1. Introduction
Of the billions of pictures taken every year, a significant portion are taken through a reflective surface such as a glass window of a car or a glass case in a museum. This presents a problem for the photographer, as glass reflects some of the incident light from the same side as the photographer back towards the camera, corrupting the captured images with reflected image content. Formally, the captured image I is the sum of the image being transmitted through the glass T and the image of the light being reflected by the glass R: \begin{equation*}I[x,y,c] = T[x,y,c] + R[x,y,c]\tag{1}\end{equation*}