Patent ID: 7417725

Claim:
Optical method for determining surface defects and/or material shortage on the neck ring ( 3 ) of a container ( 4 ) having an axis of symmetry (X), the method comprising the following steps: illuminating the surface(s) of the neck ring ( 3 ) of the container ( 4 ) with a uniform ring of light, and collecting, via a line scan camera ( 6 ), the light beams reflected by the neck ring of the container, in order to determine the presence of a surface defect and/or material shortage, the illuminating step causing the surface defect to occur as a lack of light or local concentration of light translating as a dark spot, characterized in that it consists of: obtaining the uniform ring of light (C) delimited between two light cones ( 19 and 20 ), the uniform ring of light converging towards a point of convergence (F) located on the axis of symmetry (X) of the container, and having a variable diameter (D) and/or a variable width (E), and selecting: the diameter (D) of the convergent ring of light (C) at a given value in relation to a desired mean angle of incidence (α) to illuminate the surface(s) of the neck ring ( 3 ) of the container ( 4 ), and/or the width (E) of the convergent uniform ring of light (C) at a given value in relation to the width (L) of the surface(s) of the neck ring ( 3 ) of container ( 4 ).