From the filtering to the subtraction of noise

The filtering method is essentially based on the signal-preserving properties of the so-called ``projection filters'' Soubaras (1994). This idea has been widely used to attenuate a large variety of noise in seismic data. Abma (1995) developed a solid mathematical background that introduces these projection filters and showed that they are related to the classical Wiener estimator Castleman (1996). In this section I unravel the link between the filtering and subtraction method.