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Thales Theorem: An inscribed angle in a semicircle is a right angle [16]. 

Thales Theorem: An inscribed angle in a semicircle is a right angle [16]. 

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Conference Paper
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Camera calibration is an important step in obtaining 3D information from 2D im- ages. Vanishing points of parallel lines have proven to be useful features for self- calibration task. Most tasks using vanishing points estimate parameters using three orthogonal vanishing points (OVPs). However, in a real scene it is hard to find views that capture a...

Context in source publication

Context 1
... the orthogonality of two vanishing points, the center of projection, should be on the semicircle with the center C as shown in Fig. ...

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Citations

... Later on, Hartley and Zisserman [12], Cipolla et al. [6] or He [13] used VPs with the aim of extracting the camera parameters. Two similar works [10] [16], presented the method for finding the intrinsic parameters using the calibration sphere obtained from several images containing two VPs. The authors explained the relation between the calibration sphere and the image of the absolute conic, used for extracting the calibration matrix [12]. ...
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