Abstract: Automatic process and installation for inspecting and/or sorting objects or articles belonging to at least two different categories, and made to advance approximately in a single layer, for example on a conveyor belt or a similar transport support. The process includes subjecting the advancing flow of objects or articles to at least two different types of contactless analysis by radiation, whose results are used in a combined manner for each object or article to perform a discrimination among these objects or articles and/or an evaluation of at least one characteristic of the latter, the analyses including at least one surface analysis process able to determine the physical and/or chemical composition of the outer layer of an object or article exposed to the radiation used in this process, and at least one volume analysis process able to determine the equivalent thickness of material of the same object or article.