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/EX4.18/Ex4_18.sce     | 108 +++++++++++++++++++++++++++++++++++++++++
 3176/CH4/EX4.18/Ex_4_18_2.jpeg | Bin 0 -> 46176 bytes
 3176/CH4/EX4.18/Ex_4_18_4.jpeg | Bin 0 -> 64744 bytes
 3 files changed, 108 insertions(+)
 create mode 100644 3176/CH4/EX4.18/Ex4_18.sce
 create mode 100644 3176/CH4/EX4.18/Ex_4_18_2.jpeg
 create mode 100644 3176/CH4/EX4.18/Ex_4_18_4.jpeg

(limited to '3176/CH4/EX4.18')

diff --git a/3176/CH4/EX4.18/Ex4_18.sce b/3176/CH4/EX4.18/Ex4_18.sce
new file mode 100644
index 000000000..8a3e54776
--- /dev/null
+++ b/3176/CH4/EX4.18/Ex4_18.sce
@@ -0,0 +1,108 @@
+//Ex4_18
+//Image Smoothing Using Gaussian 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'gaussian'then
+        H=exp(-(D.^2)./(2*(D0^2)));
+    else
+        disp('Unknownfiltertype.')
+    end
+endfunction
+
+
+
+///////////////////////////////////   Main Programm   ////////////////////////////////
+a=imread("Ex4_18.tif");
+//gray=rgb2gray(a);
+gray=im2double(a);
+
+figure,ShowImage(gray,'Gray Image');
+title('Original Image');
+[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('gaussian',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('gaussian',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('gaussian',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('gaussian',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('gaussian',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);
diff --git a/3176/CH4/EX4.18/Ex_4_18_2.jpeg b/3176/CH4/EX4.18/Ex_4_18_2.jpeg
new file mode 100644
index 000000000..a1ab1a125
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diff --git a/3176/CH4/EX4.18/Ex_4_18_4.jpeg b/3176/CH4/EX4.18/Ex_4_18_4.jpeg
new file mode 100644
index 000000000..2ab6ae851
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-- 
cgit