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2-D delineation of individual citrus trees from UAV-based dense photogrammetric surface models 总被引：1，自引：0，他引：1
One of the challenges of remote sensing and computer vision lies in the three-dimensional (3-D) reconstruction of individual trees by using automated methods through very high-resolution (VHR) data sets. However, a successful and complete 3-D reconstruction relies on precise delineation of the trees in two dimensions. In this paper, we present an original approach to detect and delineate citrus trees using unmanned aerial vehicles based on photogrammetric digital surface models (DSMs). The symmetry of the citrus trees in a DSM is handled by an orientation-based radial symmetry transform which is computed in a unique way. Next, we propose an efficient strategy to accurately build influence regions of each tree, and then we delineate individual citrus trees through active contours by taking into account the influence region of each canopy. We also present two efficient strategies to filter out erroneously detected canopy regions without having any height thresholds. Experiments are carried out on eight test DSMs composed of different types of citrus orchards with varying densities and canopy sizes. Extensive comparisons to the state-of-the-art approaches reveal that our proposed approach provides superior detection and delineation performances through supporting a nice balance between precision and recall measures. 相似文献
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Maria Alp Barbara L. Peckarsky Stefano M. Bernasconi Christopher T. Robinson 《Aquatic Sciences - Research Across Boundaries》2013,75(4):595-606
Stable isotopes (13C and 15N) are widely applied in studies of trophic links. We used this method to investigate the contribution of aquatic and terrestrial prey to the diet of riparian predatory arthropods in two mountain headwater streams in Colorado, USA. Aquatic and terrestrial prey and riparian predators were collected during summer 2009. To evaluate the reliability of conclusions based on stable isotope ratios, we compared the isotopic signatures of aquatic larval and terrestrial adult stages of three abundant stream insect species and assessed variation in mixing model estimates for spider diet composition under varying assumptions for trophic fractionation. Adult isotopic signatures of some aquatic prey species were indistinguishable from those of prey species with exclusively terrestrial life histories (stoneflies: 13C and 15N, chironomids: 13C). Other prey had distinctly aquatic isotopic signatures as both larvae and adults (a mayfly and a caddisfly). There was no evidence that prey with aquatic isotopic signatures contributed to the diet of the spiders near one stream. For the other stream, mixing model analysis suggested that chironomids were included in the diets of lycosid, linyphiid and liocranid spiders. Reliable estimates of the contributions of prey sources were compromised by the sensitivity of mixing models to assumptions on trophic fractionation and the presence of “isotopically cryptic” prey. This study emphasizes the importance of supporting isotope-based studies on cross-boundary trophic links with data on isotopic shifts in prey with complex life cycles and assessment of fractionation rates specific to the study system. 相似文献
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Mustafa Evren Ersahin Recep Kaan Dereli Hale Ozgun Berivan Gunes Donmez Ismail Koyuncu Mahmut Altinbas Izzet Ozturk 《洁净——土壤、空气、水》2011,39(6):543-548
Baker's yeast industry has significant effects on environment due to significant water consumption and high strength wastewater production. Effluents from baker's yeast industry are characterized by high concentrations of biological oxygen demand (BOD5), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN), total dissolved solids (TDS), sulfate, and dark brown color. The aim of this study is to provide a detailed quantitative and qualitative identification and characterization of the wastewater sources from different processes of a baker's yeast industry. It is identified that the most polluted wastewater components of the facility are coming from rotary drum filter and evaporation process. However, the highest pollution loads is identified as tank and equipment cleaning effluent due to very high flow rate from this source. The efforts should be on the way to minimize the water usage for the tank and equipment cleaning process, and to recycle less polluted waste streams back to the process. 相似文献
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Yılmaz Muhammet Alp Harun Tosunoğlu Fatih Aşıkoğlu Ömer Levend Eriş Ebru 《Natural Hazards》2022,110(2):1039-1060
Natural Hazards - Environmental changes have led to non-stationary flood risks in coastal cities. How to quantitatively characterize the future change trend and effectively adapt is a critical... 相似文献
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In this study, the removal of free cyanide from aqueous solutions by activated carbon was investigated. Effects of metal impregnation (Cu and Ag), aeration, and concentrations of adsorbent and cyanide on the rate and extent of the removal of cyanide were studied. The results have shown that the capacity of activated carbon for the removal of cyanide can be significantly improved (up to 6.3-fold) via impregnation of activated carbon with metals such as copper and silver. Silver-impregnated activated carbon was found to be the most effective at the reduction of cyanide level in solution. This appeared to be coupled with its comparatively high metal content after impregnation process where silver (5.07%) could be more readily loaded on activated carbon than copper (0.43%). Kinetics and equilibrium data for cyanide removal by plain and metal-impregnated activated carbons were determined to be consistent with the pseudo second-order kinetics and the Langmuir adsorption isotherms, respectively. Aeration (0.27 l/min) was found to exert a profound effect on the process leading to a 5.5–49.1% enhancement in the performances of plain and metal-impregnated activated carbons. This enhancement could be attributed to the increase in the availability of active sites on activated carbon for adsorption and the catalytic oxidising activity of activated carbon in the presence of oxygen. Practical limiting capacity of plain, copper- and silver-impregnated activated carbons for the removal of cyanide were experimentally determined to be 19.7, 22.4 and 29.6 mg/g, respectively. 相似文献
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Hale Ozgun Mustafa Evren Ersahin Selime Erdem Burcu Atay Sema Sayili Esra Eren Pelin Hoshan Doga Atay Mahmut Altinbas Cumali Kinaci Ismail Koyuncu 《洁净——土壤、空气、水》2013,41(12):1175-1182
A reliable wastewater characterization is a prerequisite for the selection of an acceptable treatment strategy for produced water which exhibits significant differences due to the varied kinds of wells, seasonal changes, and formation types. A complete characterization of produced water generated from oil, gas, and oil–gas fields in Turkey was performed based on seasonal and locational variations. The results showed that the produced water generated from oil field wells was highly polluted and wastewater volume was higher in comparison to gas and oil–gas field wells. Besides, the characterization of produced water was varying in a wide range based on seasonal and locational variations. Useful relationships were observed between chloride, sodium, bromide, and total dissolved solids concentrations. The results can be used in the design, operation, and optimization of wastewater treatment systems of petroleum and oil industries for future studies. 相似文献
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Comparison of fundamental properties of new types of fiber‐mesh‐reinforced seismic isolators with conventional isolators 
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下载免费PDF全文 New types of fiber‐reinforced rubber‐based seismic isolators have been a research interest for a number of engineers in the past decade. These new types of isolators can have similar seismic performances compared with the conventional ones. In most of the previous researches, the fiber‐reinforced rubber‐based isolators is usually manufactured with placing fiber sheets between precut rubber layers with the use of a bonding agent. This research differs from the previous researches in terms of manufacturing process, use of fiber mesh instead of fiber sheets, and use of lead in the core for some of the bearings. The aim of this research is to provide comparisons in fundamental seismic response properties of the new type of fiber mesh reinforced isolators and conventional isolators. In this scope, four pairs of fiber mesh reinforced elastomeric bearings and four pairs of steel‐reinforced elastomeric bearings are subjected to various levels of compression stresses and cyclic shear strains under constant vertical pressure. The tested types of isolators are fiber mesh reinforced elastomeric bearing, fiber mesh reinforced elastomeric bearing with lead core, steel‐reinforced elastomeric bearings, and steel‐reinforced elastomeric bearings with lead core. In this research, steel‐reinforced bearings are called conventional isolators. The major advantage for fiber mesh reinforced bearings observed during the tests is that these isolators can develop a considerable low horizontal stiffness compared with the conventional isolators. The damping characteristics of the new and conventional types are similar to each other. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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Interoperability is becoming essential for the today’s geographic information systems. Geographic information is usually available as datasets stored in databases and accessible via GIS. However, these information sources are increasingly heterogeneous and show differences in data formats, database schema and object concepts. To satisfy the increased demand for the use and sharing of geographic data in common applications, considering the heterogeneity and the methods to support interoperability are required by the GIS community. The implementation of Spatial Data Infrastructure (SDI) such as the European INSPIRE (Infrastructure for Spatial Information in the European Community) enables accessibility and the sharing of geographic data and interoperability among the systems. In addition to this, traditional GIS systems perform spatial queries using a keyword-based method. However, this approach remains incapable of fully expressing the users' needs due to a lack of geographic concepts (semantics) in the dataset. Different terms may refer to similar concepts, while the same terms may refer to different concepts. This causes semantic heterogeneity in the dataset. In this context, the most promising approach is the implementation of geospatial semantics by means of ontology in the geospatial dataset to overcome this kind of ambiguity. The aim of this research is to investigate the implementation of INSPIRE as a SDI standard and the use of Semantic Technology to empower the traditional GIS approach. In this regard, a public transportation geoportal has been developed for the experimental investigation which uses a revised sample transportation data complaint with the INSPIRE Transport Network Data Theme and a developed Transportation Ontology Domain, including concepts, relationships and individuals to provide a semantic spatial search. 相似文献