The Experts below are selected from a list of 195900 Experts worldwide ranked by ideXlab platform
Norihiko Nishizawa - One of the best experts on this subject based on the ideXlab platform.
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signal to background ratio and lateral resolution in deep tissue imaging by optical coherence microscopy in the 1700 nm Spectral Band
2019Co-Authors: Masahito Yamanaka, Naoki Hayakawa, Norihiko NishizawaAbstract:We quantitatively investigated the image quality in deep tissue imaging with optical coherence microscopy (OCM) in the 1700 nm Spectral Band, in terms of the signal-to-background ratio (SBR) and lateral resolution. In this work, to demonstrate the benefits of using the 1700 nm Spectral Band for OCM imaging of brain samples, we compared the imaging quality of OCM en-face images obtained at the same position by using a hybrid 1300 nm/1700 nm Spectral domain (SD) OCM system with shared sample and reference arms. By observing a reflective resolution test target through a 1.5 mm-thick tissue phantom, which had a similar scattering coefficient to brain cortex tissue, we confirmed that 1700 nm OCM achieved an SBR about 6-times higher than 1300 nm OCM, although the lateral resolution of the both OCMs was similarly degraded with the increase of the imaging depth. Finally, we also demonstrated high-contrast deep tissue imaging of a mouse brain at a depth up to 1.8 mm by using high-resolution 1700 nm SD-OCM.
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optical coherence microscopy in 1700 nm Spectral Band for high resolution label free deep tissue imaging
2016Co-Authors: Masahito Yamanaka, Tatsuhiro Teranishi, Hiroyuki Kawagoe, Norihiko NishizawaAbstract:Optical coherence microscopy (OCM) is a label-free, high-resolution, three-dimensional (3D) imaging technique based on optical coherence tomography (OCT) and confocal microscopy. Here, we report that the 1700-nm Spectral Band has the great potential to improve the imaging depth in high-resolution OCM imaging of animal tissues. Recent studies to improve the imaging depth in OCT revealed that the 1700-nm Spectral Band is a promising choice for imaging turbid scattering tissues due to the low attenuation of light in the wavelength region. In this study, we developed high-resolution OCM by using a high-power supercontinuum source in the 1700-nm Spectral Band, and compared the attenuation of signal-to-noise ratio between the 1700-nm and 1300-nm OCM imaging of a mouse brain under the condition of the same sensitivity. The comparison clearly showed that the 1700-nm OCM provides larger imaging depth than the 1300-nm OCM. In this 1700-nm OCM, the lateral resolution of 1.3 μm and the axial resolution of 2.8 μm, when a refractive index was assumed to be 1.38, was achieved.
David R Doelling - One of the best experts on this subject based on the ideXlab platform.
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a web based tool for calculating Spectral Band difference adjustment factors derived from sciamachy hyperSpectral data
2016Co-Authors: Benjamin R Scarino, David R Doelling, Patrick Minnis, Arun Gopalan, Thad Chee, Rajendra Bhatt, Constantine Lukashin, Conor O HaneyAbstract:Monitoring and adjusting calibrations of various satellite imagers is often exacerbated by differences in their Spectral response functions (SRFs). To help account for Spectral disparities among satellite imagers, a web-based Spectral Band difference correction calculator has been developed to characterize the relationship between a specified pair of satellite imager channels in the hyperSpectral wavelength range of 240-1750 nm. These Spectral Band adjustment factors (SBAFs) are derived by convolving hyperSpectral data from the SCIAMACHY instrument with the SRFs of a reference and target sensor. The SBAF tool can be used for all combinations of instrument/channel pairs over predefined Earth spectra, intercalibration domains, or user-defined spatial domains. Options are available to the user whereby SBAFs can be subsetted by time, angle, and/or precipitable water content. To evaluate the relative Spectral calibration of SCIAMACHY, comparisons of SBAFs derived from SCIAMACHY, Hyperion, and Global Ozone Monitoring Experiment-2 (GOME-2) were performed. Using observations over the Libya 4 desert pseudoinvariant calibration site, it is shown that SCIAMACHY-based SBAFs are within 0.1%-0.3% of SBAFs derived from Hyperion or GOME-2. This result implies that Spectral calibration differences, i.e., the calibration uncertainties of SCIAMACHY relative to other potential Spectral sources, have a minor impact on the SBAF compared with the influence of effective parameter-based subsetting. The SCIAMACHY instrument is most suited for calculating the SBAFs, given its high Spectral resolution, broad Spectral range, and nearly continuous global availability. The calibration community will find this SBAF tool useful for mitigating the SRF differences that can complicate the comparison and intercalibration of visible and near-infrared sensors.
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applications of Spectral Band adjustment factors sbaf for cross calibration
2013Co-Authors: Gyanesh Chander, David Aaron, Dennis L Helder, Nischal Mishra, Amit Angal, Taeyoung Choi, Xiaoxiong Xiong, David R DoellingAbstract:To monitor land surface processes over a wide range of temporal and spatial scales, it is critical to have coordinated observations of the Earth's surface acquired from multiple spaceborne imaging sensors. However, an integrated global observation framework requires an understanding of how land surface processes are seen differently by various sensors. This is particularly true for sensors acquiring data in Spectral Bands whose relative Spectral responses (RSRs) are not similar and thus may produce different results while observing the same target. The intrinsic offsets between two sensors caused by RSR mismatches can be compensated by using a Spectral Band adjustment factor (SBAF), which takes into account the Spectral profile of the target and the RSR of the two sensors. The motivation of this work comes from the need to compensate the Spectral response differences of multiSpectral sensors in order to provide a more accurate cross-calibration between the sensors. In this paper, radiometric cross-calibration of the Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and the Terra Moderate Resolution Imaging Spectroradiometer (MODIS) sensors was performed using near-simultaneous observations over the Libya 4 pseudoinvariant calibration site in the visible and near-infrared Spectral range. The RSR differences of the analogous ETM+ and MODIS Spectral Bands provide the opportunity to explore, understand, quantify, and compensate for the measurement differences between these two sensors. The cross-calibration was initially performed by comparing the top-of-atmosphere (TOA) reflectances between the two sensors over their lifetimes. The average percent differences in the long-term trends ranged from -5% to +6%. The RSR compensated ETM+ TOA reflectance (ETM+*) measurements were then found to agree with MODIS TOA reflectance to within 5% for all Bands when Earth Observing-1 Hyperion hyperSpectral data were used to produce the SBAFs. These differences were later reduced to within 1% for all Bands (except Band 2) by using Environmental Satellite Scanning Imaging Absorption Spectrometer for Atmospheric Cartography hyperSpectral data to produce the SBAFs.
Masahito Yamanaka - One of the best experts on this subject based on the ideXlab platform.
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signal to background ratio and lateral resolution in deep tissue imaging by optical coherence microscopy in the 1700 nm Spectral Band
2019Co-Authors: Masahito Yamanaka, Naoki Hayakawa, Norihiko NishizawaAbstract:We quantitatively investigated the image quality in deep tissue imaging with optical coherence microscopy (OCM) in the 1700 nm Spectral Band, in terms of the signal-to-background ratio (SBR) and lateral resolution. In this work, to demonstrate the benefits of using the 1700 nm Spectral Band for OCM imaging of brain samples, we compared the imaging quality of OCM en-face images obtained at the same position by using a hybrid 1300 nm/1700 nm Spectral domain (SD) OCM system with shared sample and reference arms. By observing a reflective resolution test target through a 1.5 mm-thick tissue phantom, which had a similar scattering coefficient to brain cortex tissue, we confirmed that 1700 nm OCM achieved an SBR about 6-times higher than 1300 nm OCM, although the lateral resolution of the both OCMs was similarly degraded with the increase of the imaging depth. Finally, we also demonstrated high-contrast deep tissue imaging of a mouse brain at a depth up to 1.8 mm by using high-resolution 1700 nm SD-OCM.
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optical coherence microscopy in 1700 nm Spectral Band for high resolution label free deep tissue imaging
2016Co-Authors: Masahito Yamanaka, Tatsuhiro Teranishi, Hiroyuki Kawagoe, Norihiko NishizawaAbstract:Optical coherence microscopy (OCM) is a label-free, high-resolution, three-dimensional (3D) imaging technique based on optical coherence tomography (OCT) and confocal microscopy. Here, we report that the 1700-nm Spectral Band has the great potential to improve the imaging depth in high-resolution OCM imaging of animal tissues. Recent studies to improve the imaging depth in OCT revealed that the 1700-nm Spectral Band is a promising choice for imaging turbid scattering tissues due to the low attenuation of light in the wavelength region. In this study, we developed high-resolution OCM by using a high-power supercontinuum source in the 1700-nm Spectral Band, and compared the attenuation of signal-to-noise ratio between the 1700-nm and 1300-nm OCM imaging of a mouse brain under the condition of the same sensitivity. The comparison clearly showed that the 1700-nm OCM provides larger imaging depth than the 1300-nm OCM. In this 1700-nm OCM, the lateral resolution of 1.3 μm and the axial resolution of 2.8 μm, when a refractive index was assumed to be 1.38, was achieved.
Conor O Haney - One of the best experts on this subject based on the ideXlab platform.
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a web based tool for calculating Spectral Band difference adjustment factors derived from sciamachy hyperSpectral data
2016Co-Authors: Benjamin R Scarino, David R Doelling, Patrick Minnis, Arun Gopalan, Thad Chee, Rajendra Bhatt, Constantine Lukashin, Conor O HaneyAbstract:Monitoring and adjusting calibrations of various satellite imagers is often exacerbated by differences in their Spectral response functions (SRFs). To help account for Spectral disparities among satellite imagers, a web-based Spectral Band difference correction calculator has been developed to characterize the relationship between a specified pair of satellite imager channels in the hyperSpectral wavelength range of 240-1750 nm. These Spectral Band adjustment factors (SBAFs) are derived by convolving hyperSpectral data from the SCIAMACHY instrument with the SRFs of a reference and target sensor. The SBAF tool can be used for all combinations of instrument/channel pairs over predefined Earth spectra, intercalibration domains, or user-defined spatial domains. Options are available to the user whereby SBAFs can be subsetted by time, angle, and/or precipitable water content. To evaluate the relative Spectral calibration of SCIAMACHY, comparisons of SBAFs derived from SCIAMACHY, Hyperion, and Global Ozone Monitoring Experiment-2 (GOME-2) were performed. Using observations over the Libya 4 desert pseudoinvariant calibration site, it is shown that SCIAMACHY-based SBAFs are within 0.1%-0.3% of SBAFs derived from Hyperion or GOME-2. This result implies that Spectral calibration differences, i.e., the calibration uncertainties of SCIAMACHY relative to other potential Spectral sources, have a minor impact on the SBAF compared with the influence of effective parameter-based subsetting. The SCIAMACHY instrument is most suited for calculating the SBAFs, given its high Spectral resolution, broad Spectral range, and nearly continuous global availability. The calibration community will find this SBAF tool useful for mitigating the SRF differences that can complicate the comparison and intercalibration of visible and near-infrared sensors.
Richard A Soref - One of the best experts on this subject based on the ideXlab platform.
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wideBand perfect light absorber at midwave infrared using multiplexed metal structures
2012Co-Authors: Joshua R Hendrickson, Junpeng Guo, Boyang Zhang, W R Buchwald, Richard A SorefAbstract:We experimentally demonstrate a wideBand near-perfect light absorber in the midwave IR region using a multiplexed plasmonic metal structure. The wideBand near-perfect light absorber is made of two different size gold metal squares multiplexed on a thin dielectric spacing layer on top of a thick metal layer in each unit cell. We also fabricate regular nonmultiplexed structure perfect light absorbers. The multiplexed structure IR absorber absorbs more than 98% of the incident light over a much wider Spectral Band than regular nonmultiplexed structure perfect light absorbers in the midwave IR region.
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a wide Band perfect light absorber at mid wave infrared using multiplexed metal structures
2012Co-Authors: Joshua R Hendrickson, Junpeng Guo, Boyang Zhang, W R Buchwald, Richard A SorefAbstract:We experimentally demonstrate a wide Band near perfect light absorber in the mid-wave infrared region using multiplexed plasmonic metal structures. The wide Band near perfect light absorber is made of two different size gold metal squares multiplexed on a thin dielectric spacing layer on the top of a thick metal layer in each unit cell. We also fabricate regular non-multiplexed structure perfect light absorbers. The multiplexed structure IR absorber absorbs above 98% incident light over a much wider Spectral Band than the regular non-multiplexed structure perfect light absorbers in the mid-wave IR region.
