The statistical independence between the distributions of different chromophores in tissue has previously been used for linear unmixing with independent component analysis (ICA). In this study, we propose exploiting this statistical property in a nonlinear model-based inversion method. The aim is to reduce the sensitivity of the inversion scheme to errors in the modelling of the fluence, and hence provide more accurate quantification of the concentration of independent chromophores. A gradient-based optimisation algorithm is used to minimise the error functional, which includes a term representing the mutual information between the chromophores in addition to the standard least-squares data error. Both numerical simulations and an experimental phantom study are conducted to demonstrate that, in the presence of experimental errors in the fluence model, the proposed inversion method results in more accurate estimation of the concentrations of independent chromophores compared to the standard model-based inversion.
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http://dx.doi.org/10.1364/BOE.8.005297 | DOI Listing |
Sci Total Environ
December 2024
School of Marine Sciences and Engineering, Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application, Nanjing Normal University, Nanjing 210023, China. Electronic address:
Accurate precipitation data is an important state variable in various application fields such as geohazard early warning, flood, and drought hazard monitoring and evaluation. This study proposed a precipitation reforecast inversion model based on Random Forest and Wavelet Multi-Resolution Analysis (RF-WMRA) method. In the basin along the Sichuan-Tibet Railway, we constructed the reforecast inversion model by using the fifth generation of atmospheric reanalysis of the European Centre for Medium-Range Weather Forecasts (ERA5) and Global Satellite Mapping of Precipitation (GSMaP) precipitation data and considering several geo-environmental variables such as elevation, humidity, temperature, and wind speed.
View Article and Find Full Text PDFJ Magn Reson Imaging
December 2024
Utah Center for Advanced Imaging Research (UCAIR), Department of Radiology and Imaging Sciences, University of Utah, Salt Lake City, Utah, USA.
Background: Modified Look-Locker imaging (MOLLI) T1 mapping sequences are acquired during breath-holding and require ECG gating with consistent R-R intervals, which is problematic for patients with atrial fibrillation (AF). Consequently, there is a need for a free-breathing and ungated framework for cardiac T1 mapping.
Purpose: To develop and evaluate a free-breathing ungated radial simultaneous multi-slice (SMS) cardiac T1 mapping (FURST) framework.
J Acoust Soc Am
December 2024
Departamento ICES, Comisión Nacional de Energía Atómica, Villa Maipú, B1650, Argentina.
In the context of ultrasonic determination of mechanical properties, it is common to use oblique incident waves to characterize fluid-immersed anisotropic samples. The lateral displacement of the ultrasonic field owing to leaky guided wave phenomena poses a challenge for data inversion because beam spreading is rarely well represented by plane wave models. In this study, a finite beam model based on the angular spectrum method was developed to estimate the influence of the transducer shape and position on the transmitted signals.
View Article and Find Full Text PDFACS Sens
December 2024
State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China.
Sulfur dioxide (SO) and nitrogen dioxide (NO) are chemical indicators of crop straw combustion as well as significant atmospheric pollutants. It is challenging to promptly detect natural "wildfires" during agricultural production, which often lead to uncontrollable and substantial economic losses. Moreover, both "wildfires" and artificial "straw burning" practices pose severe threats to the ecological environment and human health.
View Article and Find Full Text PDFClin Radiol
November 2024
Department of Radiology, Huashan Hospital, Fudan University, Shanghai, China. Electronic address:
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