image processing basics and other stuff

basics/firstone.m

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+%hold example
+a = linspace(1,2*pi);
+b = sin(a);
+c = sin(a*2);
+d = sin(a*3/2);
+% ab teeno p se comment htane p bhi sirf 3rd waala graph bchta h so if
+% someone wanted all 3 graphs nt possible without hold , unless he plans to
+% use subplot 
+hold on;
+
+plot(a,b,'green');
+plot(a,c,'magenta');
+plot(a,d,'cyan');

basics/subplotexample.m

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+%subplot example
+a = linspace(1,2*pi);
+b = sin(a);
+c = sin(a*2);
+d = sin(a*3/2);
+
+subplot(3,1,1);
+plot(a,b,'green');
+
+subplot(3,1,2);
+plot(a,c,'magenta');
+
+subplot(3,1,3);
+plot(a,d,'cyan');

doubts.txt.txt

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+1) contrast enhancement by histogram equalization
+2) imshow , double , bit planes

imageprocessing/bitmap.m

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+clc;clear all;
+img = imread('images/god.jpg');
+img = rgb2gray(img);
+x = bitget(img,8);
+
+x = uint8(x*255);
+imshow(x);
+imwrite(x,'images/bitplane.jpg');

imageprocessing/colormapexample.m

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+clc;clear all;
+
+mycolormap = [];
+
+for i = 1:32
+        mycolormap(i,1) = (i)/255;
+        mycolormap(i,2) = (i)/255;
+        mycolormap(i,3) = 0;
+end;    
+
+for i   = 33:64
+        mycolormap(i,1) = 0;
+        mycolormap(i,2) = (i/2)/255;
+        mycolormap(i,3) = (i/2)/255;
+end;    
+
+for i = 65:96
+        mycolormap(i,1) = (i/3)/255;
+        mycolormap(i,2) = 0;
+        mycolormap(i,3) = (i/3)/255;
+end;    
+img = imread('images/god.jpg');
+%colormap(mycolormap);
+
+colormap hsv;
+
+cmap = colormap;
+indexedimg = rgb2ind(img,cmap);
+imshow(indexedimg);
+
+
+%imwrite(indexedimg,'images/darklord.jpg');

imageprocessing/edge_detection.m

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+clc;clear all;
+img=imread('images/god.jpg');
+I=rgb2gray(img);
+BW1 = edge(I,'sobel');
+BW2 = edge(I,'canny');
+figure;
+imshowpair(BW1,BW2,'montage') %new function for displaying multiple graphs!
+title('Sobel Filter                                   Canny Filter');

imageprocessing/experiment.m

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+% we'll cretae our own image data array 
+a = [];
+
+k = 100;
+
+for i = 1:k
+    for j = 1:k
+        a(i,j,1) = 20 + floor(rand()*235);
+        a(i,j,2) = 30 + floor(rand()*225);
+        a(i,j,3) = floor(rand()*255);
+    end;    
+end;    
+grayimg = rgb2gray(a);
+[a,b] = imhist(grayimg);

imageprocessing/filters.m

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+clc;clear;
+
+img=imread('images/god.jpg');
+[x, map]=rgb2ind(img,256);
+f1 = ones(4)/16;
+image=filter2(f1, x);
+
+subplot(121);
+imshow(img);
+subplot(122);
+imshow(image);
+%used indexed image, but no idea about the result
+%use ye waala filter for grayscale, rgb me average k liye alag filter hai
+
+

imageprocessing/filters4rgb.m

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+img=imread('images/god.jpg');
+
+radius=27;
+h=fspecial('disk',radius);
+
+edge=fspecial('sobel');
+
+
+image1=imfilter(img,h,'replicate');
+image2=imfilter(img,edge,'replicate');
+
+subplot(221);
+imshow(img);
+subplot(222);
+imshow(image1);
+subplot(223);
+imshow(image2);
+
+%sobel is used in edge detection
+
+img=imnoise(img,'salt & pepper',0.2);
+%subplot(224); imshow(img); 
+imr=medfilt2(img(:,:,1),[3 3]);
+imgr=medfilt2(img(:,:,2),[3 3]);
+imb=medfilt2(img(:,:,3),[3 3]);
+image3=cat(3, imr, imgr, imb);
+subplot(224);
+imshow(image3);
+
+
+

imageprocessing/imagebasics.m

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+% it is read into a 3d array 
+img = imread('god.jpg');
+
+a = size(img);
+%display(a(1,2));
+% display displays vars to the command window 
+
+padding = zeros(a(1,1),a(1,2));
+
+% the colon serves as a wildcard entry so that all values in the red are
+% selected in all rows and columns 
+redimg = cat(3,img(:,:,1),padding,padding);
+blueimg = cat(3,padding,img(:,:,2),padding);
+greenimg = cat(3,padding,padding,img(:,:,3));
+
+% imshow takes the raw image array data and makes it into a figure ,
+subplot(1,3,1);
+imshow(redimg);
+
+subplot(1,3,2);
+imshow(greenimg);
+
+subplot(1,3,3);
+imshow(blueimg);
+
+% how to multiline comment in matlab ? %{%} this is a rarely used feature 
+figure ; imshow(redimg);
+figure ; imshow(blueimg);
+figure ; imshow(greenimg);
+
+imwrite(redimg,'redgod.png');
+imwrite(greenimg,'greengod.png');
+imwrite(blueimg,'bluegod.png');
+

imageprocessing/imagetransformations.m

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+img=imread('images/god.jpg');
+
+colormap jet;
+cmap1 = colormap;
+
+colormap default;
+cmap2 = colormap;
+
+colormap gray;
+cmap3 = colormap;
+
+colormap winter;
+mycmap = colormap;
+
+%[indimg,map] = rgb2ind(img,150);
+
+figure ;
+imshow(rgb2ind(img,cmap3));
+colormap(cmap3);
+
+figure;
+imshow(rgb2ind(img,cmap2));
+colormap(cmap2);
+
+figure;
+imshow(rgb2ind(img,cmap1));
+colormap(cmap1);
+
+figure;
+imshow(rgb2ind(img,mycmap));
+colormap(mycmap);
+
+%imwrite(imdimg,'images/oilpainting_255bins.jpg');

imageprocessing/invertcolors.m

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+img = imread('images/god.jpg');
+a = size(img);
+
+for i = 1:a(1,1)
+    for j = 1:a(1,2)
+        % manipulating these relation infinite number of effects can be
+        % formed 
+        % for invert change this to  img(i,j,k) = 255 - img(i,j,k);
+        img(i,j,1) = (img(i,j,1) * .393) + (img(i,j,2) *.769) + (img(i,j,3) * .189);
+        img(i,j,2) = (img(i,j,1)* .349) + (img(i,j,2) *.686) + (img(i,j,3) * .168);
+        img(i,j,3) = (img(i,j,1) * .272) + (img(i,j,2) *.534) + (img(i,j,3) * .131);
+    end;
+end;
+
+imshow(img);
+%imwrite('images/invertedgod.jpg');

imageprocessing/makefile.bat

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+@echo off 
+echo ""> newfile.m

imageprocessing/modfloor.m

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+function f = modfloor(n,k)
+f = mod(floor(n/2),2);
+for i=1:k-1
+    f = mod(floor(f/2),2);
+end

imageprocessing/randomexp.m

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+a = linspace(1,2*pi);
+b = sin(a);
+c = sin(2*a);
+
+plot(a,b,a,c);

imageprocessing/randomshit.m

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+img = imread('images/god.jpg');
+gray = rgb2gray(img);
+
+imadj = imadjust(img,[0,0.85],[]);
+k = 5;
+for i=1:k*k
+        subplot(k,k,i);
+        imadj = imadjust(imadj,[0,0.85],[]);
+        imshow(imadj);   
+end;
+
+% ruk what are we trying to do just jot it down agr 2*2 plots h 
+% to i runs from 1:2 so we need subplot(2,2,1/2/3/4) 1+0,1+1,2+1,2+2

imageprocessing/rgb2gray_code.m

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+img = imread('images/god.jpg');
+a = size(img);
+
+for i = 1:a(1,1)
+    for j=1:a(1,2)
+      img(i,j,1) =  0.2126*img(i,j,1) +0.7152*img(i,j,2)+0.0722*img(i,j,3); 
+      img(i,j,2) = 0.2126*img(i,j,1) +0.7152*img(i,j,2)+0.0722*img(i,j,3); 
+      img(i,j,3) = 0.2126*img(i,j,1) +0.7152*img(i,j,2)+0.0722*img(i,j,3); 
+    end
+end;
+
+imshow(img);
+imwrite(img,'images/grayscale.jpg')

imageprocessing/rgb2grayexample.m

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+img = imread('images/god.jpg');
+grayimg = rgb2gray(img);
+bwimage = im2bw(img);
+
+a = size(img);
+
+padding = zeros(a(1,1),a(1,2));
+redimg = cat(3,img(:,:,1),padding,padding);
+blueimg = cat(3,padding,img(:,:,2),padding);
+greenimg = cat(3,padding,padding,img(:,:,3));
+
+[yRed,x] = imhist(img(:,:,1));
+[yGreen,x] = imhist(img(:,:,2));
+[yBlue,x] = imhist(img(:,:,3));
+
+hold on;
+plot(x,yRed,'red');
+plot(x,yGreen,'green');
+plot(x,yBlue,'blue');
+%{
+subplot(1,3,1);
+plot(x,yRed,x,yGreen,x,yBlue);
+
+subplot(1,3,2);
+imhist(grayimg);
+
+subplot(1,3,3);
+imhist(bwimage);
+%}

imageprocessing/testfilters.m

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+clc; clear all;
+img=imread('images/god.jpg');
+img=rgb2gray(img);
+imgd=im2double(img);
+
+imgd=imnoise(imgd, 'salt & pepper', 0.02); %0.02 gives density of noise
+f=ones(3,3)/9;
+image=filter2(f,imgd);
+subplot(221);
+imshow(imgd);
+subplot(222);
+imshow(image);
+%works!!!!
+
+%mean filter just blurrs the image, not much useful
+%trying median filter
+
+betterimage=medfilt2(imgd);
+subplot(223);
+imshow(betterimage);
+
+

resources.txt.txt

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+octave docs 
+
+https://www.gnu.org/software/octave/doc/interpreter/
+
+matlab 
+
+http://www.bogotobogo.com/Matlab/
+
+speech processing http://www.mathworks.com/matlabcentral/profile/authors/4428430-speech-processing
+
+
+https://sites.google.com/site/butwhymath/m/convolution ( convolution )