How to zoom an image using DCT transform I am familiar with zoom using fourrier transform on an Image.
I am also aware that DCT is used mainly to compress images.
Meanwhile, how can someone use this transform to zoom an image?
The following IEEE pdf discusses image interpolation (aka zooming) by DCT. Have a look at it 
The main idea remains the same: the DCT spectra is zero padded and converted back into time to obtain the interpolated image which yields the zooming effect.