points on a sphere or angles in a circle are measured in units called position angle.
points on a sphere or angles in a circle are measured in units called position angle.
points on a sphere or angles in a circle are measured in units called?
position angle
the general spherical triangle is fully determined by three of its six characteristics (3 sides and 3 angles). the lengths of the sides of a spherical triangle are their central angles, measured in angular units rather than linear units. (on a unit sphere, the angle (in radians) and length around the sphere are numerically the same. on other spheres, the angle (in radians) is equal to the length around the sphere divided by the radius.)
solution of triangles
in the accumulation step, the image is mapped onto a bounded space called the accumulator space. the accumulator space is partitioned into units called cells. barnard assumed this space to be a gaussian sphere centered on the optical center of the camera as an accumulator space. a line segment on the image corresponds to a great circle on this sphere, and the vanishing point in the image is mapped to a point. the gaussian sphere has accumulator cells that increase when a great circle passes through them, i.e. in the image a line segment intersects the vanishing point. several modifications have been made since, but one of the most efficient techniques was using the hough transform, mapping the parameters of the line segment to the bounded space. cascaded hough transforms have been applied for multiple vanishing points.
vanishing point