Convolution is a mathematical way of combining two signals to form a third signal. It is the single most important technique in digital signal processing. This operation is mostly used together with Fourier transformations for MRI signal / image processing.

Convolution differentiation is a method of suppressing broad underlying spectral lines in order to emphasize narrower spectral lines. Strong smoothing of the spectrum (e.g., by severe negative exponential weighting of the time data) will suppress the narrow lines but minimally affect very broad ones; subtracting such a smoothed spectrum from the original will largely remove the contributions from the broad lines. This provides a means of baseline correction.