How to calculate horizontal and vertical correlation of an image in matlab???

• How to calculate horizontal and vertical correlation of an image in matlab???

[Hyderkkk]

IA=rgb2gray(im2double(orginal ));

c_diag = corrcoef(IA(1:end-1, 1:end-1), IA(2:end, 2:end));

c_vert = corrcoef(IA(1:end-1, :), IA(2:end, :));

c_horz = corrcoef(IA(:, 1:end-1, :), IA(:, 2:end));

figure;

subplot(3,3,1)

plot(IA(1:end-1, 1:end-1), IA(2:end, 2:end),'b'),title(sprintf('%s Horizontal Orginal image',b));

subplot(3,3,2)

plot(IA(1:end-1, :), IA(2:end, :),'b'),title(sprintf('%s Vertical Orginal image',b));

subplot(3,3,3)

plot(IA(:, 1:end-1, :), IA(:, 2:end),'b'),title(sprintf('%s Diagonal Orginal image',b));

IAA=rgb2gray(im2double(encrption));

c_diage = corrcoef(IAA(1:end-1, 1:end-1), IAA(2:end, 2:end))

c_verte = corrcoef(IAA(1:end-1, :), IAA(2:end, :))

c_horze = corrcoef(IAA(:, 1:end-1, :), IAA(:, 2:end))

subplot(3,3,4)

plot(IAA(1:end-1, 1:end-1), IAA(2:end, 2:end),'r'),title(sprintf('%s Horizontal chiphered image ',b));

subplot(3,3,5)

plot(IAA(1:end-1, :), IA(2:end, :),'r'),title(sprintf('%s Vertical chiphered image',b));

subplot(3,3,6)

plot(IAA(:, 1:end-1, :), IA(:, 2:end),'r'),title(sprintf('%s Diagonal chiphered image',b));

Answer 1

[elhabib]

% horizontal function rxy=H_correlation(image1)

      P=double(image1);

x1 = double(P(:,1:end-1)); 
y1 = double(P(:,2:end)); 

randIndex1 = randperm(numel(x1)); 
randIndex1 = randIndex1(1:1000); 
x = x1(randIndex1); 
y = y1(randIndex1); 

Ex=(1/(1000))*sum(x);
Ey=(1/(1000))*sum(y);
        Dx=(1/(1000))*sum((x(:)-Ex).^2);
        Dy=(1/(1000))*sum((y(:)-Ey).^2);
        coxy=(1/(1000))*(sum((x-Ex).*(y-Ey)));

rxy=coxy/(sqrt(Dx*Dy));

% vertical

function Vxy=V_correlation(image1)

      P=double(image1);

x1 = double(P(1:end-1,:)); 
y1 = double(P(2:end,:)); 

randIndex1 = randperm(numel(x1)); 
randIndex1 = randIndex1(1:1000); 
x = x1(randIndex1); 
y = y1(randIndex1); 

Ex=(1/(1000))*sum(x);
Ey=(1/(1000))*sum(y);
        Dx=(1/(1000))*sum((x(:)-Ex).^2);
        Dy=(1/(1000))*sum((y(:)-Ey).^2);
        coxy=(1/(1000))*(sum((x-Ex).*(y-Ey)));

Vxy=coxy/(sqrt(Dx*Dy));

[Abubakar Abba]

Thanks for the code. But, what is the difference between the two codes apart from the name of the Functions? is like both the Horizontal and Vertical codes are thesame here.

[Ankur Nandal]

Dear Abunakar,

Please check the initialization of x1 and X2.

[Ahmed raafat]

Thank you Sir

Thank You Very Very Much

Answer 2

[Mahdiyar]

Hi singhal

May you explain more about horizontal and vertical correlation?

Regards,

Answer 3

[praveen singhal]

http://ieeexplore.ieee.org/xpl/articleDetails.jsp?tp=&arnumber=6949981&queryText%253Dimage+encryption+using+tf+hill+cipher

Hello sir, This paper use horizontal,vertical and diagonal correlation of an image.