Image processing: Convolution & Correlation

a. What are the pixel dimensions of ct.jpg?

b. What would the pixel dimensions of ct.jpg be after correlation or convolution with itself?

Can i know whether i am doing it right

Pixel dimensions of ct.jpg

%First set colormap and and load image 

clf reset 
% colormap('gray')
ct=imread('ct.jpeg')

%Pixels of the image is identified using size function

[rows, columns] = size(ct)

whos ct %verify number of pixels in the image 

%Answer(a) Pixel dimensions of the image is [252*302]

%Convolution of image with itself

subplot(2,2,1), imagesc(ct); 
title('Raw Image'), xlabel i, ylabel j, colorbar 
subplot(2,2,2), imagesc(conv2(ct,ct)); 
title('Convolution Result'), xlabel i, ylabel j, colorbar  
ConPixel = conv2(ct,ct)
[rowsofconv, columsofconv] = size(ConPixel)

imwrite(ConPixel,'ConPixel1.jpg','jpg')
subplot(2,2,3), imagesc(ConPixel);
title('Saved Convolution Result'), xlabel i, ylabel j, colorbar  

%Answer(b) Pixel dimensions of the Convol image is [503*603]

%Correlation of image with itself

close all hidden
% colormap('gray')
subplot(2,2,1), imagesc(ct); 
title('Raw Image'), xlabel i, ylabel j, colorbar 
subplot(2,2,2), imagesc(xcorr2(ct,ct)); 
title('Correlation Result'), xlabel i, ylabel j, colorbar  
CorPixel = xcorr2(ct,ct)
[rowsofcorr, columsofcorr] = size(CorPixel)

imwrite(CorPixel,'CorrPixel1.jpg','jpg')
subplot(2,2,3), imagesc(CorPixel);
title('Saved Correlation Result'), xlabel i, ylabel j, colorbar

%Answer(b) Pixel dimensions of the Correl image is [503*603]

Answer 1

[V Sairam Reddy]

Yes, you are right.

To find the pixel dimensions of "ct.jpeg" you can read it and use "size()" command.

% Read the Image.
ct_image = imread('ct.jpeg');

% Find pixel dimensions of Image.
[no_of_rows, no_of_columns] = size(ct_image);

you can find the pixel dimensions of the image after convolution or correlation with itself the same way.

% Find pixel dimensions of Image convoluted with Itself.
[no_of_rows_in_Conv_Image, no_of_columns_in_Conv_Image] = size(conv2(ct_image,ct_image));

% Find pixel dimensions of Image Correlated with Itself.
[no_of_rows_in_Corr_Image, no_of_columns_in_Corr_Image] = size(xcorr2(ct_image,ct_image));

Please refer 2D Convolution to know more about "conv2" function and 2D Cross Correlation to know more about "xcorr2" function.