The Experts below are selected from a list of 59265 Experts worldwide ranked by ideXlab platform
Antero Kukko - One of the best experts on this subject based on the ideXlab platform.
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analysis of Incidence Angle and distance effects on terrestrial laser scanner intensity search for correction methods
Remote Sensing, 2011Co-Authors: Sanna Kaasalainen, Anssi Krooks, Anttoni Jaakkola, M Kaasalainen, Antero KukkoAbstract:The intensity information from terrestrial laser scanners (TLS) has become an important object of study in recent years, and there are an increasing number of applications that would benefit from the addition of calibrated intensity data to the topographic information. In this paper, we study the range and Incidence Angle effects on the intensity measurements and search for practical correction methods for different TLS instruments and targets. We find that the range (distance) effect is strongly dominated by instrumental factors, whereas the Incidence Angle effect is mainly caused by the target surface properties. Correction for both effects is possible, but more studies are needed for physical interpretation and more efficient use of intensity data for target characterization.
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effect of Incidence Angle on laser scanner intensity and surface data
Applied Optics, 2008Co-Authors: Antero Kukko, Sanna Kaasalainen, Paula LitkeyAbstract:We present a comprehensive experimental set of data on the dependence of the laser intensity on the Angle of Incidence to the target surface. The measurements have been performed in the laboratory for samples with a Nd:YAG laser and terrestrial laser scanner. The brightness scale data were also compared with data acquired by airborne laser scanning (ALS). The Incidence Angle effect is evident for all the targets. The effect is significant for Incidence Angles >20°, and stronger for bright targets. However, effects due to some of the other surface properties, such as roughness, were also detected. We also found a set of gravel samples for which the Incidence Angle effect was minor even up to 40°. The data provide an important reference for the interpretation and applications, e.g., full-waveform data processing of a laser scanner and ALS intensity calibration.
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Effect of Incidence Angle on laser scanner intensity and surface data
Applied Optics, 2008Co-Authors: Antero Kukko, Sanna Kaasalainen, Paula LitkeyAbstract:We present a comprehensive experimental set of data on the dependence of the laser intensity on the Angle of Incidence to the target surface. The measurements have been performed in the laboratory for samples with a Nd:YAG laser and terrestrial laser scanner. The brightness scale data were also compared with data acquired by airborne laser scanning (ALS). The Incidence Angle effect is evident for all the targets. The effect is significant for Incidence Angles >20 degrees, and stronger for bright targets. However, effects due to some of the other surface properties, such as roughness, were also detected. We also found a set of gravel samples for which the Incidence Angle effect was minor even up to 40 degrees . The data provide an important reference for the interpretation and applications, e.g., full-waveform data processing of a laser scanner and ALS intensity calibration.
Jungho Kim - One of the best experts on this subject based on the ideXlab platform.
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effect of oblique Incidence Angle of sunlight on the optimized folding Angle of v shaped organic solar cells
Current Applied Physics, 2015Co-Authors: Jiho Yoon, Kyungnam Kang, Sungchul Kim, Jungho KimAbstract:Abstract We numerically investigate the effect of the Incidence Angle of sunlight on the optimized folding Angle of V-shaped organic solar cells (VOSCs) to obtain the best power conversion efficiency in a realistically operating environment. The light absorbance at the active layer is calculated based on the finite element method with respect to the Incidence Angle of sunlight and the folding Angle of the VOSC. We calculate the generation energy density per day at each folding Angle by integrating the angular response of the short-circuit current and the open-circuit voltage with the consideration of the variation of the Incidence Angle during daytime. We show that the optimized folding Angle of the VOSC based on the variation of the generation energy density per day is close to that determined from the variation of the electric power density in normal Incidence, which has been widely used to optimize the folding Angle of VOSCs.
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effect of Incidence Angle and polarization on the optimized layer structure of organic solar cells
Solar Energy Materials and Solar Cells, 2013Co-Authors: Sanghwa Lee, Inkyung Jeong, Hyeong Pil Kim, Soon Yong Hwang, Tae Jung Kim, Young Dong Kim, Jin Jang, Jungho KimAbstract:Abstract We theoretically and experimentally investigate the effect of the Incidence Angle and polarization of sunlight on the optimized layer structure of organic solar cells (OSCs) to obtain the best absorption efficiency in a realistic deployment situation. We use the generalized transfer matrix method with respect to the Incidence Angle and polarization, which can calculate the spatial distribution of the optical power dissipation in both the incoherent glass substrate and the coherent multilayer without using any indirect correction factor. The angular dependence of the short-circuit current, the open-circuit voltage, and the output electric power is calculated and compared with the experimental results. Using the simulation parameters matched with the experimental results, we calculate the generation energy density per day by considering the variation of the Incidence Angle during daytime and determine the optimized thickness of the active region for maximum absorption efficiency. We show that the optimized active-region thickness based on the generation energy density per day is different from that determined from the variation of the short-circuit current density in only normal Incidence, which is generally used for optimizing device structure of OSCs.
Sanna Kaasalainen - One of the best experts on this subject based on the ideXlab platform.
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correction of intensity Incidence Angle effect in terrestrial laser scanning
ISPRS Annals of the Photogrammetry Remote Sensing and Spatial Information Sciences, 2013Co-Authors: Anssi Krooks, Sanna Kaasalainen, Teemu Hakala, Olli NevalainenAbstract:Abstract. In this article, we have studied the Incidence Angle effect on Terrestrial Laser Scanning (TLS) intensity. In previous tests, it has been found that the backscattered intensity of an object affects the Incidence Angle effect. We made additional experiments to investigate the potential mixing of distance and Incidence Angle effects and the role of surface parameters such as object grain size and scanning wavelength. The results indicate that distance and Incidence Angle effects do not mix and laboratory measured correction values can be used to correct intensity data from field-scanned point clouds. We also compared the laboratory measurements to real world surfaces to validate the correction procedures in practical TLS applications. The idea is also to make practical recommendations for TLS intensity correction in most common TLS applications.
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analysis of Incidence Angle and distance effects on terrestrial laser scanner intensity search for correction methods
Remote Sensing, 2011Co-Authors: Sanna Kaasalainen, Anssi Krooks, Anttoni Jaakkola, M Kaasalainen, Antero KukkoAbstract:The intensity information from terrestrial laser scanners (TLS) has become an important object of study in recent years, and there are an increasing number of applications that would benefit from the addition of calibrated intensity data to the topographic information. In this paper, we study the range and Incidence Angle effects on the intensity measurements and search for practical correction methods for different TLS instruments and targets. We find that the range (distance) effect is strongly dominated by instrumental factors, whereas the Incidence Angle effect is mainly caused by the target surface properties. Correction for both effects is possible, but more studies are needed for physical interpretation and more efficient use of intensity data for target characterization.
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effect of Incidence Angle on laser scanner intensity and surface data
Applied Optics, 2008Co-Authors: Antero Kukko, Sanna Kaasalainen, Paula LitkeyAbstract:We present a comprehensive experimental set of data on the dependence of the laser intensity on the Angle of Incidence to the target surface. The measurements have been performed in the laboratory for samples with a Nd:YAG laser and terrestrial laser scanner. The brightness scale data were also compared with data acquired by airborne laser scanning (ALS). The Incidence Angle effect is evident for all the targets. The effect is significant for Incidence Angles >20°, and stronger for bright targets. However, effects due to some of the other surface properties, such as roughness, were also detected. We also found a set of gravel samples for which the Incidence Angle effect was minor even up to 40°. The data provide an important reference for the interpretation and applications, e.g., full-waveform data processing of a laser scanner and ALS intensity calibration.
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Effect of Incidence Angle on laser scanner intensity and surface data
Applied Optics, 2008Co-Authors: Antero Kukko, Sanna Kaasalainen, Paula LitkeyAbstract:We present a comprehensive experimental set of data on the dependence of the laser intensity on the Angle of Incidence to the target surface. The measurements have been performed in the laboratory for samples with a Nd:YAG laser and terrestrial laser scanner. The brightness scale data were also compared with data acquired by airborne laser scanning (ALS). The Incidence Angle effect is evident for all the targets. The effect is significant for Incidence Angles >20 degrees, and stronger for bright targets. However, effects due to some of the other surface properties, such as roughness, were also detected. We also found a set of gravel samples for which the Incidence Angle effect was minor even up to 40 degrees . The data provide an important reference for the interpretation and applications, e.g., full-waveform data processing of a laser scanner and ALS intensity calibration.
Xiaojun Cheng - One of the best experts on this subject based on the ideXlab platform.
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correction of Incidence Angle and distance effects on tls intensity data based on reference targets
Remote Sensing, 2016Co-Authors: Kai Tan, Xiaojun ChengAbstract:The original intensity value recorded by terrestrial laser scanners is influenced by multiple variables, among which Incidence Angle and distance play a crucial and dominant role. Further studies on Incidence Angle and distance effects are required to improve the accuracy of currently available methods and to implement these methods in practical applications. In this study, the effects of Incidence Angle and distance on intensity data of the Faro Focus3D 120 terrestrial laser scanner are investigated. A new method is proposed to eliminate the Incidence Angle and distance effects. The proposed method is based on the linear interpolation of the intensity values of reference targets previously scanned at various Incidence Angles and distances. Compared with existing methods, a significant advantage of the proposed method is that estimating the specific function forms of Incidence Angle versus intensity and distance versus intensity is no longer necessary; these are canceled out when the scanned and reference targets are measured at the same Incidence Angle and distance. Results imply that the proposed method has high accuracy and simplicity in eliminating Incidence Angle and distance effects and can significantly reduce the intensity variations caused by these effects on homogeneous surfaces.
Juha Karvonen - One of the best experts on this subject based on the ideXlab platform.
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Incidence Angle dependence of first year sea ice backscattering coefficient in sentinel 1 sar imagery over the kara sea
IEEE Transactions on Geoscience and Remote Sensing, 2017Co-Authors: Marko Makynen, Juha KarvonenAbstract:We have studied the Incidence Angle ( $\theta _{0}$ ) dependence of the sea ice backscattering coefficient ( $\sigma$ °) for Sentinel-1 (S-1) extra wide (EW) mode dual-polarization (HH/HV) synthetic aperture radar (SAR) imagery acquired over the Kara Sea under winter and summer melting conditions. The determination of the $\sigma$ ° versus $\theta _{0}$ dependence was based on SAR image pairs acquired on ascending and descending orbits over the same sea ice area with a short time difference. The SAR noise floor was subtracted from the HV images. From the image pairs 1.1 by 1.1 km windows representing level first-year ice (LFYI) and deformed first-year ice (DFYI) were manually selected, and a linear regression was fit between the resulting $\sigma$ ° and $\theta _{0}$ differences of the windows to estimate the slope ${b}_{1}$ (dB/1°) between $\sigma$ ° and $\theta _{0}$ . For example, under winter condition ${b}_{1}$ for DFYI at HH- and HV-polarizations was found to be −0.24 and −0.16 dB/1°, respectively, and ${b}_{1}$ for LFYI at HH-polarization was −0.25 dB/1°. It was not possible to determine a reliable ${b}_{1}$ for LFYI at HV due to a contamination effect of the S-1 noise floor. The ${b}_{1}$ values at HH compared well with previous studies. They can be used to compensate the $\sigma$ ° Incidence Angle variation in the S-1 EW SAR images with good accuracy. The HH ${b}_{1}$ values are applicable to other S-1 imaging modes and other C-band SAR sensors like RADARSAT-2. Unfortunately, the HV ${b}_{1}$ values are specific to the S-1 EW mode due to the noise floor problem.
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Incidence Angle dependence of the statistical properties of c band hh polarization backscattering signatures of the baltic sea ice
IEEE Transactions on Geoscience and Remote Sensing, 2002Co-Authors: M Makynen, A T Manninen, Markku Simila, Juha Karvonen, M HallikainenAbstract:Incidence Angle dependence of three statistical parameters-the mean of the backscattering coefficient (/spl sigma//spl deg/), standard deviation, and autocorrelation coefficient of texture (/spl sigma//sub T/ and /spl rho//sub T/)-of the C-band horizontal-horizontal (HH) polarization backscattering signatures of the Baltic Sea ice are investigated using RADARSAT ScanSAR Narrow images and helicopter-borne Helsinki University of Technology Scatterometer (HUTSCAT) data. The analysis of the large amount of data shows that the relationship between the mean /spl sigma//spl deg/ in decibel scale and the Incidence Angle in the range from 19/spl deg/ to 46/spl deg/ is usually well described by a linear model. In general, the RADARSAT and HUTSCAT results agree with each other, and they are also supported by theoretical backscattering model calculations; the more deformed the ice, the smaller the slope between /spl sigma//spl deg/ and the Incidence Angle, and the higher the moisture content of snow or ice, the larger the slope. The derived /spl sigma//spl deg/ Incidence Angle dependencies can be used to roughly compensate the /spl sigma//spl deg/ Incidence Angle variation in the SAR images to help their visual and automated classification. The variability of /spl sigma//sub T/ and /spl rho//sub T/ with the increasing Incidence Angle is insignificant compared to the variability within each ice type. Their average changes with the Incidence Angle are so small that, in practice, their trends do not need to be compensated. The results of this study can be utilized when developing classification algorithms for the RADARSAT ScanSAR and ENVISAT HH-polarization Wide Swath images of the Baltic Sea ice.
