Figure 5.

The optimal combination of signals from an array coil requires knowledge of the spatial variation of each element's sensitivity. A pixel at point 1 of a 3‐element (channel) array, has contributions from Coil 3 and 2, but very little from Coil 1. Coil 1 will contribute primarily noise leading to a suboptimal combination of the pixel at point 1. If the contribution is weighted by the sensitivity at this location, the contribution of Coil 1 will be weighted close to zero, reducing the combined noise and hence increasing the SNR.