Search results for "PIXE"
showing 10 items of 428 documents
Monitoring global vegetation with the Yearly Land Cover Dynamics (YLCD) method
2011
Global vegetation has been traditionally monitored mainly through the use of the Normalized Difference Vegetation Index (NDVI). Land surface temperature (LST) provides additional information, and is generally less affected by atmospheric conditions when water vapor is taken into account. The Yearly Land Cover Dynamics (YLCD) method can then be used to retrieve 3 parameters which allow for a good differentiation between biomes at the global and local levels. Using NASA's Long Term Data Record (LTDR), the YLCD method has been applied to IDR (iterative Interpolation for Data Reconstruction) reconstructed LTDR data, in order to account for atmospheric contamination of part of the dataset for a …
MuPix and ATLASPix -- Architectures and Results
2020
High Voltage Monolithic Active Pixel Sensors (HV-MAPS) are based on a commercial High Voltage CMOS process and collect charge by drift inside a reversely biased diode. HV-MAPS represent a promising technology for future pixel tracking detectors. Two recent developments are presented. The MuPix has a continuous readout and is being developed for the Mu3e experiment whereas the ATLASPix is being developed for LHC applications with a triggered readout. Both variants have a fully monolithic design including state machines, clock circuitries and serial drivers. Several prototypes and design variants were characterised in the lab and in testbeam campaigns to measure efficiencies, noise, time reso…
Architecture-Driven Level Set Optimization: From Clustering to Sub-pixel Image Segmentation
2016
Thanks to their effectiveness, active contour models (ACMs) are of great interest for computer vision scientists. The level set methods (LSMs) refer to the class of geometric active contours. Comparing with the other ACMs, in addition to subpixel accuracy, it has the intrinsic ability to automatically handle topological changes. Nevertheless, the LSMs are computationally expensive. A solution for their time consumption problem can be hardware acceleration using some massively parallel devices such as graphics processing units (GPUs). But the question is: which accuracy can we reach while still maintaining an adequate algorithm to massively parallel architecture? In this paper, we attempt to…
2-D mapping of skin chromophores in the spectral range 500 - 700 nm
2009
The multi-spectral imaging technique has been used for distant mapping of in-vivo skin chromophores by analyzing spectral data at each reflected image pixel and constructing 2-D maps of the relative concentrations of oxy-/deoxy-haemoglobin and melanin. Instead of using a broad visible-NIR spectral range, this study focuses on narrowed spectral band 500–700 nm, speeding-up the signal processing procedure. Regression analysis confirmed that superposition of three Gaussians is optimal analytic approximation for the oxy-haemoglobin absorption tabular spectrum in this spectral band, while superposition of two Gaussians fits well for deoxy-haemoglobin absorption and exponential function – for mel…
An adapted optical flow algorithm for robust quantification of cardiac wall motion from standard cine-MR examinations
2012
International audience; This paper presents a method for local myocardial motion estimation from a conventional steady-state free precession cine-MRI sequence using a modified phase-based optical flow (OF) technique. Initially, the technique was tested on synthetic images to evaluate its robustness with regards to Rician noise and to brightness variations. The method was then applied to cardiac images acquired on 11 healthy subjects. Myocardial velocity is measured in centimeter per second in each studied pixel and visualized as colored vectors superimposed on MRI images. The estimated phase-based OF results were compared with a reference OF method and gave similar results on synthetic imag…
Evaluation of Deep Neural Networks for Semantic Segmentation of Prostate in T2W MRI
2020
In this paper, we present an evaluation of four encoder&ndash
Stereo Matching Tecniques for Cloud-top Height Retrieval
2006
This paper presents an ongoing study for the estimation of the cloud-top height by using only geometrical methods. It is based on the hypothesis that an infra-red camera is on board a satellite and pairs of images concern nearly the same scene. Stereo-vision techniques are therefore explored in order to test the methodology for height retrieval and in particular results of several techniques of stereo matching are evaluated. This study includes area-based matching algorithms by implementing the basic versions, without considering any further steps of optimisation to improve the results. Dense depth maps are the final outputs whose reliability is verified by computing error statistics with r…
Detection of planar defects caused by ion irradiation in Si using molecular dynamics
2007
We have analyzed the evolution of defects caused by self-irradiation of crystalline silicon. A classical molecular dynamics simulation was followed by defect analysis using the Pixel Mapping (PM) method. The PM identified {311} planar defects and long-chain structures of the so-called interstitial chains following low energy (1 keV) ion impact. The areal density obtained from simulation of self-interstitial atoms was about two thirds of that of experiments reported in the literature [Jpn. J. Appl. Phys. 30 (1991) L639], while the atomic configuration on respective planes agreed exactly.
Assessment of age-related skin changes using hyperspectral polarization imaging
2019
Abstract We report a development of hyperspectral polarization imaging approach for assessment of age-related skin changes. The degree of residual polarization is used as a quantitative marker of the age-related pathological malformations. The developed approach in frame of express analysis of the degree of residual polarization in each pixel of the image are shown.
Imaging of laser-excited tissue autofluorescence bleaching rates.
2009
Experimental methodology for imaging of laser-excited tissue autofluorescence bleaching rates has been developed and clinically tested. The fluorescence images were periodically captured from the same tissue area over a certain time, with subsequent detection of the fluorescence intensity decrease rate at each image pixel and further imaging the planar distribution of those values. Spectral features at each image pixel were analyzed with a hyperspectral imaging camera. Details of the equipment and image processing are described as well as some measurement results that confirm the feasibility of the proposed technology.