BUTTERWORTH_LOW_CVIP

butterworth_low_cvip() -performs butterworth low pass filter operation.

Contents

SYNTAX

out_s = butterworth_low_cvip(spectrum,block_size,transform_type,order,fc)

Input parameters include :

Output parameters include:

DESCRIPTION

This function performs a 2D low pass filtering operation on the spectrum of an image. It applies butterworth low pass filter of order specified by the user and allows the frequencies that are below the specified cutoff frequency.

REFERENCE

1. Scott E Umbaugh. DIGITAL IMAGE PROCESSING AND ANALYSIS: Applications with MATLAB and CVIPtools, 3rd Edition.

EXAMPLE

% Create an spectrum by available transforms

 spectrum = ones(128,256,3);

% Block size

 block_size1  = [];
 block_size2 = [64 128];

% Transform type

 transform_type1 =' fft';
 transform_type2 ='non-fft';
 transform_type3 ='center';

% Order

 order = 6;

% cutoff frequency

 fc1 = 32;
 fc2 = 23;
 fc3 = 16;


% Call function

 out_s1 = butterworth_low_cvip( spectrum,block_size1,transform_type1,order,fc1);
 out_s2 = butterworth_low_cvip( spectrum,block_size2, transform_type2,order, fc2);
 out_s3 = butterworth_low_cvip( spectrum,block_size2 , transform_type3,order,fc3);

% Display output

 figure; imshow(out_s1,[]);title(' Output with FFT Transform');
 figure; imshow(out_s2,[]);title(' Output with Non FFT Transform')
 figure; imshow(out_s3,[]);title('with center');

CREDITS

Author: Mehrdad Alvandipour, March 2017
Copyright © 2017-2018 Scott E Umbaugh
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