SYSTEM FOR INSPECTING SURFACES OF AN OPTICAL WAVE USING A GRADIENT DENSITY FILTER

The systems for inspecting an optical wave surface output from an optical device, the optical device comprising an output pupil, the inspection system comprising an optical measurement head and a computer for processing the images obtained from the optical measurement head. The optical measurement head comprises: a density gradient filter, the density varying periodically in the two directions of the space, a matrix array comprising at least four identical lenses, of square form, of the same focal length and disposed symmetrically, a matrix of photodetectors, each of the four lenses forming, of the pupil, an image in the plane of this matrix. The computer for processing the images comprises computation means that make it possible to calculate the partial derivatives∂Δ∂xx,yand∂Δ∂yx,yand of the wave surface Δ(x, y) in the plane of the output pupil.