Metrics of human perception of vanishing points in perspective sketches

This paper describes an experiment aimed at discovering how humans perceive vanishing points depicted in perspective sketches of engineering shapes. The goal is to find criteria and metrics for an algorithmic approach to replicate human perception of vanishing points. A new approach is required for Sketch-Based Modelling, since most current image analysis approaches take 2D camera images as their input, so do not solve satisfactorily the problem of geometrical imperfections inherent in sketches. We have conducted a pilot experiment to determine which vanishing points are perceived by people, and under what circumstances they are perceived. We test the hypotheses that (i) people are able to detect and locate vanishing points in sketches in spite of their inherent imperfections, and (ii) factors such as distance of vanishing points from the sketch and number and lengths of lines converging at the vanishing points influence their perception