%0 Conference Proceedings
%A Torreão, José R. A.,
%T Shape from shading and intensity gradient
%B Brazilian Symposium on Computer Graphics and Image Processing, 13 (SIBGRAPI)
%E Carvalho, Paulo Cezar Pinto,
%E Walter, Marcelo,
%J Los Alamitos
%I IEEE Computer Society
%C Gramado, RS, Brazil
%K computer vision, shape from shading, intensity gradient, shape estimation, brightness gradient, Green function approach, shape-from-shading, GSFS, single brightness image, uniform disparity field, matching image, linear expansion, reflectance map, surface gradient, closed-form depth map, free parameters, parameter estimation, depth estimate, higher-frequency components, imaged surface, real images, computer vision technique.
%X We present a novel algorithm for shape estimation, using both brightness and brightness gradient as input data. Our algorithm is an improvement of the recently introduced Green's function approach to shape-from-shading (GSFS). In GSFS, we assume that the single brightness image will be matched to a second image through a uniform disparity field, and solve for the matching image via Green's function. When a linear expansion of the reflectance map is considered, the matching image can be related to surface gradient, leading to a closed-form depth map whose free parameters are easily estimated. The author shows that the same procedure can be repeated with the gradient image as input; a second depth estimate thus results which takes into account higher-frequency components of the imaged surface. Extensive experimentation with synthetic and real images corroborates the advantage of the new method.
%O The conference was held in Gramado, RS, Brazil, from October 17 to 20.
%1 SBC - Brazilian Computer Society