Fractal Interpolation

One thing about the fractal interpolcation algorithm is that it is very sensitive to noise which means that when used on images of bad quality if may produce some strange unwanted artefacts.

I recommend using either "Fractal 9 / xin li" or "Fractal 9-square". The "Xin li 4x" method is almost identical to the default resize method in Image Analyzer as far as I remember.

A bit about the params:
"Training region size" determines how big a sorrounding area is examined when computing each new pixel. Larger will be slower but may also create better results up to some limit.
"Regularization" and "Artefact filter size" has to do with removing noise from the resulting images. Larger values will rmove more noise but may also remove more details.
The rest of the parameters I hardly rember the effect of, but the default settings for everyting should give fairly good results.