27,052 research outputs found
4D Light FIeld Ophthalmoscope: A Study of Plenoptic Imaging for Retinal Imaging
The application of 4D Light Field technique to retinal imaging is proposed as a multi- modality imaging device. A feasibility study developed with numerical simulations is presente
Learning Rigid Image Registration - Utilizing Convolutional Neural Networks for Medical Image Registration
Many traditional computer vision tasks, such as segmentation, have seen large step-changes in accuracy and/or speed with the application of Convolutional Neural Networks (CNNs). Image registration, the alignment of two or more images to a common space, is a fundamental step in many medical imaging workflows. In this paper we investigate whether these techniques can also bring tangible benefits to the registration task. We describe and evaluate the use of convolutional neural networks (CNNs) for both mono- and multi- modality registration and compare their performance to more traditional schemes, namely multi-scale, iterative registration. This paper also investigates incorporating inverse consistency of the learned spatial transformations to impose additional constraints on the network during training and investigate any benefit in accuracy during detection. The approaches are validated with a series of artificial mono-modal registration tasks utilizing T1-weighted MR brain i mages from the Open Access Series of Imaging Studies (OASIS) study and IXI brain development dataset and a series of real multi-modality registration tasks using T1-weighted and T2-weighted MR brain images from the 2015 Ischemia Stroke Lesion segmentation (ISLES) challenge. The results demonstrate that CNNs give excellent performance for both mono- and multi- modality head and neck registration compared to the baseline method with significantly fewer outliers and lower mean errors
Fast and automated oscillation frequency extraction using Bayesian multi-modality
Since the advent of CoRoT, and NASA Kepler and K2, the number of low- and
intermediate-mass stars classified as pulsators has increased very rapidly with
time, now accounting for several targets. With the recent launch of NASA
TESS space mission, we have confirmed our entrance to the era of all-sky
observations of oscillating stars. TESS is currently releasing good quality
datasets that already allow for the characterization and identification of
individual oscillation modes even from single 27-days shots on some stars. When
ESA PLATO will become operative by the next decade, we will face the
observation of several more hundred thousands stars where identifying
individual oscillation modes will be possible. However, estimating the
individual frequency, amplitude, and lifetime of the oscillation modes is not
an easy task. This is because solar-like oscillations and especially their
evolved version, the red giant branch (RGB) oscillations, can vary
significantly from one star to another depending on its specific stage of the
evolution, mass, effective temperature, metallicity, as well as on its level of
rotation and magnetism. In this perspective I will present a novel, fast, and
powerful way to derive individual oscillation mode frequencies by building on
previous results obtained with \diamonds. I will show that the oscillation
frequencies obtained with this new approach can reach precisions of about 0.1 %
and accuracies of about 0.01 % when compared to published literature values for
the RGB star KIC~12008916.Comment: 10 pages, 2 figures, accepted for publication in Frontiers in
Astronomy and Space Sciences. Invited contribution for the research topic
"The Future of Asteroseismology
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