Multispectral Techniques Research Articles

Multispectral imaging reveals biblical-period inscription unnoticed for half a century

Most surviving biblical period Hebrew inscriptions are ostraca—ink-on-clay texts. They are poorly preserved and once unearthed, fade rapidly. Therefore, proper and timely documentation of ostraca is essential. Here we show a striking example of a hitherto invisible text on the back side of an ostracon revealed via multispectral imaging. This ostracon, found at the desert fortress of Arad and dated to ca. 600 BCE (the eve of Judah’s destruction by Nebuchadnezzar), has been on display for half a century. Its front side has been thoroughly studied, while its back side was considered blank. Our research revealed three lines of text on the supposedly blank side and four "new" lines on the front side. Our results demonstrate the need for multispectral image acquisition for both sides of all ancient ink ostraca. Moreover, in certain cases we recommend employing multispectral techniques for screening newly unearthed ceramic potsherds prior to disposal.

Análise temporal (2002-2014) da expansão da espécie de samambaia dicranopteris flexuosa no Vale do Pati (Brasil) utilizando técnicas de classificação de imagens de satélite

Afim de analisar as áreas ocupadas pela espécie de samambaia invasora Dicranopteris flexuosa no período entre 2002 e 2014, no Vale do Pati (Bahia-Brasil), foram utilizadas técnicas de classificação de imagens de satélite multiespectrais a partir dos algoritmos de classificação supervisionada Redes Neurais e Máxima Verossimilhança. Os resultados apontam que a espécie tende a se expandir rapidamente, impedindo a regeneração da flora nativa. O algoritmo que apresentou maior confiabilidade para tal foi o Redes Neurais. https://doi.org/10.14195/1647-7723_24_10

Probing the binding of Azilsartan to DNA by molecular docking, steady-state/time-resolved fluorescence, viscosity, infrared, and circular dichroism spectra

ABSTRACTAzilsartan, a new antihypertensive drug, has effects on the sympathetic nervous system and expression of genes. The interaction of Azilsartan with DNA was investigated using molecular docking and multi-spectral techniques. Molecular docking revealed that Azilsartan could interact with DNA via groove binding from a theoretical perspective. Time-resolved fluorescence measurements indicated that the quenching mechanism was static, and further analysis of quenching data demonstrated that the binding was spontaneous and mainly driven by hydrophobic forces. The results of interaction with denatured DNA, viscosity, infrared spectroscopy, and circular dichroism showed that Azilsartan could bind to DNA through groove binding, which was consistent with docking analyses.

Research Method and Spectral Analysis of Ancient Polychromatic Silicate Artifacts

The spectral properties, chemical compositions and phases of materials constituting the surface of 5 ancient polychromatic silicate artifacts have been analyzed non-invasively with self-built multispectral imaging system, X-ray fluorescence spectrometer (XRF) and laser Raman spectrometer (LRS). Based on spectral response in multispectral images, materials constituting the surface of 5 samples can be divided into different areas, and most of blue, green, purple areas with fluorescence behavior are also mapped. The results of XRF indicate that the chemical compositions of areas are different, but the major compositions of them are SiO(2), PbO, BaO. 5 samples mainly belong to PbO-BaO silicates. The coloring agents of all areas with fluorescence behavior are Cu ions. A variety of mineral phases including vitreous phase, Chinese blue, Chinese purple, quartz, hematite, lead carbonate, amorphous carbon and so on, are also identified by LRS. Chinese blue and Chinese purple can emit infrared radiation when excited by visible LED. The result of LRS is verified by X-ray diffraction (XRD). Combining the multispectral imaging area-measurement technique used to research paintings, and XRF, LRS which are usually used to analyze chemical composition of silicate artifacts, the present research proposes a more efficient and non-invasive research method to analyze ancient polychromatic silicate artifacts. Spectral characteristic and chemical composition of the sample are connected when spectral images, X-ray fluorescence spectra and Laser Raman spectra are combined. It has great significance for increasing efficiency of analysis, enhancing the overall understanding of silicate artifacts and decreasing risk of damage.

Detection and assessment of cloud cover and precipitation parameters using data of scanning radiometers of polar–orbiting and geostationary meteorological satellites

Two multispectral threshold techniques have been developed and tested for the automatic classification of AVHRR/NOAA and SEVIRI/Meteosat-10 data. They provide day-and-night detection and the assessment of cloud-cover parameters, as well as the discrimination of precipitation zones and severe weather phenomena. The validation of output information products, which has been performed with ground-based conventional meteorological observations and radar data, as well as with independent satellite-based estimates of cloud cover and precipitation parameters, confirms the feasibility of developed techniques and reasonable accuracy of output products. Therefore, the technique is concurrent to those implemented in current foreign satellite centers.

Interaction of the minocycline with extracelluar protein and intracellular protein by multi-spectral techniques and molecular docking

The interaction of minocyeline (MNC) with extracelluar protein (lysozyme, LYSO) or intracellular protein (bovine hemoglobin, BHb) was investigated using multi-spectral techniques and molecular docking in vitro. Fluorescence studies suggested that MNC quenched LYSO/BHb fluorescence in a static mode with binding constants of 2.01 and 0.26 × 104 L∙mol−1 at 298 K, respectively. The LYZO−MNC system was more easily influenced by temperature (298 and 310 K) than the BHb−MNC system. The thermodynamic parameters demonstrated that hydrogen bonds and van der Waals forces played the major role in the binding process. Based on the Förster theory of nonradiative energy transfer, the binding distances between MNC and the inner tryptophan residues of LYSO and BHb were calculated to be 4.34 and 3.49 nm, respectively. Furthermore, circular dichroism spectra (CD), Fourier transforms infrared (FTIR), UV–vis, and three-dimensional fluorescence spectra results indicated the secondary structures of LYSO and BHb were partially destroyed by MNC with the α-helix percentage of LYZO−MNC increased (17.8–28.6%) while that of BHb−MNC was decreased (41.6–39.6%). UV–vis spectral results showed these binding interactions could cause conformational and some micro-environmental changes of LYSO and BHb. In accordance with the results of molecular docking, In LYZO-MNC system, MNC was mainly bound in the active site hinge region where Trp-62 and Trp-63 are located, and in MNC-BHb system, MNC was close to the subunit α 1 of BHb, molecular docking analysis supported the thermodynamic results well. The work contributes to clarify the mechanism of MNC with two proteins at molecular level.

MULTISPECTRAL ANALYSIS OF INDIGENOUS ROCK ART USING TERRESTRIAL LASER SCANNING

Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

MULTISPECTRAL ANALYSIS OF INDIGENOUS ROCK ART USING TERRESTRIAL LASER SCANNING

Abstract. Multispectral analysis is a widely used technique in the photogrammetric and remote sensing industry. The use of Terrestrial Laser Scanning (TLS) in combination with imagery is becoming increasingly common, with its applications spreading to a wider range of fields. Both systems benefit from being a non-contact technique that can be used to accurately capture data regarding the target surface. Although multispectral analysis is actively performed within the spatial sciences field, its extent of application within an archaeological context has been limited. This study effectively aims to apply the multispectral techniques commonly used, to a remote Indigenous site that contains an extensive gallery of aging rock art. The ultimate goal for this research is the development of a systematic procedure that could be applied to numerous similar sites for the purpose of heritage preservation and research. The study consisted of extensive data capture of the rock art gallery using two different TLS systems and a digital SLR camera. The data was combined into a common 2D reference frame that allowed for standard image processing to be applied. An unsupervised k-means classifier was applied to the multiband images to detect the different types of rock art present. The result was unsatisfactory as the subsequent classification accuracy was relatively low. The procedure and technique does however show potential and further testing with different classification algorithms could possibly improve the result significantly.

Characterization of colorimetric sensor arrays by a multi-spectral technique

A new method based on a multi-spectral technique was proposed to characterize the signal of colorimetric sensor arrays for gas detection.

Advances in Metal Artifact Reduction Techniques for Periprosthetic Soft Tissue Imaging.

Artifact from metallic orthopedic prosthesis is caused by inhomogeneity in the B0 magnetic field, particularly in the frequency encoding direction. This results in signal voids, signal pileup, and geometric distortion. Advances in reducing this artifact allow us to assess the complications of joint replacement and improve imaging of nearby tissues such as within the pelvis. Selection of titanium implants and lower field strength MR units provide optimal conditions for artifact reduction. Conventional sequences can be optimized by using inversion recovery sequences, large matrices, high receiver bandwidths, and thin slices. Optimizing these parameters comes with a penalty in terms of signal-to-noise ratio or increased acquisition times. Successful artifact reduction depends on the strength of the frequency encoding gradients. Newer dedicated artifact reduction sequences include view-angle-tilting and a selection of multispectral techniques including multiacquisition variable-resonance image combination (MAVRIC) and slice encoding for metal artifact correction (SEMAC). Many of these are being used in combination. The multispectral sequences acquire three-dimensional data at very narrow frequencies and use of phase encoding for spatial localization. Planar images can then be reconstructed with very little susceptibility artifact.

Interaction of cyanidin-3-O-glucoside with three proteins

We studied the binding of cyanidin-3-O-glucoside (C3G) with bovine serum albumin (BSA), hemoglobin (Hb) and myoglobin (Mb), using multi-spectral techniques and molecular modeling. Fluorescence and time-resolved fluorescence studies suggested that C3G quenched BSA, Hb or Mb fluorescence in a static mode with binding constants of 4.159, 0.695 and 1.545×104Lmol−1 at 308K, respectively. The thermodynamic parameters represented hydrogen bonds and van der Waals forces dominated the binding. Furthermore, CD, UV–vis, and three-dimensional fluorescence spectra results indicated the secondary structures of BSA, Hb and Mb were partially destroyed by C3G with the α-helix percentage of C3G-Hb and C3G-Mb decreased while that of C3G-BSA was increased. UV–vis spectral results showed these binding interactions partially affected the heme bands of Hb and Mb. In addition, molecular modeling analysis supported the experimental results well. The calculated results of equilibrium fraction showed that the concentration of free C3G in plasma was high enough to be stored and transported from the circulatory system to reach their target sites to provide their therapeutic effects.

Characterization of coastal environment by means of hyper- and multispectral techniques

The management of the coastal environment is a complex issue, which needs for appropriate methodologies. Erosional processes and longshore currents present in the submerged beach represent a serious danger for both people and human infrastructures. A proper integration between traditional and innovative techniques can help in the characterization and management of the beach environment. Several different multispectral and hyperspectral techniques were used to retrieve information about the hydro and morphodynamic settings of the Pisa province coast (Tuscany, Italy). Results were validated using about 130 samples collected along the study area, between the mouths of the Serchio river and the Scolmatore canal. The composition of sand samples was evaluated by means of petrographic microscopy and grain size analyses. The same samples were analyzed using an Analytical Spectral Device (ASD) Fieldspec. The obtained sediment spectral library was used to evaluate the differences in mineralogical composition, which can be related to different source areas. Results coming from spectroscopy were compared to those obtained from the petrographic and grain size analysis. Furthermore a multispectral aerial image was used to evaluate sediment distribution along the submerged beach, to map the geomorphic features and to detect the presence of longshore and rip currents. This works suggests that optical remote sensing technique can be profitably used in order to reduce the need for expensive and time consuming conventional analysis.

Multispectral Bayesian reconstruction technique for real-time two color fluorescence microscopy

We have developed a real-time imaging method for two-color widefield fluorescence microscopy using a combined approach that integrates multi-spectral imaging and Bayesian image reconstruction technique.

Binding of hydroxylated single-walled carbon nanotubes to two hemoproteins, hemoglobin and myoglobin

Herein, we studied the binding interactions between hydroxylated single-walled carbon nanotubes and hemoglobin and myoglobin by the use of multi-spectral techniques and molecular modeling. The ultraviolet–vis absorbance and circular dichroism spectral results indicated that the binding interactions existed between hydroxylated single-walled carbon nanotubes and hemoglobin/myoglobin. These binding interactions partially affected the soret/heme bands of hemoglobin and myoglobin. The secondary structures of hemoproteins were partially destroyed by hydroxylated single-walled carbon nanotubes. Fluorescence studies suggested that the complexes formed between hydroxylated single-walled carbon nanotubes and hemoglobin/myoglobin by hydrogen bonding, hydrophobic, and π–π stacking interactions. In addition, molecular modeling analysis well supported the experimental results.

Magnetic resonance imaging of metal artifact reduction sequences in the assessment of metal-on-metal hip prostheses

Magnetic resonance imaging of metal artifact reduction sequences in the assessment of metal-on-metal hip prostheses Sharief M Aboelmagd, Paul N Malcolm, Andoni P Toms Department of Radiology, Norfolk and Norwich University Hospital National Health Service Trust, Norwich, UK Abstract: Recent developments in metal artifact reduction techniques in magnetic resonance (MR) have, in large part, been stimulated by the advent of soft tissue complications associated with modern metal-on-metal total hip replacements. Metallic orthopedic implants can result in severe degradation of MR images because ferromagnetic susceptibility causes signal loss, signal pile-up, geometric distortion, and failure of fat suppression. There are several approaches to controlling these susceptibility artifacts. Standard fast spin echo sequences can be adapted by modifying echo times, matrix, receiver bandwidth, slice thickness, and echo trains to minimize frequency encoding misregistration. Short tau inversion recovery and 2-point Dixon techniques are both more resistant to susceptibility artifacts than spectral fat suppression. A number of dedicated metal artifact reduction sequences are now available commercially. The common approach of these multispectral techniques is to generate three dimensional datasets from which the final images are reconstructed. Frequency encoding misregistration is controlled using a variety of techniques, including specific resonant frequency acquisition, view-angle tilting, and phase encoding. Metal artifact reduction MR imaging has been the key to understanding the prevalence, severity, and prognosis of adverse reactions to metal debris in metal-on-metal hip replacements. Conventional radiographs are typically normal or demonstrate minimal change and are unable to demonstrate the often extensive soft tissue abnormalities, which include necrosis, soft tissue masses and fluid collections, myositis, muscle atrophy, tendon avulsions, and osteonecrosis. These MR findings correlate poorly with clinical and serological measures of disease, and therefore MR imaging is the principal tool for the diagnosis of soft tissue disease and surveillance in metal-on-metal hip replacements. Keywords: MRI, artifact, hip, arthroplasty, soft tissue

Generalized method for partial volume estimation and tissue segmentation in cerebral magnetic resonance images

An artifact found in magnetic resonance images (MRI) called partial volume averaging (PVA) has received much attention since accurate segmentation of cerebral anatomy and pathology is impeded by this artifact. Traditional neurological segmentation techniques rely on Gaussian mixture models to handle noise and PVA, or high-dimensional feature sets that exploit redundancy in multispectral datasets. Unfortunately, model-based techniques may not be optimal for images with non-Gaussian noise distributions and/or pathology, and multispectral techniques model probabilities instead of the partial volume (PV) fraction. For robust segmentation, a PV fraction estimation approach is developed for cerebral MRI that does not depend on predetermined intensity distribution models or multispectral scans. Instead, the PV fraction is estimated directly from each image using an adaptively defined global edge map constructed by exploiting a relationship between edge content and PVA. The final PVA map is used to segment anatomy and pathology with subvoxel accuracy. Validation on simulated and real, pathology-free T1 MRI (Gaussian noise), as well as pathological fluid attenuation inversion recovery MRI (non-Gaussian noise), demonstrate that the PV fraction is accurately estimated and the resultant segmentation is robust. Comparison to model-based methods further highlight the benefits of the current approach.

Multi-phase Characterization of Asphalt Concrete Using X-ray Microfluorescence

The objective of this study was to develop a microstructure characterization technique to capture the multi-phase nature of asphalt concrete using x-ray microfluorescence. This study examines the morphology and positions of aggregates, sand mastic and air void phases of asphalt concrete. Three different samples with targeted air void levels of 4%, 7%, and 10% were analyzed using an X-ray microscope. The cylindrical asphalt specimens were cut into slabs and then polished, and finally white zinc-oxide powder was pressed into the voids. The zinc-oxide powder helped to discern air voids from aggregate and mastic. After sample preparation, elemental maps were constructed using characteristic Kα x-rays from the following elements: aluminum, silicon, sulfur, chlorine, potassium, calcium, iron, zinc, and strontium. The relative intensities of pixels in the elemental maps were used to categorize pixels in each image according to sand mastic, air voids, and aggregate using multi-spectral analysis techniques. Air void contents in the three images (A, B and C) are correlated to those computed from the asphalt concrete. It was found that the air void contents in the three images (A, B) are highly correlated to those computed from the asphalt concrete. The images were utilized to calculate aggregate gradations and compared with the real gradation. It is concluded that the microstructure characterization technique to capture the multi-phase nature of asphalt concrete using x-ray microfluorescence was moderately successful.

A Multispectral Decomposition Technique for the Recovery of True SeaWiFS Top-of-Atmosphere Radiances

A method for correcting the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) out-of-band (OOB) effects in the Level-1B radiance data product through a multispectral decomposition transform (MDT) is described. The crosstalk information contained in multichannel spectral radiometer data provides the possibility of using the MDT technique to make the corrections. An MDT matrix for the SeaWiFS optical system is derived from the laboratory-measured filter transmittance functions. The OOB correction can be performed by a product between the SeaWiFS MDT matrix and a multispectral image vector. Performance of the SeaWiFS MDT method for the OOB correction is demonstrated by simulation results using hyperspectral data measured with both the AVIRIS and Hyperspectral Imager for the Coastal Ocean sensors. This OOB correction technique is very different from that currently implemented in the operational SeaWiFS data-processing software package.

Pigments and Mixtures Identification by Visible Reflectance Spectroscopy

Non-invasive techniques, as well assessed, are commonly used as preliminary investigations on the superficial constitutive materials of works of art.In particular, when the sampling on the artwork is not permitted, non-invasive techniques, such as Visible Reflectance Spectroscopy, can face successfully the problem of pigments’ identification and characterization.Nevertheless, the application of this diagnostic tool could be more difficult when pigments’ mixtures are present in the painting layer. Moreover, the various ratio possibilities among different pigments and the eventual yellowing due to the binder's decay could modify the spectral reflectance behaviour.In this study, about a hundred of standards of different pigments and mixtures have been realized using linseed stand-oil as binder, in order to simulate simple and complex pictorial layers. All the standards were analysed by Visible Reflectance Spectrometry, building up a specific database of reference spectrophotometric curves. Besides, every standard was analysed by XRF analysis and multispectral techniques to implement the database itself.In this paper an extract from the database and some case-studies, among the most interesting and complex ones, will be presented, highlighting the importance of an integrated use of different non-invasive techniques for the identification of pigments and mixtures.

Assessment of Liquid Saturations in Sand by Image Analysis

This research investigates the relationship between optical density and liquid saturations in unsaturated sand using multispectral image analysis technique. The tested liquids are water, diesel, and parafin liquid. The experiments are performed on two-fluid phase systems (water-air, diesel-air, and parafin liquid-air) and three-fluid phase systems (diesel-water-air and parafin liquid-water-air). Water is dyed with Brilliant Blue FCF, whereas diesel and parafin liquid are dyed with Red Sudan III. Using consumer-grade digital cameras, two images of sand specimens with various liquid saturations are taken with two different band-pass filters. The analysis results show that, for the sand and investigated fluids, the optical density defined for the reflected luminous intensity is a linear function of the degrees of fluid saturation for each spectral band and for any two- and three-fluid phase systems.