how to calculate image prediction ?

i was asked to calculate correlation between pixels

and then to claculate the prediction of image with this hint :

e(i,j)=img(i,j)- img(i,j-l) if i=0

e(i,j)=img(i,j)-img(i-l,j) if j=0

and then the correlation of this image

anyone can help me please !!,

Answer 1

[Deepak]

Hi Narimen,

As I understand it, you want to calculate the prediction error image “e (i,j)” of the input image, based on the given hint formulas. You also want to calculate the correlation of this image based on the prediction error image.

To accomplish this task, we can load the input image in MATLAB and convert it to grayscale and double format using the “rgb2gray” and “double” functions for accurate calculations. Next, we can iterate over the rows and columns of the image using nested for loops to calculate the prediction error image. Finally, we can calculate the correlation of the image by using the “corrcoef” function in MATLAB.

Below is the complete MATLAB code to accomplish this task:

img = imread('your_image.jpg'); 
img = double(rgb2gray(img)); % Convert to grayscale and double for calculations 

[rows, cols] = size(img); 

% Initialize the prediction error image 
e = zeros(rows, cols); 

for i = 1:rows 
    for j = 1:cols 
        if i == 1 && j > 1 
            e(i, j) = img(i, j) - img(i, j-1); % Use the previous pixel in the row 
        elseif j == 1 && i > 1 
            e(i, j) = img(i, j) - img(i-1, j); % Use the previous pixel in the column 
        elseif i > 1 && j > 1 
            % For other pixels, you can choose one of the predictions or a combination 
            e(i, j) = img(i, j) - img(i-1, j); 
        end 
    end 
end 

% correlation of the prediction error image 
correlation = corrcoef(e(:)); 

disp('Correlation of the prediction error image:'); 
disp(correlation); 

Please find attached documentation of functions used for reference:

imread - www.mathworks.com/help/matlab/ref/imread.html

rgb2gray - www.mathworks.com/help/matlab/ref/rgb2gray.html

corrcoef - www.mathworks.com/help/matlab/ref/corrcoef.html

I hope this assists in resolving the issue.