Hossein Ragheb Edwin R. Hancock Surface Normals and Height from Non-Lambertian Image Data. 18-25 2004 conf/3dpvt/2004 3DPVT http://csdl.computer.org/comp/proceedings/3dpvt/2004/2223/00/22230018abs.htm db/conf/3dpvt/3dpvt2004.html#RaghebH04