This article deals with the vision sensors, and, in particular describes the operation and properties of laser vision sensors for robotic applications. Geometrical analysis for usual triangulation method, synchronized scanning geometry, and bidimensional scanning is presented. Variations of the range and depth of field as a function of the baseline are reported. The position of image point on the photodetector as a function of scanning angle for the case of usual triangulation and synchronized geometries is investigated. Autosynchronized scanners based on using polygonal or pyramidal mirrors are also described. A few examples are presented to show the factors affecting vision sensor performance. Typical examples are given to show potential applications of such systems in robot - mounted systems.