The invention relates to a method of estimating a distance to a surface, whereby an emitter emits light towards a surface, at least some light being reflected by the surface, the surface comprising a detectable feature, the reflected light being received by a first receptor and by a second receptor, the surface being in movement relative to the receptors, the first and the second receptor receiving the light reflected at a first and at a respectively second angle thereby producing a first and a respectively second dataset, each dataset including data representing said feature, the first and the second angle being different, whereby the distance is estimated using the first and the second dataset.