- 标题
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Multi-resolution Image Fusion in Remote Sensing () || Literature Review
摘要： In many remote sensing applications, the spatial information of a fused image is as important as the spectral information. In other words, it is necessary to have images that have the spectral resolution of multi-spectral (MS) images and the spatial resolution of a panchromatic image. A sensor with spatial and spectral resolution, at the same time is hardly feasible [139]. The coarse spatial resolution of MS images is the result of a trade off due to physical and technical constraints. The quantity of light energy which arrives onto the detector is proportional to the width of its spectral range and hence, is smaller in the MS sensor than in the Pan sensor. It is therefore necessary to increase the energy that impinges onto the MS detector to obtain acceptable signal-to-noise ratio. However, this is not possible due to technological limitations. Further, if the MS images had high spatial resolution, the amount of data to transmit would be larger. The difficulties in on-board storage and data transmission to the ground also restrict the spatial resolution of MS images. This makes the remote sensing satellite sensors acquire MS images with low spatial resolution and the Pan image with high spatial resolution. Thus, the MS images have high spectral but low spatial resolution and the Pan image has high spatial but low spectral resolution.
关键词： image fusion,remote sensing,spectral resolution,spatial resolution,multi-spectral images,panchromatic image,Pan-sharpening
更新于2025-09-04 15:30:14
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Multi-resolution Image Fusion in Remote Sensing () || Image Fusion Using Different Edge-preserving Filters
摘要： In this chapter, we discuss fusion approaches using two edge-preserving filters, namely, guided filter and difference of Gaussians (DoGs). Since the MS and Pan images have high spectral and high spatial resolutions, respectively, one can obtain the resultant fused image using these two images by injecting the missing high frequency details from the Pan image into the MS image. The quality of the final fused image will then depend on the method used for the extraction of high frequency details and also on the technique for injecting those details into the MS image. In the literature on multi-resolution image fusion, various approaches have been proposed based on the aforementioned process that also include state-of-the-art methods such as additive wavelet luminance proportional (AWLP) [178] and generalized Laplacian pyramid-context based decision (GLP-CBD) [13]. Motivated by these works, we first address the fusion problem by using different edge-preserving filters in order to extract the high frequency details from the Pan image. Specifically, we have chosen the guided filter and difference of Gaussians (DoGs) for detail extraction since these are more versatile in applications involving feature extraction, denoising, etc.
关键词： image fusion,multi-resolution,edge-preserving filters,remote sensing,guided filter,difference of Gaussians
更新于2025-09-04 15:30:14
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Eu <sup>3+</sup> /Tb <sup>3+</sup> functionalized Bi-based metal–organic frameworks toward tunable white-light emission and fluorescence sensing applications
摘要： The rational design strategy to construct lanthanide ion functionalized metal organic frameworks (MOFs) has attracted tremendous attention as they are promising candidates for developing novel long-lived and tunable luminescence materials and optical sensors owing to their intense, luminescence performances. In this work, a series of Eu3+/Tb3+ singly doped or codoped bismuth-based MOFs were prepared under in situ facile solvothermal conditions using BiOBr nanoplates as bismuth resources. A red-green-blue-based trichromatic white-light emission can be finely achieved by modulating the doping ratio of Eu3+/Tb3+ in the blue-emitting Bi-MOF host material and such photoluminescence tuning can also be realized by controlling the excitation wavelength. In addition, the Eu3+/Tb3+ singly incorporated Bi-MOF can serve as a multifunctional fluorescent probe for sensing Fe3+ and Cr2O7 2? ions in aqueous solution, as well as small organic pollutants of acetone molecules, and their sensing mechanisms have also been analyzed. These lanthanide ion functionalized Bi-MOF materials exhibit great potential in exploring white-light emitting devices and construction of supersensitive multifunctional sensors.
关键词： Eu3+/Tb3+ doped Bi-MOF,solvothermal synthesis,lanthanide ion functionalized MOFs,white-light emission,fluorescence sensing
更新于2025-09-04 15:30:14
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Monitoring Crop Evapotranspiration and Crop Coefficients over an Almond and Pistachio Orchard Throughout Remote Sensing
摘要： In California, water is a perennial concern. As competition for water resources increases due to growth in population, California’s tree nut farmers are committed to improving the efficiency of water used for food production. There is an imminent need to have reliable methods that provide information about the temporal and spatial variability of crop water requirements, which allow farmers to make irrigation decisions at field scale. This study focuses on estimating the actual evapotranspiration and crop coefficients of an almond and pistachio orchard located in Central Valley (California) during an entire growing season by combining a simple crop evapotranspiration model with remote sensing data. A dataset of the vegetation index NDVI derived from Landsat-8 was used to facilitate the estimation of the basal crop coefficient (Kcb), or potential crop water use. The soil water evaporation coefficient (Ke) was measured from microlysimeters. The water stress coefficient (Ks) was derived from airborne remotely sensed canopy thermal-based methods, using seasonal regressions between the crop water stress index (CWSI) and stem water potential (Ψstem). These regressions were statistically-significant for both crops, indicating clear seasonal differences in pistachios, but not in almonds. In almonds, the estimated maximum Kcb values ranged between 1.05 to 0.90, while for pistachios, it ranged between 0.89 to 0.80. The model indicated a difference of 97 mm in transpiration over the season between both crops. Soil evaporation accounted for an average of 16% and 13% of the total actual evapotranspiration for almonds and pistachios, respectively. Verification of the model-based daily crop evapotranspiration estimates was done using eddy-covariance and surface renewal data collected in the same orchards, yielding an R2 ≥ 0.7 and average root mean square errors (RMSE) of 0.74 and 0.91 mm·day?1 for almond and pistachio, respectively. It is concluded that the combination of crop evapotranspiration models with remotely-sensed data is helpful for upscaling irrigation information from plant to field scale and thus may be used by farmers for making day-to-day irrigation management decisions.
关键词： thermal images,pistachio,almond,evapotranspiration,CWSI,remote sensing
更新于2025-09-04 15:30:14
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Classification of Rice Heavy Metal Stress Levels Based on Phenological Characteristics Using Remote Sensing Time-Series Images and Data Mining Algorithms
摘要： Heavy metal pollution in crops leads to phenological changes, which can be monitored by remote sensing technology. The present study aims to develop a method for accurately evaluating heavy metal stress in rice based on remote sensing phenology. First, the enhanced spatial and temporal adaptive reflectance fusion model (ESTARFM) was applied to blend Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat to generate a time series of fusion images at 30 m resolution, and then the vegetation indices (VIs) related to greenness and moisture content of the rice canopy were calculated to create the time-series of VIs. Second, phenological metrics were extracted from the time-series data of VIs, and a feature selection scheme was designed to acquire an optimal phenological metric subset. Finally, an ensemble model with optimal phenological metrics as classification features was built using random forest (RF) and gradient boosting (GB) classifiers, and the classification of stress levels was implemented. The results demonstrated that the overall accuracy of discrimination for different stress levels is greater than 98%. This study suggests that fusion images can be utilized to detect heavy metal stress in rice, and the proposed method may be applicable to classify stress levels.
关键词： ensemble model,feature selection,time-series,MODIS and Landsat,remote sensing phenology,heavy metal stress
更新于2025-09-04 15:30:14
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A Fiber Bragg-Grating-Based Miniature Sensor for the Fast Detection of Soil Moisture Profiles in Highway Slopes and Subgrades
摘要： A fiber Bragg grating (FBG)-based aluminum oxide tube packed sensor (ATPS) was developed for the fast detection of the soil moisture profile in highway slopes and subgrades. The novel ATPS consists of an aluminum oxide tube with a diameter of 5 mm, an optical fiber containing a quasi-distributed FBG sensors, a “U”-shaped resistance wire, and a flange. There are four 0.9-mm diameter holes in the ATPS. Laboratory experiments were carried out to calibrate the relationship between the thermal response of ATPS and the soil moisture content. Two laboratory rainfall validation model tests were performed to validate the ATPS for capturing the soil moisture profile in highway slopes and subgrades. During the validations, the accuracy of the ATPS was quantified, and water infiltration through grassy and grassless ground surfaces were investigated. The calibrations indicate that the ATPS can detect and record real-time changes in the highway slope and subgrade moisture after rainfall, and reveal the most dangerous zones that occur at the connection between different construction materials. The average measurement accuracy of soil moisture monitoring was 0.015 m3/m3. Please note that the connection is where cracks form easily and the soil hydraulic conductivity increases significantly. The test results also indicate that grassy cover (lawn) significantly prevents water infiltration during the first few minutes of rainfall (twelve minutes in this study), after which, however, the infiltration rate drops sharply. The influence of lawn on water infiltration depends on the soil structure, hydraulic conductivity, and rainfall time. In summary, due to its small size and fast detection, the ATPS is a portable probe that can be used for moisture monitoring in highway slopes and subgrades.
关键词： temperature sensing,aluminum oxide tube packed sensor (ATPS),highway slope and subgrade,fiber Bragg grating (FBG),soil moisture
更新于2025-09-04 15:30:14