Add/Modify Data (3/3) Background Removal

This same tool, used to define the background to be removed from the measurements prior to inversion, is subsequently used to modify it.

Use Data > Add Data on the VOXI Manager tree to define the background to be removed from the measurements prior to inversion.

Subsequently, to modify the data of an existing VOXI document use Data > Data Source > Modify.

Add/Modify Background Removal dialog options

No background removal	By default, VOXI will calculate a reasonable background and assign it to all voxel model elements. If however you would like to model the data as provided, you will have to select this option. Note that for FTG data the default is not to remove the background as the gradient of the field components should already have a zero background.
Remove Constant background Background value	If you would like to apply a DC shift to the input measured data, select Remove Constant Backgroundand provide the background value to be removed. The default value suggested is the mean of the observed data covering the study area. However, you may want to replace this default.
Remove a linear trend     Intercept X slope Y slope X origin Y origin	This is the default for all data types except for FTG. The linear trend plane is defined by the equation aX +bY + c = 0. The subsequent entries relate to the stated plane equation as follows: c = Intercept a = X slope b = Y slope X = X origin Y = Y origin
Measured Data Statistics	This group is updated to reflect the statistics of the observed data after the chosen background removal method has been applied. It is intended as an aide and as verification that the proper background has been applied.

Application Notes

VOXI models the residual signature of the observed data, as a result, it is important to ensure that the regional effect has been removed prior to modelling. The effect of the poorly handled regional field will cause erroneous results and undesirable edge effects. In the event that you have not removed the background prior to entering VOXI, VOXI offers this feature as a recourse. If you have removed the background by other means and are confident on the method applied, you are encouraged not to remove it again in VOXI.