An apparatus for generating a surface normal map of an object may include a plurality of light sources having intensities that are controllable so as to generate one or more gradient illumination patterns. The light sources are configured and arranged to illuminate the surface of the object with the gradient illumination patterns. A camera may receive light reflected from the illuminated surface of the object, and generate data representative of the reflected light. A processing system may process the data so as to estimate the surface normal map of the surface of the object. A specular normal map and a diffuse normal map of the surface of the object may be generated separately, by placing polarizers on the light sources and in front of the camera so as to illuminate the surface of the object with polarized spherical gradient illumination patterns.