Dear Salamma,

Can you explain why it is not the name of the index?

Yeah.  I have gone through that. Rather it was a derived index from T-cap. Im searching on the Bare soil index using: 

( ( (float(b1)+float(b2)) - (float(b3)+float(b4)) ) / ( (float(b1)+float(b2)) + (float(b3)+float(b4)) ) )

b1 = L5

b2 = L3

b3 = L4

b4 = L1

Bare soil index is primarily for bare land extraction from satellite data. The index is prepared for analyzing bare soils, as bare-soil plays an important role by being the reason of dust storms in most arid regions.