reduction image using spline interpolation

Hello

I want to Reduction of the image size to 50% of the original size using spline interpolation what the best code to do this

Answer 1

[Image Analyst]

smallImage = imresize(rgbImage, 0.5);

[Omar Yonis]

Thanks for your answer but i want it withouut using imresize

[Image Analyst]

Why? Why make it more complicated than it needs to be? If you want a more complicated method you can use interp2():

Vq = interp2(X,Y,V,Xq,Yq,'spline');

However, interp2() is also a built in function that you're probably going to not allow yourself to use either.

What can be programmed "without any built-in functions" ? - MATLAB Answers - MATLAB Central

Sorry, but I don't have a completely manual way to do it. You'll have to program that up yourself.

[Omar Yonis]

i tried this code and it works only when i convert rgb to gray but i want to reduction rgb image using interp2 only what ishould to do?

rgbImage=imread('rgb.jpg');
grayImage=rgb2gray(rgbImage);
imshow(grayImage);
[rows, columns] = size(grayImage);
[X,Y] = meshgrid(1:columns,1:rows);
xi = linspace(1,columns,170); 
yi = linspace(1,rows,209);  
[Xi,Yi] = meshgrid(xi,yi) ; 
resizedImage = uint8(interp2(X,Y,double(grayImage),Xi,Yi,'spline'));
figure
imshow(resizedImage);

[Image Analyst]

Use imsplit() to extract the separate color channels

[r, g, b] = imsplit(rgbImage);

Then recombine them with cat():

resizedRGBImage = cat(3, resizedR, resizedG, resizedB);

You never answered my question about why you want to do it this more complicated way rather than using the built-in imresize(). So, why? It doesn't make sense to me.