility-Pattern-Based Anomaly Detection Algorithm in Mobile Networks
Numerous approaches have been proposed for intrusion detection in immobile networks. However, little research work has been done in actually implementing them, especially for anomaly detection, in mobile networks. In this paper, we present an efficient mobility-pattern-based (MPB) anomaly detection algorithm. It can effectively identify abnormal mobility patterns of the nodes in mobile networks. In the proposed algorithm, the normal mobility profile of a specific node is characterized by a multi-leaf tree structure in which each node corresponds to a possible destination cluster. A normal mobility profile is generated during the training process through data mining and fuzzy logic techniques. More specifically, data mining techniques are used for cluster classifications, and fuzzy logic techniques are used to integrate the 'similar'' pattern strings after the corresponding cluster generation. These two techniques are also used during the testing process for distinguishing abnormal mobility patterns of the node from those of the normal in mobile networks. Simulation results demonstrate that our proposed MPB anomaly detection algorithm can achieve good performance in terms of detection rate and false alarm rate for nodes with regular movement behaviors by fine tuning the design parameter - threshold, that can be chosen efficiently.