Patent ID: 7583196
Filing Date: 2009-09-01
Classification: G08B

Abstract:
1. A method for detecting an object in a zone situated in the proximity of an interface between two liquid and/or gaseous media; the said object being illuminated by electromagnetic radiation comprising at least two different wavelengths; the said media having different absorption coefficients as a function of the wavelengths of the electromagnetic radiation; the said method comprising: choosing, from among the wavelengths of the electromagnetic radiation, at least two wavelengths or two wavelength regions, creating, for each of the said wavelengths or wavelength regions, an image of the said interface and of the said zone, producing electrical signals representative of each image, digitizing the electrical signals to produce data corresponding to each image, extracting, from the said data corresponding to each image, two groups of data, wherein the groups are representative of at least part of the said object in the near infrared region and in the blue-green region respectively, and comparing the said groups of data, the producing, the digitizing, the extracting, and the comparing being referred to hereinafter as the process of deducing the presence of an object, whereby detecting the presence of an object and/or determining the position of the detected object relative to the said interface, while discriminating between an object situated entirely under the interface and an object situated at least partly above the interface.