Automatic Extraction of Roads from UAV Using Thresholding and Morphometric Parameters

2020 ◽  
pp. 45-51
Author(s):  
R. Sree Ram ◽  
Srinivasa Raju Kolanuvada ◽  
M. Shanmugam
Keyword(s):  
Morphometric Parameters ◽  
Automatic Extraction

scholarly journals Extração Automática de Drenagem: uma Análise Comparativa a Partir de Diferentes Ferramentas e Bases de Dados (Draining automatic extraction: a comparative analysis of different from the tools and databases )

2016 ◽  
Vol 9 (6) ◽  
pp. 1849
Author(s):  
Reurysson Chagas de Sousa Morais ◽  
Marta Celina Linhares Sales
Keyword(s):  
Large Scale ◽  
River Basins ◽  
Morphometric Parameters ◽  
Topographic Mapping ◽  
Automatic Extraction ◽  
Drainage Network ◽  
Computational Tools ◽  
Digital Elevation ◽  
Elevation Model ◽  
Manual Correction

A necessidade de planejamento e gerenciamento de bacias hidrográficas tem incitado pesquisa que buscam compreender sua dinâmica hidrológica. Em regiões que apresentam carência de mapeamento topográfico em grande escala, é comum o uso de modelos digitais de elevação (MDE) para extração automática da rede de drenagem, delimitação de bacias hidrográficas e obtenção de parâmetros hidrográficos e morfométricos. Diante deste cenário o presente trabalho teve como objetivo avaliar a eficiência de duas ferramentas computacionais (Hydrology e TauDEM) e três bases de dados (SRTM, AGEDM e AW3D) para a extração de rede de drenagem e cálculo de parâmetros hidrográficos. Concluiu-se que o software TauDEM representa a melhor solução da extração de drenagem, pois minimiza a geração de drenagem retilínea e paralela em áreas de relevo plano. Dentre as bases de dados, a drenagem extraída dos dados AW3D apresentaram maior correspondência com drenagem de referência do IBGE. De modo geral, os parâmetros morfométricos calculados para a Bacia Hidrográfica do Alto Gurguéia (BHAG), a partir das três bases de dados selecionadas, não apresentaram diferenças significativas, indicando o potencial das ferramentas e bases de dados para análises hidrográficas de médias e grandes bacias. Em todo caso, recomenda-se a inspeção e correção manual da rede de drenagem ao aplicar qualquer método de extração automática, com o intuito de reduzir os erros decorrentes das limitações dos softwares.   A B S T R A C T The need for planning and management of river basins has prompted research that seek to understand their hydrological dynamics. In regions with lack of topographic mapping on a large scale, it is common to use digital elevation models (DEM) for automatic drainage network extraction, delineation of watersheds and obtain hydrographic and morphometric parameters. Against this background the present study aimed to evaluate the efficiency of two computational tools (Hydrology and TauDEM) and three databases (SRTM, AGEDM and AW3D) for drainage network extraction and calculation of hydrographic parameters. It was concluded that the TauDEM software is the best solution drain extraction, because it minimizes the generation of rectilinear and parallel drainage in flat terrain areas. Among those databases, the drainage extracted of the AW3D data had higher correlation with the IBGE reference drainage. Overall, the morphometric parameters calculated for the basin of the Upper Gurguéia (BHAG), from the three selected databases, no show significant differences, indicating the potential of tools and databases for hydrographic analysis of averages and large basins. In any case, it is recommended to inspection and manual correction of the drainage network when applying any automatic extracting method, in order to reduce errors due to limitations of the software. Keywords: Drainage Neytwork. Digital Elevation Model. Geoprocessing.  

Clinical and Radiographic Correlation (According to CT) in Patients with Degenerative Lumbar Spinal Stenosis

2017 ◽  
pp. 124-130 ◽  
Author(s):  
S. G. Mlyavykh ◽  
A. Y. Aleynik ◽  
A. E. Bokov ◽  
M. V. Rasteryaeva ◽  
M. A. Kutlaeva
Keyword(s):  
Ct Scan ◽  
Spinal Canal ◽  
Clinical Manifestations ◽  
Intervertebral Discs ◽  
Morphometric Parameters ◽  
Neurogenic Claudication ◽  
Clinical Group ◽  
Lumbar Stenosis ◽  
Degenerative Lumbar Spinal Stenosis ◽  
Lumbar Spinal

Сomputed tomography (CT) is widely used in the diagnosis of  degenerative pathology of the lumbar spine, but the relationship  between clinical manifestations of lumbar stenosis and its anatomical prerequisites has not been sufficiently studied to date.The objective: to determine the significance of the morphometric  parameters of lumbar stenosis according to CT scans and to  establish their relationship with the prevailing symptoms of the disease.Material and methods. Seventy-five consecutive patients with  clinically significant lumbar stenosis who underwent CT scan before  surgery were enrolled in this study. The average values of thirteen  different morphometric parameters were calculated at LIII–SI levels of the intervertebral discs and of the pedicels in the axial and sagittal views. The possibility of classification of clinical observations and the correlation of morphometric parameters with the clinical forms of lumbar stenosis were investigated using discriminant and logistic regression analysis. Results. CT scan with high probability allocates patients with  predominant symptoms of neurogenic claudication or bilateral  radiculopathy. The most significant morphometric predictors of this  clinical group are the depth of the lateral recesses and the cross-sectional area of the spinal canal.Conclusion. CT scan significantly expands the informative value of  magnetic resonance imaging and can be used in planning the  decompressive stage of the surgery intervention in patients with lumbar spinal canal stenosis.

The influence of pregnancy on the change in morphometric parameters of the vision organ

2020 ◽  
pp. 28-29
Author(s):  
K.I. Manaenkov ◽  
◽  
A.A. Morozov ◽  
A.A. Chestnykh ◽  
E.N. Khomyakova ◽  
...  
Keyword(s):  
Morphometric Parameters

Актуальность. Нормально протекающую беременность принято считать особым физиологическим состоянием организма женщины. Интерес к изменению органа зрения у беременных в различные триместры обусловлен как выявлением офтальмологической патологии, а также выбором тактики ведения родов, постановки терапевтического и акушерского диагноза. Цель. Изучить морфометрические показатели плотности макулярного пигмента и толщины хориоидеи при миопии различной степени в первом и третьем триместрах беременности. Материал и методы. В открытое проспективное рандомизированное исследование вошли 38 соматически здоровых беременных (76 глаз). Средний возраст составил 29±4,3 лет (22-39 лет). Миопия слабой (МСлС) наблюдалась у 38% пациенток, средней (МСС) у 42%, высокой (МВС) 20% соответственно. Помимо стандартного офтальмологического обследования применяли фоторегистрацию глазного дна с определением плотности макулярного пигмента (показателей объема и площади) с помощью цифровой фундус-камеры VISUCAM 500 фирмы ZEISS Meditec, Inc. (Германия) и проводили анализ изменений слоёв сетчатки и толщины хориоидеи с помощью SPECTRALIS HRA+OCT (HEIDELBERG ENGINERING GmbH, Germany). Результаты. Выявлено достоверное снижение оптической плотности макулярного пигмента в среднем на 18%±3,5% (p<0,001) при сравнении показателей I и III триместра у беременных при миопии и увеличение толщины хориоидеи при МВС на 8,16%, МСС на 6,53%, МСлС на 8,28% при p<0,05 во всех группах. Эквивалентное изменение в противоположных направлениях толщины хориоидеии и объёма распределения макулярного пигмента подтверждено обратным коэффициентом корреляции -0,89. Выводы. Выявлена достоверная прямая зависимость между снижением площади и объёма распределения макулярного пигмента, увеличением толщины хориоидеи во время беременности и возникновением ретинальной патологии. Полученные данные можно использовать для выявления ранних патологических изменений со стороны органа зрения.

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