Abstract: The invention relates to optoelectronic instrumentation engineering and, in particular, to cutting process control systems for CNC machine tools. A control system includes an optical transducer (2) mounted on a carriage (1) of a machine tool in the zone of movement of a cutting tool (8) and made up of a laser (10), and, mounted in the path of a beam (10') of said laser (10), a narrow-field slit diaphragm (12), a reference half plane (13) arranged in the plane of an axis (15) of rotation of a workpiece (9), a Fourier lens (19), and an electronic interface unit (3). The reference half plane (13) is located on the side opposite an apex (8') of a cutting wedge of the tool (8) in relation to the workpiece (9) so as to define an optically transparent slit (16) with the profile of a surface (17) of the workpiece (9).