“…In our case each regression function in the cascade efficiently estimates the shape from an initial estimate and the intensities of a sparse set of pixels indexed relative to this initial estimate. Our work builds on the large amount of research over the last decade that has resulted in significant progress for face alignment [9,4,13,7,15,1,16,18,3,6,19]. In particular, we incorporate into our learnt regression functions two key elements that are present in several of the successful algorithms cited and we detail these elements now.…”