How to implement the following equations in image encryption

Upto finding D(i,j),I have found below

clear all
close all
clc
im1 = imread('lena.bmp');% Read the input image
im2 = im1;
im2(10,10) = 255; % im2 is the image with one pixel difference
[M N] = size(im1);
r = uint8(randi([0,256],h,w)); % Generate a random matrix for encryption
C1 = bitxor(im1,r); % Encryption-1
% imdec = bitxor(xored,r);
C2 = bitxor(im2,r); % Encryption-2
% find D(i,j)
for i=1:M
    for j=1:N
        if C1(i,j)== C2(i,j)
           D(i,j) =0;
        else
           D(i,j) =1;
        end
    end
end  
D = uint8(D); % change D to uint8 format

how to find the NPCR and UCAI as shown below

[Hina Naz]

hi, did you complete that code to implement this equation for encryption?

Answer 1

[Walter Roberson]

http://www.mathworks.com/matlabcentral/answers/318478-can-i-find-npcr-value-for-two-images-of-different-dimensions-using-matlab-code

[Renjith V Ravi]

Yes,I have tried this already.But I got wrong answer

[Walter Roberson]

NPCR = mean(D(:)) * 100;

But watch out: your code expects the image to be grayscale, which might not be true for lena.bmp