Colon centreline calculation for CT colonography using optimised 3D opological thinning

CT colonography is an emerging technique for colorectal cancer screening. This technique facilitates noninvasive imaging of the colon interior by generating virtual reality models of the colon lumen. Manual navigation through these models is a slow and tedious process. It is possible to automate navigation by calculating the centreline of the colon lumen. There are numerous well documented approaches for centreline calculation. Many of these techniques have been developed as alternatives to 3D topological thinning which has been discounted by others due to its computationally intensive nature. This paper describes a fully automated, optimised version of 3D topological thinning that has been specifically developed for calculating the centreline of the human colon

A novel technique for reducing false positive detections in CAD-CTC

Computed tomography colonoscopy (CTC) is an emerging alternative to conventional colonoscopy for colorectal cancer screening. A series of computer assisted diagnosis (CAD) techniques have been developed for use in CTC. Although high levels of accuracy for polyp detection have been reported, the problem of excessive false positive detections still warrants attention. We present a CAD-CTC technique that has been developed specifically to reduce the number of false positive detections without compromising polyp detection accuracy. The technique incorporates a novel intermediate stage that restructures initial polyp candidates so that they conform more closely to the shape of actual polyps. The restructuring process causes false positives to expand to include more false positive characteristics, whereas, actual polyps retain their original polyp-like characteristics. An evaluation of the documented technique demonstrated that it can be successfully applied to the majority of polyp candidates, and that its use can reduce the number of false positive detections by up to 57.8%

A visual programming environment for machine vision engineers

This paper details a free image analysis and software development environment for machine vision application development. The environment provides high-level access to over 300 image manipulation, processing and analysis algorithms through a well-defined and easy to use graphical interface. Users can extend the core library using the developer's interface via a plug-in which features automatic source code generation, compilation with full error feedback and dynamic algorithm updates. Also discusses key issues associated with the environment and outline the advantages in adopting such a system for machine vision application development

Identification of body fat tissues in MRI data

In recent years non-invasive medical diagnostic techniques have been used widely in medical investigations. Among the various imaging modalities available, Magnetic Resonance Imaging is very attractive as it produces multi-slice images where the contrast between various types of body tissues such as muscle, ligaments and fat is well defined. The aim of this paper is to describe the implementation of an unsupervised image analysis algorithm able to identify the body fat tissues from a sequence of MR images encoded in DICOM format. The developed algorithm consists of three main steps. The first step pre-processes the MR images in order to reduce the level of noise. The second step extracts the image areas representing fat tissues by using an unsupervised clustering algorithm. Finally, image refinements are applied to reclassify the pixels adjacent to the initial fat estimate and to eliminate outliers. The experimental data indicates that the proposed implementation returns accurate results and furthermore is robust to noise and to greyscale in-homogeneity

Natural convective heat transfer from a recessed narrow vertical flat plate with a uniform heat flux at the surface

Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.The natural convective heat transfer rate from a relatively narrow heated vertical plate with a uniform heat flux over its surface has been numerically studied. This heated plate is embedded in a large plane adiabatic surface, the surface of the heated plate being somewhat “below” that of the adiabatic surface, i.e., the heated plate surface is recessed in the adiabatic surface. The main aim of the present work was to study how the recessing of the heated plate into the surface affects the mean heat transfer rate from the plate. It has been assumed that the flow is steady and laminar and that the fluid properties are constant except for the density change with temperature which gives rise to the buoyancy forces, this having been treated by using the Boussinesq approach. It has also been assumed that the flow is symmetrical about the vertical centre-plane of the plate. The solution has been obtained by numerically solving the full three-dimensional form of the governing equations, these equations being written in dimensionless form. The solution was obtained using a commercial finite element method based code, FIDAP. The solution has the Rayleigh number based on the plate height and the surface heat flux, the dimensionless plate width, the dimensionless depth that the heated plate is recessed into the adiabatic surface, and the Prandtl number as parameters. Results have only been obtained for Pr = 0.7. A relatively wide range of values of the other input parameters have been considered and the effects of these parameters on the mean Nusselt number have been determined and used to study the effects that arise due to the plate being recessed and that arise due to the fact that the plate is relatively narrow

A novel technique for identifying the individual regions of the human colon at CT colonography

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