The use of some new techniques such as self-calibration and calibration from partial a priori information about the observed scene (angles, distances), together with the use of some classical techniques of video sequence processing, such as features extraction and token tracking, makes the computation of three-dimensional measurements of the observed scene from video sequences possible. Depending upon the kind of calibration that has been obtained for the camera, these measurements are projective, affine or metric measurements. They can be obtained directly from the images without any reconstruction process. The self-calibration technique described in this article is the generalization to a large number of images of the algorithm developped by Luong and Faugeras\cite{faugeras-luong-etal:92} based on the Kruppa equations. A theoretical study of these equations as well as experimental results on real video sequences are presented.