A method and an apparatus for fault-tolerant computing in a parallel processing environment. Intermediate data points are determined from a set of input data by a plurality of processing elements operating in parallel. Preferably, the resolution of the intermediate data points is greater than the resolution required in an output imaging data set. The intermediate data points are spatially re-gridded to the resolution required in the output imaging data set, ignoring any missing data as a result of a processing element failing.