# IMAGE PROCESSING

Lets Learn together... Happy Reading

" Two roads diverged in a wood, and I,
I took the one less traveled by,
And that has made all the difference "-Robert Frost

### Rainbow

Last night I was watching dragon tales, a cartoon series. I saw a scene with rainbow and my mind started to think to implement that rainbow in MATLAB. To my surprise, what I learned in the tenth grade mathematics came in handy, the equation of a circle.  Many times our lower class basic mathematics will come throughout our life. As a result I have started to read tenth grade mathematics once again ;-)
I followed the same procedure, 'How to draw a circle'. Instead of finding the midpoint for x co-ordinate I took the image size, so that I may get a half a circle.
sz=400;
rad=200;
clear RGB
RGB(1:sz,1:sz,1:3)=255;
RGB=uint8(RGB);
[x y z]= find(RGB==255);

xc=sz;
yc=ceil((sz+1)/2);

for i=1:12
radius=(rad-10*i).^2;
r=find(((x-xc).^2+(y-yc).^2)<=radius);

for j=1:size(r,1)

if(mod(i,2)==0)
RGB(x(r(j)),y(r(j)),:)=255;
end
if(mod(i,3)==1)
RGB(x(r(j)),y(r(j)),:)=0;
end

end

end

B=rgb2gray(RGB);

D=edge(B);
SE=strel('disk',2);
D1=~imdilate(D,SE);

I colored the image based on label

[BW ,L]=bwlabel(D1,8);

mycolor(:,1)=[128;128;255];
mycolor(:,2)=[215;0;0];
mycolor(:,3)=[255;128;0];
mycolor(:,4)=[255;255;0];
mycolor(:,5)=[0;128;64];
mycolor(:,6)=[10;160;220];
mycolor(:,7)=[0;0;70];
mycolor(:,8)=[65;0;128];
mycolor(:,9)=[128;128;255];
for n=1:9
[r c]=find(BW==n);

for i=1:size(r,1)
RGB(r(i,1),c(i,1),:)=mycolor(:,n);
end
end
imshow(RGB);

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