نتایج جستجو برای: standard ellipse

تعداد نتایج: 519492  

1980
K. L. Brown

Ray optics and phase ellipse Optics are developed as tools for designing charged particle beam guidance systems. Specific examples of basic optical systems and of phase ellipse matching are presented as illustrations of these mathematical techniques. Presented at the Conference on Charged Particle Optics Giessen, West Germany September 8-12, 1980 also submitted to Nuclear Instruments and Method...

Journal: :محیط شناسی 0
حمیدرضا جعفری استاد مدیریت و برنامه ریزی محیط زیست، دانشکدۀ محیط زیست، دانشگاه تهران سیروس حسن پور دانشجوی کارشناسی ارشد سنجش از دور و gis، دانشکدۀ جغرافیا، دانشگاه تهران لیلا رحیلی خراسانی دانشجوی کارشناسی ارشد مهندسی زمین شناسی، دانشکدۀ علوم پایه، دانشگاه آزاد واحد علوم و تحقیقات تهران احمد پور احمد استاد جغرافیا و برنامه ریزی شهری، دانشکدۀ جغرافیا، دانشگاه تهران

introduction: the process of urbanism in countries that are developing, like islamic republic of iran with increasing of the number and the size of cities and the fast accepting of population have been caused the forming of problems like an in-official economics and in-official settlement and was become creating high population in main and old places of city and increasing of air pollution and ...

Journal: :Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics 2000
Kleman Lavrentovich

The most frequently observed focal conic domains (FCD's) in lamellar phases are those based on confocal paris of ellipse and hyperbola. Experimentally, the eccentricity of the ellipse takes a broad range of values 0</=e<1. We present an analytical expression for the curvature energy of a FCD that is valid in the entire range 0</=e<1. Generally, the curvature energy of an isolated FCD reaches a ...

Journal: :J. Electronic Imaging 1994
Peng-Yeng Yin Ling-Hwei Chen

We propose a new approach for detecting ellipses. The approach is based on the geometrical property that five points on an ellipse can determine the parameters of the ellipse, and the symmetry of ellipses is used to obtain these points. Using symmetry, we classify the edge points in an input image into several subimages. Ellipses with different symmetric axes will lie in different subimages. In...

2005
Ioannis Z. Emiris George M. Tzoumas

We study the external tritangent Apollonius (or Voronoi) circle to three ellipses. This problem arises when one wishes to compute the Apollonius (or Voronoi) diagram of a set of ellipses, but is also of independent interest in enumerative geometry. This paper is restricted to non-intersecting ellipses, but the extension to arbitrary ellipses is possible. We propose an efficient representation o...

Journal: :Geoscience Letters 2023

Abstract With the population projections indicating continued growth during this century, construction of large dams can be considered as one best available options to meet future increases in water, food, and energy demands. While there are reports that thousands will built near future, a key question is: what appropriate conditions for selecting sites these dams? The site dam should carefully...

2009
Akihiro Sugimoto Mitsuhiro Kimura Takashi Matsuyama

We propose a two-step method for detecting human heads with their orientations. In the first step, the method employs an ellipse as the contour model of human-head appearances to deal with wide variety of appearances. Our method then evaluates the ellipse to detect possible human heads. In the second step, on the other hand, our method focuses on features inside the ellipse, such as eyes, the m...

2011
Nicola Greggio José António Gaspar Alexandre Bernardino José Santos-Victor

Abstract: Real-Time tracking of elliptical objects, e.g. a ball, is a well studied field. However, the question between a monocular and binocular approach for 3D objects localization is still an open issue. In this work we implemented a real-time algorithm for 3D ball localization and tracking from 2D image ellipse fitting with calibrated cameras. We will exploit both approaches, together with ...

Journal: :Informatica (Slovenia) 2005
Bogdan Kwolek

People attending teleconference meetings usually follow specific trajectories corresponding to their intentions. In most situations the meeting video content can by sufficiently characterized by capturing the head trajectories. The tracking of the head is done using a particle filter built on cues such as color, gradient and shape. The head is represented by an ellipse with fuzzy color histogra...

2004
Akihiro Sugimoto Mitsuhiro Kimura Takashi Matsuyama

We propose a two-step method for detecting human heads and estimating face orientations under the dynamic environment. In the first step, the method employs an ellipse as the contour model of humanhead appearances to deal with wide variety of appearances. Our method then evaluates the ellipse to detect possible human heads. In the second step, on the other hand, our method focuses on features, ...

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