Subhajit Sanyal Mayank Bansal Subhashis Banerjee Prem Kumar Kalra Modeling of Free-Form Surfaces and Shape From Shading. 600-607 2004 conf/3dpvt/2004 3DPVT http://doi.ieeecomputersociety.org/10.1109/TDPVT.2004.1335294 db/conf/3dpvt/3dpvt2004.html#SanyalBBK04