- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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Improving NDVI by removing cirrus clouds with optical remote sensing data from Landsat-8 – A case study in Quito, Ecuador
摘要： The Andean region has a high cloud density throughout the year. The use of optical remote sensing data in the computation of environmental indices of this region has been hampered by the presence of clouds. To maximize accuracy in the computation of several environmental indices including the normalized difference vegetation index (NDVI), we compared the performance of two algorithms in removing clouds in Landsat-8 Operational Land Imager (OLI) data of a high-elevation area. The study area was Quito, Ecuador, which is a city located close to the equator and in a high-elevation area crossed by the Andes Mountains. The first algorithm was the automatic cloud removal method (ACRM), which employs a linear regression between the different spectral bands and the cirrus band. The second algorithm was independent component analysis (ICA), which considers the noise (clouds) as part of independent components applied over the study area. These methods were evaluated based on several images from different years with different cloud conditions. The results indicate that neither algorithm is effective over this region for the removal of clouds or for NDVI computation. However, after improving ACRM, the NDVI computed using ACRM showed a better correlation than ICA with the MODIS NDVI product.
关键词： Quito,optical remote sensing,cloud removal,NDVI,Landsat-8 OLI
更新于2025-09-10 09:29:36
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[Lecture Notes in Electrical Engineering] Advanced Multimedia and Ubiquitous Engineering Volume 518 (MUE/FutureTech 2018) || Superpixel Based ImageCut Using Object Detection
摘要： The edge preserving image segmentation required by online shopping malls or the design ?eld is clearly limited to pixel based image machine learning, making it dif?cult for the industry to accept the results of the latest machine learning techniques. Existing studies of image segmentation have shown that using any size square as a study unit without targeting meaningful pixels provides a simple method of learning, but produces a high error rate in image segmentation and also there is no way to calibrate the resulting images. Therefore, this paper proposes image segmentation techniques through superpixel based machine learning to develop technologies for automatically identifying and separating objects from images. In addition, the main reasons for superpixel based imagecut using object detection is to reduce the amount of data processed, thereby effectively delivering higher computational rates and larger image processing.
关键词： Removal image background,Superpixel,Image segmentation,Machine learning,Object detection
更新于2025-09-10 09:29:36
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[Lecture Notes in Computer Science] Pattern Recognition and Computer Vision Volume 11258 (First Chinese Conference, PRCV 2018, Guangzhou, China, November 23-26, 2018, Proceedings, Part III) || Large-Scale Visible Watermark Detection and Removal with Deep Convolutional Networks
摘要： Visible watermark is extensively used for copyright protection with the wide spread of online image. To verify its effectiveness, there are many researches attempt to detect and remove visible watermark thus it increasingly becomes a hot research topic. Most of the existing methods require to obtain the prior knowledge from watermark, which is not applicable for images with unknown and diverse watermark patterns. Therefore, developing a data-driven algorithm that suits for various watermarks is more significant in realistic application. To address the challenging visible watermark task, we propose the first general deep learning based framework, which can precisely detect and remove a variety of watermark with convolutional networks. Specifically, general object detection methods are adopted for watermark detection and watermark removal is implemented by using image-to-image translation model. Comprehensive empirical evaluation are conducted on a new large-scale dataset, which consists of 60000 watermarked images with 80 watermark classes, the experimental results demonstrate the feasible of our introduced framework in practical. This research aims to increase copyright awareness for the spread of online images. A reminder of this paper is that visible watermark should be designed to not only be striking enough for ownership declaration, but to be more resistant for removal attacking.
关键词： Watermark removal,Deep convolutional networks,Watermark detection,Visible watermark
更新于2025-09-10 09:29:36
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Materials Science and Technology of Optical Fabrication || Material Removal Rate
摘要： This chapter covers the last of the four major characteristics of optical fabrication, material removal rate (see Figure 1.6). As discussed in Chapter 1, the macroscopic material removal rate is governed by the Preston equation (Equation (1.3)), where removal rate largely scales linearly with applied pressure and relative velocity, and all the process and material parameters are lumped into the Preston coefficient kp. The Preston equation can be applied to both grinding (which is discussed in Section 5.1) and polishing (Section 5.2). The parameters that govern material removal rate and resulting surface roughness are intimately connected. Hence, the principles of the ensemble Hertzian multi-gap (EHMG) and island distribution gap (IDG) models, as discussed in Chapter 4, can be largely applied when discussing polishing material removal rate.
关键词： optical fabrication,IDG model,material removal rate,Preston equation,grinding,polishing,EHMG model
更新于2025-09-10 09:29:36
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Extendibility of a Thin-Cloud Removal Algorithm to Hi-Resolution Visible Bands of Sentinel-2 Data
摘要： The RTM-based algorithm developed to remove thin-cloud effects for Landsat-8 visible bands was extended to those of Sentine-2A visible bands. In the assessment of the extendibility, a cloud-covered Sentinel-2A image acquired on 18 February 2017 was downloaded. Another cloud-free Sentinel-2A image of the same area acquired on 8 February 2017 was selected as reference image. The three assumptions made in the original RTM-based algorithm were evaluated, and were valid for Sentinel-2A data. The algorithm was qualitatively and quantitatively effective in the thin-cloud removal for Sentinel-2A data of visible bands. Therefore, the algorithm developed for Landsat sensors was directly applicable to Sentinel-2 spectral data.
关键词： RTM-based algorithm,Thin clouds removal,Sentinel-2 spectral bands
更新于2025-09-10 09:29:36
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Impact of Cu particles on adsorption and photocatalytic capability of mesoporous Cu@TiO2 hybrid towards ciprofloxacin antibiotic removal
摘要： In this study, Cu@TiO2 hybrids consisting of Cu nanoparticles and mesoporous TiO2 nanoaggregates have been successfully synthesized through a simple reduction method. The Cu2+ concentration can not only engineer the mass ratio of Cu specie in the hybrids, but also tailored the size of Cu particles during this synthesis. The adsorption and photocatalytic performance towards degrading ciprofloxacin of the as-synthesized Cu@TiO2 hybrids were determined by the mass ratio as well as the Cu particle size of Cu@TiO2 in the hybrids. It was found that the Cu@TiO2 hybrid with low Cu content promoted photocatalytic performance, while high Cu content improves the adsorption efficiency. Among the as-prepared Cu@TiO2 samples, the 0.1-Cu@TiO2 sample with Cu particle content of 0.1 wt% displayed the best charge separation and transfer efficiency for photogenerated electrons and holes, and accordingly, presented the best photocatalytic efficiency, which is around 3 times higher than that for pure TiO2. In contrast, 10-Cu@TiO2 with 10 wt% Cu showed the highest adsorption capability (888.57 mg/g, about 5 times larger than that of TiO2), since it had the most negative zeta potential, although its Brunauer-Emmett-Teller surface area was less than that of the pure TiO2 material. This work has not only developed a facile approach to prepare Cu-based hybrids, but also reveals how Cu@TiO2 hybrids can be tailored and optimized for adsorption and photocatalytic removal of antibiotic pollution.
关键词： Antibiotic removal,Cu-TiO2 hybrid,Photocatalysis,Adsorption
更新于2025-09-10 09:29:36
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Synthesis of Flower-Like AgI/BiOCOOH p-n Heterojunctions With Enhanced Visible-Light Photocatalytic Performance for the Removal of Toxic Pollutants
摘要： In this study, flower-like AgI/BiOCOOH heterojunctions were constructed through a two-step procedure involving the solvothermal synthesis of BiOCOOH microflowers followed by AgI modification using a precipitation method. These novel photocatalysts were systematically examined by XRD, UV–vis DRS, SEM, TEM, EDS, and PL spectroscopy techniques. The AgI/BiOCOOH heterojunction were studied as a decent photocatalyst for the removal of the industrial dye (rhodamine B, and methyl blue) and antibiotic (tetracycline) under visible light. The AgI/BiOCOOH heterojunctions are much more active than bare BiOCOOH, and AgI, which could be ascribed to the improved separation of charge carriers, resulting from the formation of p-n heterojunction between two constituents. The holes (h+) and superoxide radical (?O?2 ) were detected as the main active species responsible for the pollutant degradation. The results showed that a highly efficient visible-light-driven photocatalytic system was developed for the decomposition of toxic pollutants.
关键词： antibiotic removal,dye removal,p-n heterojunction,AgI/BiOCOOH,photocatalysis
更新于2025-09-09 09:28:46
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Ghost and Noise Removal in Exposure Fusion for High Dynamic Range Imaging
摘要： For producing a single high dynamic range image (HDRI), multiple low dynamic range images (LDRIs) are captured with different exposures and combined. In high dynamic range (HDR) imaging, local motion of objects and noise in a set of LDRIs can influence a final HDRI: local motion of objects causes the ghost artifact and LDRIs, especially captured with under-exposure, make the final HDRI noisy. In this paper, we propose a ghost and noise removal method for HDRI using exposure fusion with subband architecture, in which Haar wavelet filter is used. The proposed method blends weight map of exposure fusion in the subband pyramid, where the weight map is produced for ghost artifact removal as well as exposure fusion. Then, the noise is removed using multi-resolution bilateral filtering. After removing the ghost artifact and noise in subband images, details of the images are enhanced using a gain control map. Experimental results with various sets of LDRIs show that the proposed method effectively removes the ghost artifact and noise, enhancing the contrast in a final HDRI.
关键词： Ghost Removal,High Dynamic Range Imaging,Exposure Fusion,Noise Removal
更新于2025-09-09 09:28:46
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Effect of the preparation method and metal content on the synthesis of metal modified titanium oxide used for the removal of salicylic acid under UV light
摘要： Titanium dioxide modified with Ag and Fe was synthesized using two preparation methods, characterized and applied to the photocatalytic degradation of salicylic acid in aqueous solution. The modified TiO2 samples were prepared by the sol-gel and wet impregnation methods starting from titanium(IV) isopropoxide and using AgNO3 and Fe(NO3)3·9H2O as precursors of the modifiers, with their content varying between 0 and 5 wt.%. Catalysts characterization was based on powder X-ray diffraction (PXRD), nitrogen physisorption at 77 K, temperature programmed reduction (H2-TPR), chemisorption of NH3 at 343 K and X-ray photoelectron spectroscopy (XPS). The photocatalytic degradation of salicylic acid by modified TiO2 was investigated under ultraviolet irradiation at 298 K considering various concentrations of the catalyst, between 100 and 1000 mgcatalyst/dm3, and of the organic molecule, between 0 and 15 mg/dm3. The catalysts most active in the degradation of salicylic acid were those having the highest Fe content.
关键词： salicylic acid removal,photocatalysis,sol-gel method,Doped titanium oxide,wet impregnation method
更新于2025-09-09 09:28:46
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End-of-life of silicon PV panels: A sustainable materials recovery process
摘要： In this paper, the management of end-of-life PV modules based on an advanced eco-sustainable process has been presented and discussed. The thermal removal of the polymeric compounds contained in c-Si PV modules has been investigated to separate and recover Si, Ag, Cu, Al and glass. A two-step thermal process has been employed. In the first step, the rear polymeric layer has been removed without emissions of dangerous fluorinated substances. In the second step, the remaining polymers have been completely removed with low volatile organic compounds (VOCs) emissions. The polymers degradation has been studied at combustion equivalent ratios U varying from 0.5 to 2 and at 500 °C. The materials recovery has been evaluated from an environmental point of view and optimized by considering the energy cost, through the identification of the best operating conditions, in terms of temperature, time, atmosphere and gas flow. One hour of heat treatment and a slightly oxidizing atmosphere have been enabled to separate and recover the different materials of the module. The elemental compositions of the PV sample and the residue condensed organic products have been determined. The gaseous degradation products have been characterized by gas chromatographic analysis (GC).
关键词： Recycling,Photovoltaic module,Thermal treatment,Polymer removal,Energy consumption
更新于2025-09-09 09:28:46