Self-calibration from the absolute conic on the plane at infinity

Author(s):  
Marc Pollefeys ◽  
Luc Van Gool
2017 ◽  
Vol 77 (11) ◽  
pp. 14055-14075 ◽  
Author(s):  
Nabil El Akkad ◽  
Mostafa Merras ◽  
Aziz Baataoui ◽  
Abderrahim Saaidi ◽  
Khalid Satori

Filomat ◽  
2009 ◽  
Vol 23 (2) ◽  
pp. 90-96 ◽  
Author(s):  
Sonja Krasic ◽  
Vladan Nikolic

When they are collinear, projective spaces set with five pairs of biuni-vocally associated points are general. In order to map quadrics (II degree surfaces), in these spaces, the absolute conic was used. Geometrical position of all the absolute points in the infinitely distant plane of one space, i.e. an absolute conic of space cannot be graphically represented. To the infinitely distant planes are associated by the vanishing planes, and the absolute conics are associated by the conic in the vanishing planes, that is, figures of the absolute conics. Prior to mapping the quadrics, it is necessary to constructively determine the characteristics parameters such as the vanishing planes, axes and centers of space, and then the figures of the absolute conics, in the vanishing planes of both spaces. In order to constructively determine the figure of the absolute conic in the second space, a sphere in the first space was used, which maps into a rotating ellipsoid in the second space. The center of the sphere is on the axis of the first space, and the infinitely distant plane intersects it along the absolute conic. The associated rotational ellipsoid, whose center is on the axis of the seconds space is intersected by the vanishing plane of the first space along the imaginary circumference aI, whose real representative is circumference az. The circumference aI is the figure of the absolute conic of the first space. General collinear spaces are presented in a pair of Monge's projections.


2011 ◽  
Vol 9 (2) ◽  
pp. 269-275
Author(s):  
Sonja Krasic ◽  
Biserka Markovic

For graphic representation of the projective creations, such as the quadrics (II degree surfaces) in projective, general collinear spaces, it is necessary to firstly determine the characteristic parameters, such as: vanishing planes, axes and centers of space. An absolute conic of a space is an imaginary conic, residing in the infinitely distant plane of that space. The common elements of the absolute conic and infinitely distant conic of a quadric in the infinitely distant plane of that space are the autopolar triangle and two double straight lines which are always real and it is necessary to use the common elements of their associated pair of conics in the vanishing plane of the associated space. The quadric axes are passing through the apices of the autopolar triangle, and they are important for graphic representation of the quadrics. In order to map a sphere in the first space into the triaxial ellipsoid in the second space, it is necessary to select a sphere so that its center is not on the axis of that space and that it intersects the vanishing plane of the second space along the imaginary circumference, which is in general position with the figure of the absolute conic of the second space (the associated pair of conics in the vanishing plane).


2008 ◽  
Vol 41 (12) ◽  
pp. 3624-3635 ◽  
Author(s):  
Jean-Yves Guillemaut ◽  
John Illingworth

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2367
Author(s):  
Guo Zhang ◽  
Mingjun Deng ◽  
Chenglin Cai ◽  
Ruishan Zhao

Geometric calibration is an important means of improving the absolute positioning accuracy of space-borne synthetic aperture radar imagery. The conventional calibration method is based on a calibration field, which is simple and convenient, but requires a great deal of manpower and material resources to obtain ground control points. Although newer cross-calibration methods do not require ground control points, calibration accuracy still depends on a periodically updated reference image. Accordingly, this study proposes a geometric self-calibration method based on the positioning consistency constraint of conjugate image points to provide rapid and accurate calibration of the YaoGan-13 satellite. The proposed method can accurately calibrate geometric parameters without requiring ground control points or high-precision reference images. To verify the absolute positioning accuracy obtained using the proposed self-calibration method, YaoGan-13 Stripmap images of multiple regions were collected and evaluated. The results indicate that high-accuracy absolute positioning can be achieved with a plane accuracy of 3.83 m or better for Stripmap data, without regarding elevation error. Compared to the conventional calibration method using high-accuracy control data, the difference between the two methods is only about 2.53 m, less than the 3-m resolution of the image, verifying the effectiveness of the proposed self-calibration method.


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