IN is used in order to balance the illumination in an image. It may be part of a face recognition pipeline, but on its own does not provide recognition. It would need to be followed by machine learning algorithms which do provide recognition.
ANN and CNN on the other hand are machine learning algorithms and can provide recognition, with or without IN. In generally preprocessing is used for extracting more meaningful features for the classifiers. It is an optional but useful step of the pipeline for a recognition system.