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.
A=imread('person.jpg');
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

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.