Process menu: 
The Uniformity Correction tool is used to correct intensity non-uniformity, typically found on MRI scans when using surface receiver coils or other tightly-fitting coils such as head, neck and knee coils. This non-uniformity is often known as the "bias field", and while exact correction is not possible without a detailed mapping of the coil properties, an approximate correction often improves the uniformity markedly.
The Uniformity Correction tool works on the principle that the introduction of image non-uniformities leads to a blurring of the image intensity histogram. Thus, correction of the non-uniformity involves finding the bias field that will create the sharpest intensity histogram when corrected. The bias field is modelled as a smooth polynomial surface, the order of which is selectable by the user.
To start the Uniformity Correction tool, select it from the
Process menu:
This brings up the Uniformity Correction tool:
