Search results for "SPECTRA"
showing 10 items of 3542 documents
Using VIS/NIR and IR spectral cameras for detecting and separating crime scene details
2012
Detecting invisible details and separating mixed evidence is critical for forensic inspection. If this can be done reliably and fast at the crime scene, irrelevant objects do not require further examination at the laboratory. This will speed up the inspection process and release resources for other critical tasks. This article reports on tests which have been carried out at the University of Jyväskylä in Finland together with the Central Finland Police Department and the National Bureau of Investigation for detecting and separating forensic details with hyperspectral technology. In the tests evidence was sought after at an assumed violent burglary scene with the use of VTT's 500-900 nm wave…
Methods for estimating forest stem volumes by tree species using digital surface model and CIR images taken from light UAS
2012
In this paper we consider methods for estimating forest tree stem volumes by species using images taken from light unmanned aircraft systems (UAS). Instead of using LiDAR and additional multiband imagery a color infrared camera mounted to a light UAS is used to acquire both imagery and the DSM of target area. The goal of this study is to accurately estimate tree stem volumes in three classes. The status of the ongoing work is described and an initial method for delineating and classifying treetops is presented.
Scalable implementation of dependence clustering in Apache Spark
2017
This article proposes a scalable version of the Dependence Clustering algorithm which belongs to the class of spectral clustering methods. The method is implemented in Apache Spark using GraphX API primitives. Moreover, a fast approximate diffusion procedure that enables algorithms of spectral clustering type in Spark environment is introduced. In addition, the proposed algorithm is benchmarked against Spectral clustering. Results of applying the method to real-life data allow concluding that the implementation scales well, yet demonstrating good performance for densely connected graphs. peerReviewed
Detecting explosive substances by the IR spectrography
2014
Fast and safe detection methods of explosive substances are needed both before and after actualized explosions. This article presents an experiment of the detection of three selected explosives by the ATR FTIR spectrometer and by three different IR hyperspectral imaging devices. The IR spectrometers give accurate analyzing results, whereas hyperspectral imagers can detect and analyze desired samples without touching the unidentified target at all. In the controlled explosion experiment TNT, dynamite and PENO were at first analyzed as pure substances with the ATR FTIR spectrometer and with VNIR, SWIR and MWIR cameras. After three controlled explosions also the residues of TNT, dynamite and P…
The challenges of analysing blood stains with hyperspectral imaging
2014
Hyperspectral imaging is a potential noninvasive technology for detecting, separating and identifying various substances. In the forensic and military medicine and other CBRNE related use it could be a potential method for analyzing blood and for scanning other human based fluids. For example, it would be valuable to easily detect whether some traces of blood are from one or more persons or if there are some irrelevant substances or anomalies in the blood. This article represents an experiment of separating four persons' blood stains on a white cotton fabric with a SWIR hyperspectral camera and FT-NIR spectrometer. Each tested sample includes standardized 75 _l of 100 % blood. The results s…
Hyperspectral imaging based biomass and nitrogen content estimations from light-weight UAV
2013
Hyperspectral imaging based precise fertilization is challenge in the northern Europe, because of the cloud conditions. In this paper we will introduce schemes for the biomass and nitrogen content estimations from hyperspectral images. In this research we used the Fabry-Perot interferometer based hypespectral imager that enables hyperspectral imaging from lightweight UAVs. During the summers 2011 and 2012 imaging and flight campaigns were carried out on the Finnish test field. Estimation mehtod uses features from linear and non-linear unmixing and vegetation indices. The results showed that the concept of small hyperspectral imager, UAV and data analysis is ready to operational use.
TDDFT Analysis of Optical Properties of Thiol Monolayer-Protected Gold and Intermetallic Silver–Gold Au144(SR)60 and Au84Ag60(SR)60 Clusters
2014
The optical absorption spectra of atomistic model structures for experimentally isolated all-gold Au144(SR)60 and intermetallic Au84Ag60(SR)60 clusters are systematically analyzed from linear-response time-dependent density functional theory (LR-TDDFT) and time-dependent density functional perturbation theory (TD-DFPT) calculations. The computed spectra, utilizing the atomistic model for Au144(SR)60 published by us in 2009, reproduce closely the experimental observations for corresponding isolated compounds, reported previously by Kumara and Dass in 2011. A collective dipole oscillation within the metal cores of the all-gold and intermetallic clusters is formed as response to light in the v…
Optical Properties of Monolayer-Protected Aluminum Clusters: Time-Dependent Density Functional Theory Study
2015
We examine the electronic and optical properties of experimentally known monolayer-protected aluminum clusters Al4(C5H5)4, Al50(C5Me5)12, and Al69(N(SiMe3)2)183– using time-dependent density functional theory. By comparing Al4(C5H5)4 and the theoretical Al4(N(SiMe3)2)4 cluster, we observe significant changes in the optical absorption spectra caused by different hybridization between metal core and ligands. Using these initial observations, we explain the calculated spectra of Al50(C5Me5)12 and Al69(N(SiMe3)2)183–. Al50(C5Me5)12 shows a structured spectrum with clear regions of low-intensity core-to-core transitions followed by high-intensity ligand-to-core transitions due to its high symmet…
Coupling high-resolution satellite imagery with ALS-based canopy height model and digital elevation model in object-based boreal forest habitat type …
2014
We developed a classification workflow for boreal forest habitat type mapping. In object-based image analysis framework, Fractal Net Evolution Approach segmentation was combined with random forest classification. High-resolution WorldView-2 imagery was coupled with ALS based canopy height model and digital terrain model. We calculated several features (e.g. spectral, textural and topographic) per image object from the used datasets. We tested different feature set alternatives; a classification accuracy of 78.0 % was obtained when all features were used. The highest classification accuracy (79.1 %) was obtained when the amount of features was reduced from the initial 328 to the 100 most imp…
A "DUAL" MODEL OF A MASSIVE SPIN-1/2 POINT PARTICLE, AND A THEORETICAL EXPLANATION FOR THE EFFECT OF "MAXIMAL PARITY-VIOLATION"
2006
The open question left by elementary particle physics about the origin of the so-called ``maximal parity-violation'' is dealt with. It is shown that an actual theoretical answer could be found within a new relativistic quantum field formalism being a strictly covariant fermion--antifermion extension of the usual one for massive fermions. This formalism can account naturally for the effect at issue, in such a way as even to restore both parity and charge-conjugation symmetries: it spontaneously provides a true ``chiral field'' approach, which gives rise to the conjecture of a pseudoscalar (extra) charge variety anticommuting with the scalar (ordinary) one and just underlying the ``maximally …