China 
Africa 
Explore chapters and articles related to this topic
C
Published in Splinter Robert, Illustrated Encyclopedia of Applied and Engineering Physics, 2017
[computational, general] Measuring device that is designed for analog measurements of size with relative accuracy, generally in the order of 0.01 – 0.05 mm. In geometry this refers to a mechanism of calculating the configuration of a polygon, expressed by its antipodal points forming pairs and vertices. The computational rotating caliper respectively aligns a “caliper line” with the edges of a polygon, thus defining the corners or antipodal pairs while successively moving the caliper line around the polygon. Also used to describe the disk-break pressure clamp for the wheels of an automobile or motorcycle, also called “calliper” (see Figure C.3).
A triangle mesh-based corner detection algorithm for catadioptric images
Published in The Imaging Science Journal, 2018
The projection model of a camera describes the mathematical relationship between 3D coordinates of a world point and its projection onto the image plane of a camera. In the case of a central catadioptric camera, all incident light rays, which are emitted from the 3D space, pass through a single effective viewpoint (Figure 3(a)) [1]. It was proved that a central catadioptric camera can be modelled using two consecutive projections [21]. First, 3D point is projected from the single effective viewpoint to a pair of antipodal points on the unit sphere, then from a specific point on the axis of the sphere these points are projected to a pair of points on the plane perpendicular to the chosen axis (Figure 3(b)). Based on this projection model, we derive a complete model for real central catadioptric cameras. Let be a world point in the mirror reference frame. The projection of the 3D point on the unit sphere is determined asThis point is then projected from a specific point onto the normalized image plane:To improve the projection model for real cameras, we take into account distortions introduced by camera's lenses [23].where radial and tangential distortion coefficients; .