<Table> <Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (December 2008) </Td> </Tr> </Table> <Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (December 2008) </Td> </Tr> <P> This is a metric often used in computer vision that can be minimized by least squares estimation. (1) (2) For curves or surfaces given by the equation x T C x = 0 (\ displaystyle x ^ (\ text (T)) Cx = 0) (such as a conic in homogeneous coordinates), the algebraic distance from the point x ′ (\ displaystyle x') to the curve is simply x ′ T C x ′ (\ displaystyle x' ^ (\ text (T)) Cx'). It may serve as an "initial guess" for geometric distance to refine estimations of the curve by more accurate methods, such as non-linear least squares . </P> <P> In mathematics, in particular geometry, a distance function on a given set M is a function d: M × M → R, where R denotes the set of real numbers, that satisfies the following conditions: </P>

What is the definition of distance in physics