Depolarization index from Mueller matrix descatters imaging in turbid water

Polarimetry is today a widely used and powerful tool for nondestructive analysis of the structural and morphological properties of a great variety of material samples, including aerosols and hydrosols, among many others. For each given scattering measurement configuration, absolute Mueller polarimeters provide the most complete polarimetric information, intricately encoded in the 16 parameters of the corresponding Mueller matrix. Thus, the determination of the mathematical structure of the polarimetric information contained in a Mueller matrix constitutes a topic of great interest. In this work, besides a structural decomposition that makes explicit the role played by the diattenuation-polarizance of a general depolarizing medium, a universal synthesizer of Muller matrices is developed. This is based on the concept of an enpolarizing ellipsoid, whose symmetry features are directly linked to the way in which the polarimetric information is organized.

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Optical Chirality Determined from Mueller Matrices

Applied Sciences ◽

10.3390/app11156742 ◽

2021 ◽

Vol 11 (15) ◽

pp. 6742

Author(s):

Hans Arwin ◽

Stefan Schoeche ◽

James Hilfiker ◽

Mattias Hartveit ◽

Kenneth Järrendahl ◽

...

Keyword(s):

Circular Dichroism ◽

Constitutive Relations ◽

Mueller Matrix ◽

Optical Path ◽

Electromagnetic Modeling ◽

Structural Effects ◽

Polarization Effects ◽

Optical Chirality ◽

Mueller Matrices ◽

Circular Dichroïsm

Optical chirality, in terms of circular birefringence and circular dichroism, is described by its electromagnetic and magnetoelectric material tensors, and the corresponding optical activity contributes to the Mueller matrix. Here, spectroscopic ellipsometry in the spectral range 210–1690 nm is used to address chiral phenomena by measuring Mueller matrices in transmission. Three approaches to determine chirality parameters are discussed. In the first approach, applicable in the absence of linear polarization effects, circular birefringence and circular dichroism are evaluated directly from elements of a Mueller matrix. In the second method, differential decomposition is employed, which allows for the unique separation of chirality parameters from linear anisotropic parameters as well as from depolarization provided that the sample is homogeneous along the optical path. Finally, electromagnetic modeling using the Tellegen constitutive relations is presented. The last method also allows structural effects to be included. The three methods to quantify optical chirality are demonstrated for selected materials, including sugar solutions, α-quartz, liquid crystals, beetle cuticle, and films of cellulose nanocrystals.

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Strain-optical behavior of polyethylene terephthalate film during uniaxial stretching investigated by Mueller matrix ellipsometry

Polymer ◽

10.1016/j.polymer.2019.121842 ◽

2019 ◽

Vol 182 ◽

pp. 121842

Author(s):

Zhikang Zhou ◽

Hao Jiang ◽

Honggang Gu ◽

Xiuguo Chen ◽

Haiyan Peng ◽

...

Keyword(s):

Polyethylene Terephthalate ◽

Mueller Matrix ◽

Uniaxial Stretching ◽

Polyethylene Terephthalate Film ◽

Optical Behavior

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Remote Estimation of Trophic State Index for Inland Waters Using Landsat-8 OLI Imagery

Remote Sensing ◽

10.3390/rs13101988 ◽

2021 ◽

Vol 13 (10) ◽

pp. 1988

Author(s):

Minqi Hu ◽

Ronghua Ma ◽

Zhigang Cao ◽

Junfeng Xiong ◽

Kun Xue

Keyword(s):

Yangtze River ◽

Trophic State ◽

Inland Waters ◽

Landsat 8 ◽

Trophic State Index ◽

Type I ◽

Water Type ◽

Type Ii ◽

Turbid Water ◽

State Index

Remote monitoring of trophic state for inland waters is a hotspot of water quality studies worldwide. However, the complex optical properties of inland waters limit the potential of algorithms. This research aims to develop an algorithm to estimate the trophic state in inland waters. First, the turbid water index was applied for the determination of optical water types on each pixel, and water bodies are divided into two categories: algae-dominated water (Type I) and turbid water (Type II). The algal biomass index (ABI) was then established based on water classification to derive the trophic state index (TSI) proposed by Carlson (1977). The results showed a considerable precision in Type I water (R2 = 0.62, N = 282) and Type II water (R2 = 0.57, N = 132). The ABI-derived TSI outperformed several band-ratio algorithms and a machine learning method (RMSE = 4.08, MRE = 5.46%, MAE = 3.14, NSE = 0.64). Such a model was employed to generate the trophic state index of 146 lakes (> 10 km2) in eastern China from 2013 to 2020 using Landsat-8 surface reflectance data. The number of hypertrophic and oligotrophic lakes decreased from 45.89% to 21.92% and 4.11% to 1.37%, respectively, while the number of mesotrophic and eutrophic lakes increased from 12.33% to 23.97% and 37.67% to 52.74%. The annual mean TSI for the lakes in the lower reaches of the Yangtze River basin was higher than that in the middle reaches of the Yangtze River and Huai River basin. The retrieval algorithm illustrated the applicability to other sensors with an overall accuracy of 83.27% for moderate-resolution imaging spectroradiometer (MODIS) and 82.92% for Sentinel-3 OLCI sensor, demonstrating the potential for high-frequency observation and large-scale simulation capability. Our study can provide an effective trophic state assessment and support inland water management.

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