Surface roughness measuring device - compares specularly reflected and diffused light from same monochromatic incident beam

The device is used to determine the roughness parameters of an object by comparing the specularly reflected light with the diffused light when the object is illuminated by a monochromatic incident beam. A system is provided which enables a rapid assessment to be made, either by reading or direct counting, of at least one roughness parameter. A head is provided into which the incident beam penetrates, the position of this beam being fixed. A reflected beam leaves the head, also with a feed position. The incident and reflected rays are parallel and the angle of incidence can have one of several prefixed values.