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- 实验方案
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Pixelated-polarization-camera-based polarimetry system for wide real-time optical rotation measurement
摘要： Chirality is an essential consideration in the field of life sciences and pharmaceutical industry because most biomolecules and pharmaceuticals are chiral, and optical rotation measurement is a simple and efficient means for identification, purity test and content detection of chiral materials. However, there are some drawbacks in existing methods, such as small measurement range, non-real-time performance, low measurement accuracy and resolution. This paper presents a novel system to implement optical rotation measurement, and pixelated polarization cameras and Stokes parameters are employed in the system. The polarization information of linearly polarized incident light can be recorded and extracted by a pixelated polarization camera and Stokes parameters respectively. Experiments demonstrate that the proposed system has the necessary advantages for optical rotation measurement, such as real time, wide range ( ?90 ° ～ +90 °), high accuracy ( ±4 ×10?6 °) and high resolution ( 6 ×10?11 °). Thus, this measurement system has great practical prospects in the hospital clinical diagnosis, chemical research, sugar production and pharmaceutical industry.
关键词： pixelated micropolarizer array,optical rotation,chiral drug,polarimetry,Stokes parameters
更新于2025-11-25 10:30:42
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[IEEE 2018 International Conference on Radar (RADAR) - Brisbane, Australia (2018.8.27-2018.8.31)] 2018 International Conference on Radar (RADAR) - Multiband Polarimetric SAR in Arctic Scenarios
摘要： In relation to a working group on future capabilities for applications in the Arctic region, the Danish Defence Acquisition and Logistics Organization (DALO) has conducted test campaigns with the multi-band, fully polarimetric F-SAR system owned by the German Aerospace Center (DLR) in order to explore the possibilities that advanced synthetic aperture radar (SAR) systems provide for surveillance, change detection, moving target identification and high resolution imaging. Examples of results and some preliminary conclusions are presented in this paper.
关键词： detection,SAR,polarimetry,surveillance,Arctic,recognition
更新于2025-09-23 15:23:52
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3D Mueller-Matrix Diffusive Tomography of Polycrystalline Blood Films for Cancer Diagnosis
摘要： The decomposition of the Mueller matrix of blood films has been carried out using differential matrices with polarized and depolarized parts. The use of a coherent reference wave is applied and the algorithm of digital holographic reconstruction of the field of complex amplitudes is used. On this basis, the 3D Mueller-matrix diffuse tomography method—the reconstruction of distributions of fluctuations of linear and circular birefringence of depolarizing polycrystalline films of human blood is analytically justified and experimentally tested. The dynamics of the change in the magnitude of the statistical moments of the first-fourth order, which characterize layer-by-layer distributions of fluctuations in the phase anisotropy of the blood film, is examined and analyzed. The most sensitive parameters for prostate cancer are the statistical moments of the third and fourth orders, which characterize the asymmetry and kurtosis of fluctuations in the linear and circular birefringence of blood films. The excellent accuracy of differentiation obtained polycrystalline films of blood from healthy donors and patients with cancer patients was achieved.
关键词： polarimetry,Mueller-matrix,blood,cancer diagnostics,polarization
更新于2025-09-23 15:23:52
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PolSAR Image Semantic Segmentation Based on Deep Transfer Learning--Realizing Smooth Classification With Small Training Sets
摘要： Suffering from speckle noise and complex scattering phenomena, classification results of SAR images are usually noisy and shattered, which makes them difficult to use in practical applications. Deep-learning-based semantic segmentation realizes segmentation and categorization at the same time, and thus can obtain smooth and fine-grained classification maps. However, this kind of methods require large data sets with pixel-wise categorical annotations, which are time consuming and tedious to retrieve. Compared with photographs and optical remote sensing images, manually annotating SAR data is even harder, which results in a delay of using relevant techniques in this field. In this letter, a new data set is proposed to support semantic segmentation for high-resolution PolSAR images. Limited by the aforementioned problems, the data set is only a small one with 50 image patches. Therefore, two transfer learning strategies are proposed, which adopt the fully convolutional network (FCN) and U-net architecture, respectively, and use distinct pretraining data sets to adapt to different situations. The experiments demonstrate the good performance of both methods and a promising applicability of using small training sets. Moreover, although trained with small patches, both networks can perfectly apply on large images. The new data set and methods are hopeful to support various PolSAR applications as baselines.
关键词： polarimetry,SAR,image classification,Deep learning,image segmentation
更新于2025-09-23 15:22:29
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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 - Validation of SAR Iceberg Detection with Ground-Based Radar and GPS Measurements
摘要： Calving of icebergs at the tidewater glacier fronts is a component of the mass loss in Polar regions. Studying the regional distribution of icebergs, their volume, motion, and interaction with the environment is of interest. Here, we present the results from a fieldwork campaign conducted in Kongsfjorden, Svalbard in April 2016, where both satellite and ground-based remote sensing instruments were used to observe dynamics of sea ice, icebergs, and growlers. We used a ground-based radar system, imaging the study area every second minute during five days. During the same observation period, we collected four RADARSAT-2 (RS-2) quad-pol images, that are used for automatic detection of icebergs. In addition, the fieldwork team collected GPS positions of some drifting and grounded icebergs in the fjord to be used as ground-truth data. The comparison and combination of satellite, ground-based radar, and in-situ data contribute to cross-validate the results.
关键词： synthetic aperture radar,ground-based radar,polarimetry,GPS mapping,Iceberg,detection,sea ice
更新于2025-09-23 15:22:29
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A Reflection Symmetry Approximation of Multilook Polarimetric SAR Data and its Application to Freeman-Durden Decomposition
摘要： Freeman–Durden decomposition is a frequently used technique to analyze the scattering characteristics of multilook Polarimetric Synthetic Aperture Radar (POLSAR) data. When it is applied to the real POLSAR data, two problems emerge, namely, the volume scattering overestimation and negative powers. Many researchers think these two problems are caused by the insufficient decomposition algorithm, and the improved decomposition algorithms become more and more complicated, and some new problems such as the decomposed component is not model based also emerge. In this paper, we try to solve the two problems through another way. We think they are caused not by the insufficient decomposition algorithm but by the dogmatic input. Freeman–Durden decomposition explicitly assumes reflection symmetry. Its input is a direct truncation of the measured coherency matrix. The truncation can be regarded as a reflection symmetry approximation (RSA) of the measured coherency matrix. We first show some reasons why we do not think the truncation is a good RSA. Then, a new RSA is proposed based on the sum of three reflection symmetry components derived from the measured coherency matrix. Experimental results with several real POLSAR images show that, if the new RSA is used as the input of Freeman–Durden decomposition, the above-mentioned two problems no longer exist.
关键词： Polarimetric Synthetic Aperture Radar (POLSAR),radar polarimetry,Polarimetric decomposition
更新于2025-09-23 15:22:29
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A Sensitivity Analysis of the Standard Deviation of the Copolarized Phase Difference for Sea Oil Slick Observation
摘要： In this paper, a time series of 33 TerraSAR-X copolarized synthetic aperture radar (SAR) imagery collected in Stripmap mode over the Gulf of Mexico in a wide range of incidence angles and sea-state condition is exploited, together with a theoretical framework based on the X-Bragg scattering model, to analyze the effects of noise, angle of incidence, (AOI) and wind speed on the standard deviation of the copolarized phase difference (στc ) evaluated over sea surface with and without oil slicks. This large data set represents an unprecedented opportunity to analyze, for the ?rst time, the in?uence of both SAR acquisition and surface parameters on the broadening of the copolarized phase difference probability density function (pdf), (τc). Experimental results show that the X-Bragg scattering model, here adopted to predict the sea surface pτc (τc), gives an understanding of the increasing trend of στc with respect to AOI. It is shown that the noise signi?cantly contributes to broaden pτc (τc) over both slick-free and slick-covered sea surface, while the effects of low-to-moderate wind regimes are negligible. In addition, στc exhibits a larger sensitivity to the scene variability, if compared to single-polarization intensity channels, over both slick-free and oil-covered sea surface. This sensitivity is more pronounced at lower AOIs due to the higher noise equivalent sigma zero (NESZ) that affects larger AOIs.
关键词： Oceans,oil pollution,synthetic aperture radar,radar polarimetry
更新于2025-09-23 15:22:29
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Urban Tomographic Imaging Using Polarimetric SAR Data
摘要： In this paper, we investigate the potential of polarimetric Synthetic Aperture Radar (SAR) tomography (Pol-TomoSAR) in urban applications. TomoSAR exploits the amplitude and phase of the received data and offers the possibility to resolve multiple scatters lying in the same range–azimuth resolution cell. In urban environments, this issue is very important since layover causes multiple coherent scatterers to be mapped in the same range–azimuth image pixel. To achieve reliable and accurate results, TomoSAR requires a large number of multi-baseline acquisitions which, for satellite-borne SAR systems, are collected with long time intervals. Then, accurate tomographic reconstructions would require multiple scatterers to remain stable between all the acquisitions. In this paper, an extension of a generalized likelihood ratio test (GLRT)-based tomographic approach, denoted as Fast-Sup-GLRT, to the polarimetric data case is introduced, with the purpose of investigating if, in urban applications, the use of polarimetric channels allows for reduction of the number of baselines required to achieve a given scatterer’s detection performance. The results presented show that the use of dual polarization data allows the proposed detector to work in an equivalent or better way than use of a double number of independent single polarization channels.
关键词： generalized likelihood ratio test,synthetic aperture radar,sparse signals,polarimetry,radar detection,tomography
更新于2025-09-23 15:22:29
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On the Test Method for Determining Residual Stress on the Surface of Tempered Glass
摘要： The residual stress on the surface of tempered glass is very important for its safe service and the quality control. In this study, the sphere indentation and grazing angle surface polarimetry are compared to evaluate the surface residual stress of tempered glass. The test results showed that the measured results are similar, but the data dispersion of the sphere indentation method is little larger. The main reason is stemmed from the different tested area, of which residual stress is a mean value measured by the grazing angle polarization method. Yet for the indentation method, the residual stress in the micro region of glass is more susceptible to the inhomogeneity of material itself. However, it is difficult to select the right multiple optical path difference for the grazing angle polarization method, and it is only applicable when inspecting the tin surface of tempered glass, as well as the tin surface examination instrument. Thus, as a nondestructive testing method, indentation method can be widely used to measure the surface residual stress of glass without being influenced by other factors.
关键词： Indentation method,Surface residual stress,Grazing angle surface polarimetry,Tempered glass
更新于2025-09-23 15:22:29
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[IEEE 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Lausanne (2018.7.29-2018.8.2)] 2018 International Conference on Optical MEMS and Nanophotonics (OMN) - Nanofabricated Infrared Polarization and Color Filters for Cloud Thermodynamic Phase Determination
摘要： Polarization and wavelength filters for the short-wave infrared based on metal-coated subwavelength-period silicon gratings are designed and fabricated. The nanostructure-based approach enables the realization of the desired polarization and wavelength selectivity for each filter element while also facilitating the integration of these elements into an array with varying polarizer orientation and passband center wavelength. These filters are optimized for a polarimetric imaging application in atmospheric science, namely, the discrimination of cloud thermodynamic phase (ice/water composition). Preliminary results support the viability of this approach.
关键词： wire-grid polarizer,polarization,atmospheric science,optical nanostructures,polarimetry,form-birefringence
更新于2025-09-23 15:21:21