Active contour and morphological filters for geometrical normalization of human face

Abstract

In this paper we resolve the problem of automatically normalize front view photos from a database that contain images of human faces with different size, angle and position. It was used a template with a standardized inter eye distance and dimensions. We are mapping all images to this template applying a geometrical transformation. It is necessary to obtain the eyes positions on image to calculate the transforms parameters. That is not a trivial problem. We use active contour to detect the human face. After that, we apply morphological filters to highlight image signal amplitude in the eyes positions. A set of criterion is applied to select a pair of point with more possibility to be the eyes. Then, a subroutine is feed with eyes coordinates to calculate and apply the geometrical transformation. Our method was applied to 500 photos and it performs very well in the 94% of all cases. © Springer-Verlag Berlin Heidelberg 2005.