How to scale up image using imresize

I'm doing a machine learning project for letter recognition. i have problem when doing resize program. is there any way how to keep image used still in 128 x 128 pixel. Regardless how big or small user's input picture.

Answer 1

[KALYAN ACHARJYA]

result=imresize(input_image,[128,128]); % 'bicubic' is default

If you are specific on up/down sampling method ( Interpolation method), please see here