Long range active hyperspectral target identification using near-IR supercontinuum light source

This paper describes the optical analysis, construction, testing, and application of a cell for measuring in situ IR reflection spectra in the C-H stretching region of monolayer films of long-chain alkanethiolates on evaporated Au films beneath a thin overlayer (∼1 µm) of aqueous solution. The cell facilitates the interchange of sample (monolayer-coated) and reference substrates—a major improvement over previous designs. This allows the acquisition of an IR reflection spectrum of a monolayer without the application of electrochemical or polarization-modulation methods. The optical properties of the cell are analyzed within the context of classical electromagnetic theory; the effects of angle of incidence, solution layer thickness, and solution composition (H 2 O and D 2 O) and the refractive indices of the IR-transparent window material on the observed spectrum are specifically examined. Calculations of both the mean-square electric fields and the reflection spectra for a monolayer of octadecanethiolate on Au are presented. From these results, conditions to achieve high surface detectability are identified, and optically induced alterations in the intensities and shapes of the monolayer spectrum are delineated. Spectra for the same monolayer are measured to test these predictions as well as to assess the practical limitations of the experimental technique.

The development of reliable, cost effective and high accuracy instrument to mass flow rate measurement is becoming increasingly important in many industries. Appropriate measurement method and design leads to improvement of pneumatic conveyors operation and process efficiency. This paper present an instrument design based on passive charge detection using a single electrostatic sensor. A time domain signal processing algorithm is developed to measurement of mass flow rate from acquired electrical charge signal. The findings is led to a low cost and high accuracy design, the experimental test results of the design shows less than ±5% error between measured mass flow rate and reference reading acquired from the manual weighing.

Phosphate detection in water samples is still completed using colorimetric standard methods, which have a number of disadvantages, to such as being time consuming, requiring filtration, a number of different reagents, frequent calibration and proper disposal of waste chemicals generated. Hence, a simple cost effective analytical method and instrumentation is highly desirable to aid the optimisation of treatment processes and assist the water industry in their efforts to comply with stringent regulations such as the EU's Water Framework Directive. A sensor based on molecular imprinted polymer (MIP) and a conductance transducer was developed for direct and label-free detection of phosphate in water. The sensor was able to measure the presence of phosphate in wastewater samples with good reproducibility, a linear range of 0.66-8 mg P L(-1) and a lower detection limit of 0.16 mg P L(-1). The sensor was further tested to measure phosphate concentrations in unfiltered field samples such as domestic wastewater treatment influent and river water and demonstrated a close correlation with reference measurements. The phosphate MIP sensor offers a way forward as either a handheld sensor for use in the field, or as a potential solution for remote, continuous monitoring of phosphate.

Background: Risk stratification in early-stage breast cancer patients still remains a clinical challenge. It is well known that expression of ER/ PR, HER2 and Ki-67 are valuable prognostic and predictive markers. According to the commonly used St. Gallen classification (2013), breast cancer treatment decisions can be based on four different subtypes (Luminal A-like, Luminal B-like [HER2+/-], HER2 + [non-luminal] and Basal-like). Immunohistochemistry is predominantly used to determine the receptor status, although semi-quantitative analysis shows significant inter-observer variability. Several quantitative gene expression tests – such as Oncotype DX© and EndoPredict© – are available as diagnostic tools but their use is often limited due to financial considerations. MammaTyper© has been shown to be a precise and reproducible biomarker determination tool to investigate the expression of ER/ PR, HER2 and Ki-67 and may prove to be a cost efficient quantitative diagnostic tool. Methods: This study tested ESR-1, PGR, MKI67 and ERBB2 mRNA-levels by RT-qPCR in 100 FFPT-samples using MammaTyper© kit. The test identified breast cancer subgroups according to St. Gallen classification. RT-qPCR results were correlated to IHC-test results via χ2-Test and to risk groups of Oncotype DX©- (n=55) and EndoPredict©-testing (n=45). Oncotype©-Recurrence Score levels were separated into low (RS <18), intermediate (RS 18-30) and high risk (RS ≥ 31). EndoPredict© EPScore© and EPclin Risk Score© cut off levels defining high and low risk levels were 7.0, respectively 3.3. Linear regression model was performed investigating the prediction of EPscore© and Recurrence Score© via MammaTyper© mRNA-results. Results: IHC-testing resulted in 43 Luminal A-like samples (43%) and 57 Luminal B-like [HER2 negative] (57%) tumors. MammaTyper ©-based classification showed significant correlation to IHC-based classification (χ2=12,68; p=0,005). EndoPredict©-data showed low-risk levels in 36 patients (80%) and high-risk status in 9 cases (20%). Correlation to mRNA-based St. Gallen-subtypes approved significance (χ2=17,32, p<0,001). In linear regression model only MKI67-mRNA showed independent correlation to EPScore© (p<0,001; R2 0,290) A total of 34 patients (61,8%) showed low risk, 13 (26,3%) intermediate risk (RS 18-30) and 8 (14,5%) high-risk recurrence score levels (RS≥31) in OncotypeDX©. MammaTyper© results correlated to OncotypeDX© risk-levels (χ2=27,98; p<0,001). In linear regression model mRNA-levels of ESR-1, PGR and MKI67 were significant predictors of OncotypeDX© RS (p-values: p=0,003, p<0,001, p=0,033, R2= 0,602) Conclusion: This study shows mRNA-testing is a valid marker to identify breast cancer subtypes. Additionally, MammaTyper© results are significantly correlated to Oncotype DX©- and EndoPredict©-results, indicating it might be an efficient as well as cost effective diagnostic instrument. However a large prospective multicenter study should be performed to prove its diagnostic validity in predicting the most appropriate and effective treatment in early-stage breast cancer. Citation Format: Eckhoff K, Pokorny J, Baumann K, Perner S, Pursche T, Rody A. MammaTyper© – An in vitro quantitative local gene expression test as a predictor of OncotypeDX©- and EndoPredict©-results [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-08-34.

In order to measure frequency responses of O/ E conversion devices such as photodiodes (PDs), we developed a measurement instrument named lightwave frequency response analyzer (LFRA). LFRA, which is based on a heterodyne technique utilizing an optical modulator, provides precise measurement solution with cost effective instrument. Measured results of two individual LFRAs show standard deviations less than 0.15 dB and maximum instrument difference less than 0.7 dB.

Vicarious calibration of airborne hyperspectral sensors in operational environments

Using the method of Fourier spectroscopy, the IR absorption and reflection spectra were obtained in the frequency region 240 divided by 5000 cm-1 for different types of high- purity silica glasses (v-Sao2), containing from 0.1 to 103 ppm of the hydroxyl groups OH. The analysis of the positions of both the fundamental structural band (v approximately 1120 cm-1) monitored in IR reflection mode and an overtone of this band (v approximately 2260 cm-1) monitored in IR transmission mode was carried out for various as-received silica glasses and their fictive temperatures were determined. On the basis of the classical dispersion analysis the absorption band parameters and the spectra of optical constants ((epsilon) ', (epsilon) '', n and k) were calculated for vitreous Sao2.© (2000) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

In this paper, we investigated high-resolution IR absorption and reflection spectra in one-sided periodical 2D macroporous silicon structures with nano-coatings of SiO2 and CdS, ZnO nanoparticles, as well as two-sided structures of macroporous silicon without nano-coatings. After changing the resolution of spectra measurements from 2 to 1 cm–1, the oscillation period of Wannier-Stark electro-optical effect decreases by 3 times, and absorption increases by 60–100 times; and for two-sided structures the oscillation period decreases by 1.5 times and absorption increases by 25–30 %. In addition, giant absorption oscillations with positive and negative amplitudes of 107 arb. un. were evaluated in spectral regions of Si–Si–bonds and Pb centers. Similar oscillations in the reflection spectra have much less amplitudes up to 4·104 arb. un. In the spectral area of the transverse phonon ωTO (Si–Si–bonds) absorption spectra of 2D macroporous silicon structures consistent fully with data for phonon polaritons in microresonators as a result of resonance interaction of dipole-active vibrations with the frequency of ωTO in thin films with the surface modes of microresonator. In addition, microresonators interact both with each other in one-sided macroporous silicon structures and in the system of two-sided macroporous silicon. The giant absorption oscillations testify the strong interaction of surface polaritons with photons. The coherence of oscillations and large-scale spatial correlation are а result of exciton-polariton condensation on macropores as microresonators. In 2D macroporous silicon structures with nano-coatings band bending on the surface of the macropores are significant. Therefore, the generated photoelectrons link with holes, forming electron-hole pairs named as exciton-polaritons according to phenomenon of Bose-Einstein condensation.

We have considered an optical model of a porous rough surface with optical properties of objects (bone, flint) that are typical of archeology and paleontology. We have formulated an approach that makes it possible to perform mathematical processing of the IR reflection spectra of objects of this kind using standard algorithms and determine criteria that ensure obtaining reliable information on objects with a rough surface in the course of interpretation of frequencies in their IR reflection spectra. The potential of the approach has been demonstrated using as an example an investigation by the IR Fourier-transform reflection spectroscopy of mineralization processes of mammoth tusks from two paleolithic sites (14000 and 16000 BCE) located by the town of Yudinovo, Bryansk oblast, Russia.

Measurement of cutaneous microcirculation is of great importance for clinical evaluations as many biological processes (i.e. inflammation) activate superficial vessels. Diffuse Reflectance Spectroscopy (DRS) is a widely used method to assess cutaneous microcirculation since it is based on the spectral characteristics of skin chromophores, particularly the strong absorption bands of blood in the visible spectral range. However, the DRS system only provides a snapshot of the blood content in tissue from the reflectance detected at a single exposure time, and it fails to demonstrate dynamic changes of blood flow inside the tissues. In the present study, a prototype system for functional DRS (fDRS) has been developed for the sequential acquisition of multiple reflectance spectra in the visible range at sub-second intervals. Twelve healthy subjects with skin phototype I-III were recruited for a UV skin phototest where the subject's back was exposed to an increasing dose of solar-simulated radiation at a maximum of 3 minimum erythema dose (MED). Evaluations included conventional DRS, functional DRS, and a laser Doppler flowmeter/imaging system. In a frequency analysis results, there were two distinctive frequency components. A low-frequency component was found near 0.03-0.1 Hz, and another high-frequency component near 0.9-1.2 Hz which is synchronous with heart pulsations. The magnitude of the high-frequency and the steady-state components of the fDRS signal increased with increase in exposure dose. These results demonstrate the potential of this technique for noninvasive assessment of cutaneous microcirculation.

An expansion of the capabilities of high-speed, multichannel spectroscopic ellipsometry (SE) is described that involves simultaneous measurement of the reflectance spectrum along with the two spectra in the ellipsometric angles (ψ, Δ). Previously, a novel rotating-polarizer spectroscopic ellipsometer has been perfected that employs a photodiode array detector for high-speed acquisition of (ψ, Δ) spectra, designed for real-time studies of thin-film growth. For a polarizer angular rotation frequency of ω0, the (ψ, Δ) values at a given photon energy are deduced from the 2ω0 Fourier components of the detector irradiance, normalized by the dc component. A third parameter, the weighted reflectance RA, can be obtained from the dc component and from a calibration based on the known optical properties of the substrate measured prior to film growth. With (ω0/2π)=12.5 Hz, three-parameter data sets, [ψ(hν), Δ(hν), RA(hν); 1.5≤hν≤4.5 eV], can be acquired with a time resolution as short as 40 ms. Although RA provides complementary information to (ψ, Δ), it has yet to be exploited in conjunction with real-time SE until this study. A resilient analysis approach, based on mathematical inversion and least-squares fitting of the real-time three-parameter data sets, is designed to yield the film dielectric functions and thicknesses independently at each time during the early stages of thin-film growth. The three-parameter approach has been applied successfully in studies of amorphous silicon (a-Si:H) thin films prepared by plasma-enhanced chemical vapor deposition, and aluminum and silver films prepared by physical vapor deposition. For the a-Si:H films, RA(hν) exhibits deviations as large as ∼3% from that predicted in modeling (ψ, Δ) alone. The deviations result from light scattering by plasma particulates, and we show how additional information can be extracted from the spectral dependence of the scattering loss.

Vis-NIR spectroscopy based rapid and non-destructive method to quantitate microplastics: An emerging contaminant in farm soil

We present novel optical system capable for fast acquisition of two-dimensional distribution of reflection spectra with high spatial resolution. It is based on a subspace vector model of surface reflections. The system consists of a computer controlled set of light-emitting diodes (LED) and a monochrome CCD camera. Spatial distribution of reflection spectra is acquired in the compressed form. These compressed data can be directly used for accurate classification or recognition of different parts of the surface under study. We demonstrated experimentally that 2D distribution of spectral reflectance from the object surface can be captured within 140ms. Such a fast instrument of multispectral imaging could be extremely useful particularly for researchers who study living biological objects.

Analysis of Probe-1 hyperspectral data obtained during July 1998 revealed that neither the spectroscopic nor the radiometric laboratory calibrations supplied with the data were applicable, presumably because the sensor had suffered an undocumented opto-mechanical realignment between the calibration and the flight. In this paper the calculation of a new set of calibration coefficients is described, based upon the simultaneous acquisition of high-resolution GER3700 field spectra for a calibration site within the Probe-1 image. For the calibration calculations, an average ground-based reflectance spectrum for the target area was convolved and resampled to match the spectral characteristics of the Probe-1 sensor. The MODTRAN3 radiative-transfer code was used to correct the Probe-1 radiance spectra to surface reflectance, and an iterative numerical technique was applied to adjust the Probe-1 radiometric coefficients, to reduce the absolute reflectance difference between the GER3700 and Probe-1 spectra for the calibration site to 0.02 percent. This technique for the vicarious calibration of hyperspectral data has been implemented into the Imaging Spectrometer and Data Analysis System developed at the Canada Centre for Remote Sensing (CCRS).

Polarization-selected IR transmission, IR reflection, and IR absorption spectra of arrays of V-shaped gold structures are experimentally studied for various structure periods. To form a local region of the enhanced electromagnetic field in subwavelength nanogaps, arrays with unit cells consisting of two V-shaped structures, facing each other by acute angles with gaps of 0, 50, 100 nm were also used. The results of comparison of spectral data with measurements of dimensional parameters using atomic-force microscopy and scanning electron microscopy are presented. The possibility of using the fabricated structures to achieve the effect of surface-enhanced IR absorption by quantum dots is shown.