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Gaussian Bandpass Filter for Image Processing



01 Apr 2011 (Updated )

This function performs Gaussian bandpass filtering in the frequency domain

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Butterworth Bandpass Filter
This simple function was written for my Digital Image Processing course
at Eastern Mediterranean University taught by
Assoc. Prof. Dr. Hasan Demirel
for the 2010-2011 Spring Semester
for the complete report:

Written By:
Leonardo O. Iheme (leonardo.iheme@cc.emu.edu.tr)
24th of March 2011

  I = The input grey scale image
  d0 = Lower cut off frequency
  d1 = Higher cut off frequency

The function makes use of the simple principle that a bandpass filter
can be obtained by multiplying a lowpass filter with a highpass filter
where the lowpass filter has a higher cut off frquency than the high pass filter.

ima = imread('grass.jpg');
ima = rgb2gray(ima);
filtered_image = gaussianbpf(ima,30,120);
Gaussian Bandpass Filter

Required Products Image Acquisition Toolbox
Image Processing Toolbox
MATLAB release MATLAB 7.10 (R2010a)
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Comments and Ratings (5)
14 Jul 2015 John D

John D (view profile)

Hi Leonardo, Why is the fft of the original image being added to the filtered version of the fft?

filtered_image = fftI + filter3.*fftI;

12 Nov 2014 Leonardo O. Iheme

Hello Sudarshan,
Thanks for the 5* rating.
Have you tried initializing with zeros instead? I think you should and then tell us all what happens.

Comment only
11 Nov 2014 Sudarshan

Why do you initialise the filters that way? lines 45-47. Would be of great help.. Thanks in advance

25 Nov 2013 Anfisa

Anfisa (view profile)

14 Oct 2013 Robin Martin  
04 Apr 2011 1.1

Updated the title

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