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The Spatial Transformation of Sound Fields (STSF) technique permits a 3D sound field mapping based on a 2D scan measurement in the near field of a source. By measurement of the cross spectra between a set of references and the cross spectra from each scan position to each of the references, a principal component representation of the sound field is extracted which can be applied for near field holography and Helmholtz' integral equation calculations. Basically, this sound field representation includes only the part of the sound field, which is coherent with the reference signals. More precisely, only "views" of the independent parts of the sound field seen by the references are included. Therefore, provided the references do not pick up the background noise, the background noise will not be part of the sound field model processed by STSF. However, if the background noise is picked up by the reference transducers, it will become part of the model and cause errors in the calculations. In order to overcome this problem, the possibility of using a set of "exclude references" has been implemented in the STSF system. These references should pick up only the uncorrelated background noise to be suppressed in the model.