Enlarging an image with spline interpolation

I want to enlarge the number of pixels of the input image using spline interpolation. Please tell me how.

Answer 1

[KSSV]

I = imread("image.jpeg") ;  % assuming image to m*n
I=rgb2gray(I);
[m,n] = size(I) ; 
x = 1:n ;
y = 1:m ; 
% Inteprolate to double
xi = linspace(1,n,2*n) ;
yi = linspace(1,m,2*m) ;
I = double(I) ; 
I1 = zeros(m,2*n) ; 
% Row wise inteprolation 
for i = 1:m
  I1(i,:) = spline(x,I(i,:),xi) ; 
end
Inew = zeros(2*m,2*n) ; 
% Column wise interpolation 
for j = 1:2*n
  Inew(:,j) = spline(y,I1(:,j),yi) ; 
end
Inew = uint8(Inew) ; 
figure
imshow(Inew)

[T.K]

Thank you for your replying!

I understood!

[Mehri Mehrnia]

main problem of this is it does not preserve image size, I mean the size of primary matrix

Answer 2

[Mehri Mehrnia]

Hi,

I really appreciate this Q/A, helped me.

I have a countour which is a complex shape(left atrial of heart). I want to select some points(control ones) to dilate or erode the shape? any idead?

[Image Analyst]

Maybe the attached demos???

Otherwise start a new question and attach your image and data and code after you read this:

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