Hi Neil, just answering quickly to your second question (someone will still have to answer the first one!).

2. I'm currently working with large images and it often useful to work with down-sampled versions. A quick way to do this is using views:

im_small = im[::4, ::4]

Is there a quick way to do the inverse? i.e. something like:

im_big = im[::0.25, ::0.25]

At the moment I'm just resizing the image, which has more overhead. Anything I'm missing?

I use scipy.ndimage.zoom for this purpose. Cheers, Emmanuelle