Abstract: A sensor unit (50), a device, and a process for inspection of a surface (10′, 10&Dgr;) of an object (10) for the purpose of identifying surface characteristics, such as structural defects. The device contains an emitting module (51) and a receiving module (52). The emitting module emits at least one beam bundle (6, 6′, 6″). The receiving module has at least one light receiver (15, 16, 20). A rotating polygonal mirror wheel (2) is located in the focal point of a parabolic mirror (1). A beam bundle (6) of the laser (3, 4) is directed onto the mirror (1) by means of a telecentric lens, which guides the emitter and receiver beam on the same optical axis, whereby the parabolic mirror (1) guides the deflected beam bundle (6, 6′, 6″) under a constant angle relative to the axis of symmetry (7) of the parabolic mirror (1) along a scanning line (23, 24) over the object (10).