Method, system and computer program product for producing a raised relief map from images of an object

Abstract

A method for obtaining a model of an object surface from a plurality of images of said object, wherein the object is illuminated with one or more illumination sources, the method comprising: •—obtaining a set of images each comprising an array of pixels and representing similar views of an object, wherein the similar views are obtained under different illumination conditions; •—defining a model function that expresses the known pixel intensity values of the images in terms of the following unknown model components: •—a first model component (A) representing the albedo of the object at each pixel location and being the same for the plurality of images and being an albedo value; •—a second model component (L) representing an intensity of illumination for each image and being an illumination source intensity value being the same for all pixels of each image; •—a third model component (V) representing a specific illumination direction and being different for each image and being an illumination vector and being the same for all pixels of each image; •—a fourth model component (N) representing surface normal directions of the object surface at each pixel position and being the same for all images and being a normal vector; •—performing one or more sequences of minimization operations to minimize a difference function between the pixel values obtained from the set of images and pixel values calculated using said model function, each minimization operation being performed by allowing one of said model components (A, L, V, N) to vary while the others remain unchanged; •—outputting the fourth model component (N) as said model of the object surface.