Two-dimensional spatial frequency filtering by FFT using Matlab

Detail

Language

English

Title

Two-dimensional spatial frequency filtering by FFT using Matlab

Free Keywords

Matlab, FFT, Fourier Tansform, Spatial Frequency, Filtering

Description

Matlab scripts for band-pass filtering a 2-dimensional image using FFT. One does isotropic filtering. The second one performs oriented band-pass filtering similar to an array of simple cells in V1.
Also see demo of Fourier and Inverse Fourier transform demo (in Japanese) at YouTube:
http://www.youtube.com/watch?v=qB0cffZpw-A

Last Modified Date

Jan 27, 2010 10:41:03

Created Date

Feb 28, 2008 15:16:43

Contributor

Izumi OHZAWA (ohzawa)

Item Type

Model

Change Log(History)

Jan 27, 2010	Modified; Related to.
Jan 27, 2010	Modified; Description.
Jan 27, 2010	Modified; Related to.
Jan 27, 2010	Modified; Related to.
Jan 27, 2010	Modified; Related to.
May 1, 2009	Modified; Description, Related to.
Mar 1, 2008	Modified; Related to.
Feb 28, 2008	Modified; Index.

Model type

Matlab

Creator

Kota S. Sasaki

Izumi Ohzawa

Preview


Isotropic Band-pass Spatial Frequency Filter	Oriented Band-pass Spatial Frequency Filter

Model file

SF-filtering.zip

Type	: application/x-zip
Size	: 1.6 MB
Last updated	: Feb 28, 2008
Downloads	: 1329

Total downloads since Feb 28, 2008 : 1329

Readme

README.txt

Two-dimensional spatial frequency filtering by FFT using Matlab

Authors: Kota S. Sasaki and Izumi Ohzawa
Graduate School of Frontier Biosciences, Osaka University
kota@fbs.osaka-u.ac.jp, ohzawa@fbs.osaka-u.ac.jp

License: BSD license, http://creativecommons.org/licenses/BSD/

Date: 2007-12-20

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SFFiltering1script.m:

This Matlab script band-pass filters a 2-dimensional image using FFT.
Computed results are displayed in a window.  A captured version of this
is in results/SFFiltering1script.png.
Top left: the original image (gray scaled)
Top right: amplitude spectrum (logarithmically scaled amplitude)
Bottom left: 2-d filter (circularly symmetric Gaussian band-pass filter)
Bottom right: filtered image.

SFFiltering2script.m:

This Matlab script applies an oriented band-pass filter on a 2-dimensional image using FFT.
Computed results are displayed in a window.  A captured version of this
is in results/SFFiltering2script.png.
The filter shape is equivalent to that of a filter by a single simple cell in V1.
(Think of the results as an image encoded by a single type of simple cell
tuned to one spatial frequency band and one orientation band.)

Top left: the original image (gray scaled)
Top right: amplitude spectrum (logarithmically scaled amplitude)
Bottom left: 2-d filter (oriented Gaussian band-pass filter)
Bottom right: filtered image.


GetLuminanceImage.m:

Reads in an image (may be color) and converts it into a gray scale image
for computation.

Myff2.m:

My version of 2D FFT for better handling.

Rights

This work is licensed under a Creative Commons Attribution 2.5 License

Index

/ Public / Visiome 2004 / Visual System / Perception/Cognition / Spatiotemporal Perception / Spatial Frequency
/ Public / Model
/ Public / Demonstration

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Item summary

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