What is Filter bank

In signal processing, a filter bank is an array of band-pass filters that separates the input signal into multiple components, each one carrying a single frequency sub-band of the original signal. The process of decomposition performed by the filter bank is called analysis which means analysis of the signal in terms of its components in each sub-band. The output of analysis is referred to as a sub-band signal with as many sub-bands as there are filters in the filter bank.  The reconstruction process is called synthesis, meaning reconstitution of a complete signal resulting from the filtering process. Following figure shows Gabor filter bank and its result.