i'm looking for a free/opensource solution for digital image processing with reasonable performances processing quite large images (e.g. actual smartphones have resolutions of 8-10Mpx) and being ready for fast-prototyping/research.

• Octave would be a good solution as it provides a lot of statistical and matrix manipulation tools. However octave is too slow when running nested loops and the provided image package is too slow when displaying images.
• Octave + MIJ would be a better solution but actually seems unusable and unstable because of slowness and because of the different datatype handling needs.
• OpenCV has excellent performances but it's not really handy for fast prototyping because i actually would need something like a scripting language (no compilation, online code/variable modification and so on...) and some tools (like octave has) for plotting functions, graphs, histograms and make statistical calculations.

Any advise? Thank you very much