Abstract: An exploration device for the surface of a body uses a laser pencil beam ch successively illuminates quasi-pinpoint regions on the surface of the body. At least two distinct view taking devices are provided for forming respective images of the illuminated quasi-pinpoint region on discrete element photosensitive receivers, each element energized by one of said images supplying an electrical indication for use by a computer to determine the position of the quasi-pinpoint region. The receivers are advantageously linear in shape, for example photodiode bars. Three view-taking stations each equipped with a respective one of these photosensitive bars may be used, each supplying a coordinate of the image position to the computer. In order to allow using receivers comprising faulty photosensitive elements, for each view taking station, at least two identical images are formed on photosensitive receivers the faulty elements of which are not coincident.