1. A method for electronic imaging, comprising: controlling an image sensor to capture a first sequence of first input images at a first frame rate having a first spatial resolution, and to capture a second sequence of second input images, interleaved with the first sequence and having at least one second spatial resolution lower than the first spatial resolution; and processing the first and second sequences of the input images to generate a third sequence of output images at a second frame rate higher than the first frame rate and having a third spatial resolution higher than the at least one second spatial resolution, the first and second input images being sampled according to a non-uniform spatio-temporal sampling pattern, and the processing the first and second sequences comprising determining a spatio-temporal filtering function responsively to the sampling pattern, and applying the spatio-temporal filtering function to the first and second input images.