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hyperspectral imaging

Jonathan Douissard, Frederic Ris, Philippe Morel, Nicolas Christian Buchs
Iatrogenic ureteral injuries are a source of major concern among surgeons performing colorectal procedures. Although they are uncommon, these lesions lead to severe morbidity and long-term functional disabilities, as well as an increase in mortality, hospital stay, and cost. The laparoscopic approach has gained popularity in the field of colorectal surgery and is associated with improved global postoperative outcomes. However, it is also considered to increase the risk of ureteral injury when compared to open surgery, especially during left colonic and rectal resections...
June 1, 2018: Surgical Technology International
Sanaz Jarolmasjed, Lav R Khot, Sindhuja Sankaran
Bitter pit is one of the most important disorders in apples. Some of the fresh market apple varieties are susceptible to bitter pit disorder. In this study, visible⁻near-infrared spectrometry-based reflectance spectral data (350⁻2500 nm) were acquired from 2014, 2015 and 2016 harvest produce after 63 days of storage at 5 °C. Selected spectral features from 2014 season were used to classify the healthy and bitter pit samples from three years. In addition, these spectral features were also validated using hyperspectral imagery data collected on 2016 harvest produce after storage in a commercial storage facility for 5 months...
May 15, 2018: Sensors
Camille Scotté, Hilton B de Aguiar, Didier Marguet, Ellen Marie Green, Pascaline Bouzy, Sébastien Vergnole, Charles Peter Winlove, Nicholas Stone, Herve Rigneault
We experimentally implement a compressive Raman technology (CRT) that incorporates chemometric analysis directly into the spectrometer hardware by means of a digital micromirror device (DMD). The DMD is a programmable optical filter on which optimized binary filters are displayed. The latter are generated with an algorithm based on the Cramer-Rao lower bound. We com-pared the developed CRT microspectrometer with two conventional state-of-the-art Raman hyperspectral imaging systems on samples mimicking microcalcifications relevant for breast cancer diagnosis...
May 15, 2018: Analytical Chemistry
Huda Asfour, Shuyue Guan, Narine Muselimyan, Luther Swift, Murray Loew, Narine Sarvazyan
In vivo autofluorescence hyperspectral imaging of moving objects can be challenging due to motion artifacts and to the limited amount of acquired photons. To address both limitations, we selectively reduced the number of spectral bands while maintaining accurate target identification. Several downsampling approaches were applied to data obtained from the atrial tissue of adult pigs with sites of radiofrequency ablation lesions. Standard image qualifiers such as the mean square error, the peak signal-to-noise ratio, the structural similarity index map, and an accuracy index of lesion component images were used to quantify the effects of spectral binning, an increased spectral distance between individual bands, as well as random combinations of spectral bands...
May 1, 2018: Biomedical Optics Express
Stefano Fornasaro, Annalisa Vicario, Luigina De Leo, Alois Bonifacio, Tarcisio Not, Valter Sergo
Raman hyperspectral imaging is an emerging practice in biological and biomedical research for label free analysis of tissues and cells. Using this method, both spatial distribution and spectral information of analyzed samples can be obtained. The current study reports the first Raman microspectroscopic characterisation of colon tissues from patients with Coeliac Disease (CD). The aim was to assess if Raman imaging coupled with hyperspectral multivariate image analysis is capable of detecting the alterations in the biochemical composition of intestinal tissues associated with CD...
May 14, 2018: Integrative Biology: Quantitative Biosciences From Nano to Macro
Teemu Hakala, Lauri Markelin, Eija Honkavaara, Barry Scott, Theo Theocharous, Olli Nevalainen, Roope Näsi, Juha Suomalainen, Niko Viljanen, Claire Greenwell, Nigel Fox
Drone-based remote sensing has evolved rapidly in recent years. Miniaturized hyperspectral imaging sensors are becoming more common as they provide more abundant information of the object compared to traditional cameras. Reflectance is a physically defined object property and therefore often preferred output of the remote sensing data capture to be used in the further processes. Absolute calibration of the sensor provides a possibility for physical modelling of the imaging process and enables efficient procedures for reflectance correction...
May 3, 2018: Sensors
Eric Larry Wisotzky, Florian Cornelius Uecker, Philipp Arens, Steffen Dommerich, Anna Hilsmann, Peter Eisert
We address the automatic differentiation of human tissue using multispectral imaging with promising potential for automatic visualization during surgery. Currently, tissue types have to be continuously differentiated based on the surgeon's knowledge only. Further, automatic methods based on optical in vivo properties of human tissue do not yet exist, as these properties have not been sufficiently examined. To overcome this, we developed a hyperspectral camera setup to monitor the different optical behavior of tissue types in vivo...
May 2018: Journal of Biomedical Optics
Georg Daeschlein, Rico Rutkowski, Stine Lutze, Sebastian von Podewils, Claudia Sicher, Thomas Wild, Hans-Robert Metelmann, Thomas von Woedkte, Michael Jünger
An important clinical potential of cold atmospheric plasma (CAP) lies in tumor and wound treatment, whereby the last-mentioned is well-referenced already. However, the underlying mechanisms of improved wound healing have not been sufficiently clarified yet, in particular the influence of CAP on microcirculation. Hyperspectral imaging (HSI) enables the visualization of microcirculation of large tissue areas, thus this technique seems to be a candidate to examine CAP effects on perfusion and oxygen saturation in wounds...
May 4, 2018: Biomedizinische Technik. Biomedical Engineering
Chang Chun Li, Peng Chen, Guo Zheng Lu, Chun Yan Ma, Xiao Xiao Ma, Shuang Ting Wang
Nitrogen balance index (NBI) is one of the important indicators for crop growth. The high and low status of nitrogen can be quickly monitored by measuring NBI, which can provide accurate information of agricultural production and management. The relationship between NBI and original spectrum and derivative spectrum of infrared and near infrared wavelength from flowering to maturity stage was analyzed based on high definition digital image and hyperspectral data on unmanned aerial vehicles. Then, the sensitive bands were selected and the vegetation indexes were calculated...
April 2018: Ying Yong Sheng Tai Xue Bao, the Journal of Applied Ecology
Rayko I Stantchev, Jessica C Mansfield, Ryan S Edginton, Peter Hobson, Francesca Palombo, Euan Hendry
Terahertz-spectroscopy probes dynamics and spectral response of collective vibrational modes in condensed phase, which can yield insight into composition and topology. However, due to the long wavelengths employed (λ = 300 μm at 1THz), diffraction limited imaging is typically restricted to spatial resolutions around a millimeter. Here, we demonstrate a new form of subwavelength hyperspectral, polarization-resolved THz imaging which employs an optical pattern projected onto a 6 μm-thin silicon wafer to achieve near-field modulation of a co-incident THz pulse...
May 2, 2018: Scientific Reports
Hoonsoo Lee, Moon S Kim, Santosh Lohumi, Byoung-Kwan Cho
Extensive research has been conducted on non-destructive and rapid detection of melamine in powdered foods in the last decade. While Raman and near-infrared (NIR) hyperspectral imaging techniques have been successful in terms of non-destructive and rapid measurement, they have limitations with respect to measurement time and detection capability, respectively. Therefore, the objective of this study was to develop a mercury cadmium telluride (MCT)-based short wave infrared (SWIR) hyperspectral imaging system and algorithm to detect melamine quantitatively in milk powder...
May 2, 2018: Food Additives & Contaminants. Part A, Chemistry, Analysis, Control, Exposure & Risk Assessment
Raul O Freitas, Christoph Deneke, Francisco C B Maia, Helton G Medeiros, Thierry Moreno, Paul Dumas, Yves Petroff, Harry Westfahl
Synchrotron infrared nanospectroscopy is a recently developed technique that enables new possibilities in the broadband chemical analysis of materials in the nanoscale, far beyond the diffraction limit in this frequency domain. Synchrotron infrared ports have exploited mainly the high brightness advantage provided by electron storage rings across the whole infrared range. However, optical aberrations in the beam produced by the source depth of bending magnet emission at large angles prevent infrared nanospectroscopy to reach its maximum capability...
April 30, 2018: Optics Express
Jun Zhao, Wenxi Cao, Zhantang Xu, Haibin Ye, Yuezhong Yang, Guifen Wang, Wen Zhou, Zhaohua Sun
An empirical algorithm is proposed to estimate suspended particulate matter (SPM) ranging from 0.675 to 25.7 mg L-1 in the turbid Pearl River estuary (PRE). Comparisons between model predicted and in situ measured SPM resulted in R2 s of 0.97 and 0.88 and mean absolute percentage errors (MAPEs) of 23.96% and 29.69% by using the calibration and validation data sets, respectively. The developed algorithm demonstrated the highest accuracy when compared with existing ones for turbid coastal waters. The diurnal dynamics of SPM was revealed by applying the proposed algorithm to reflectance data collected by a moored buoy in the PRE...
April 16, 2018: Optics Express
James Grant, Mitchell Kenney, Yash D Shah, Ivonne Escorcia-Carranza, David R S Cumming
We experimentally demonstrate a CMOS compatible medium wave infrared metal-insulator-metal (MIM) metamaterial absorber structure where for a single dielectric spacer thickness at least 93% absorption is attained for 10 separate bands centred at 3.08, 3.30, 3.53, 3.78, 4.14, 4.40, 4.72, 4.94, 5.33, 5.60 μm. Previous hyperspectral MIM metamaterial absorber designs required that the thickness of the dielectric spacer layer be adjusted in order to attain selective unity absorption across the band of interest thereby increasing complexity and cost...
April 16, 2018: Optics Express
Yang Ou, Bin Zhang, Ke Yin, Zhongjie Xu, Shengping Chen, Jing Hou
A new novel method, hyperspectral imaging (HSI), is presented in this work to measure the beam divergence angle and beam profile uniformity of supercontinuum lasers. The obtained results of divergence angles are consistent with theoretically calculated values. The uniformity of different-size projected Gaussian beams was measured through referencing the data sets provided by HSI camera under the wavelength variation. HSI, compared with traditional methods, is much faster and capable of providing critical reference to supercontinuum output parameters measurements and practical application in far-field situation...
April 16, 2018: Optics Express
Chunguang Zhang, Hao Wang, Zhonghua Zhang, Jiangwei Yuan, Lei Shi, Zhenfei Sheng, Xiaofa Zhang
A method of spectral resolution improvement was presented based on the double filtering in a single AOTF. A special narrowband hyperspectral imaging system using this single-AOTF double-filtering method was established. The spectral bandwidth of double-filtered spectra was 39% narrower than that of the single-filtered optical signal experimentally. We achieved hyperspectral images of the resolution target with better image resolutions than the single-filtering images because of the improved spectral resolution after the double-filtering process...
May 1, 2018: Optics Letters
Cong Ba, Jean-Marc Tsang, Jerome Mertz
Hyperspectral imaging in scattering tissue generally suffers from low light collection efficiency. In this Letter, we propose a microscope based on Fourier transform spectroscopy and oblique back-illumination microscopy that provides hyperspectral phase and amplitude images of thick, scattering samples with high throughput. Images can be acquired at >0.1  Hz rates with spectral resolution better than 200  cm-1 , over a wide spectral range of 450-1700 nm. Proof-of-principle demonstrations are presented with chorioallantoic membrane of a chick embryo, illustrating the possibility of high-resolution hemodynamics imaging in thick tissue, based on transmission contrast...
May 1, 2018: Optics Letters
Øyvind Ødegård, Aksel Alstad Mogstad, Geir Johnsen, Asgeir J Sørensen, Martin Ludvigsen
By applying an underwater hyperspectral imager (UHI) to a selection of archaeological artifacts, we have found spectral signatures that are representative of materials likely to be present at wreck sites. By successfully using the signatures to classify a subset of said artifacts placed on the seabed at 61 m depth, we demonstrate that it is possible to detect archaeological objects of interest in UHI data acquired by a remotely operated vehicle. Correct UHI classification of rust and glass bottles in situ on a historical wreck site further supports the viability of the method for marine archaeological applications...
April 20, 2018: Applied Optics
Jueqin Qiu, Haisong Xu, Zhengnan Ye, Changyu Diao
Metamer mismatching is a phenomenon where two objects that are colorimetrically indistinguishable under one lighting condition become distinguishable under another one. Due to the unavailability of spectral information, metamer mismatching introduces an inherent uncertainty into cameras' color reproduction. To investigate the degree of image quality degradation by the metamer mismatching, a large spectral reflectance database was compiled in this study to search the object-color metamers sets of the spectra in hyperspectral images...
April 10, 2018: Applied Optics
Santosh Lohumi, Hoonsoo Lee, Moon S Kim, Jianwei Qin, Lalit Mohan Kandpal, Hyungjin Bae, Anisur Rahman, Byoung-Kwan Cho
The potential adulteration of foodstuffs has led to increasing concern regarding food safety and security, in particular for powdered food products where cheap ground materials or hazardous chemicals can be added to increase the quantity of powder or to obtain the desired aesthetic quality. Due to the resulting potential health threat to consumers, the development of a fast, label-free, and non-invasive technique for the detection of adulteration over a wide range of food products is necessary. We therefore report the development of a rapid Raman hyperspectral imaging technique for the detection of food adulteration and for authenticity analysis...
2018: PloS One
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