Resizing images using interp1()

So I have got this image that I am trying to resize which I have already attached. The requirement for me is to resize the image without using the functions imresize() or immse() but use interp1(). And I have no clue where exactly to begin.

[Dingbang Liang]

Did you figure out how to enlarge the column?

Answer 1

[KSSV]

I = imread('lighthouse.png') ;

N = 1000 ;   % interp1 along row 
[m,n,p] = size(I) ;
iwant = zeros(m,N,p) ;
xi = linspace(1,n,N) ;
for i = 1:m
    for j = 1:p
        T = interp1(1:n,double(I(i,:,j)),xi) ;
        iwant(i,:,j) = T ;
    end
end
iwant = uint8(iwant) ;
imshow(iwant)

[Quan Seah]

Thank you so much!

[Quan Seah]

I realized that your code only interp1 along row, what if i want to interp1 along columns, since the code you showed me only changes the width not the length.

[Image Analyst]

For each pixel you need to call it twice, once with the top and bottom neighbors, and once with the right and left neighbors.