Method for analysing the optical quality of a glazing element, method for calibrating a camera, glazing element thus analysed

A method of analyzing an optical quality of a region of a glazing from analysis of images of a reference pattern, the method comprising:

• 1) A digital image acquisition step comprising:
• acquiring at least one image of a first fixed reference pattern M1 comprising a first set of patterns extending in two dimensions, at an at least centimetric distance L1 from an optical device for image acquisition along an optical axis of the optical device, the acquiring of said at least one image of a first fixed reference pattern M1 comprising:
• 1a) providing a first reference image I1, simulated or acquired, of the reference pattern M1, in an absence of said glazing,
• 1′a) the glazing being placed between the optical device and the first reference pattern M1, with said surface region in a field of view of the optical device, the acquisition of a first distorted image I′1 of said first reference pattern M1,
• acquiring at least one image of a fixed reference pattern Mi selected from the first reference pattern M1 or another reference pattern M2 comprising a second set of patterns extending in two dimensions, the reference pattern Mi being at a distance L2 distinct from L1 of the optical device along the optical axis of the optical device, the acquiring of said at least one image of a fixed reference pattern Mi comprising:
• 1b) providing a second reference image I2, simulated or acquired, of the reference pattern Mi, in the absence of said glazing,
• 1′b) the glazing being placed between the optical device and the reference pattern Mi, with said region in the field of view of the optical device, the acquisition of a second distorted image I′2 of the reference pattern Mi,
• wherein after or as images are acquired 1), the method comprises:
• 2) a step of generating image points which are:
• first points of the first reference pattern M1 on the first reference image I1 corresponding to points of the first reference pattern M1,
• first other offset points of the first reference pattern M1 on the first distorted image I′1 corresponding to the same points of the first reference pattern M1,
• second points of the reference pattern Mi on the second reference image I2 corresponding to points of the reference pattern Mi,
• second other offset points of the second reference pattern M2 on the second distorted image I′2 corresponding to the same points of the reference pattern Mi,
• and wherein after or during step 2), the method comprises:
• 3) a step of determining, by calculation, a field of first apparent displacements, in pixels, between each first point and its corresponding first other offset point and a field of second apparent displacements, in pixels, between each second point and its corresponding second offset point,
• and wherein after step 3) the method comprises:
• 4) A step of determining, by calculation, with the fields of the first and second apparent displacements, a field of simulated apparent displacements of points, for a distance L3 distinct from L1 and L2 of a reference pattern with the optical device.