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## Gaussian Bandpass Filter for Image Processing

version 1.1 (2.33 KB) by

This function performs Gaussian bandpass filtering in the frequency domain

Updated

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:
http://www.scribd.com/doc/51981950/HW4-Frequency-Domain-Bandpass-Filtering

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.

Usage GAUSSIANBPF(I,DO,D1)
Example
ima = rgb2gray(ima);
filtered_image = gaussianbpf(ima,30,120);
Gaussian Bandpass Filter

When I am executing this code getting error
'Undefined function 'gaussianbpf' for input arguments of type 'uint8'.'

while my code is
>> c = rgb2gray(c);
>> filtered_image = gaussianbpf(c,30,120);

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;

Leonardo O. Iheme

### Leonardo O. Iheme (view profile)

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.

Sudarshan

### Sudarshan (view profile)

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

Anfisa

Robin Martin