John P. Chiverton

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Tomographic biomedical images are commonly affected by an imaging artefact known as the partial volume (PV) effect. The PV effect produces voxels composed of a mixture of tissues in anatomical magnetic resonance imaging (MRI) data resulting in a continuity of these tissue classes. Anatomical MRI data typically consist of a number of contiguous regions of(More)
A new fully automatic object tracking and segmentation framework is proposed. The framework consists of a motion-based bootstrapping algorithm concurrent to a shape-based active contour. The shape-based active contour uses finite shape memory that is automatically and continuously built from both the bootstrap process and the active-contour object tracker.(More)
This paper describes a novel automatic statistical morphology skull stripper (SMSS) that uniquely exploits a statistical self-similarity measure and a 2-D brain mask to delineate the brain. The result of applying SMSS to 20 MRI data set volumes, including scans of both adult and infant subjects is also described. Quantitative performance assessment was(More)
An active contour based tracking framework is described that generates and integrates dynamic shape information without having to learn a priori shape constraints. This dynamic shape information is combined with dynamic photometric foreground model matching and background mismatching. Boundary based optical flow is also used to estimate the location of the(More)
We present segmentation and tracking of deformable objects using non-linear on-line learning of high-level shape information in the form of a level set function. The emphasis is for successful tracking of objects that undergo smooth arbitrary deformations, but without the a priori learning of shape constraints. The high-level shape information is learnt(More)
In this work we consider a probabilistic methodology that models the intensity distributions found in pure and partial volume (PV) voxels. We introduce some methodological developments that enable explicit modeling of the PV voxels prior Probability Density Function (PDF). This new formulation can be applied generically across different imaging modalities(More)
Accurate classification of signals composed of two or more classification classes (e.g., biomedical imaging data with pathological structures) might utilize a density that takes account of the signal acquisition process. A new density based on a Gaussian point spread function (PSF) and another utilizing a phenomenological observation known as Benford's Law(More)
A method to monitor elderly people in an indoor environment using conventional cameras is presented. The method can be used to identify people's activities and initiate suitable actions as needed. The originality of our approach is in combining spatial and temporal contexts with the position and orientation for the detected person. Preliminary evaluation,(More)
Accurate automatic segmentation of anatomical structures is usually considered a difficult problem to solve because of anatomical variability and varying imaging conditions. A prior description of the shape of the anatomical structure to be segmented can reduce the ambiguity associated with the segmentation task. However this prior information has to be(More)