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Kombinasi baseline data pengindraan jauh sistem aktif dan pasif memiliki banyak keuntungan dalam pemantauan dinamika genangan pesisir. Kedua jenis sensor satelit mengatasi kesenjangan informasi genangan, terutama pada area yang ditutupi awan/bayangan. Tujuan utama penelitian ini adalah untuk mengkaji dinamika genangan di wilayah pesisir Jakarta berdasarkan data multi-temporal sensor optik dari Landsat 8 dan Synthetic Aperture Radar (SAR) Sentinel 1A. Metode penelitian ini menggunakan dua algoritma indeks air. Algoritma tersebut yaitu Modified Normalized Difference Water Index (MNDWI) dan Dynamic Surface Water Extent (DSWE) berdasarkan nilai spektral reflektansi dan formula empirik. Metode lainnya adalah menggunakan nilai rata-rata koefisien backscatter air dari analisis polarisasi tunggal Vertikal Vertikal (VV) dan Vertikal Horisontal (VH). Hasil studi menunjukkan bahwa penggunaan kedua tipe data satelit dengan baseline data 8, 9, 15 dan 16 hari cukup efektif memantau dinamika genangan selama 8-49 hari, termasuk area yang tertutup awan dan bayangan. Berdasarkan nilai threshold dari MNDWI >0,123 dan koefisien backscattering air -19dB cukup efisien digunakan untuk mengesktrak informasi data satelit. Algoritma empiris tersebut menghasilkan kenampakan genangan, terutama di sepanjang tanggul pantai, waduk, ekosistem mangrove dan lahan terbangun. Hasil pemantauan satelit menunjukkan bahwa puncak genangan terjadi pada 30 Mei 2016 dan masih terlihat pada 15 Juni 2016. Kombinasi metode pengindraan jauh tersebut cukup efektif dan efisien untuk memantau genangan secara dinamis.

The present study addresses the potential of RADARSAT-2 data for Land Use Land Cover (LULC) Classification in parts of Ahmedabad, Gujarat, India. Texture measures of the original SAR data were obtained by the Gray Level Co-occurrence Matrix (GLCM). Results suggested False Colour Composite (FCC) of Mean, Homogeneity and Entropy showed a good discrimination of different land cover classes. Further, Principal Component Analysis (PCA) was also applied to the eight texture measures and FCC of Principal components is generated. Unsupervised classification is carried out for the above generated FCCs and accuracy assessment is carried out. The result of classification shows that the PCA generated from GLCM texture measures could obtain higher accuracy than using only the classification carried out by texture measures. Overall results of the study suggested possible use of single polarization and single date Radarsat-2 data for LULC classification with better accuracy using PCA generated image.

This study compares the accuracy of visually estimated ice concentrations by eight analysts at the Canadian Ice Service with three standards: (i) ice concentrations calculated from automated image segmentation, (ii) ice concentrations calculated from automated image segmentation that were validated by the analysts, and (iii) the modal ice concentration estimate by the group. A total of 76 predefined areas in 67 RADARSAT-2 images are used in this study. Analysts overestimate ice concentrations when compared to all three standards, most notably for low ice concentrations (1/10–3/10). The spread of ice concentration estimates is highest for middle concentrations (5/10, 6/10) and smallest for the 9/10 ice concentration. The overestimation in low concentrations and high variability in middle concentrations introduce uncertainty into the ice concentration distribution in ice charts. The uncertainty may have downstream implications for numerical modelling and sea ice climatology. Inter-analyst agreement is also measured to determine which classifier's ice concentration estimates (analyst or automated image segmentation) disagreed the most. It was found that one of the eight analysts disagreed the most, followed second by the automated segmentation algorithm. This suggests high agreement in ice concentration estimates between analysts at the Canadian Ice Service. The high agreement, but consistent overestimation, results in an overall accuracy of ice concentration estimates in polygons to be 39 %, 95 % CI [34 %, 43 %], for an exact match in the ice concentration estimate with calculated ice concentration from segmentation and, 84 %, 95 % CI [80 %, 87 %], for the ±1 ice concentration category. Only images with high contrast between ice and open water and well-defined floes are used: true accuracy is expected to be lower than what is found in this study.

Texture features are important characteristics in distinguishing collapsed buildings and intact buildings. However, texture features currently used in synthetic aperture radar (SAR) building damage assessment are extracted following the methods of optical images directly, which do not consider the statistical feature of speckles and limit the accuracy improving. Therefore, a statistical texture feature-G0-para-was proposed to reflect the homogeneity of buildings in complex urban areas after a disaster. The G0-para is arising from the G0 distribution of SAR image and used to distinguish collapse buildings and intact buildings. First, the G0-para is unified to satisfy different polarization data-single-/dual-/quad-/compact-polarization. Second, the distinguishing ability of G0-para is under comparison in single-/dual-/quad-/compact-polarization, through the receiver operating characteristic (ROC) curve and the area under the ROC curve analysis. Then, collapsed buildings with RADARSAT-2 and ALOS-1 data are evaluated, selecting the optimal combinations of each mode and comparing with the preferable existing texture features. The results show that the statistical texture parameter-G0-para-is better than the variance of gray-level histogram and the contrast of gray level co-occurrence matrix in distinguishing intact buildings and collapsed ones and G0-para can be applied to single-/dual-/quad-/compact-polarimetric SAR data. For experimental data, VV and HH in single polarization, VH/VV and HH/HV in dual polarization, and hybrid mode in compact polarization are recommended when the best quad polarization is unavailable.

In this paper we propose a novel type of highly-birefringent and ultra-wideband low-loss photonic crystal fiber (PCF) incorporating elliptical holes in the cladding and rhombic holes located along the transversal axes. The PCF is simulated and analyzed with finite-difference time-domain method. The properties of PCFs were investigated for various distribution, shape and size of air holes. For the optimized PCF design the birefringence reaches 8 × 10−3 at 1550 nm and the confinement loss is as low as 5 × 1 0 − 4 dB/km with single mode operation in an ultra-broad transmission band (500 nm–1800 nm). Furthermore, the single mode and single polarization transmission could be achieved in this PCF at longer wavelengths beyond 1600 nm. This kind of PCF has potentials in optical long haul communication and optical fiber sensing.

A polarization filter based on simple structure photonic crystal fiber (PCF) coated with gold air holes is designed in this work. The full vector finite element method (FEM) is used to calculate the characteristic parameters of PCF. In the final numerical simulation results, the loss peak in the [Formula: see text] polarization direction is 2305.72 dB/cm and the [Formula: see text]-polarized loss is as low as 75.86 dB/cm at 1.31 [Formula: see text]m. For the fiber length of 1000 [Formula: see text]m, the CT reaches 1936.83 dB and a wide bandwidth greater than 20 dB can provide above 800 nm. The content of this paper can provide a new idea for filter structure design.

The TerraSAR-X add on for Digital Elevation Measurement (TanDEM-X) mission provides Interferometric Synthetic Aperture Radar (InSAR) wall-to-wall data (not sparse) at high resolution and at global scale. In addition, the NASA Global Ecosystem Dynamics Investigation (GEDI) is a new spaceborne system that provides (from 51.6°N and 51.6°S) sparse measurements (not images) through LiDAR waveforms. Both systems are sensitivity to the canopy structure such as the forest height but with their own limitations. The TanDEM-X single polarization (HH) interferometric coherence magnitude at X-band provides a continuous mapping of the forest while GEDI provides accurate (but sparse) measurements of the forest. In this paper a methodology of how to combine both systems to estimated forest height is presented and applied to more than 900 TanDEM-X scenes over Gabon in Africa. The forest height results over an area of 1° by 1° are shown and compared respect to GEDI. Finally, a wall-to-wall forest map over the entire country of Gabon is presented as an example of large scale mapping towards a potential global (entire earth) forest height map.

When NASA/JPL UAVSAR imaged the curved and graded Coronado Bridge over San Diego Bay, CA, USA, it was shown as three separate features consisting of dots, short curved segments, and a continuously curved segment on the L-band images. Coupled with the images acquired in the opposite look directions toward the bridge, we analyzed the features, attributed the cause for the unidentifiable direct surface backscatter from the bridge roadway, and assessed the azimuth angle effects linked to the features. A two-step procedure was then articulated to resolve the azimuth angle effect on the decomposition of the quad-pol SAR imagery where orientated man-made objects and trees existed. Next, an algorithm using the single polarization data to estimate the curved and graded bridge height and width was developed. With reference to the Lidar-derived heights and the constant bridge width, we evaluated the algorithm using the difference values of 26 samples. L-HH and L-VV results of two UAVSAR datasets were obtained. Of the bridge height or width, the overall mean and one standard deviation values of the differences were ≤3.7 m and ≤2.8 m, respectively. The values were smaller than the azimuth and ground-range resolutions (5 m × 5 m) of the SAR datasets. Thus, the estimated bridge height and width should be acceptable. Finally, we studied the applicability of the algorithm to ALOS/PALSAR datasets of different data acquisition modes.

Changes in the soil moisture are a key factor in the deterioration of the ecological environment caused by mining geological disasters. In this study, which presents a case study of the arid and semi-arid aeolian sand mining area along the Inner Mongolia-Shaanxi Province boundary, a method for retrieving the soil moisture based on RADARSAT-2 SAR scattering data and Terra MODIS surface reflectance data was proposed. The retrieval of RADARSAT-2 mainly used the Alpha approximation model based on the change detection technique, a model proposed by Balenzano et al., which can effectively decouple the impact of surface vegetation and roughness on radar backscattering coefficient, when the volume scattering is not dominant. Using 12 periods of RADARSAT-2 HH polarization data in conjunction with the Alpha approximation model, a matrix equation was constructed, which contains 11 equations and 12 unknowns. To solve this underdetermined system, a bounded linear least-squares optimization was adopted. Once the unknowns were determined, the relative dielectric constant could be analytically derived and then the soil moisture could be estimated by using the dielectric mixing model and compared with the MODIS retrieval results based on the spatial feature method. Finally, the DInSAR results of RADARSAT-2 were used to investigate the effects of high-intensity underground mining activities on the surface soil moisture. The study found that the RADARSAT-2 soil moisture estimates demonstrated good consistency with the MODIS retrieval results. Among four comparison groups, the maximum correlation coefficient was 0.599, and the highest proportion of sampling points for which the absolute error was less than 3 % was 55.6 %. The absolute error of all of the sampling points did not exceed 10 %, which demonstrates the reliability of the RADARSAT-2 retrieval results. A comparison among the 72 soil moisture values from six mining subsidence areas and corresponding non-subsidence areas in the study area in 2012 showed that 38 soil moisture values from the non-subsidence areas were higher than those from the subsidence areas. These values accounted for 53 % of the total, indicating that high-intensity mining activities have a certain negative impact on the surface soil moisture, although this impact is slightly insignificant.

In this study, it is aimed to calculate snow density, depth, and snow water equivalent with the help of single polarization TerraSAR-X data. In this context, Mount Erciyes/Turkey was chosen as the pilot study area and TerraSAR-X data with HH polarization were used. In addition, in situ measurements were performed simultaneously with the satellite pass to be used as input and validation data for the model to be used. Also, snow densities were obtained by inverse approach, Kriging, and ISO-4355 methods. Snow densities, in situ measurements, and SAR data were integrated into the produced D-InSAR snow depth model; snow depth, snow volume, and snow water equivalent were estimated. Consequently, it has been revealed that the snow depth, snow volume, and snow water equivalent parameters vary according to the snow density-calculated methods. Also, in this study performed with a single polarization, it is revealed that snow parameters can be accessed without multiple polarization. Snow densities were evaluated separately for 0.31g/cm3 and 0.36 g/cm3, and snow depth, snow volume, and snow water equivalent maps were produced. Our study, which is supported by in situ measurements, has been shown to be consistent with the snow depth results in the region. Besides, the results of the model produced in the study were found to be compatible with in situ measurements. © 2021, Saudi Society for Geosciences., European Space Agency, ESA: 39890; Aksaray Üniversitesi: 2017-010, This study was supported by Aksaray University Scientific Research Projects Coordination Unit in 2017-010 and European Space Agency under the project number 39890 entitled “Calculation of Snow Depth and Volume from Radar Images; Erciyes Mountain Example.”

One-dimensional grating couplers based on hybrid silicon-LNOI platform for polarization-independent and high-efficient single-polarization coupling efficiencies are reported. Over 70% coupling efficiency for single polarization and 51% for polarization independent coupling designs can be achieved based on the simple uniform silicon grating design.

Graphical representations of the polarization state of an antenna or an electromagnetic wave propagating through space are useful tools to supplement rigorous mathematical analyses. One such example, the polarization ellipse, is frequently used in combination with the mathematical development of polarization theory. The Poincare sphere is another graphical representation but is much less widely used. Since each possible polarization state appears as a point on the surface of the sphere, it has limited value in representing a single polarization state. However, it can be quite useful for visualizing the relationships between multiple polarization states. In this paper, we show a different way of presenting the Poincare sphere using a Mercator projection and elliptical parameters. We also describe a tool that implements this technique and provides a real-time display of polarization state as a function of frequency.

Recent interest in dual polarization Synthetic Aperture Radar (SAR) systems, in which a single polarization is transmitted (e.g. linear horizontal or right circular), followed by reception of two orthogonal polarization, has lead to a novel approach to dual-pol SAR, the so-called compact polarimetric imaging (CPSAR) mode. This paper provides techniques that allow construction of pseudo quad-pol information from dual-polarization SAR systems based on a few simple assumptions. Compact polarimetry showed promise of being able to reduce the complexity, cost, mass, and data rate of a SAR system while attempting to maintain many capabilities of a fully polarimetric system.

In this paper, generation of specific inhomogeneous polarization distribution using single reflection from spatial light modulatoris demonstrated.An attempt hasbeen made to obtain cylindrical vector beams by modulation of single linear polarization component.

This paper tackles the problem of estimating 3D body shape of clothed humans from single polarized 2D images, i.e. polarization images. Polarization images are known to be able to capture polarized reflected lights that preserve rich geometric cues of an object, which has motivated its recent applications in reconstructing surface normal of the objects of interest. Inspired by the recent advances in human shape estimation from single color images, in this paper, we attempt at estimating human body shapes by leveraging the geometric cues from single polarization images. A dedicated two-stage deep learning approach, SfP, is proposed: given a polarization image, stage one aims at inferring the fined-detailed body surface normal; stage two gears to reconstruct the 3D body shape of clothing details. Empirical evaluations on a synthetic dataset (SURREAL) as well as a real-world dataset (PHSPD) demonstrate the qualitative and quantitative performance of our approach in estimating human poses and shapes. This indicates polarization camera is a promising alternative to the more conventional color or depth imaging for human shape estimation. Further, normal maps inferred from polarization imaging play a significant role in accurately recovering the body shapes of clothed people.

© COPYRIGHT SPIE. Downloading of the abstract is permitted for personal use only. To overcome the crosstalk happening between two degenerately fundamental modes of a fiber in Terahertz (THz) regime, a novel photonic crystal fiber (PCF) that yields a wide range of single-polarization-single-mode (SPSM) propagation with large loss differences (LDs) is designed. The method used to realize this SPSM PCF is to deposit an epsilon-near-zero (ENZ) material in four selected air holes in the cladding, which ends up with four ENZ rings. These ENZ rings introduce significant LDs between the wanted (X-polarized) and unwanted (Y-polarized and high order) modes. Extensive simulation results demonstrate that the LDs between the wanted and unwanted modes vary with the thickness of ENZ rings. With a very short length (4 cm) of the proposed PCF, pure SPSM propagation, i.e., the unwanted modes are 20 dB lower than the wanted mode, can be achieved from 1 to 1.2 THz.

A dual communication band single-polarization photonic crystal fibre polarizing filter based on surface plasmon resonance is presented in this paper. Numerical simulation results demonstrate that the resonance strength of x- and y-polarized direction can reach 569.83 and 719.25 dB.cm−1 simultaneously at the communication wavelength of 1.31 and 1.55 µm. By filling liquid analyte, the confinement loss of x- and y-polarized direction can simultaneously reach 831.7 and 580.53 dB.cm−1 at the wavelength of 1.31 and 1.55 µm. Furthermore, when the fibre length L is equal to 700 µm, the peak value of the crosstalk can reach 493.86 and −323.67 dB at the same time at the wavelength of 1.31 and 1.55 µm, and when the length of the fibre L is 400 µm, the bandwidths of the crosstalk better than 20 dB and less than −20 dB are about 160 and 210 nm, respectively. These performances make it an ideal candidate for designing dual-band polarization filter equipment.

The synthetic aperture radar scale-invariant feature transform (SAR-SIFT) algorithm has been applied to synthetic aperture radar (SAR) image registration and has good performance. However, compared with single polarization radar images, polarimetric synthetic aperture radar (PolSAR) images have more polarization combinations, which can obtain more polarization information. Therefore, based on the scattering mechanism of PolSAR, this paper proposes a registration algorithm suitable for PolSAR images. The algorithm improves the SAR-SIFT algorithm and uses the polarization information of the PolSAR images to introduce a new gradient definition and construct new scale spaces. The algorithm proposed in this paper is tested on multi-time and multi-angle PolSAR images. The experimental results show that the proposed method can make feature points more widely distributed and obtain more correct matching point pairs, which effectively improves the registration performance of PolSAR images.

We report a receiver using a single-polarization optical low-noise pre-amplifier and a burst-mode, time-gated clock recovery unit (CRU). Timing jitter and bit-error-ratio (BER) measurements are presented for data rates from 72 Mb/s to 2.880 Gb/s, both with and without atmospheric fading. At the lowest burst-mode data rate of 72 Mb/s, temporal gating improves the recovered clock’s timing jitter below receive power levels of −65 dBm, enabling comm-limited performance as opposed to CRU-limited performance. Gating extends the CRU and receiver range down to −88 dBm, a 3-dB sensitivity improvement over the non-gated case. For all data rates and channels measured, jitter values remain below 9 ps (3% of the clock period) with gating enabled. The BER performance is

We present the design and investigation of a single-polarization suspended-core fiber with an elliptical core consisting of crossed rectangular-shaped dielectric strips. By optimizing the fiber configuration parameters, single-polarization single-mode transmission with a bandwidth of 400 nm can be obtained. Also, the power fraction in air of the x-polarization fundamental mode is relatively high, which facilitates its applications in high precision sensors.

We propose a novel broadband single-polarization single-mode (SPSM) photonic crystal fiber with hexagonally latticed circular airholes. Combined with our fabricated polarization maintaining fiber, it has demonstrated that the enlarged air holes in the outmost layer are superior for the confinement loss reduction. At the optimized parameters, the wavelength of SPSM region ranges from 1.52 to 2.13 $\mu$ m, where only y-polarized fundamental mode exists and the confinement loss is 0.051 dB/km at 1.55 $\mu$ m. The influence of realistic fabrication errors involving structure deviation on SPSM operation has also been systematically investigated.

A segmented long period fiber grating (LPFG)-based torsion sensor with both high sensitivity and ability to discriminate torsion direction is proposed and experimentally investigated. The sensor is made up of three spatial orthogonal short LPFGs by using a CO2 laser notched method. Experimental results show that the torsion sensitivities can reach −0.54 and 0.33 dB/(rad/m) in dip depth and 0.30 and −0.14 nm/(rad/m) in resonance wavelength for clockwise and counterclockwise, respectively, in a single polarization state. Torsion rate and torsion direction can be measured simultaneously by the sensor. Moreover, the temperature sensitivity of the sensor has been determined as 0.067 nm/°C. Therefore, the proposed segmented-LPFG would have great potential applications in engineering and fiber sensors.

This article proposes the mapping of the concentration of sea ice in the oceanic region of the western Antarctic Peninsula using backscatter coefficients and textural features from synthetic aperture radar (SAR) C-band, horizontal single polarization (HH) images obtained by the Sentinel 1 A satellite sensor. Pure samples of open water and sea ice were obtained from SAR images with the aid of PlanetScope optical images during the austral winter. The statistical technique of logistic regression was applied to identify the best textural features to discriminate the two sampled targets. These selected textural features were used with the backscatter coefficients of SAR images in a maximum likelihood supervised classifier to analyze the images. With sea ice classified in the time series between 2016 and 2019 during winter and austral spring, the concentration of sea ice in the study region was calculated and mapped. The textural features statistically indicated by the logistic regression were gray level co-occurrence matrix (GLCM) Mean and GLCM Variance, resulting in the supervised classification having an accuracy of 86% and precision ranging from 86% to 98% in the validation stage.

We propose a systematic solution to the problem on dispersion engineering in single-polarization single-mode (SPSM) photonic crystal fibers (PCFs) for a nearly zero flattened profile. Based on dispersion-approximating and -normalizing methods as well as a clever engineering strategy, we have succeeded in a design of SPSM PCF with nearly zero flattened dispersion ${\text{0.82}}\pm {\text{0.30}}\,\text{ps}/\text{nm}/\text{km}$ over a broad band of ${\text{1.12}}\sim {\text{1.51}}\,\mu{\text{m}}$. Moreover, such a fiber presents a very low confinement-loss level, which is less than 0.001 dB/km over the operation band.

It is put forward that solar vector can be obtained with polarization sensors in this paper, which plays an important role as a great clue of navigation. First, the design of the polarization sensor is introduced with the extraction method of azimuth angle from the polarization pattern. Then, it is advanced that solar vector can be attained through observing different directions using one or two polarization sensors. Consequently, an experiment is conducted and the results indicate that both algorithms of measuring solar vector are feasible. For the method of measuring solar vector with two polarization sensors, the accuracy of solar azimuth angle is 0.2°(1σ), and the accuracy of solar elevation angle is 0.4°(1σ) approximately. By contrast, the accuracy is relatively low for the method of using single polarization sensor.

The wavelength-dependent polarization absorber based on multi-cladding fiber (MCF) with surface plasmon resonance (SPR) is proposed and demonstrated. In order to obtain the SPR effect both in the x- and y- polarized direction, the MCF is polished in two sides. The numerical simulations show that the polarization absorber with the wavelengths of 980/1550 nm and 1310/1550 nm can be obtained by adjusting the parameters of dielectric layer. Each wavelength only transmits a single polarization in the wavelength-dependent polarization absorber, and the loss of unwanted polarized mode is more than 95 dB/cm. In addition, when the length of fiber is only 550 µm, the bandwidths of polarization absorber are 29 nm at 980 nm and 413 nm at 1550 nm, respectively; meanwhile, the bandwidth of 1310/1550 nm polarization absorber reaches 102 nm and 302 nm, respectively.