A5049612660- Medical Imaging Techniques and Applications
- EEG and Brain-Computer Interfaces
- Advanced MRI Techniques and Applications
- Advanced X-ray Imaging Techniques
- Image and Signal Denoising Methods
- Blind Source Separation Techniques
- Neural dynamics and brain function
- Advanced X-ray and CT Imaging
- Advanced Memory and Neural Computing
- Neural Networks and Reservoir Computing
- Sleep and Work-Related Fatigue
- Advanced Image Processing Techniques
- Sparse and Compressive Sensing Techniques
- Medical Image Segmentation Techniques
- ECG Monitoring and Analysis
- Image Processing Techniques and Applications
- Cardiac Imaging and Diagnostics
- AI in cancer detection
- Epilepsy research and treatment
- Image and Object Detection Techniques
- Radiation Dose and Imaging
- Reservoir Engineering and Simulation Methods
- Gaze Tracking and Assistive Technology
- Neural Networks and Applications
- Cardiac electrophysiology and arrhythmias
University of Canterbury
2014-2024
MacDiarmid Institute for Advanced Materials and Nanotechnology
2023
Unitec Institute of Technology
2014
New Zealand Brain Research Institute
2012
Christ University
2007
Christchurch Hospital
2000
Imperial College London
1986
Princess Margaret Hospital
1977-1984
Maintaining alertness is critical for safe and successful performance of most human activities.Consequently, microsleeps during continuous visuomotor tasks, such as driving, can be very serious, not only disrupting but sometimes leading to injury or death due accidents.We have investigated the neural activity underlying behavioral -brief (0.5-15 s) episodes complete failure respond accompanied by slow eye-closures -and EEG theta drowsiness in a task.Twenty healthy normally-rested...
The complex self-assembled network of neurons and synapses that comprises the biological brain enables natural information processing with remarkable efficiency. Percolating networks nanoparticles (PNNs) are nanoscale systems have been shown to possess many promising brain-like attributes which therefore appealing for neuromorphic computation. Here experiments performed show PNNs can be utilized as physical reservoirs within a nanoelectronic reservoir computing framework demonstrate...
The Compton scattering camera (sometimes called the electronically collimated camera) has been shown by others to have potential better photon counting statistics and energy resolution of Anger for imaging in SPECT. By using coincident detection events on two detecting planes, a can be localized having sourced surface cone. New algorithms are needed achieve fully three-dimensional reconstruction source distribution from such camera. If complete set cone-surface projections collected over an...
Self-assembled networks of nanoparticles and nanowires have recently emerged as promising systems for brain-like computation. Here, we focus on percolating which exhibit dynamics. We use a combination experiments simulations to show that the network dynamics emerge from atomic-scale switching inside tunnel gaps are distributed throughout network. The emulate leaky integrate fire (LIF) mechanisms in biological neurons, leading generation critical avalanches signals. These quantitatively same...
Summary We investigated the occurrence of lapses responsiveness (lapses) in 15 non‐sleep‐deprived subjects performing a 1D continuous tracking task during normal working hours. Tracking behaviour, facial video, and electroencephalogram (EEG) were recorded simultaneously two 1‐h sessions. Rate duration estimated for identified by flat spot and/or video sleep. Fourteen had one or more lapses, with an overall rate 39.3 ± 12.9 per hour (mean SE) lapse 3.4 0.5 s. also found that subjects’...
Equalizing image noise is shown to be an important step in the automatic detection of microcalcifications digital mammography. This study extends a well established film-screen equalization scheme developed by Veldkamp et al. for application full-field mammogram (FFDM) images. A simple model determined based on assumption that quantum dominant direct X-ray imaging. Estimation as function gray level improved calculating statistics using truncated distribution method. Experimental support...
A system capable of reliably detecting lapses in responsiveness ('lapses') has the potential to increase safety many occupations. We have developed an approach for state lapsing with second-scale temporal resolution using data from 15 subjects performing a one-dimensional (1D) visuomotor tracking task two 1 h sessions while their electroencephalogram (EEG), facial video, and performances were recorded. Lapses identified combination video behaviour used train classification models. Linear...
Spectral molecular imaging is a new technique able to discriminate and quantify different components of tissue simultaneously at high spatial energy resolution. Our MARS scanner an x-ray based small animal CT system designed be used in the diagnostic range (20–140 keV). In this paper, we demonstrate use scanner, equipped with Medipix3RX spectroscopic photon-processing detector, fat, calcium, water tissue. We present data collected from sample lamb meat including bone as illustrative example...
Reservoir computing (RC) has attracted significant interest as a framework for the implementation of novel neuromorphic architectures. Previously attention been focussed on software-based reservoirs, where it demonstrated that reservoir topology plays role in task performance, and functional advantage attributed to small-world scale-free connectivity. However hardware systems, such electronic memristor networks, mechanisms responsible dynamics are very different is largely unknown. Here we...
Wavelet based signal analysis provides a powerful new means for the of nonstationary signals such as human EEG. The properties discrete wavelet transform are reviewed in illustrated application examples. continuous is shown to provide better detection and representation isolated transients. An approach extract features edges transients from outlined. Matching pursuit presented more general method that covers both oscillation spindles. A statistical model background EEG found. spike system on...
Acebutolol ('Sectral'), a cardioselective beta-blocking drug, was administered intravenously in dose of 25 mg to 10 patients with congestive cardiomyopathy. All them were stable condition on antifailure regimens. The drug resulted statistically significant decline left ventricular contractility as judged by peak dP/dT and the index. mean aortic blood pressure also fell. There increase end-diastolic end-systolic volumes. Mean values for heart rate, ejection fraction, stroke work index,...
A device capable of continuously monitoring an individual's levels alertness in real-time is highly desirable for preventing drowsiness and microsleep related accidents. This paper presents a development non-intrusive light-insensitive video-based system that uses computer-vision methods to measure facial metric identifying visible signs behavioral microsleep. The developed remotely placed camera with near-infrared illumination acquire the video. are then applied sequentially localize face,...
This paper discusses methods for reducing beam hardening effects and metal artefacts using spectral x-ray information in biomaterial samples. A small-animal scanner was operated the 15 to 80 keV energy range this study. We use photon-processing features of a CdTe-Medipix3RX ASIC charge summing mode reduce associated artefacts. present data collected alloy samples, its analysis algebraic 3D reconstruction software volume visualisation custom rendering software. The cupping effect streak are...
Abstract Two improved compressed sensing (CS)‐based image reconstruction methods for MRI are proposed: prior estimate‐based (PECS) and sensitivity encoding‐based (SENSECS). PECS allows knowledge of the underlying to be intrinsically incorporated in recovery process, extending use data sorting as first proposed by Adluru DiBella (Int J Biomed Imaging 2008: 341648). It does so rearranging elements based on magnitude information gathered from a estimate, that can recovered new form exhibits...
There is currently a great deal of interest in the use nanoscale devices to emulate behaviors neurons and synapses facilitate brain-inspired computation. Here, it shown that percolating networks nanoparticles exhibit stochastic spiking behavior strikingly similar observed biological neurons. The rate can be controlled by input stimulus, "rate coding" biology, distributions times between events are log-normal, providing insights into atomic-scale mechanism. stochasticity then used for true...
In response to increasing interest in the area of subdiffraction-limited near-field imaging, performance several different realizable and theoretical superresolving silver-based lenses is simulated for a variety input object profiles. A computationally-efficient T-matrix technique used model lenses, which consist layers silver with total width 40 nm sandwiched between polymethyl methacrylate silicon dioxide. The are exposed nonperiodic bright- dark-slit patterns, feature size varied 1 2.5...
The biological brain is a highly efficient computational system in which information processing performed via electrical spikes. Neuromorphic computing systems that work on similar principles could support the development of next generation artificial intelligence and, particular, enable low-power edge computing. Percolating networks nanoparticles (PNNs) have previously been shown to exhibit critical spiking behavior, with promise for natural computation. Here we employ rate coding scheme...
The technique of multireference adaptive noise canceling (MRANC) is applied to enhance transient nonstationarities in the electroeancephalogram (EEG), with adaptation implemented by means a multilayer-perception artificial neural network (ANN). method was recorded EEG segments and performance on documented recorded. results show that (nonlinear) gives an improvement (i.e., signal-to-noise ratio (SNR) nonstationarities) compared linear implementation MRANC. In both cases SNR obtained....
Summary: The hypotensive action of verapamil given orally was assessed in the outpatient management patients with raised blood pressure, a single blind study. Twenty‐six hypertensive on no therapy, 14 beta blockers and eight methyldopa were more satisfactorily controlled when substituted for initial drug. There marked reduction number side‐effects, drug many situations where blockade contra‐indicated.
An algorithm is presented for processing and analysis of differential interference contrast (DIC) microscopy images the fovea to study cone mosaic. The automatically locates cones their boundaries in such assessed by comparison with results from manual analysis. Additional algorithms are that analyze positions extract information on neighbor relationships as well short-range order domain structure methods applied DIC human fovea.