Search results for "Imaging"

Microchimerism and multiple sclerosis: a study on the impact of the sex of offspring on clinical, radiological, and paraclinical features of maternal…

2023

Background. Multiple sclerosis (MS) is a chronic autoimmune disorder characterised by inflammation and neurodegeneration and representing one of the most common causes of neurologic disability among young adults. Over the last 40 years, several authors have confirmed the existence of fetal cells in maternal blood and their pregnancy-related origin, demonstrating that pregnancy may establish a long-term, low-grade chimeric state in women. The biological and clinical significance of fetal microchimeric cells (fMCs) in maternal health is largely unknown, although a role in autoimmune diseases have been hypothesised. Aims. The overarching aim of my PhD dissertation was to investigate the role o…

A Shape-based Statistical Method to Retrieve 2D TRUS-MR Slice Correspondence for Prostate Biopsy

2012

International audience; This paper presents a method based on shape-context and statistical measures to match interventional 2D Trans Rectal Ultrasound (TRUS) slice during prostate biopsy to a 2D Magnetic Resonance (MR) slice of a pre-acquired prostate volume. Accurate biopsy tissue sampling requires translation of the MR slice information on the TRUS guided biopsy slice. However, this translation or fusion requires the knowledge of the spatial position of the TRUS slice and this is only possible with the use of an electro-magnetic (EM) tracker attached to the TRUS probe. Since, the use of EM tracker is not common in clinical practice and 3D TRUS is not used during biopsy, we propose to per…

Emulation of Sun-Induced Fluorescence from Radiance Data Recorded by the HyPlant Airborne Imaging Spectrometer

2021

The retrieval of sun-induced fluorescence (SIF) from hyperspectral radiance data grew to maturity with research activities around the FLuorescence EXplorer satellite mission FLEX, yet full-spectrum estimation methods such as the spectral fitting method (SFM) are computationally expensive. To bypass this computational load, this work aims to approximate the SFM-based SIF retrieval by means of statistical learning, i.e., emulation. While emulators emerged as fast surrogate models of simulators, the accuracy-speedup trade-offs are still to be analyzed when the emulation concept is applied to experimental data. We evaluated the possibility of approximating the SFM-like SIF output directly based…

A Multi-Projector Calibration Method for Virtual Reality Simulators with Analytically Defined Screens

2017

The geometric calibration of projectors is a demanding task, particularly for the industry of virtual reality simulators. Different methods have been developed during the last decades to retrieve the intrinsic and extrinsic parameters of projectors, most of them being based on planar homographies and some requiring an extended calibration process. The aim of our research work is to design a fast and user-friendly method to provide multi-projector calibration on analytically defined screens, where a sample is shown for a virtual reality Formula 1 simulator that has a cylindrical screen. The proposed method results from the combination of surveying, photogrammetry and image processing approac…

Multispectral filter arrays: Recent advances and practical implementation

2014

Thanks to some technical progress in interferencefilter design based on different technologies, we can finally successfully implement the concept of multispectral filter array-based sensors. This article provides the relevant state-of-the-art for multispectral imaging systems and presents the characteristics of the elements of our multispectral sensor as a case study. The spectral characteristics are based on two different spatial arrangements that distribute eight different bandpass filters in the visible and near-infrared area of the spectrum. We demonstrate that the system is viable and evaluate its performance through sensor spectral simulation. Multispectral filter arrays: Recent advan…

Shoulder ultrasound: current concepts and future perspectives

2021

Ultrasonography is an established and effective imaging technique that can be used to evaluate articular and periarticular structures around the shoulder. It has been shown to be useful in a wide range of rotator cuff diseases (e.g. tendon tears, rotator cuff calcific tendinopathy and bursitis) as well as non-rotator cuff abnormalities (instability, synovial joint diseases and nerve entrapment syndrome). A scanning protocol is highly recommended to reduce the rate of operators’ errors by following a standardized scheme including a list of main structures. Shoulder ultrasound has several advantages: it is a relatively cheap and widely available technique, free from ionizing radiation, that c…

Mapping soil water content under sparse vegetation and changeable sky conditions: comparison of two thermal inertia approaches

2013

A critical analysis of a thermal inertia approach to map surface soil water content on bare and sparsely vegetated soils by means of remotely sensed data is reported. The study area is an experimental field located in Barrax, Spain. In situ data were acquired within the Barrax 2011 research project. An advanced hyperspectral scanner airborne imager provides images in the visible/near-infrared and thermal infrared bands. Images were acquired both in day and night times by the Instituto Nacional de Técnica Aeroespacial between 12th and 13th of June 2011. The scene covers a corn irrigation pivot surrounded by bare soil, where a set of in situ data have been collected both previously and simult…

Spatio-temporal Dynamical Analysis of Brain Activity during Mental Fatigue Process

2021

Mental fatigue is a common phenomenon with implicit and multidimensional properties. It brings dynamic changes of functional brain networks. However, the challenging problem of false positives appears when the connectivity is estimated by Electroencephalography (EEG). In this paper, we propose a novel framework based on spatial clustering to explore the sources of mental fatigue and functional activity changes caused by them. To suppress the false positive observations, spatial clustering is implemented in brain networks. The nodes extracted by spatial clustering are registered back to functional magnetic resonance imaging (fMRI) source space to determined the sources of mental fatigue. The…

Development of 2D & 3D cadmium–zinc–telluride spectroscopic imagers for X-ray and gamma ray applications

2021

Remote Sensing of 3-D Geometry and Surface Moisture of a Peat Production Area Using Hyperspectral Frame Cameras in Visible to Short-Wave Infrared Spe…

2016

Miniaturized hyperspectral imaging sensors are becoming available to small unmanned airborne vehicle (UAV) platforms. Imaging concepts based on frame format offer an attractive alternative to conventional hyperspectral pushbroom scanners because they enable enhanced processing and interpretation potential by allowing for acquisition of the 3-D geometry of the object and multiple object views together with the hyperspectral reflectance signatures. The objective of this investigation was to study the performance of novel visible and near-infrared (VNIR) and short-wave infrared (SWIR) hyperspectral frame cameras based on a tunable Fabry–Pérot interferometer (FPI) in measuring a 3-D digital sur…