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The Monte Carlo Ray-Trace Method in Radiation Heat Transfer and Applied Optics || Extension of the MCRT Method to Non-Diffuse, Non-Gray Enclosures
摘要： The assumption of diffuse emission and diffuse-specular reflection in gray enclosures is adequate for many applications encountered in engineering practice. This is especially true in the conceptual and preliminary design stages. However, final design and performance studies often require the use of bidirectional surface optical models restricted to a specified wavelength interval. In this chapter we develop the concept of the band-averaged spectral radiation distribution factor, which is the most general tool available for treating radiant exchange among surfaces, but first we learn through extended examples how to compose and use models to simulate the optical behavior of non-diffuse surfaces.
关键词： Monte Carlo Ray-Trace Method,Non-Gray Enclosures,Radiation Heat Transfer,Applied Optics,Bidirectional Spectral Surfaces,Non-Diffuse
更新于2025-09-04 15:30:14
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The Effective Conjugation Length is Responsible for the Red/Green Spectral Tuning in the Cyanobacteriochrome Slr1393g3
摘要： The origin of the spectral shift from a red- to a green-absorbing form in a cyanobacteriochrome, Slr1393g3, is identified by application of combined quantum mechanics/molecular mechanics simulations. This protein, related to classical phytochromes, carries the open-chain tetrapyrrole chromophore phycocyanobilin. Our calculations reveal that the effective conjugation length in the chromophore becomes shorter upon conversion from the red to the green form. This is related to the planarity of the entire chromophore. A large distortion is found for the terminal pyrrole rings A and D, however, the D ring contributes stronger to the photoproduct tuning, despite a larger change in the twist of the A ring. Our findings implicate that the D ring twist can be exploited to regulate absorption of the photoproduct. Hence, mutations that affect the D ring twist can lead to rational tuning of the photoproduct absorption that allows tailoring of cyanobacteriochromes for biotechnological applications such as optogenetics and bioimaging.
关键词： Chromophore,Cyanobacteriochrome,Tetrapyrrole,Spectral Tuning,Hybrid QM/MM
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Fuzzy Fusion of Change Vector Analysis and Spectral Angle Mapper for Hyperspectral Change Detection
摘要： Change Vector Analysis (CVA) is one of the most widely used approaches for change detection in multispectral and hyperspectral images. Although, in CVA, the spectral change vector (CV) comprises the angle as well as the magnitude of the change, typically only the magnitude measure is used as change criterion. On the other hand, the spectral angle mapper (SAM) uses only the angle measure as criterion for change detection. It is envisaged that combining the angle and magnitude for change detection (i.e. combining SAM and magnitude CVA) can improve the change detection performance, yet only a limited number of approaches have been proposed in the literature so far. This paper presents a novel fuzzy inference combination strategy that combines the angle and magnitude distances, referred to as Fuzzy CVA (FuzCVA), and is shown that the proposed approach can provide improved change detection performance by effectively combining magnitude and angle measures.
关键词： Hyperspectral Imaging,change detection,spectral angle mapper,fuzzy inference,change vector analysis
更新于2025-09-04 15:30:14
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Alteration Minerals Mapping Using MTMF and CEM Based on ASTER in Zedang Orefield of Tibet, China
摘要： Zedang copper polymetallic ore field, including several middle and large skarn-porphyry deposits for large metallogenic scale and special mineralized combination, locates in south rim of Eastern of Gangdise mountains in Tibet. Using the ASTER imagery and MTMF and CEM methods and field sample spectra, the alteration minerals of the Zedang ore field were mapped. From measuring the spectral of rock and mineral using SVC portable spectrograph, it derived consequence of exists some main alteration minerals. According to alteration minerals spectral feature, distribution map of alteration minerals is displayed using MTMF and CEM algorithm. Through compare analysis, it is considered that the CEM approach can suppress the background and extract more accuracy minerals than MTMF method in the high topographic relief area. The result is very important meaning for mineral prospecting.
关键词： Mineral Exploration,Zedang Orefield,Spectral Feature,Alteration Minerals,ASTER
更新于2025-09-04 15:30:14
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Spectral-Domain Optical Coherence Tomography Features in Open-Angle Glaucoma With Diabetes Mellitus and Inadequate Glycemic Control
摘要： PURPOSE. To evaluate spectral-domain optical coherence tomography (SD-OCT) features according to glycemic control status in open-angle glaucoma with diabetes mellitus. METHODS. Subjects underwent comprehensive ocular examination, visual ?eld testing, and SD-OCT imaging (Cirrus HD-OCT). The relationship between glycosylated hemoglobin (HbA1c) and OCT measurements was compared between diabetic nonglaucomatous eyes and diabetic glaucomatous eyes. Glaucoma-discriminating ability was assessed using the area under the receiver operating characteristic curves (AUCs) for OCT parameters and compared between groups relative to the glycemic control group. RESULTS. Analysis was performed on 69 nonglaucomatous and 87 glaucomatous eyes in the nondiabetic group, and on 72 nonglaucomatous and 56 glaucomatous eyes in the diabetic group. Average, inferonasal, inferior, and inferotemporal ganglion cell–inner plexiform layer (GCIPL) thicknesses were positively correlated with HbA1c in diabetic nonglaucomatous eyes (P ? 0.040, 0.037, 0.025, and 0.013, respectively). The AUC of the average cup-to-disc area ratio (CDR), vertical CDR, and cup volume in diabetic eyes with poor glycemic control was signi?cantly higher than those in nondiabetic eyes (P ? 0.011, 0.003, and 0.043, respectively). The AUC of cube volume, cube average thickness, and minimal GCIPL thickness in diabetic eyes with poor glycemic control was lower than those in nondiabetic eyes (P ? 0.006, 0.007, and 0.004, respectively). CONCLUSIONS. In this study, optic nerve head parameters had a superior ability to discriminate glaucoma in diabetic eyes with poor glycemic control. Conversely, the ability to discriminate glaucoma using macular parameters tended to be lower for diabetic eyes with inadequate glycemic control.
关键词： spectral-domain optical coherence tomography,diabetes mellitus,ganglion cell-inner plexiform layer,glaucoma
更新于2025-09-04 15:30:14
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Comprehensive Three-Dimensional Analysis of the Neuroretinal Rim in Glaucoma Using High-Density Spectral-Domain Optical Coherence Tomography Volume Scans
摘要： To describe spectral-domain optical coherence tomography (OCT) methods for quantifying neuroretinal rim tissue in glaucoma and to compare these methods to the traditional retinal nerve fiber layer thickness diagnostic parameter. Neuroretinal rim parameters derived from three-dimensional (3D) volume scans were compared with the two-dimensional (2D) Spectralis retinal nerve fiber layer (RNFL) thickness scans for diagnostic capability. This study analyzed one eye per patient of 104 glaucoma patients and 58 healthy subjects. The shortest distances between the cup surface and the OCT-based disc margin were automatically calculated to determine the thickness and area of the minimum distance band (MDB) neuroretinal rim parameter. Traditional 150-lm reference surface–based rim parameters (volume, area, and thickness) were also calculated. The diagnostic capabilities of these five parameters were compared with RNFL thickness using the area under the receiver operating characteristic (AUROC) curves. The MDB thickness had significantly higher diagnostic capability than the RNFL thickness in the nasal (0.913 vs. 0.818, P ? 0.004) and temporal (0.922 vs. 0.858, P ? 0.026) quadrants and the inferonasal (0.950 vs. 0.897, P ? 0.011) and superonasal (0.933 vs. 0.868, P ? 0.012) sectors. The MDB area and the three neuroretinal rim parameters based on the 150-lm reference surface had diagnostic capabilities similar to RNFL thickness. The 3D MDB thickness had a high diagnostic capability for glaucoma and may be of significant clinical utility. It had higher diagnostic capability than the RNFL thickness in the nasal and temporal quadrants and the inferonasal and superonasal sectors.
关键词： neuroretinal rim,spectral-domain optical coherence tomography,glaucoma,optic disc,optic nerve
更新于2025-09-04 15:30:14
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Correlation between optic nerve head structural parameters and glaucomatous visual field indices
摘要： We examined associations between optic nerve head structural parameters and glaucomatous visual field indices. The study population included patients with glaucomatous optic neuropathy who were evaluated at Aichi Medical University, Nagakute, Aichi, Japan, from October 2010 to January 2011. A total of 57 eyes from 33 patients were assessed. We measured visual field using a Humphrey field analyzer, peripapillary retinal nerve fiber layer thickness (RNFL-T), and Bruch’s membrane opening-minimum rim width (BMO-MRW) using spectral domain optical coherence tomography, and rim area with referring three-dimensional photography. Spearman’s rank correlation coefficients were calculated between the threshold of visual sensitivity or total deviation of visual field and the following five optic nerve head structural parameters: RNFL-T length, BMO-MRW length, rim area, and calculated RNFL-T and BMO-MRW volumes (each length multiplied by rim area). The Akaike information criterion was calculated to determine which structural parameter was the best predictor of each visual field index. Threshold of visual sensitivity had correlation coefficients of 0.23 with global sector of RNFL-T, 0.32 with BMO-MRW, 0.14 with rim area, 0.21 with RNFL-T volume, and 0.26 with BMO-MRW volume. The correlation coefficients for each parameter with total deviation of visual field were 0.22, 0.33, 0.28, 0.36, and 0.37, respectively. The Akaike information criterion of BMO-MRW showed the smallest values in analyses of both threshold of visual sensitivity and total deviation. The present results show that RNFL-T volume and BMO-MRW volume were more strongly correlated with total deviation than BMO-MRW, but BMO-MRW appeared to be the best predictor of the two glaucomatous visual field indices.
关键词： retinal nerve fiber layer thickness,rim area,visual field,glaucoma,spectral domain optical coherence tomography,Bruch’s membrane opening-minimum rim width
更新于2025-09-04 15:30:14
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Sugar Contents and Firmness of Apples Based on Multi-Spectral Imaging Technology
摘要： The paper proposed a prediction method of apple sugar content and firmness based on multi-spectral imaging. Firstly, four characteristic wavelengths (670, 750, 780 and 810 nm) were selected by correlation coefficient method. The gray images of samples at different wavelengths were collected by multi-spectral imaging system, then fitted with Lorenz function, modified Lorenz function, Gaussian function and polynomial function, respectively. It was found that the fitting effect of modified Lorenz function was best. Therefore, the experiment was performed by multiple linear regression and partial least square regression analysis of sugar content and firmness with the fitting parameters of modified Lorenz function. The result showed that the prediction of multiple linear regression model was better than partial least squares regression model. The modeling correction correlation coefficient, calibration standard deviation, the prediction correlation coefficient and predicted standard deviation of sugar content were 0.8568, 0.6736, 0.8395 and 0.7068, respectively. The modeling correction correlation coefficient, calibration standard deviation, the prediction correlation coefficient and the predicted standard deviation of firmness were 0.8660, 0.3275, 0.8407 and 0.3555, respectively. The results also showed that this method was feasible for the prediction of apple sugar content and firmness.
关键词： Firmness,Multi-spectral imaging,Curve fitting,Apple,Multiple linear regression,Sugar content
更新于2025-09-04 15:30:14
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Smithsonian Astrophysical Observatory Ozone Mapping and Profiler Suite (SAO OMPS) formaldehyde retrieval
摘要： This paper presents our new formaldehyde (H2CO) retrievals, obtained from spectra recorded by the nadir instrument of the Ozone Mapping and Profiler Suite (OMPS) flown on board NASA’s Suomi National Polar-orbiting Partnership (SUOMI-NPP) satellite. Our algorithm is similar to the one currently in place for the production of NASA’s Ozone Monitoring Instrument (OMI) operational H2CO product. We are now able to produce a set of long-term data from two different instruments that share a similar concept and a similar retrieval approach. The ongoing overlap period between OMI and OMPS offers a perfect opportunity to study the consistency between both data sets. The different spatial and spectral resolution of the instruments is a source of discrepancy in the retrievals despite the similarity of the physic assumptions of the algorithm. We have concluded that the reduced spectral resolution of OMPS in comparison with OMI is not a significant obstacle in obtaining good-quality retrievals. Indeed, the improved signal-to-noise ratio of OMPS with respect to OMI helps to reduce the noise of the retrievals performed using OMPS spectra. However, the size of OMPS spatial pixels imposes a limitation in the capability to distinguish particular features of H2CO that are discernible with OMI. With root mean square (RMS) residuals ～ 5×10?4 for individual pixels we estimate the detection limit to be about 7.5 × 1015 molecules cm?2. Total vertical column density (VCD) errors for individual pixels range between 40 % for pixels with high concentrations to 100 % or more for pixels with concentrations at or below the detection limit. We compare different OMI products (SAO OMI v3.0.2 and BIRA OMI v14) with our OMPS product using 1 year of data, between September 2012 and September 2013. The seasonality of the retrieved slant columns is captured similarly by all products but there are discrepancies in the values of the VCDs. The mean biases among the two OMI products and our OMPS product are 23 % between OMI SAO and OMPS SAO and 28 % between OMI BIRA and OMPS SAO for eight selected regions.
关键词： formaldehyde,OMPS,H2CO,retrieval,AMFs,vertical column density,air mass factors,spectral fitting,OMI,VCD
更新于2025-09-04 15:30:14
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Fully convolutional networks in multimodal nonlinear microscopy images for automated detection of head and neck carcinoma: A pilot study
摘要： Background: A fully convolutional neural networks (FCN)-based automated image analysis algorithm to discriminate between head and neck cancer and non-cancerous epithelium based on nonlinear microscopic images was developed. Methods: Head and neck cancer sections were used for standard histopathology and co-registered with multimodal images from the same sections using the combination of coherent anti-Stokes Raman scattering, two-photon excited fluorescence, and second harmonic generation microscopy. The images analyzed with semantic segmentation using a FCN for four classes: cancer, normal epithelium, background, and other tissue types. Results: A total of 114 images of 12 patients were analyzed. Using a patch score aggregation, the average recognition rate and an overall recognition rate or the four classes were 88.9% and 86.7%, respectively. A total of 113 seconds were needed to process a whole-slice image in the dataset. Conclusion: Multimodal nonlinear microscopy in combination with automated image analysis using FCN seems to be a promising technique for objective differentiation between head and neck cancer and noncancerous epithelium.
关键词： digital pathology,semantic segmentation,diagnostics,second-harmonic generation,convolutional neural networks,two-photon excited fluorescence,spectral histopathology,image analysis,head and neck cancer,coherent anti-stokes Raman scattering
更新于2025-09-04 15:30:14