A method for detec the direction of a light source from an image

摘要

The present invention relates to a method of detecting a direction of a light source from an image, in which the actual image intensity h (x, y), which is a value obtained by expressing the brightness of an image from an image as a function of image coordinates x, y, Values are expressed as k_One, k₂In other words, Searching for a convex region that satisfies the following equation; Approximating a convex region to a predetermined shape surface; Calculating an approximated image intensity I (x, y) from the approximated shape surface, assuming a predetermined light source direction; When the difference between the actual image intensity h (x, y) and the approximated image intensity I (x, y) in the convex region is obtained as follows, And determining a variable describing the light source direction and the approximated predetermined shape.;According to the present invention, in order to detect the direction of the illumination light from an image, regions having convex surfaces distributed in the image are found, and the direction of the illumination light is obtained by approximating the regions with an ellipsoidal shape and a bump shape. The direction of the illumination light can be obtained.