From b1f5c3f8d6671b4331cef1dcebdf63b7a43a3a2b Mon Sep 17 00:00:00 2001
From: priyanka
Date: Wed, 24 Jun 2015 15:03:17 +0530
Subject: initial commit / add all books

---
 3176/CH4/EX4.17/Ex4_17.sce | 112 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 112 insertions(+)
 create mode 100644 3176/CH4/EX4.17/Ex4_17.sce

(limited to '3176/CH4/EX4.17/Ex4_17.sce')

diff --git a/3176/CH4/EX4.17/Ex4_17.sce b/3176/CH4/EX4.17/Ex4_17.sce
new file mode 100644
index 000000000..2e5966dd5
--- /dev/null
+++ b/3176/CH4/EX4.17/Ex4_17.sce
@@ -0,0 +1,112 @@
+//Ex4_17
+// Image Smoothing with a Butterworth LowPass Filter
+// Version : Scilab 5.4.1
+// Operating System : Window-xp, Window-7
+//Toolbox: Image Processing Design 8.3.1-1
+//Toolbox: SIVP 0.5.3.1-2
+//Reference book name : Digital Image Processing
+//book author: Rafael C. Gonzalez and Richard E. Woods
+
+clc;
+close;
+clear;
+xdel(winsid())//to close all currently open figure(s).
+
+function[H]=lowpassfilter(type1,M,N,D0,n)//lowpassfilter is used to filter an image .
+    u=0:(M-1);
+    v=0:(N-1);
+    idx=find(u>M/2);
+    u(idx)=u(idx)-M;
+    idy=find(v>N/2);
+    v(idy)=v(idy)-N;
+    [U,V]=meshgrid(v,u);
+    D=sqrt(U.^2+V.^2);
+    select type1
+        
+    case'butterworth'then
+        if argn(2)==4 then
+            n=1;
+        end
+        H = ones(M,N)./(1+(D./D0).^(2*n));
+   
+    else
+        disp('Unknownfiltertype.')
+    end
+endfunction
+
+
+
+///////////////////////////////////   Main Programm   ////////////////////////////////
+a=imread("Ex4_17.tif");
+//gray=rgb2gray(a);
+gray=im2double(a);
+
+figure,ShowImage(gray,'Gray Image');
+title('Original Image','color','blue','fontsize',4);
+[M,N]=size(gray);
+
+h=fft2(gray);//fft2() is used to find 2-Dimensional Fast Fourier Transform of an matrix
+i=log(1+abs(h));
+in=fftshift(i);//fftshift() is used to rearrange the fft output, moving the zero frequency to the center of the spectrum.
+inm=mat2gray(in)
+figure,ShowImage(inm,'Frequency Spectrum');
+title('Frequency Spectrum','color','blue','fontsize',4);
+
+/////////////////////////// Filtering With Cut-off Frequency 10   ///////////////////////
+filt=lowpassfilter('butterworth',M,N,10); // Function which generate Filter Mask Corresponding to Low Frequency
+//filt_shift=fftshift(filt);
+//figure,ShowImage(filt_shift,'Filter Mask');
+//title('Filter Mask to Specific Cut-Off Frequency');
+n=filt.*h;//Multiply the Original Spectrum with the Filter Mask.
+Image_filter=real(ifft(n));
+Image_filter=mat2gray(Image_filter)
+figure,ShowImage(Image_filter,'Filtered Image');
+title('Filtered Image with Cut-Off Frequency 10','color','blue','fontsize',4);
+
+
+/////////////////////////// Filtering With Cut-off Frequency 30   ///////////////////////
+filt=lowpassfilter('butterworth',M,N,30); // Function which generate Filter Mask Corresponding to Low Frequency
+//filt_shift=fftshift(filt);
+//figure,ShowImage(filt_shift,'Filter Mask');
+//title('Filter Mask to Specific Cut-Off Frequency');
+n=filt.*h;//Multiply the Original Spectrum with the Filter Mask.
+Image_filter=real(ifft(n));
+Image_filter=mat2gray(Image_filter)
+figure,ShowImage(Image_filter,'Filtered Image');
+title('Filtered Image with Cut-Off Frequency 30','color','blue','fontsize',4);
+
+
+/////////////////////////// Filtering With Cut-off Frequency 60   ///////////////////////
+filt=lowpassfilter('butterworth',M,N,60); // Function which generate Filter Mask Corresponding to Low Frequency
+//filt_shift=fftshift(filt);
+//figure,ShowImage(filt_shift,'Filter Mask');
+//title('Filter Mask to Specific Cut-Off Frequency');
+n=filt.*h;//Multiply the Original Spectrum with the Filter Mask.
+Image_filter=real(ifft(n));
+Image_filter=mat2gray(Image_filter)
+figure,ShowImage(Image_filter,'Filtered Image');
+title('Filtered Image with Cut-Off Frequency 60','color','blue','fontsize',4);
+
+
+/////////////////////////// Filtering With Cut-off Frequency 160   ///////////////////////
+filt=lowpassfilter('butterworth',M,N,160); // Function which generate Filter Mask Corresponding to Low Frequency
+//filt_shift=fftshift(filt);
+//figure,ShowImage(filt_shift,'Filter Mask');
+//title('Filter Mask to Specific Cut-Off Frequency');
+n=filt.*h;//Multiply the Original Spectrum with the Filter Mask.
+Image_filter=real(ifft(n));
+Image_filter=mat2gray(Image_filter)
+figure,ShowImage(Image_filter,'Filtered Image');
+title('Filtered Image with Cut-Off Frequency 160','color','blue','fontsize',4);
+
+
+/////////////////////////// Filtering With Cut-off Frequency 460   ///////////////////////
+filt=lowpassfilter('butterworth',M,N,460); // Function which generate Filter Mask Corresponding to Low Frequency
+//filt_shift=fftshift(filt);
+//figure,ShowImage(filt_shift,'Filter Mask');
+//title('Filter Mask to Specific Cut-Off Frequency');
+n=filt.*h;//Multiply the Original Spectrum with the Filter Mask.
+Image_filter=real(ifft(n));
+Image_filter=mat2gray(Image_filter)
+figure,ShowImage(Image_filter,'Filtered Image');
+title('Filtered Image with Cut-Off Frequency 460','color','blue','fontsize',4);
-- 
cgit