Patent ID: 11953381
Assignee: SORBONNE UNIVERSITE
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 0:
1. A method for determining wavefront shapes of N spectral channels of a multispectral light beam from a single signal image I(x,y) acquisition of said multispectral signal light beam,
the method using a device comprising an optical assembly made at least of an optical mask and an imaging sensor for generating and recording intensity patterns of incident beams by having the incident beams reflect on, or propagate through, the optical mask,
wherein the optical mask is configured with optical properties:
i) to cause the intensity patterns to depend on each of the wavefront shapes, so that a tilt applied to each of the wavefront shapes results in a displacement amount of the intensity patterns,
ii) to produce uncorrelated intensity patterns over at least one surface area (A) of the imaging sensor for a plurality of respective incident monochromatic beams of different wavelengths each having a same wavefront shape,
wherein two uncorrelated random intensity patterns are defined as statistically orthogonal relatively to a zero-mean cross-correlation product,
the method comprising:
a) recording reference intensity patterns RL(x, y) using the device, each of the reference intensity patterns RL(x, y) being generated by a respective reference incident monochromatic beam L with wavelengths λL, L varying from 1 to N, with N being a number of different reference incident monochromatic beams, x and y being coordinates;
b) recording one single signal image I(x, y) of the intensity patterns generated by said multispectral signal light beam which comprises at least the N wavelengths, using the device, the single signal image I(x, y) being representative of light impinging on the at least one surface area (A);
c) computing intensity-weight data WLI(x, y) and deformation data TLI(x, y), for all L varying from 1 to N, the intensity-weight data WLI(x, y) and the deformation data TLI(x, y) being representative of an intensity modulation and a diffeomorphism, respectively, of each of the reference intensity patterns RL(x, y), at wavelength λL, for the single signal image I(x, y),
all N intensity-weight data WLI(x, y) and N deformation data TLI(x, y) being computed, for L varying from 1 to N, so as to minimize, for all sampling points (x, y) of the at least one surface area (A), from the single signal image I(x, y):
a difference DA between the single signal image I(x, y), and sum of the reference intensity patterns RL(x, y) multiplied by the intensity-weight data WLI(x, y) and deformed by the deformation data TLI(x, y) is represented by:, D
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where symbol ∥·∥A designates a norm calculated for all (x, y) sampling points in the at least one surface area (A);
wherein for the at least one surface area (A), each of the reference intensity patterns RL(x, y) are orthogonal to each reference intensity patterns RK(x, y) relatively to the zero-mean cross-correlation product,
when K represents a different incident monochromatic beam other than L and chosen between [1; N]; and
d) generating data for each of the wavelengths λL representative of:
each of the wavefront shapes by integrating the deformation data TLI(x, y), and
an intensity map based on the intensity-weight data WLI(x, y).