2700551
Combining Front Propagation with Shape Knowledge for Accurate Curvilinear Modelling
In this paper, we propose an approach to accurately modelling tubular, anatomical structures as curvilinear entities. Current optimal path and centerline extraction techniques are either prone to introducing spurious tortuosity, or unable to consistently avoid taking shortcuts at high curvature positions. These problems not only affect spatial appreciation of the structure but may also significantly impact the accuracy of length, angle and tortuosity measurements. Our approach overcomes the above deficiencies through the combination of a front propagation method and a model in which a priori shape knowledge is embedded. This approach is designed to be used in endovascular and neurological surgical planning. The efficacy of our method is demonstrated using synthetic and clinical data.
12450253
Towards a Visual Programming Environment Based on ITK for Medical Image Analysis
Medical image analysis experiments usually require a certain level of programming skills and are often time-consuming. Visual programming can address these issues by providing a high-level user interface to visually access and combine underlying medical image analysis functionalities. This paper describes the ITKBoard, an extension of the Insight Toolkit for Registration and Segmentation (ITK). Unlike traditional approaches, ITKBoard, a visual tool for experimentation and prototyping, allows rapid visual construction of filter pipelines, via a graphical user interface. An overview of the main functionalities and the system design is presented in this paper. The approaches that we have developed to resolving critical issues such as pipeline handling, automatic object wrapping and plugin mechanism are discussed in detail. This is a first step towards a visual programming environment designed for medical image analysis, in which the specific needs in terms of visual data-flow and control-flow programming will be progressively addressed. It is envisaged that when the software is released in the near future it will be significantly beneficial to the medical image analysis community.
14672206
Using marker-based deformable models for deriving anatomical models from medical image databases
The outcome of the application of a deformable model is dependent on its initialization and parameter settings. This is an obstacle to robust automatic segmentation. An approach to reducing the dependences is proposed in this paper based on geodesic topographic distance transforms from two manually or automatically placed markers. This is a novel method that uses object and background differentiation in deformable models via watershed theories. The implementation is based on efficient numerical methods. Experiments have shown that it is a highly promising approach. This approach has been applied to the determination of tissue characteristics in early childhood using a CT database of neonates. We believe that by relaxing dependences on the initialization and parameters this approach will enable a degree of automation needed for segmentation-based construction of organ models from large image databases, particularly when the markers can be determined automatically on the basis of a priori knowledge
46225184
Spatial Technologies for Coastal Management
This demonstration will be presented at the 2004 National Conference on Digital Government Research. The third year results of the project "Digitalization of Coastal Management and Decision Making Supported by Multi-Dimensional Geospatial Information and Analysis" will be presented. Mobile wireless communications, internet web services, and web GIS are integrated into a web-based decision-making system for coastal management. Employing three-dimensional visualization technology, athe system also provides a visualization tool for multisource spatial-temporal data integration and uncertainty analysis. Also demonstrated is an interactive QuickBird image processing subsystem used for high resolution DEM and three-dimensional shoreline extraction of Tampa Bay.The goal of this project is to develop technologies to enhance the operational capabilities of federal, state, and local agencies responsible for coastal management and decision making. The pilot test site is along the Lake Erie coastline from Port Clinton to East Cleveland, Ohio. Research strategies are currently being applied to Painesville, OH and Tampa Bay, Florida. The demonstration will include the following sections.
34397649
Architecture support of a descriptor computer on object-orientation
17885452
Commutativity-based concurrency control in groupware
Commutativity of operations is often exploited in concurrent systems to attain high levels of concurrency. A commutativity-based concurrency control method, called operational transformation (OT), has been actively researched in groupware over the past 15 years. However, much progress can still be made on more practicable approaches to developing and proving OT algorithms. Several constraints have been proposed previously but they are generally difficult to follow and verify in practice. This paper proposes an alternative approach to address this problem. A new consistency model is defined which greatly simplifies the design and proof of OT algorithms
27953110
Every 3-connected distance claw-free graph is Hamilton-connected
A graph G is said to be distance claw-free (in DC) if for each vertex v in V(G) the independence number of the subgraph of G induced by the set of vertices at distance i from v is at most 2 for each i>=0. It is shown that every 3-connected graph in DC is hamilton-connected, answering affirmatively a question of Shepherd.
7717414
A time interval based consistency control algorithm for interactive groupware applications
Traditional concurrency control methods such as locking and serialization are not suitable for distributed interactive applications that demand fast local response. Operational transformation (OT) is the standard solution to concurrency control and consistency maintenance in group editors, an important class of interactive groupware applications. It generally trades consistency for local responsiveness, because human users can often tolerate temporary inconsistencies but do not like their interactions be lost or nondeterministically blocked. This paper presents a time interval based operational transformation algorithm (TIBOT) that overcomes the various limitations of previous related work. Our approach guarantees content convergence and is significantly more simple and efficient than existing approaches. This is achieved in a pure replicated architecture by using a linear clock and by posing some constraints on communication that are reasonable for the application domain.