# IMAGE PROCESSING

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

### Some Random effects

• Negative Image
Subtract 255 from the RGB image, to obtain negative image.
MATLAB CODE:
%Here the  I am subtracting 255 from R,G and B.
imshow(255-A);

 Original Image
 Negative Image

• Sine Wave

First find the mid point of the RGB image.
Convert the points from Cartesian to polar co_ordinates
Find the sine value for the angle 'theta'
Again convert the points to Cartesian co_ordinates

SAMPLE CODE:
x2=zeros([size(A,1) size(A,2)]);
y2=zeros([size(A,1) size(A,2)]);
for i=1:size(A,1)
x=i-midx;
for j=1:size(A,2)
%Cartesian to Polar co-ordinates
[theta1,rho1]=cart2pol(i,j-midy);

phi=sin(theta1);

%Polar to Cartesian co-ordinates
[l,m]=pol2cart(phi,rho1);
x2(i,j)=ceil(l)+midx;
y2(i,j)=ceil(m)+midy;

end
end

 Sine wave

 Original Image

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### Number of occurrences in cell array

To find the number of occurrence of a string in an array:

Consider a cell array
c={'one';'two';'three';'nine';'five';'two';'six';'one'; 'two';'five';};

The number of times the string ‘one’ occurs in the array

sum(strcmp('one',c))

ans =

2

To find the number of occurrence of all the elements in the array:

%c={'one';'two';'three';'nine';'five';'two'; 'six';'one'; 'two';'five';}; %dim=1

c='one','one','two','two','three','three','three','four','five','six','five','five'};%dim=2;

dim=2;
%Initialize the 'cell_array'
cell_array=cell([2 size(c,dim)]);
display(c);
inc=1;
for i=1:size(c,dim)
%Compare the elements in the 'cell_array' with the elements in 'c'
if(strcmp(cell_array(1,:),c(i))==0)
%If the element is not present, then add it to 'cell_array'.
cell_array(1,inc)=c(i);
%Find the number of occurence of the element
num=   sum(strcmp(c(i),c));
cell_array(2,inc)=num2cell(num);
inc=inc+1;
else
%Delete if the element is already present in the 'cell_array'.
cell_array(:,inc)='';

end

end

display(cell_array);

The result shows the elements in the first row and the number of occurrences in the second row.
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