Image processing method

Patent metadata

Field	Value
Publication number	US-2016320485-A1
Application number	US-201514945636-A
Country	US
Kind code	A1
Filing date	Nov 19, 2015
Priority date	Apr 29, 2015
Publication date	Nov 3, 2016
Grant date	—

Abstract

An image processing method for processing a plurality of holograms includes the steps of: performing a Fourier transform operation on the holograms to result in a plurality of corresponding spectra in a spectrum space;
calculating a sum of the plurality of spectra to obtain the synthetic spectrum; multiplying the synthetic spectrum by a weight function associated with the spectrum space to obtain a normalized synthetic spectrum, each function value of the weight function corresponding to a respective position in the spectrum space and being associated with distribution of the plurality of spectra in the spectrum space; and performing the inverse Fourier transform operation on the normalized synthetic spectrum to result in a normalized synthetic hologram.

First claim

What is claimed is:

1 . An image processing method for processing a plurality of holograms which are associated with an object and which are generated through the synthetic aperture technique, the image processing method to be implemented by an image processing apparatus, and comprising the steps of:
performing a Fourier transform operation on the holograms to result in a plurality of spectra, which correspond respectively to the holograms, in a spectrum space; calculating a sum of the plurality of spectra to obtain a synthetic spectrum; multiplying the synthetic spectrum by a weight function associated with the spectrum space to obtain a normalized synthetic spectrum, each function value of the weight function corresponding to a respective position in the spectrum space, and being associated with distribution of the plurality of spectra in the spectrum space; and performing the inverse Fourier transform operation on the normalized synthetic spectrum to result in a normalized synthetic hologram corresponding to the object.

2 . The image processing method according to claim 1 , subsequent to the step of performing the inverse Fourier transform operation, further comprising:
performing the numerical reconstruction process on the normalized synthetic hologram to result in a reconstructed complex image of the normalized synthetic hologram.

3 . The image processing method according to claim 1 , wherein the spectrum space of each of the plurality of spectra, the synthetic spectrum and the normalized synthetic spectrum is a two-dimensional spectrum plane, each of the plurality of spectra, the synthetic spectrum and the normalized synthetic spectrum to be represented in a three-dimensional (U-V-W) coordinates system, coordinates (u, v, w) of each of the plurality of spectra, the synthetic spectrum and the normalized synthetic spectrum in the three-dimensional (U-V-W) coordinates system being defined as a spectrum position (u, v) on the two-dimensional spectrum plane having a corresponding magnitude of w.

4 . The image processing method according to claim 3 , wherein:
each of the plurality of spectra and the synthetic spectrum is distributed in a respective frequency pass band on the two-dimensional spectrum plane; and in the step of multiplying the synthetic spectrum by a weight function, within the frequency pass band where the synthetic spectrum is distributed, the function value of the weight function corresponding to the spectrum position (u, v) is equal to

a

N


(

u
,
v

)

,

in which a is a real number greater than zero and not greater than one, and N(u, v) is a positive integer and is defined as a number of the plurality of spectra whose frequency pass bands cover the spectrum position (u, v), the function value of the weight function corresponding to a spectrum position beyond the frequency pass band where the synthetic spectrum is distributed being equal to zero.

5 . The image processing method according to claim 4 , wherein, in the step of multiplying the synthetic spectrum by a weight function, a is equal to one.

6 . An image processing method for processing a plurality of holograms which are associated with an object and which are generated through the synthetic aperture technique, the image processing method to be implemented by an image processing apparatus, and comprising the steps of:
performing a Fourier transform operation on the holograms to result in a plurality of spectra, which correspond respectively to the holograms, in a spectrum space; multiplying each of the plurality of spectra by a weight function associated with the spectrum space to obtain a plurality of weighted spectra, respectively, each function value of the weight function corresponding to a respective position in the spectrum space, and being associated with distribution of the plurality of spectra in the spectrum space; calculating a sum of the plurality of weighted spectra to obtain a normalized synthetic spectrum; and performing the inverse Fourier transform operation on the normalized synthetic spectrum to result in a normalized synthetic hologram corresponding to the object.

7 . The image processing method according to claim 6 , subsequent to the step of performing the inverse Fourier transform operation, further comprising:
performing the numerical reconstruction process on the normalized synthetic hologram to result in a reconstructed complex image of the normalized synthetic hologram.

Assignees

• Univ Nat Taiwan Normal

Inventors

• Cheng Chau-Jern
• Lin Yu-Chih
• Lai Xin-Ji

Classifications

• G01S15/8977

  using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution · CPC title

• G01S15/8997

  using synthetic aperture techniques · CPC title

• G01S15/897 Primary

  using application of holographic techniques · CPC title

• G03H1/265

  Angle multiplexing; Multichannel holograms (G03H1/268 takes precedence) · CPC title

• G03H2001/046

  Synthetic aperture · CPC title