Patent ID: 8254659

Claim:
Method comprising: providing a light source; providing an image detecting device; providing a grid having, a plurality of parallel stripes; providing a body, said body having a cylindrical symmetry and a longitudinal axis, said body being arranged between said grid and said image detecting device, and said grid being arranged between said light source and said body, and in such way that said longitudinal axis is orthogonal with respect to said stripes of said grid; projecting a light and shade pattern obtained by said grid and defined by preset optic parameters through said body, said light and shade pattern comprising a striped pattern which in its turn comprises stripes that are substantially orthogonal to the longitudinal axis of said body; detecting by said image detecting device an image of said light and shade pattern through said body to obtain a detected image, so that said detected image comprises a plurality of lines, said lines being substantially orthogonal to said longitudinal axis; processing said detected image to highlight any irregularities of said light and shade pattern in said detected image, said processing comprising filtering by means of a Gabor filter said detected image to obtain a processed image.