In this paper we describe an efficient method to impose the constraints existing between the collineations which can be computed from a sequence of views of a planar structure. These constraints are usually not taken into account by multi-view techniques in order not to increase the computational complexity of the algorithms. However, imposing the constraints is very useful since it allows a reduction in the geometric errors in the reprojected features and provides a consistent set of collineations which can be used for several applications such as mosaicing, reconstruction and self-calibration. In order to show the validity of our approach, this paper focus on self-calibration from unknown planar structures proposing a new method exploiting the consistent set of collineations. Our method can deal with an arbitrary number of views and an arbitrary number of planes and varying camera internal parameters. However, for simplicity this paper will only discuss the case with constant camera internal parameters. The results obtained with synthetic and real data are very accurate and stable even when using only a few images.