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CN-115272041-B - Polarizer and analyzer configuration optimization method and polarizer and analyzer system

CN115272041BCN 115272041 BCN115272041 BCN 115272041BCN-115272041-B

Abstract

The invention discloses a polarizer and analyzer configuration optimization method and a polarizer and analyzer configuration optimization system, wherein the polarizer and analyzer configuration optimization method comprises the following steps of adjusting an instrument matrix W of a polarizer and an instrument matrix A of an analyzer to enable equal weight variance EWV of the polarizer and the analyzer instrument matrix to be minimum so as to realize optimization for Gaussian noise; and the sum of each row of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer is 0, so that the estimated variance caused by the poisson noise is independent of the sample, and the estimated variance reaches the minimum value. The invention can inhibit noise to the maximum extent, and makes the noise rule independent of the sample, and the noise distribution rule is the same no matter what sample is measured.

Inventors

  • MA HUI
  • HU ZHENG
  • ZHAO QIANHAO
  • HUANG TONGYU

Assignees

  • 清华大学深圳国际研究生院

Dates

Publication Date
20260505
Application Date
20220718
Priority Date
20220621

Claims (11)

  1. 1. A polarizer and analyzer configuration optimization method is characterized by comprising the following steps: Adjusting the instrument matrix W of the polarizer and the instrument matrix A of the analyzer to minimize the equal weight variance EWV of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer to optimize for Gaussian noise, and The sum of each row of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer is 0, so that the estimated variance caused by the poisson noise is independent of the sample, and the estimated variance reaches the minimum value; the method comprises the steps of configuring polarizers and analyzers of a measurement system to enable polarization states of the polarizers and analyzers to be in two-to-two orthogonality, then searching minimum equal weight variances EWV of instrument matrixes of the polarizers and the analyzers, and obtaining optimal configuration when the instrument matrixes of the polarizers and the analyzers meet the conditions of row sum 0 and minimum EWV simultaneously; when the polarizer and the analyzer are a rotary polarizer and a rotary 1/4 wave plate respectively, the polarization states of the polarizer and the analyzer are orthogonal in pairs, and the following relation is satisfied: In the formula, The direction of the transmission axis of the polarizer configured for the first measurement, The fast axis direction of the 1/4 wave plate configured for the first measurement, The direction of the transmission axis of the polarizer configured for the second measurement, The method adjusts the polarized main light transmission direction through a polaroid and then realizes the modulation of a specific polarization state through the 1/4 wave plate; when the polarizer and analyzer system includes a fixed polarizer, a rotating 1/2 wave plate and a rotating 1/4 wave plate, the polarization states of the polarizer and analyzer are arranged in pairs in quadrature to satisfy the following relationship: In the formula, The fast axis direction of the 1/2 wave plate configured for the first measurement, The fast axis direction of the 1/4 wave plate configured for the first measurement, The fast axis direction of the 1/2 wave plate configured for the second measurement, The fast axis angle direction of the 1/4 wave plate configured for the second measurement; according to the method, the modulation of the direction of linearly polarized light is changed from single-polaroid modulation to fixed-polaroid and a 1/2 wave plate is added, so that the condition that the light intensity of linearly polarized light in different directions is inconsistent due to the fact that the incident light is not ideal natural light can be avoided; When the polarizer and analyzer system includes a fixed polarizer, two full-wave retardation phase modulation devices, the polarization states of the polarizer and analyzer are configured to satisfy the following relationship: In the formula, Is the phase delay of the first full wave delay phase modulation device of the first measurement configuration, Is the fast axis angle of the bearing and the bearing, Is the phase delay of the second full wave delay phase modulation device of the first measurement configuration, Is the fast axis angle of the bearing and the bearing, Is the phase delay of the first full wave delay phase modulation device of the second measurement configuration, The method first measures the phase delay of the second full-wave delay phase modulation device of the configuration, and the method first measures the phase delay of the second full-wave delay phase modulation device on the bungjia sphere The planar circle is modulated and then the target polarization state is obtained by means of a second full wave retardation phase modulation device.
  2. 2. The polarizer and analyzer configuration optimization method of claim 1, wherein when the polarizer and analyzer are a rotating polarizer and a rotating 1/4 wave plate, respectively, the optimal four-point measurement configuration of the polarizer and analyzer satisfies the following relationship: In the formula, The direction of the transmission axis of the polarizer configured for the first measurement, The fast axis direction of the 1/4 wave plate configured for the first measurement, The direction of the transmission axis of the polarizer configured for the second measurement, The fast axis direction of the 1/4 wave plate configured for the second measurement, The direction of the transmission axis of the polarizer configured for the third measurement, The fast axis direction of the 1/4 wave plate configured for the third measurement, The direction of the transmission axis of the polarizer configured for the fourth measurement, The fast axis direction of the 1/4 wave plate configured for the fourth measurement.
  3. 3. The polarizer and analyzer configuration optimization method of claim 1 wherein when the polarizer and analyzer system includes a fixed polarizer, a rotating 1/2 wave plate and a rotating 1/4 wave plate, the four-point measurement configuration that optimizes the polarizer and analyzer instrument satisfies the following relationship: In the formula, The fast axis direction of the 1/2 wave plate configured for the first measurement, The fast axis direction of the 1/4 wave plate configured for the first measurement, The fast axis direction of the 1/2 wave plate configured for the second measurement, The fast axis direction of the 1/4 wave plate configured for the second measurement, The fast axis direction of the 1/2 wave plate configured for the third measurement, The fast axis direction of the 1/4 wave plate configured for the third measurement, The fast axis direction of the 1/2 wave plate configured for the fourth measurement, The fast axis direction of the 1/4 wave plate configured for the fourth measurement.
  4. 4. The polarizer and analyzer configuration optimization method of claim 1, wherein when the polarizer and analyzer system includes one fixed polarizer, two full wave retardation phase modulation devices, the four-point measurement configuration optimizing the polarizer and analyzer satisfies the following relationship: In the formula, Is the phase delay of the first full wave delay phase modulation device of the first measurement configuration, Is the fast axis angle of the bearing and the bearing, Is the phase delay of the second full wave delay phase modulation device of the first measurement configuration, Is the fast axis angle of the bearing and the bearing, Is the phase delay of the first full wave delay phase modulation device of the second measurement configuration, Is the phase delay of the second full wave delay phase modulation device of the second measurement configuration, Is the phase delay of the first full wave delay phase modulation device of the third measurement configuration, Is the phase delay of the second full wave delay phase modulation device of the third measurement configuration, Is the phase delay of the first full wave delay phase modulation device of the fourth measurement configuration, Is the phase delay of the second full wave delay phase modulation device of the fourth measurement configuration.
  5. 5. The polarizer and analyzer configuration optimization method of claim 1, wherein when the polarizer and analyzer system includes one fixed polarizer, two half-wave retardation phase modulation devices, the four-point measurement configuration optimizing the polarizer and analyzer satisfies the following relationship: In the formula, 、 The linear phase delays of the two half-wave delay phase modulation devices configured for the first measurement respectively, 、 Then the fast axis angles thereof are respectively, 、 The linear phase delays of the two half-wave delay phase modulation devices configured for the second measurement respectively, 、 The linear phase delays of the two half-wave delay phase modulation devices configured for the third measurement respectively, 、 The linear phase delays of the two half-wave delay phase modulation devices configured for the fourth measurement respectively.
  6. 6. A polarizer and analyzer configuration optimization method according to any of claims 1-5, characterized in that the polarization states represented by the actual configuration form an instrument matrix, and that the instrument matrix is subjected to a minimum EWV optimization by means of a genetic algorithm or an optimization algorithm, i.e. each group is provided with a variable, and the remaining polarization states in the group, which can be represented explicitly by the variable, are obtained from the variable, after which the polarization states form an instrument matrix with a number of unknown variables, and that the instrument matrix is subjected to a minimum EWV optimization by means of a genetic algorithm, i.e. the instrument matrix EWV can be calculated as to what value the number of unknown variables is.
  7. 7. A polarizer and analyzer configuration optimization method according to any of claims 1-4, wherein both polarizer and analyzer meet modulation of the full polarization state.
  8. 8. A polarization analysis system is characterized by comprising a rotary polaroid and a rotary 1/4 wave plate, and is configured as follows: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = ; = , = ; = , = ; = , = ; Or: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = ; = , = ; = , = ; = , = ; Or: when the acquisition point number is 8, parameters and actual configuration are as follows: = , = ; = , = ; = , = ; = , = ; = , = ; = , = ; = , = ; = , = ; the direction of the transmission axis of the polarizer configured for the first measurement, The configuration satisfies that the sum of each row of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer is 0, and EWV of the instrument matrix A of the polarizer and the analyzer is optimal so as to optimize the performance of the Mueller measurement system for resisting Gaussian-poisson mixed noise.
  9. 9. The polarization analysis system is characterized by comprising a fixed polaroid, a rotation 1/2 wave plate and a rotation 1/4 wave plate, and is configured as follows: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = , = ; = , = , = ; = , = , = ; = , = , = ; Or: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = , = ; = , = , = ; = , = , = ; = , = , = ; Or: when the acquisition point number is 8, parameters and actual configuration are as follows: = , = , = ; = , = , = ; = , = , = ; = , = , = ; = , = , = ; = , = , = ; = , = , = ; = , = , = ; the direction of the transmission axis of the polarizer configured for the first measurement, The fast axis direction of the 1/2 wave plate configured for the first measurement, The configuration satisfies that the sum of each row of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer is 0, and EWV of the instrument matrix A of the polarizer and the analyzer is optimal so as to optimize the performance of the Mueller measurement system for resisting Gaussian-poisson mixed noise.
  10. 10. A polarizing analyzer system comprising a fixed polarizer, two full wave retardation phase modulating devices configured as follows: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; Or: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; Or: when the acquisition point number is 8, parameters and actual configuration are as follows: = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; the direction of the transmission axis of the polarizer configured for the first measurement, Is the phase delay of the first full wave delay phase modulation device of the first measurement configuration, Is the fast axis angle of the bearing and the bearing, Is the phase delay of the second full wave delay phase modulation device of the first measurement configuration, The configuration satisfies that the sum of each row of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer is 0, and EWV of the instrument matrix of the polarizer and the instrument matrix A of the analyzer are optimal so as to optimize the performance of the mueller measurement system for resisting Gaussian-poisson mixed noise.
  11. 11. The polarization analysis system is characterized by comprising a fixed polaroid and two half-wave delay phase modulation devices, and is configured as follows: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; Or: when the acquisition point number is 4, the parameters and actual configuration are as follows: = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; = , = , = , = , = ; the direction of the transmission axis of the polarizer configured for the first measurement, 、 The linear phase delays of the two half-wave delay phase modulation devices configured for the first measurement respectively, 、 The fast axis angles thereof are respectively; The configuration satisfies that the sum of each row of the instrument matrix W of the polarizer and the instrument matrix A of the analyzer is 0, and EWV of the polarizer and the instrument matrix A of the analyzer are optimal to optimize the performance of the mueller measurement system against Gaussian-poisson mixed noise.

Description

Polarizer and analyzer configuration optimization method and polarizer and analyzer system Technical Field The invention relates to the technical field of polarized optical imaging, in particular to a polarizer and analyzer configuration optimization method and a polarization analysis system. Background The polarization imaging technology has the advantages of non-invasiveness, no damage, in-situ in-vivo, large data volume and the like, and is widely applied to the fields of biomedicine, ocean science, atmosphere remote sensing and the like. Depending on the form of the polarization information ultimately obtained, polarization imaging can be categorized into stokes vector measurements and muller matrix measurements. The stokes vector is mainly used for describing the polarization characteristic of light, the mueller matrix is used for representing the polarization characteristic of a sample, and microstructure information of a medium can be further extracted through the mueller matrix, so that the polarization measurement is the greatest advantage compared with the traditional optical measurement. When the mueller matrix measurement is performed, polarization modulation is required to be performed on incident light, and meanwhile, polarization properties of emergent light are detected, so that what influence and change are caused on the polarization properties of the sample are known. Through multiple modulations and detection, the complete polarization characteristic of the sample, namely the mueller matrix of the sample, can be obtained. In this process, a device that modulates the polarization state of incident light is called a Polarizer (PSG), and a device that detects the polarization property of light is called a polarization analyzer (PSA). The polarizer is similar to the analyzer in structure, and has the core of modulating the polarization state of light, modulating natural light into polarized light with specific polarization state, and modulating the incident polarized light reversely to obtain the polarization attribute of the incident polarized light on a specific polarization state component through calculation. The stokes vector is a method for describing the polarization property of light, and is expressed as s= [ S 0 S1 S2 S3]T ] which is a four-dimensional vector, S 0 represents the intensity of light, S 1＝I0-I90 is the difference between the light intensity component of light in the polarization direction of 0 degrees and the light intensity component of light in the polarization direction of 90 degrees, S 2＝I45-I135 is the difference between the light intensity component of light in the polarization direction of 45 degrees and the light intensity component of light in the polarization direction of 135 degrees, and S 4＝IR-IL is the difference between the light intensity component of light in the polarization direction of right hand and the light intensity component of light in the polarization direction of left hand. Normally, we only care about the polarization property of light, so the normalization process is performed on S 0, i.e. S 0 =1, and the remaining three components are also normalized in the same proportion. The Ponga sphere is a unit sphere for graphically describing a Stokes vector with a polarization state, any one polarization state can be mapped to a point on the Ponga sphere, and S 1、S2、S3 of the Stokes vector is respectively used as x, y and z coordinates to be drawn in a Cartesian coordinate system, namely the Ponga sphere representation of the Stokes vector. The mueller matrix is a transformation matrix, which reflects the change of Stokes vector of a beam of light before and after scattering, and Sout＝M×Sin Where S out is the stokes vector of the outgoing light, S in is the stokes vector of the incoming light, M is the muller matrix, and is a 4 x 4 matrix. Since the CCD (charge coupled device) cannot receive polarization information, only light intensity information can be received. Therefore, in practical measurement, at least four independent polarization and polarization checks are required. The polarization is to use a beam of polarized light with a known polarization state for incidence, and the polarization detection is to obtain the polarization state S out of the emergent light through measurement and calculation. Because the stokes vector has four components, at least the light intensity of the four projection components needs to be measured during the polarization analysis to obtain the stokes vector of one beam of light. Thus, the change matrix of the Stokes vector, namely the Mueller matrix, can be calculated by measuring the emergent polarization states of the polarized light with various different polarization states after illumination. At present, polarization modulation is mainly realized by adding one polaroid and one or a series of phase delay devices, and a plurality of different polarization states are obtained by means of the cooperation betwee