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US 6,411,406 B1Granted
Holographic microscope and method of hologram reconstruction
AssigneeDalhousie University
InventorH. Juergen Kreuzer
Life of this patent
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Abstract
A holographic microscope is described along with a method for numerically reconstructing a holographic image. The method uses a coordinate transformation of the Kirchhoff-Helmholtz equation to remove the non-linear component from the phase factor. The intensity distribution in the transformed coordinate system is then interpolated on an equidistant point grid and Fast-Fourier-Transforms are used to compute the result.
Claims25
A method of numerically reconstructing a holographic image comprising the steps of:
- measuring and recording the intensity distribution of a sample;
- performing a coordinate transformation of the intensity distribution to produce a transformed intensity distribution which removes a non-linearity in a phase factor of a Kirchhoff-Helmholtz formula applied to the intensity distribution producing a phase factor linearized Kirchhoff-Helmholtz formula;
- interpolating on an equidistant point grid the transformed intensity distribution to produce an interpolated intensity distribution;
- taking a Fast-Fourier-Transform of a summation form of the phase factor linearized Kirchhoff-Helmholtz formula to produce a transformed Kirchhoff-Helmholtz formula;
- calculating an image using the transformed Kirchhoff-Helmholtz formula on the interpolated intensity distribution.
2 more elements
A method of numerically reconstructing a holographic image comprising the steps of:
- measuring and recording the intensity distribution with a sample present;
- measuring and recording the intensity distribution without the sample present;
- subtracting the intensity distribution without the sample present from the intensity distribution with the sample present to obtain a net intensity distribution;
- performing a coordinate transformation of the net intensity distribution to produce a transformed intensity distribution which removes a non-linearity in a phase factor of a Kirchhoff-Helmholtz formula applied to the net intensity distribution producing a phase factor linearized Kirchhoff-Helmholtz formula;
- interpolating on an equidistant point grid the transformed intensity distribution to produce an interpolated intensity distribution;
- taking a Fast-Fourier-Transform of a summation form of the phase factor linearized Kirchhoff-Helmholtz formula to produce a transformed Kirchhoff-Helmholtz formula;
- calculating an image using the transformed Kirchhoff-Helmholtz formula on the interpolated intensity distribution.
4 more elements
A holographic microscope comprising:
- a radiation emitting point source;
- a radiation measuring and recording apparatus which measures and records the intensity of the radiation impinging on a surface of it;
- a sample holder interposed between the radiation emitting point source and the radiation measuring source and being positioned significantly closer to the radiation emitting point source than to said radiation measuring and recording apparatus;
- an image recording and processing means which:
- measures and records the intensity distribution with a sample present;
- measures and records the intensity distribution without the sample present;
- subtracts the intensity distribution without the sample present from the intensity distribution with the sample present to obtain a net intensity distribution;
- an image reconstruction processing means which:
- performs a coordinate transformation of the net intensity distribution to produce a transformed intensity distribution which removes a non-linearity in a phase factor of a Kirchhoff-Helmholtz formula applied to the net intensity distribution producing a phase factor linearized Kirchhoff-Helmholtz formula;
- interpolates on an equidistant point grid the transformed intensity distribution to produce an interpolated intensity distribution;
- takes a Fast-Fourier-Transform of a summation form of the phase factor linearized Kirchhoff-Helmholtz formula to produce a transformed Kirchhoff-Helmholtz formula;
- calculates an image using the transformed Kirchhoff-Helmholtz formula on the interpolated intensity distribution.
9 more elements
A method of numerically reconstructing a holographic image comprising the steps of:
- measuring and recording an intensity distribution of a sample;
- performing a coordinate transformation of the intensity distribution to produce a transformed intensity distribution which removes a non-linearity in a phase factor of a Kirchhoff-Helmholtz formula;
- interpolating on an equidistant point grid the transformed intensity distribution to produce an interpolated intensity distribution;
- calculating an image of the sample using a Kreuzer implementation of the transformed Kirchhoff-Helmholtz formula on the interpolated intensity distribution.
1 more element
A method of numerically performing a reconstruction from an intensity distribution comprising the steps of:
- performing a coordinate transformation of the intensity distribution to produce a transformed intensity distribution which removes a non-linearity in a phase factor of a Kirchhoff-Helmholtz formula applied to the intensity distribution producing a phase factor linearized Kirchhoff-Helmholtz formula;
- interpolating on an equidistant point grid the transformed intensity distribution to produce an interpolated intensity distribution;
- taking a Fast-Fourier-Transform of a summation form of the phase factor linearized Kirchhoff-Helmholtz formula to produce a transformed Kirchhoff-Helmholtz formula;
- calculating a reconstruction using the transformed Kirchhoff-Helmholtz formula on the interpolated intensity distribution.
1 more element
A computer readable medium having instructions stored thereon for causing a processing platform to implement a reconstruction of a recorded intensity distribution, the instructions comprising:
- code means for performing a coordinate transformation of the intensity distribution to produce a transformed intensity distribution which removes a non-linearity in a phase factor of a Kirchhoff-Helmholtz formula applied to the intensity distribution producing a phase factor linearized Kirchhoff-Helmholtz formula;
- code means for interpolating on an equidistant point grid the transformed intensity distribution to produce an interpolated intensity distribution;
- code means for taking a Fast-Fourier-Transform of a summation form of the phase factor linearized Kirchhoff-Helmholtz formula to produce a transformed Kirchhoff-Helmholtz formula;
- and
- code means for calculating a reconstruction using the transformed Kirchhoff-Helmholtz formula on the interpolated intensity distribution.
2 more elements
Dependencies are inferred from the claim text.