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In this paper, a new hybrid medical image segmentation method in the level-set framework is proposed. The method uses both the objectpsilas boundary and region information to achieve robust and accurate segmentation results. The boundary information can help to detect the precise location of the target object and the region information can help to prevent(More)
In 2 experiments exploring memory for unfamiliar 3-dimensional objects, Ss studied drawings under conditions that encouraged encoding of global object structure. Implicit memory for objects was assessed by a judgment of structural possibility; explicit memory was assessed by recognition. The principal manipulation was the relationship between the sizes or(More)
A novel method is proposed to segment objects in medical images whose boundaries can be described as closed curves. Based on an image with the enhanced boundary of an object of interest, the segmentation method consists of three key steps, namely, the polar transformation, dynamic programming and curve fitting. A 3D object in volumetric data can be(More)
This paper describes results of a quantitative evaluation of a flexible spring mass system image registration technique previously proposed by the authors. The method is assessed against two well-known registration algorithms namely the Demons and the B-spline free form deformations (FFD) implemented in Insight Segmentation and Registration Toolkit (ITK).(More)
Any single valued function over a sphere or cylinder can be parameterised in terms of the spherical or cylindrical coordinate systems respectively. An organ structure created during medical image segmentation can be written as such a function if the shape is polar (i.e. star shaped), the polar radial distance from a reference point inside the structure to(More)
When applying 2D deformable registration to crosssectional images from 3D data, it is assumed the images represent the same object. However, in reality, they are acquired at different axial positions and with different coronal and sagittal rotations. Therefore, if the crosssection's position and orientation can be corrected, it should offer better(More)
The use of time-of-treatment imaging is increasingly commonplace in radiotherapy, with cone beam CT (CBCT) the primary modality. To make full use of this technology, the tumour target and critical organs need to be segmented from the image volumes. CBCT images unfortunately often suffer from poor contrast and significant image artefacts compared with the(More)
This paper describes warp assisted tumour delineation from the images in a CT scan sequence, and the first algorithm to realistically close the tumour volume prior the automated generation of the larger planning target volume, on which a cancer patient's radiotherapy treatment is based. Space variant dilation, driven by box-guides indicating multiple(More)
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