Patent ID: 11953236
Assignee: FUNDACIÓN CENER-CIEMAT
Field: Thermal processes and apparatus (Mechanical engineering)
Classification: CPC F  G  Y | IPC F  G

Claim 10:
11. A characterization method for characterizing a shape and deformations of a surface of a first reflective element by the quality of light reflected from the surface, comprising the following steps:
a) providing a characterization device for characterizing a shape and deformations of a surface of a reflective element through a combination of light beams reflected by the surface and images of the surface, the device comprising:
at least two variable-gain detectors for capturing the reflected light beams, at least one pin-hole camera for taking images of the surface of the reflective element,
wherein the at least two variable-gain detectors and at least one pin-hole camera are located on a structure for receiving the light beams reflected by the reflective element, and
the device further comprising a processor unit that calculates an orientation of said surface and a deviation with respect to a design shape of said surface based on a combination of the reflected light beams and the images of the surface; and
wherein each of the at least two variable-gain detectors comprises:
a lens with an aperture angle smaller than 15° for increasing signal-to-noise ratio of the light beams,
at least one optical sensor on which the light beams captured by the lens are focused,
an automatic gain selection system, associated with the at least one optical sensor, with a data capture and processing unit, to select or adjust a gain of the variable-gain detector, in an automated manner, as a result of the data capture and processing unit, with respect to the light beams reflected by the surface of the reflective element, and

data communication means associated with the variable-gain detector;
b) arranging the characterization device in a field of reflective elements comprising said first reflective element,
c) keeping the first reflective element immobile, in a fixed position, during a time corresponding to a relative movement of the sun so that the light reflected by the first reflective element sweeps across the at least two variable-gain detectors in the characterizing device,
d) selecting a gain of each of the detectors of the device for reducing noise signal as a function of intensity of the light reflected by the first reflective element and received by each of said at least two variable-gain detectors with a given angle,
e) capturing and taking measurements, by the at least two variable-gain detectors of the device, the light reflected by the first reflective element while the first reflective element immobile, in a fixed, position, and continuously and simultaneously taking, by the pin-hole camera, images of the surface,
f) normalizing the measurements taken by the at least two variable-gain detectors of the device for the estimation of radiant energy on the device, and
g) processing said taken measurements, reconstructing the light beam reflected by the first reflective element, determining an orientation of the first reflective element over the entire surface of the first reflective element, and determining a shape and deformations relative to a design shape of the first reflective element.