Patent ID: 6157453
Filing Date: 2000-12-05
Classification: G01J

Abstract:
A process for discriminating the color of a surface, comprising the steps of:a) acquiring at least one color of a colored acquisition surface;b) comparing the color of a detecting surface with said at least one color previously acquired, so that said color can be recognized; wherein the acquisition step a) comprises the following steps:a1) sequentially illuminating the acquisition surface with each of three light beams corresponding to three primary colors, each of said light beams being generated by a respective emission source supplied with a supply current IR, IG, IB;a2) picking up by means of a light-receiving element the light scattered from the illuminated acquisition surface;a3) generating an electric signal VR, VG, VB proportional to the luminous intensity of the picked-up light, as the acquisition surface is being illuminated with each of the three beams;a4) controlling the supply current IR, IG, IB of the emission sources such that at least two of the electric signals VR, VG, VB generated are identical with each other within a predetermined tolerance margin; and wherein the recognition step b) includes the following steps:b1) sequentially illuminating, with the aforesaid three light beams, the detecting surface bearing the color to be recognized;b2) picking up, by means of the light-receiving element, the light scattered from said illuminated surface;b3) generating an electric signal VR', VG', VB' proportional to the luminous intensity of the picked-up light, as the detecting surface is being illuminated with each of the three beams;b41) checking that the electric signals VR', VG', VB' generated are lower than a predetermined saturation value and that their sum is higher a predetermined minimum value and:b41a) if both of said checks give a positive result, checking that at least two of the values of the electric signals VR', VG', VB' generated are equal, within a predetermined tolerance margin, to those of the electric signals VR, VG, VB acquired during step a);b41b) if at least one of said checks gives a negative result, indicating that the color of the surface being scanned is not recognized.