Optical imaging system and method based on random light field spatial structure engineering

Patent metadata

Field	Value
Publication number	US-12203845-B2
Application number	US-202117797685-A
Country	US
Kind code	B2
Filing date	Jun 21, 2021
Priority date	Jun 7, 2021
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

An optical imaging system and a method based on spatial structure engineering of random light are disclosed. The method includes performing scattering processing on transmitted light to obtain a to-be-measured light; splitting polarization of the to-be-measured light. One light is split into x-polarized and y-polarized beams, and the other one is firstly combined with a reference beam and then split into x-polarized and y-polarized beams; measuring the intensity distributions of x-polarized and y-polarized parts of the to-be-measured light, the combined light, and the reference light; obtaining a real part and an imaginary part of the cross spectral density of the to-be-measured light, retrieving the intensity distribution of the light on the scattering medium and calculating the intensity to obtain the shape and location of the object to be measured.

First claim

What is claimed is:

1. An optical imaging system based on random light field spatial structure engineering, comprising:
a scattering assembly configured to scatter a beam transmitted through free space via a scattering medium to obtain light to be measured, the beam carrying information on an object to be measured;
a first beam polarization splitting assembly configured to split the polarization of the light to be measured, in which one light beam to be measured is split into x-polarized light and y-polarized light and the other light beam to be measured is combined with a reference light beam and then split into x-polarized light and y-polarized light, where the reference light is completely coherent with the light to be measured;
an optical measurement assembly configured to measure intensity distribution of the x-polarized and y-polarized parts of the light to be measured, intensity distribution of the x-polarized and y-polarized parts of the light after beam combination of the reference light and the light to be measured and intensity distribution of x-polarized and y-polarized parts of the reference light which has not been combined with the other light beam to be measured; and
a calculation unit configured to obtain a real part and an imaginary part of the cross spectral density of the light to be measured according to the intensity distributions, retrieve the intensity distribution of light on the scattering medium by using the real part and the imaginary part of the cross spectral density and calculate the intensity distribution on the scattering medium to obtain the shape and location of the object to be measured.

2. The optical imaging system based on random light field spatial structure engineering of claim 1 , further comprising a Fourier lens provided between the scattering medium and the first beam polarization splitting assembly.

3. The optical imaging system based on random light field spatial structure engineering of claim 2 , further comprising a first half-wave plate provided between the Fourier lens and the first beam polarization splitting assembly.

4. The optical imaging system based on random light field spatial structure engineering of claim 3 , wherein the first beam polarization splitting assembly comprises a first beam splitting element and a first beam polarization splitting element, the first beam splitting element being provided between the first half-wave plate and the first beam polarization splitting element.

5. The optical imaging system based on random light field spatial structure engineering of claim 2 , wherein the optical measurement assembly comprises a first charge-coupled device unit, a second charge-coupled device unit and a third charge-coupled device unit arranged in an array, the first charge-coupled device unit, the second charge-coupled device unit and the third charge-coupled device unit each comprising at least two individual charge-coupled devices, in which the optical distance from the uppermost individual charge-coupled device in the first charge-coupled device unit to the Fourier lens is equal to the focal length of the Fourier lens.

6. The optical imaging system based on random light field spatial structure engineering of claim 5 , wherein the optical distances from all the individual charge-coupled devices in the first charge-coupled device unit and the second charge-coupled device unit to a first beam splitting element of the first beam polarization splitting assembly are equal to each other and equal to the optical distances from all the individual charge-coupled devices in the second charge-coupled device unit and the third charge-coupled device unit to a third beam splitting element of a second beam polarization splitting assembly.

7. The optical imaging system based on random light field spatial structure engineering of claim 1 , further comprising a second beam polarization splitting assembly connected to the optical measurement assembly, the second beam polarization splitting assembly comprising a second beam splitting element, a third beam splitting element, a second beam polarization splitting element, a third beam polarization splitting element and a reflective element, the reference light being split by the second beam splitting element, in which one reference light beam and the light beam to be measured are combined at the third beam splitting element and the combined light is split into x-polarized light and y-polarized light by the second beam polarization splitting element, and the other reference light beam is reflected by the reflective element and split into x-polarized light and y-polarized light by the third beam polarization splitting element.

8. An optical imaging method based on random light field spatial structure engineering, comprising:
scattering a beam transmitted through free space via a scattering medium to obtain light to be measured, the beam carrying information on an object to be measured;
splitting and polarizing the light to be measured, in which one light beam to be measured is split into x-polarized light y-polarized light and the other light beam to be measured is combined with a reference light beam and then split into x-polarized light and y-polarized light, the reference light being light that is completely coherent with the light to be measured;
measuring intensity distribution of the x-polarized and y-polarized parts of the light to be measured, intensity distribution of the x-polarized and y-polarized parts of the light after beam combination of the reference light and the light to be measured and intensity distribution of x-polarized and y-polarized parts of the reference light which has not been combined with the other light beam to be measured
obtaining a real part and an imaginary part of the cross spectral density of the light to be measured according to the intensity distributions, retrieving the intensity distribution of light on the scattering medium by using the real part and the imaginary part of the cross spectral density and calculating the intensity distribution to obtain the shape and location of the object to be measured.

9. The optical imaging method based on random light field spatial structure engineering of claim 8 , wherein the obtaining a real part and an imaginary part of the cross spectral density W(r 1 , r 2 ) of the light to be measured according to the intensity distributions and retrieving the intensity distribution of the scattering medium by using the real part and the imaginary part of the cross spectral density comprises:
calculating the real part W′(r 1 , r 2 ) and the imaginary part W″(r 1 , r 2 ) of the cross spectral density of the light to be measured by the equations:

W
′

(

r
1

,

r
2

)

=

〈

I
x
C

(

r
1

)

Assignees

• Univ Soochow

Inventors

• Chen Yahong
• Peng Deming
• Liu Yonglei
• Wang Fei
• Cai Yangjian

Classifications

• G01B11/24

  for measuring contours or curvatures · CPC title

• G01B11/00

  Measuring arrangements characterised by the use of optical techniques · CPC title

• G01N2021/479

  Speckle · CPC title

• G01N21/4795

  spatially resolved investigating of object in scattering medium (in vivo A61B) · CPC title

• G02B27/00 Primary

  Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00 · CPC title