System for locating a woven preform tracer

A system for locating at least one strand comprising fibers of a first material of a woven preform of a composite material part, the preform comprising on its surface strands of fibers of a second material and at least one strand comprising fibers of the first material forming a tracer, the system comprising a camera,

• the system further comprising:
• a light source emitting an unpolarized incident beam adapted to be directed towards the preform;
• a polarizer having a first polarization direction, the polarizer being adapted to polarize the unpolarized incident beam before interacting with the preform to obtain a polarized incident beam;
• a cross analyzer having a second polarization direction,
• the first material being selected from glass, aramid and alumina oxide;
• the second material being selected from carbon and silicon carbide;
• the camera being adapted to film a reflected beam resulting from the interaction of the polarized incident beam with the preform, the reflected beam having previously passed through the cross analyzer, so as to locate the tracer of the preform.