A wide array of problems in Visual Computing can be naturally formulated as optimization tasks. In this context one wants to optimize an objective function that measures how well a set of hidden parameters fits to the observed visual data. The popularity of these approaches stems from the fact that most processes related to Visual Computing are typically characterized by a lack of closed form solutions, and uncertainties (due to noise, imperfect sensors, ambiguities in the visual interpretation etc.). As a result perfect or exact solutions hardly exist, whereas inexact but optimal (in an application-specific sense) solutions and their efficient computation is what one aims at. Computer vision, computer graphics and medical imaging are three...