Imaging system using polarization effects to enhance image quality
First Claim
1. A system for imaging a section of a medium which receives and returns light from the section and from sites adjacent to the section, said system comprising:
- optics for directing light in beams of different polarization in said medium along an optical axis and collecting returned light from the medium;
means for generating an image of the section from said returned light in response to a polarization parameter of said returned light; and
wherein said beams are overlapping in said medium to reduce the part of said returned light from the sites adjacent to said section which are spaced generally along said optical axis.
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Accused Products
Abstract
The quality of images produced by confocal microscopy, and especially scanning laser confocal microscopy, is enhanced especially for images obtained in turbid mediums such as many biological tissue specimens, by reducing speckle from scatterers that exist outside (above and below) the section which is being imaged by utilizing sheared beams, both of which are focused to laterally or vertically offset spots and polarizing the beams to have opposite senses of circular polarization (right and left handed circular polarization). The return light from the section of certain polarization is detected after passing through the confocal aperture of the confocal microscope. Images can be formed using optical coherence detection of the return light. Light from scatterers outside the section of interest, which are illuminated by both of the sheared beams, interfere thereby reducing speckle due to such scatterers, and particularly scatters which are adjacent to the section being imaged. Sheared beams having orthogonal linear polarization, as may be obtained from a Wollaston or Nomarski prism are converted into circularly polarized beams of opposite polarization sense by a quarter wave plate and focused into laterally displaced spots. A Dyson type lens is used to obtain sheared beams which when focused form vertically displaced spots. The optical signals representing reflections from the section are derived by polarizing optics which may either be a polarizing beamsplitter in the incident beam path or a retarder and analyzer. The retarder may be selected to provide different polarization phase shifts of the return light, and with the analyzer, detects the degree of elliptical polarization representing the optical activity and circular dichroism producing the optical signal representing the image.
70 Citations
12 Claims
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1. A system for imaging a section of a medium which receives and returns light from the section and from sites adjacent to the section, said system comprising:
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optics for directing light in beams of different polarization in said medium along an optical axis and collecting returned light from the medium;
means for generating an image of the section from said returned light in response to a polarization parameter of said returned light; and
wherein said beams are overlapping in said medium to reduce the part of said returned light from the sites adjacent to said section which are spaced generally along said optical axis.
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2. A system for imaging a section of a medium which receives and returns light from the section and from sites adjacent to the section, said system comprising:
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optics for directing light in beams of different polarization in said medium along an optical axis and collecting returned light from the medium;
means for generating an image of the section from said returned light in response to a polarization parameter of said returned light; and
wherein said beams are incident in said medium at spots spaced from each other along said optical axis. - View Dependent Claims (3, 4)
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5. A method for imaging a section of a medium which receives and returns light from the section and from sites adjacent to the section, said method comprising the steps of:
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directing light in beams of different polarization in said medium along an optical axis;
collecting returned light from the medium;
generating an image of the section from said returned light in response to a polarization parameter of said returned light; and
wherein said beams are overlapping in said medium to reduce the part of said returned light from the sites adjacent to said section which are spaced generally along said optical axis.
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6. A method for imaging a section of a medium which receives and returns light from the section and from sites adjacent to the section, said method comprising the steps of:
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directing light in beams of different polarization in said medium along an optical axis;
collecting returned light from the medium;
generating an image of the section from said returned light in response to a polarization parameter of said returned light; and
wherein said beams are incident in said medium at spots spaced from each other along said optical axis. - View Dependent Claims (7, 8)
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9. An optical coherence imaging system comprising:
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a source providing light which is of low coherence;
optics which directs the light from said source into a reference arm and a sample arm to an image plane in a specimen section;
a polarization separator which shears said light into two beams;
a polarization retarder between said separator and said specimen providing said sheared beams each with an opposite sense of generally orthogonal polarization;
an objective having an optical axis for focusing said two beams at spots offset from each other in a direction generally along said axis which beams overlap outside the vicinity of said image plane;
a detection arm into which light is directed by said beam splitter from said reference and sample arms; and
means for providing images in response to interference of light in said detection arm. - View Dependent Claims (10, 11, 12)
a beam splitter for directing light into a reference arm and a sample arm to an image plane; and
a scanner for scanning light of the sample arm in said plane in one or more directions.
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11. The system according to claim 9 wherein said separator is a Dyson type lens to obtain said spots offset in said direction along said axis.
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12. The system according to claim 9 wherein said orthogonal polarization is generally circular polarization.
Specification
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Current AssigneeCaliber Imaging & Diagnostics, Inc.
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Original AssigneeLucid Inc.
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InventorsZavislan, James M.
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Primary Examiner(s)Pham, Hoa Q.
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Application NumberUS09/641,798Time in Patent Office1,026 DaysField of Search356/364-369, 356/450, 356/453, 356/487, 356/489, 356/491, 356/520, 250/225, 250/234, 250/235, 250/236, 359/386, 359/370, 359/385, 359/371, 600/473, 600/476US Class Current356/369CPC Class CodesG01J 4/00 Measuring polarisation of l...G02B 21/0032 Optical details of illumina...G02B 21/0056 based on optical coherence,...G02B 21/0068 arrangements using polarisa...
