共查询到20条相似文献，搜索用时 15 毫秒
1.
Y. Divya S. Sanjeevi K. Ilamparuthi 《Journal of the Indian Society of Remote Sensing》2014,42(3):589-600
This paper examines the hyperspectral signatures (in the Visible Near Infrared (VNIR)-Shortwave Infrared (SWIR) regions) of soil samples with varying colour and minerals. 36 samples of sands (from river and beach) with differing clay contents were examined using a hyperspectral radiometer operating in the 350–2,500 nm range, and the spectral curves were obtained. Analysis of the spectra indicates that there is an overall increase in the reflectance in the VNIR-SWIR region with an increase in the content of kaolinite clay in the sand samples. As regards the red and black clays and sand mixtures, the overall reflectance increases with decreasing clay content. Several spectral parameters such as depth of absorption at 1,400 nm and 1,900 nm regions, radius of curvature of the absorption troughs, slope at a particular wavelength region and the peak reflectance values were derived. There exists a correlation between certain of these spectral parameters (depth, slope, position, peak reflectance, area under the curve and radius of the curve) and the compositional and textural parameters of the soils. Based on these well-defined relations, it is inferred that hyperspectral radiometry in the VNIR and SWIR regions can be used to identify the type of clay and estimate the clay content in a given soil and thus define its geotechnical category. 相似文献
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Spectral reflectance Studies have been carried out on various features (man-made as well as natural) with reference to urban environment using a portable spectro-radiometer in wavelength regions ranging from 0.45 to 1.0 μm of Kanpur city and its surrounding areas. The signature values, thus collected, were used to draw spectral reflectance curves of each feature separately and to determine/select the optimum wavelength regions suitable for urban area studies. It has been observed that the best band width suitable for urban feature discrimination are between 0.45 to 0.55 μm (blue region) & 0.69 to 0.80 μm (near-infrared region) of the spectrum. 相似文献
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Geological studies in the area around Badami, Bijapur District, Karnataka, were carried out with the help of Landsat imagery and aerial photographs. The study are forms a part Kaladgi Basin which is located on the northernmost fringes of the exposed Dharwar Craton. Archaen Peninsular Gneiss and intrusive Granodiorite/Granites (≈Clospet Granite) form the basement for the Middle to Late Proterozoic Kaladgi Super Group sediments which are, in turn, overlain in the north by the Upper Cretaceous to Lower Eocene Deccan flood basalt lavas. Geological mapping of the study area and inferences about the structural setup were primarily based on interpretation of the remotely sensed data. The combined interpretative study of Landsat imagery and aerial photographs was instrumental in mapping of the lithostratigraphic units exposed in the study area along with the structures associated with them. 相似文献
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Wasteland map (1∶100,000) of Rewasa catchment (Sikar district) has been prepared using aerial photographs and Landsat TM imagery. Thematic Mapper data were helpful in identifying the types of wastelands and details could be derived from the aerial photographs. The types of wastelands identified are sands, gullied land, salt affected areas, and barren rocky area. Depending upon the nature of wasteland, suitable rehabilitation measures like plantations, afforestation have been proposed. 相似文献
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Land cover classification and economic assessment of citrus groves using remote sensing 总被引：1，自引：0，他引：1
《ISPRS Journal of Photogrammetry and Remote Sensing》2007,61(5):341-353
The citrus industry has the second largest impact on Florida's economy, following tourism. Estimation of citrus area coverage and annual forecasts of Florida's citrus production are currently dependent on labor-intensive interpretation of aerial photographs. Remotely sensed data from satellites has been widely applied in agricultural yield estimation and cropland management. Satellite data can potentially be obtained throughout the year, making it especially suitable for the detection of land cover change in agriculture and horticulture, plant health status, soil and moisture conditions, and effects of crop management practices. In this study, we analyzed land cover of citrus crops in Florida using Landsat Enhanced Thematic Mapper Plus (ETM+) imagery from the University of Maryland Global Land Cover Facility (GLCF). We hypothesized that an interdisciplinary approach combining citrus production (economic) data with citrus land cover area per county would yield a correlation between observable spectral reflectance throughout the year, and the fiscal impact of citrus on local economies. While the data from official sources based on aerial photography were positively correlated, there were serious discrepancies between agriculture census data and satellite-derived cropland area using medium-resolution satellite imagery. If these discrepancies can be resolved by using imagery of higher spatial resolution, a stronger correlation would be observed for citrus production based on satellite data. This would allow us to predict the economic impact of citrus from satellite-derived spectral data analysis to determine final crop harvests. 相似文献
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In the vast alluvial plains of West Bengal and Orissa several deltaic plains exist, occurring in an off-lap sequence. These deltas were formed in the background of eustatic fluctuations during the Quaternary Period. They were built partly during rising sea level and pertly during stationary sea level stages. Landform analysis through aerial photographs as well as Landsat imagery interpretation, attested by field study, helped to establish the palaeogeomorphology of these Quaternary deltas. Possible mode of sedimentation during different phases of sea level fluctuations has been worked out 相似文献
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Paresh H. Rathod Carsten Brackhage Ingo Müller Freek D. Van der Meer Marleen F. Noomen 《Journal of the Indian Society of Remote Sensing》2018,46(12):1925-1937
The aim of this study was to monitor changes in leaf spectral reflectance due to phytoaccumulation of trace elements (Cd, Pb, and As) in sunflower mutant (M5 mutant line 38/R4-R6/15-35-190-04-M5) grown in spiked and in situ metal-contaminated potted soils. Reflectance spectra (350–2500 nm) of leaves were collected using portable ASD spectroradiometer, and respective leaves sample were analyzed for total metal contents. The spectral changes were quite noticeable and showed increased visible and decreased NIR reflectance for sunflower grown in soil spiked with 900 mg As kg?1, and in in situ metal-contaminated soils. These changes also involved a blue-shift feature of red-edge position in the first derivatives spectra, studied vegetation indices and continuum removed absorption features at 495, 680, 970, 1165, 1435, 1780, and 1925 nm wavelength. Correlograms of leaf-metal concentration and reflectance values show highest degrees of overall correlation for visible, near-infrared, and water-sensitive wavelengths. Partial least square and multiple linear regression statistical models (cross-validated), respectively, based on Savitzky–Golay filter first-order derivative spectra and combination of spectral feature such as vegetation indices and band depths yielded good prediction of leaf-metal concentrations. 相似文献
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Spectral feature fitting (SFF) is a commonly used strategy for hyperspectral imagery analysis to discriminate ground targets. Compared to other image analysis techniques, SFF does not secure higher accuracy in extracting image information in all circumstances. Multi range spectral feature fitting (MRSFF) from ENVI software allows user to focus on those interesting spectral features to yield better performance. Thus spectral wavelength ranges and their corresponding weights must be determined. The purpose of this article is to demonstrate the performance of MRSFF in oilseed rape planting area extraction. A practical method for defining the weighted values, the variance coefficient weight method, was proposed to set up criterion. Oilseed rape field canopy spectra from the whole growth stage were collected prior to investigating its phenological varieties; oilseed rape endmember spectra were extracted from the Hyperion image as identifying samples to be used in analyzing the oilseed rape field. Wavelength range divisions were determined by the difference between field-measured spectra and image spectra, and image spectral variance coefficient weights for each wavelength range were calculated corresponding to field-measured spectra from the closest date. By using MRSFF, wavelength ranges were classified to characterize the target's spectral features without compromising spectral profile's entirety. The analysis was substantially successful in extracting oilseed rape planting areas (RMSE ≤ 0.06), and the RMSE histogram indicated a superior result compared to a conventional SFF. Accuracy assessment was based on the mapping result compared with spectral angle mapping (SAM) and the normalized difference vegetation index (NDVI). The MRSFF yielded a robust, convincible result and, therefore, may further the use of hyperspectral imagery in precision agriculture. 相似文献
10.
Mehdi Amoon Gholam-ali Rezai-rad Mohammad Reza Daliri 《Journal of the Indian Society of Remote Sensing》2014,42(3):483-493
Target discrimination is the key step of automatic target detection in synthetic aperture radar (SAR) images. In this paper, a new algorithm, effective and robust feature sets for target discrimination in high resolution SAR images has been proposed. Two main steps in target discrimination of SAR images have been developed, the feature extraction based on Zernike moments (ZMs) having linear transformation invariance properties and the PSO based feature selection to select the optimal feature subset of Zernike moments for decreasing computational complexity of feature extraction step. The input regions of interest (ROIs) have been segmented and passed to a number of preprocessing stages such as histogram equalization, position and size normalization. Two groups of Zernike moments (shape and margin (intensity) characteristic) have been extracted from the preprocessed images and they have been applied to the feature selection step. Each group includes 34 moments with different orders and iterations. The selected moments have been applied to a SVM classifier. The proposed scheme has been tested on the MSTAR database. The Receiver Operational Characteristics (ROC) curve and the performance of proposed method using some measured data have been analyzed. Experimental results demonstrate the efficiency of the proposed approach in target discrimination of SAR imagery. 相似文献
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Mountain Glaciers are natural resources of fresh water and these affect the stream flow of the rivers, regional climate and further global climate. Observed trends and projected future evolutions of climate and Cryospheric variables clearly suggest a need to monitor these changes. Accordingly, the article presents the glacier features mapping using Hyperspectral remote sensing imagery. A freely available Hyperion satellite imagery acquired over Gepang Gath glacier in Himachal Pradesh, India is used for the study. Each class is identified based on their surface characteristics of spectral reflectance properties. Identification is simplified by demarcating the study glacier into accumulation and ablation areas through snowline. Accumulation area is characterized with high reflectance clean snow/ice and reduced moderate reflectance Snow/firn. The identification of classes in Hyperion imagery is validated using the spectral library from USGS and ASTER, and field spectra obtained from literature. 相似文献
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Utilising aerial photographs as the chief source of information an attempt has been made to study the land units, land use, land capability and limitations in relation to geomorphology of an area of about 350 sq. kms. in Krishna district of Andhra Pradesh. Besides identifying major individual landforms, the area is divided into four geomorphic environments each characterised by dominant landform pattern and relief. Each form and unit is described. Nine types of land units based on amount of slope and six land use classes were chosen after preliminary interpretation and a reconnaissance field check. The estimated range in slope is given for each land unit. The land’s capability and limitations are brought out from consideration of landforms, land units (slopes), nature of soil and water resources. Soil samples were collected from each geomorphic unit and analysed. The results are presented in the form of 3 maps and 2 tables, which may be of use for planning and development of the area. 相似文献
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Desertification is a severe stage of land degradation, manifested by “desert-like” conditions in dryland areas. Climatic conditions together with geomorphologic processes help to mould desert-like soil surface features in arid zones. The identification of these soil features serves as a useful input for understanding the desertification process and land degradation as a whole. In the present study, imaging spectrometer data were used to detect and map desert-like surface features. Absorption feature parameters in the spectral region between 0.4 and 2.5 μm wavelengths were analysed and correlated with soil properties, such as soil colour, soil salinity, gypsum content, etc. Soil groupings were made based on their similarities and their spectral reflectance curves were studied. Distinct differences in the reflectance curves throughout the spectrum were exhibited between groups. Although the samples belonging to the same group shared common properties, the curves still showed differences within the same group.Characteristic reflectance curves of soil surface features were derived from spectral measurements both in the field and in the laboratory, and mean reflectance values derived from image pixels representing known features. Linear unmixing and spectral angle matching techniques were applied to assess their suitability in mapping surface features for land degradation studies. The study showed that linear unmixing provided more realistic results for mapping “desert-like” surface features than the spectral angle matching technique. 相似文献
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针对全球导航卫星系统（global navigation satellite system,GNSS）拒止环境下大范围无人机视觉绝对定位问题,提出了一种聚合深度学习特征的卫星基准影像检索方法。首先,利用预训练的深度学习模型提取无人机与卫星基准影像的局部卷积特征;然后,对局部特征描述符进行聚合,生成影像全局表达;最后,利用影像全局特征进行相似性检索,并采用检索结果精匹配重排序的后处理方法,进一步提高检索准确率。设计了一个新的面向无人机绝对定位的卫星基准影像数据集并进行实验,结果表明,使用所提方法检索无人机影像适配区域的卫星基准影像的准确率达76.07%,可为后续基于视觉的无人机绝对定位提供参考。 相似文献
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Soil maps have been prepared hitherto by conventional ground surveys and by using aerial photographs. In this paper, the use of LANDSAT data for preparation of small scale soil maps upto association of sub-group level has been discussed. Typical spectral curves for various soils and landuse categories were given based on the mean spectral levels for each LANDSAT band obtained from Multispectral Data Analysis System (M-DAS). Soil characterization using the multispectral data could be done by both image oriented and numerically oriented approaches. The small scale soil maps thus prepared by using the satellite data could be used for regional planning and as map base for further detailed surveys. 相似文献
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Landsat imagery have been interpreted visually and under Additive Colour Viewer to interpret the regional geology and geomorphology in parts of Subarnarekha-Baitarani basin. The area lies south of Singhbhum shear zone and represents Precamrain shield. Important Simlipal ultrabasic volcanic complex of Orissa is included in the area. Although detailed map of the area is available, yet an attempt has been made to interpret the imagery for evaluating the results provided in comparison to the existing maps. Delineation of main lithological groups is possible. Having some data from the existing maps, lithoiogical boundary delineation of Mica Schist-Phyllite-Quartzite, Granites and Gneisses, Dhanjori Lava, Anorthosite-Gabbro Complex and Dolerite dykes, all of Precambrian age, has been done. Laterite and Quaternary sediments are also picked up. Lineament mapping has been carried out from imagery, which is difficult to map in the field. N--S and NNW-SSE lineament system is very prominent in Simlipal complex whereas in other parts NNW-SSE and NNE-SSW trends are common. The major fault plane running NNE-SSW in the area is responsible for the present-day configuration of Subarnarekha river. Identification of different geomorphological units is perhaps best done on imagery. Several geomorphic units like structural Hill, Denudational Hill, Pediment, Buried Pediment, Lateritic Clay Plain, Laterite upland, Terrace Plain etc have been mapped. Valley fills are wellpicked up from imagery. Hydrogeological potentiality of the different geologic and geomorphic units have been evaluated qualitatively. Ground water occurrence, movement and potentiality are mainly controlled by structural, geological and geomorphological set-up of the area. Buried Pediment, Laterite upland, Laterite clay plain and alluvial fills are the potential zones from the view point of ground water occurrences. Comparative study of the different Landsat bands and band-filter combinations under Additive Colour Viewer has been undertaken to find out the enhancement capability in delineating features. It is found that small scale geological and geomorphological maps can be prepared from Landsat imagery. 相似文献
20.
Kathleen M. Baker Andrew C. Johnson Caitlin N. Callahan Heather L. Petcovic 《制图学和地理信息科学》2016,43(2):176-187
Topographic maps and aerial photographs are particularly useful when geoscientists are faced with fieldwork tasks such as selecting paths for observation, establishing sampling schemes, or defining field regions. These types of images are crucial in bedrock geologic mapping, a cognitively complex field-based problem-solving task. Geologic mapping requires the geologist to correctly identify rock types and three-dimensional bedrock structures from often partial or poor-quality outcrop data while navigating through unfamiliar terrain. This paper compares the walked routes of novice to expert geologists working in the field (n = 66) with the results of a route planning and navigation survey of a similar population of geologists (n = 77). Results show clearly that those geologists with previous mapping experience make quick and decisive determinations about field areas from available imagery and maps, regardless of whether they are or not physically present in the field area. Recognition of geologic features enabled experts to form and verbalize a specific plan for travel through a landscape based on those features. Novices were less likely to develop specific travel route plans and were less likely to identify critical landscape cues from aerial photographs. 相似文献