Reconstruction of medical images by perspective shape-from-shading

Shape-from-shading (SfS) is a fundamental problem in computer vision; it is based upon the image irradiance equation. Recently, the authors proposed to solve the image irradiance equation under the assumption of perspective projection rather than the common orthographic one. The solution was a modification of the fast marching method of Kimmel and Sethian. This paper presents an application of this novel perspective algorithm to reconstruction of medical images. We focus on gastrointestinal endoscopy and compare the two versions of the fast marching method (orthographic vs. perspective). The examples and comparison show that, unlike orthographic SfS, perspective SfS is robust and can be utilized for real-life applications.