... Shiradkar, Ping Tan, Sim Heng Ong, “Auto-calibrating Photometric Stereo using Ring Light Constraints”,Machine Vision and Applications, vol 25, no 3, pp 801-809, 2014 Conference proceedings Rakesh ... assisted surgeries to material identification and classification 1.1 Lambertian Photometric Stereo Since photometric stereo mainly relies on shading cues, accurate estimates of inten...