Transformed Soil Adjusted Vegetation Index (TSAVI)

"The Transformed Soil Adjusted Vegetation Index (TSAVI) is a vegetation index that attempts to minimize soil brightness influences by assuming the soil line has an arbitrary slope and intercept.

TSAVI=(s(NIR-s*Red-a))/(a*NIR+Red-a*s+X*(1+s2))

    NIR = pixel values from the near-infrared band
    R = pixel values from the red band
    s = the soil line slope
    a = the soil line intercept
    X = an adjustment factor that is set to minimize soil noise

Reference: Baret, F. and G. Guyot, 1991, "Potentials and limits of vegetation indices for LAI and APAR assessment," Remote Sensing of Environment, Vol. 35, 161–173." (ESRI, 2018)

Sources

"Indices gallery". ArcGIS Pro, ESRI. 2018. 
http://pro.arcgis.com/en/pro-app/help/data/imagery/indices-gallery.htm.
Accessed February 1, 2019.