# US 8,786,755 B2 · Method and apparatus for polarization imaging

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 8,786,755 B2
- Document ID: US8786755B2
- Status: Granted
- Kind: B2
- Application number: 13/807,117
- Filed: 2011-06-22
- Published: 2013-04-25
- Granted: 2014-07-22
- Earliest claimed: 2010-06-29
- Assignees: National University Corporation Kyoto Institute of Technology
- Applicants: Yasuhiro Awatsuji; Tatsuki Tahara
- Inventors: Yasuhiro Awatsuji; Tatsuki Tahara
- Web page: https://patentgrep.com/patent/US8786755B2

## CPC

- H04N 23/56: provided with illuminating means
- G01N 21/21: Polarisation-affecting properties (G01N21/19 takes precedence)
- G03H 1/0443: {Digital holography, i.e. recording holograms with digital recording means (holobject computation G03H1/0866)}
- G01N 2021/1765: {Method using an image detector and processing of image signal}
- G03H 2001/0458: {Temporal or spatial phase shifting, e.g. parallel phase shifting method}
- G03H 2001/2276: {Polarisation dependent holobject (G03H2001/0495 takes precedence)}
- G03H 2222/31: Polarised light
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- G03H: HOLOGRAPHIC PROCESSES OR APPARATUS (holograms, e.g. point holograms, used as ordinary optical elements G02B5/32; producing stereoscopic or other three-dimensional effects G02B30/00; diffraction-grating systems G02B27/44; systems using moiré fringes G02B27/60; optical logic elements G02F3/00; stereo-photography G03B35/00; photosensitive materials or processes for photographic purposes G03C; {stereo-photographic or similar processes G03C9/00}; apparatus for processing exposed photographic materials G03D; analogue computers performing mathematical operations with the aid of optical elements G06E3/00; authentication by radiation, of concealed information carried by holograms or diffraction gratings G06K19/16; holographic storage G11B7/0065, G11C13/04; {stereoscopic or other three dimensional effects in television systems H04N13/00})

## Abstract

A polarization imaging apparatus includes a laser light source and an image pickup element. Object light and reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction. The image pickup element simultaneously captures an image of an interference pattern including (i) a first interference figure, (ii) a second interference figure, (iii) a third interference figure, and (iv) a fourth interference figure. The polarization imaging apparatus includes a reconstructing section generating respective reconstructed images of the object in regard to the first and second polarized-light components, from the first to fourth interference figures, and a polarized-light-image-calculating section obtaining polarized-light images from the reconstructed images.

## Claims

### Claim 1

An in-line type polarization imaging apparatus comprising:
at least one light source for supplying light including reference light and object light;
an image pickup section capturing images of interference figures each formed from the reference light and the object light that reaches the image pickup section through an object;
a reconstructed-image-producing section producing reconstructed images;
a polarized-light-image-calculating section obtaining polarized-light images;
a beam splitter splitting the light supplied from the light source into the reference light and the object light;
a phase-shift-array section including first phase-shift regions and second phase-shift regions, and making (a) a phase of the reference light having entered the first phase-shift regions different from (b) a phase of the reference light having entered the second phase-shift regions, the reference light being a divisional portion of the light split by the beam splitter; and
a beam-combining element combining the object light with the reference light having passed through the phase-shift-array section, the object light reaching after having passed through the object, wherein:
the object light and the reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction, both of which object light and reference light enter the image pickup section;
the image pickup section simultaneously captures an image of an interference pattern including (i) a first interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a first phase, (ii) a second interference figure folioed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a second phase, (iii) a third interference figure formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the first phase, and (iv) a fourth interference figure formed by interference between the object light which has the second light component and the reference light which has the second polarized-light component and the second phase;
the reconstructed-image-producing section (I) produces a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) produces a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
the polarized-light-image-calculating section obtains the polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
wherein the reconstructed-image-producing section (i) obtains two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light, (ii) calculates respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light, and (iii) obtains a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
wherein the polarized-light-image-calculating section obtains the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 2 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, wherein:
the object light and the reference light each further include a third polarized-light component polarized in a third direction and a fourth polarized-light component polarized in a fourth direction;
the interference pattern further includes (v) a fifth interference figure formed by interference between the object light which has the third polarized-light component and the reference light which has the third polarized-light component and the first phase, (vi) a sixth interference figure formed by interference between the object light which has the third polarized-light component and the reference light which has the third polarized-light component and the second phase, (vii) a seventh interference figure formed by interference between the object light which has the fourth polarized-light component and the reference light which has the fourth polarized-light component and the first phase, and (viii) an eighth interference figure formed by interference between the object light which has the fourth polarized-light component and the reference light which has the fourth polarized-light component and the second phase;
the reconstructed-image-producing section (III) produces a third reconstructed image of the object in regard to the third polarized-light component, after (a) extraction of pixels corresponding to the fifth interference figure and the sixth interference figure from the interference pattern and (b) pixel interpolation and (IV) produces a fourth reconstructed image of the object in regard to the fourth polarized-light component, after (a) extraction of pixels corresponding to the seventh interference figure and the eighth interference figure from the interference pattern and (b) pixel interpolation; and
the polarized-light-image-calculating section obtains the polarized-light images of the object from the first to fourth reconstructed images, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object.

### Claim 3 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, wherein:
the interference pattern further includes (v) a fifth interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a third phase, (vi) a sixth interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a fourth phase, (vii) a seventh interference figure formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the third phase, and (viii) an eighth interference figure formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the fourth phase;
the reconstructed-image-producing section (III) produces a third reconstructed image of the object in regard to the first polarized-light component, after (a) extraction of pixels corresponding to the first interference figure, the second interference figure, the fifth interference figure and the sixth interference figure from the interference pattern and (b) pixel interpolation and (IV) produces a fourth reconstructed image of the object in regard to the second polarized-light component, after extraction of pixels corresponding to the third interference figure, the fourth interference figure, the seventh interference figure and the eighth interference figure from the interference pattern and (b) pixel interpolation; and
the polarized-light-image-calculating section obtains the polarized-light images of the object from the third and fourth reconstructed images, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object.

### Claim 4 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, wherein the light source is made of (a) two light sources supplying light of two wavelength types, (b) three light sources supplying light of three wavelength types, or (c) four light sources supplying light of four wavelength types.

### Claim 5 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, further comprising a polarization-direction-changing-array section including (a) first-direction regions converting the reference light having entered the first-direction regions into reference light polarized in the first direction and (b) second-direction regions converting the reference light having entered the second-direction regions into reference light polarized in the second direction.

### Claim 6 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, further comprising a polarizer-array section which the reference light and the object light enter, the polarizer-array section including (a) first polarizer regions allowing the first polarized-light components of the reference light and the object light to exit from the first polarizer regions, and (b) second polarizer regions allowing the second polarized-light components of the reference light and the object light to exit from the second polarizer regions.

### Claim 7 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, wherein:
the reconstructed-image-producing section obtains (a) a first phase distribution of the object in regard to the first polarized-light component, from the first interference figure and the second interference figure associated with the first polarized-light components and (b) the second amplitude distribution and a second phase distribution of the object in regard to the second polarized-light component, from the third interference figure and the fourth interference figure associated with the second polarized-light components; and
the polarized-light-image-calculating section obtains polarization states at respective positions in each of the reconstructed images of the object from the first and second phase distributions and the first and second amplitude distributions.

### Claim 8 (depends on 1)

The polarization imaging apparatus as set forth in claim 1 further comprising:
a magnifying optical section for magnifying an image of the object, the magnifying optical section being provided between the object and the image pickup section; and
a wavefront-transforming section for converting the reference light to a spherical or aspherical wave so that the reference light enters the image pickup section as a spherical or aspherical wave.

### Claim 9 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, further comprising:
a plurality of light sources each being the light source supplying the reference light and the object light; and a wavelength selection filter, wherein:
the plurality of light sources each supply reference light of a different wavelength and object light of a different wavelength; and
the wavelength selection filter includes wavelength-selecting regions each transmitting light of a different wavelength, and each of the wavelength-selecting regions selectively transmits the reference light and the object light depending on wavelengths.

### Claim 10 (depends on 1)

The polarization imaging apparatus as set forth in claim 1, wherein the first direction is orthogonal to the second direction.

### Claim 11

An in-line type polarization imaging apparatus comprising:
a light source for supplying reference light and object light;
an image pickup section capturing images of interference figures each formed from the reference light and the object light that reaches the image pickup section through an object;
a reconstructed-image-producing section producing reconstructed images; and
a polarized-light-image-calculating section obtaining polarized-light images, wherein:
the light source supplies light of at least one wavelength type;
the object light and the reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction, both of which object light and reference light enter the image pickup section;
the image pickup section simultaneously captures an image of an interference pattern including (i) a first interference figure formed by interference between the object light which has the first polarized-light component and a first optical path length and the reference light which has the first polarized-light component and the first optical path length, (ii) a second interference figure formed by interference between the object light which has the first polarized-light component and a second optical path length and the reference light which has the first polarized-light component and the second optical path length, (iii) a third interference figure formed by interference between the object light which has the second polarized-light component and the first optical path length and the reference light which has the second polarized-light component and the first optical path length, and (iv) a fourth interference figure formed by interference between the object light which has the second polarized-light component and the second optical path length and the reference light which has the second polarized-light component and the second optical path length;
the reconstructed-image-producing section (I) produces a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) produces a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
the polarized-light-image-calculating section obtains the polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
wherein the reconstructed-image-producing section (i) obtains two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light, (ii) calculates respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light, and (iii) obtains a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
wherein the polarized-light-image-calculating section obtains the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 12 (depends on 11)

The polarization imaging apparatus as set forth in claim 11, further comprising:
a polarizer-array section which the reference light and the object light enter, the polarizer-array section including (a) first polarizer regions allowing the first polarized-light components of the reference light and the object light to exit from the first polarizer regions, and (b) second polarizer regions allowing the second polarized-light components of the reference light and the object light to exit from the second polarizer regions; and
an optical-path-length-shift-array section which the reference light and the object light enter, the optical-path-length-shift-array section including first optical-path-length-shifting regions and second optical-path-length-shifting regions,
the polarizer-array section and the optical-path-length-shift-array section being provided between the object and the image pickup section,
the optical-path-length-shift-array section (i) making (a) a phase of the reference light having entered the first-optical-path-length-shift regions different from (b) a phase of the reference light having entered the second-optical-path-length-shift regions, and also (ii) making (a) a phase of the object light having entered the first-optical-path-length-shift regions different from (b) a phase of the object light having entered the second-optical-path-length-shift regions.

### Claim 13 (depends on 11)

The polarization imaging apparatus as set forth in claim 11, wherein:
the reconstructed-image-producing section obtains (a) a first phase distribution of the object in regard to the first polarized-light component, from the first interference figure and the second interference figure associated with the first polarized-light components and (b) the second amplitude distribution and a second phase distribution of the object in regard to the second polarized-light component, from the third interference figure and the fourth interference figure associated with the second polarized-light components; and
the polarized-light-image-calculating section obtains polarization states at respective positions in each of the reconstructed images of the object from the first and second phase distributions and the first and second amplitude distributions.

### Claim 14 (depends on 11)

The polarization imaging apparatus as set forth in claim 11 further comprising:
a magnifying optical section for magnifying an image of the object, the magnifying optical section being provided between the object and the image pickup section; and
a wavefront-transforming section for converting the reference light to a spherical or aspherical wave so that the reference light enters the image pickup section as a spherical or aspherical wave.

### Claim 15 (depends on 11)

The polarization imaging apparatus as set forth in claim 11, further comprising:
a plurality of light sources each being the light source supplying the reference light and the object light; and a wavelength selection filter, wherein:
the plurality of light sources each supply reference light of a different wavelength and object light of a different wavelength; and
the wavelength selection filter includes wavelength-selecting regions each transmitting light of a different wavelength, and each of the wavelength-selecting regions selectively transmits the reference light and the object light depending on wavelengths.

### Claim 16 (depends on 11)

The polarization imaging apparatus as set forth in claim 11, wherein the first direction is orthogonal to the second direction.

### Claim 17

A method for polarization imaging in which a polarization state of object light is obtained by capturing images of interference figures each formed by reference light and the object light that reaches through an object, the method comprising the steps of:
(A) splitting light supplied from a light source into the reference light and the object light each including a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction;
(B) making (a) a phase of the reference light having entered the first phase-shift regions different from (b) a phase of the reference light having entered the second phase-shift regions, by use of a phase-shift-array section including first phase-shift regions and second phase-shift regions;
(C) combining the object light with the reference light having different phases, the object light reaching after having passed through the object;
(D) capturing, simultaneously, an image of an interference pattern including first to fourth interference figures formed from the object light and the reference light, the first interference figure being formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a first phase, the second interference figure being formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a second phase, the third interference figure being formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the first phase, and the fourth interference figure being formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the second phase;
(E) producing (I) a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
(F) obtaining polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
the step (E) including the sub-steps of:
obtaining two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light;
calculating respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light; and
obtaining a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
the step (F) including the sub-step of obtaining the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 18

A method for polarization imaging in which a polarization state of object light is obtained by capturing images of interference figures each formed by reference light and the object light that reaches through an object, the method comprising the steps of:
(A) capturing, simultaneously, an image of an interference pattern including first to fourth interference figures formed from the object light and the reference light, the object light and the reference light each including a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction, the first interference figure being formed by interference between the object light which has the first polarized-light component and a first optical path length and the reference light which has the first polarized-light component and the first optical path length, the second interference figure being formed by interference between the object light which has the first polarized-light component and a second optical path length and the reference light which has the first polarized-light component and the second optical path length, the third interference figure being formed by interference between the object light which has the second polarized-light component and the first optical path length and the reference light which has the second polarized-light component and the first optical path length, and the fourth interference figure being formed by interference between the object light which has the second polarized-light component and the second optical path length and the reference light which has the second polarized-light component and the second optical path length;
(B) producing (I) a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
(C) obtaining a polarization state from the first reconstructed image and the second reconstructed image, the polarization state corresponding to each position in each of the reconstructed images of the object,
the step (B) including the sub-steps of:
obtaining two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light;
calculating respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light; and
obtaining a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
the step (C) including the sub-step of obtaining the polarization state corresponding to each position in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 19

An in-line type polarization imaging apparatus comprising:
at least one light source for supplying light including reference light and object light;
an image pickup section capturing images of interference figures each formed from the reference light and the object light that reaches the image pickup section through an object;
a reconstructed-image-producing section producing reconstructed images;
a polarized-light-image-calculating section obtaining polarized-light images;
a beam splitter splitting the light supplied from the light source into the reference light and the object light;
inclination means for inclining the reference light at an inclination angle based on a wavelength of the reference light and a distance between pixels of the image pickup section, the reference light being a divisional portion of the light split by the beam splitter; and
a beam-combining element combining the object light with the reference light having been inclined by the inclination means, the object light reaching after having passed through the object, wherein:
the reference light enters the image pickup section, being inclined at the inclination angle relative to the object light;
the object light and the reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction, both of which object light and reference light enter the image pickup section;
the image pickup section simultaneously captures an image of an interference pattern including (i) a first interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a first phase, (ii) a second interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a second phase, (iii) a third interference figure formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the first phase, and (iv) a fourth interference figure formed by interference between the object light which has the second light component and the reference light which has the second polarized-light component and the second phase;
the reconstructed-image-producing section (I) produces a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) produces a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
the polarized-light-image-calculating section obtains the polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
wherein the reconstructed-image-producing section (i) obtains two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light, (ii) calculates respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light, and (iii) obtains a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
wherein the polarized-light-image-calculating section obtains the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 20 (depends on 19)

The polarization imaging apparatus as set forth in claim 19, wherein:
the reference light enters the image pickup section, being inclined, with respect to the object light, at an inclination angle obtained by:
sin−1(λ/4τ)
where the wavelength of the reference light is λ and the distance between pixels of the image pickup section is τ.

### Claim 21 (depends on 19)

The polarization imaging apparatus as set forth in claim 19, further comprising a spatial-carrier-phase-shifting region obtaining complex amplitude distributions of the object from interference figures of regions that are adjacent to each other along an inclination direction of the reference light.

### Claim 22

An in-line type polarization imaging apparatus comprising:
at least one light source for supplying light including reference light and object light;
an image pickup section capturing images of interference figures each formed from the reference light and the object light that reaches the image pickup section through an object;
a reconstructed-image-producing section producing reconstructed images;
a polarized-light-image-calculating section obtaining polarized-light images;
a beam splitter splitting the light supplied from the light source into the reference light and the object light;
a phase-shift means for spatially shifting a phase of the reference light being a divisional portion of the light split by the beam splitter; and
a beam-combining element combining the object light with the reference light having a phase shifted by the phase-shift means, the object light reaching after having passed through the object, wherein:
the object light and the reference light each include a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction, both of which object light and reference light enter the image pickup section;
the image pickup section simultaneously captures an image of an interference pattern including (i) a first interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a first phase, (ii) a second interference figure formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a second phase, (iii) a third interference figure formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the first phase, and (iv) a fourth interference figure formed by interference between the object light which has the second light component and the reference light which has the second polarized-light component and the second phase;
the reconstructed-image-producing section (I) produces a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) produces a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
the polarized-light-image-calculating section obtains the polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
wherein the reconstructed-image-producing section (i) obtains two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light, (ii) calculates respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light, and (iii) obtains a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
wherein the polarized-light-image-calculating section obtains the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 23

A method for polarization imaging in which a polarization state of object light is obtained by capturing images of interference figures each formed by reference light and the object light that reaches through an object, the method comprising the steps of:
(A) splitting light supplied from a light source into the reference light and the object light each including a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction;
(B) inclining the reference light at an inclination angle based on a wavelength of the reference light and a distance between pixels of the image pickup section, the reference light being a divisional portion of the light split by the beam splitter;
(C) combining the object light with the reference light, the object light reaching after having passed through the object;
(D) making the reference light enter the image pickup section, the reference light being inclined at the inclination angle relative to the object light
(E) capturing, simultaneously, an image of an interference pattern including first to fourth interference figures formed from the object light and the reference light, the first interference figure being formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a first phase, the second interference figure being formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a second phase, the third interference figure being formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the first phase, and the fourth interference figure being formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the second phase;
(F) producing (I) a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
(G) obtaining polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
the step (F) including the sub-steps of:
obtaining two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light;
calculating respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light; and
obtaining a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
the step (G) including the sub-step of obtaining the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.

### Claim 24

A method for polarization imaging in which a polarization state of object light is obtained by capturing images of interference figures each formed by reference light and the object light that reaches through an object, the method comprising the steps of:
(A) splitting light supplied from a light source into the reference light and the object light each including a first polarized-light component polarized in a first direction and a second polarized-light component polarized in a second direction that is different from the first direction;
(B) spatially shifting a phase of the reference light being a divisional portion of the light split;
(C) combining the object light with the reference light whose phase has been shifted, the object light reaching after having passed through the object;
(D) capturing, simultaneously, an image of an interference pattern including first to fourth interference figures formed from the object light and the reference light, the first interference figure being formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a first phase, the second interference figure being formed by interference between the object light which has the first polarized-light component and the reference light which has the first polarized-light component and a second phase, the third interference figure being formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the first phase, and the fourth interference figure being formed by interference between the object light which has the second polarized-light component and the reference light which has the second polarized-light component and the second phase;
(E) producing (I) a first reconstructed image of the object in regard to the first polarized-light component, the first reconstructed image corresponding to the first interference figure and the second interference figure, after (a) extraction of pixels corresponding to the first interference figure and the second interference figure from the interference pattern and (b) pixel interpolation and (II) a second reconstructed image of the object in regard to the second polarized-light component, the second reconstructed image corresponding to the third interference figure and the fourth interference figure, after (a) extraction of pixels corresponding to the third interference figure and the fourth interference figure from the interference pattern and (b) pixel interpolation; and
(F) obtaining polarized-light images from the first reconstructed image and the second reconstructed image, the polarized-light images corresponding to respective positions in each of the reconstructed images of the object,
the step (E) including the sub-steps of:
obtaining two respective intensity distributions of the first polarized-light component and the second polarized-light component of only the reference light;
calculating respective complex amplitude distributions of the first polarized-light component and the second polarized-light component from the first to fourth interference figures and the two intensity distributions of only the reference light; and
obtaining a first amplitude distribution and a first phase distribution each as the first reconstructed image in regard to the first polarized-light component and a second amplitude distribution and a second phase distribution each as the second reconstructed image in regard to the second polarized-light component, from the complex amplitude distributions,
the step (F) including the sub-step of obtaining the polarized-light images corresponding to respective positions in each of the reconstructed images of the object, from the first amplitude distribution and the first phase distribution of the object and the second amplitude distribution and the second phase distribution of the object.