Hi，I have a question，i’ve already done some preprocessing（apply orbit>TNR>CAL>multilooking>filtering>TC>slope normalisation>to db）,but when I want to linear the band （via right click）generated by the slope normalisation process，i found that the “linear to db” button cannot be selected.So I use the bandmath tool to generate db images.**However, the calculated results（Histograms ，data distribution，max and min） are inconsistent**.I want to know which method is wrong and where is the problem.

First method:

10*log10((Sigma0_VV*sin(PI*projectedLocalIncidenceAngle/180))/sin(PI*incidenceAngleFromEllipsoid/180))

Second method:(Sigma0_VV_db*sin(PI*projectedLocalIncidenceAngle/180))/sin(PI*incidenceAngleFromEllipsoid/180)

**The first method is that calculate directly from Bandmath；**

**The second method is linear the band generating by TC to db，and then use slope normalisation.**

Zhang