US 12,270,753 B2
Device for polarimetrically characterising the anisotropy of a medium, and corresponding imaging system
Yann Le Grand, Brest (FR); Sylvain Rivet, Plouarzel (FR); Matthieu Dubreuil, Plougonvelin (FR); and Xavier Theillier, Brest (FR)
Assigned to UNIVERSITE DE BRETAGNE OCCIDENTALE, Brest (FR)
Appl. No. 18/005,740
Filed by UNIVERSITE DE BRETAGNE OCCIDENTALE, Brest (FR)
PCT Filed Jul. 16, 2021, PCT No. PCT/EP2021/070053
§ 371(c)(1), (2) Date Jan. 17, 2023,
PCT Pub. No. WO2022/013448, PCT Pub. Date Jan. 20, 2022.
Claims priority of application No. 2007550 (FR), filed on Jul. 17, 2020.
Prior Publication US 2023/0273116 A1, Aug. 31, 2023
Int. Cl. G01N 21/21 (2006.01); G01N 21/359 (2014.01)
CPC G01N 21/21 (2013.01) [G01N 21/359 (2013.01)] 12 Claims
OG exemplary drawing
 
12. An imaging system comprising:
a polarimetric characterisation device for obtaining polarimetric characterisation measurement data, including anisotropy of a medium, the polarimetric characterisation device comprising:
a light source capable of emitting multi-wavelength light;
a spectral polarisation coding block arranged between the light source and the medium, configured to spectrally polarisation code the emitted light, said coding block comprising a first polariser defining a first polarisation axis, called a reference axis, and a spectral modulator arranged as an output of the first polariser, said spectral modulator comprising first and second chromatic phase delay plates arranged successively and shaped so as to produce first and second distinct phase delays respectively;
a light detector defining a predetermined intensity saturation threshold; and
a spectral polarisation decoding block arranged between the medium and the light detector and configured to spectrally polarisation decode light returned by the medium, said decoding block comprising a second polariser defining a second polarisation axis oriented perpendicular to the reference axis,
wherein the first phase delay plate has a first neutral axis defining, with the reference axis, a tilt angle whose value is in a range of 0 degrees to 90 degrees and is a function of a saturation threshold of the light detector and intensity level of the multi-wavelength light emitted by the light source to obtain an increased sensitivity of said device; and
a polarimetric image generator, which is configured to generate a polarimetric image of the medium taking account of said polarimetric characterisation measurement data.