Optimized Soil Adjusted Vegetation Index
When surveying young fields there will be a lot of soil/ bare earth included in the calculation of your Vegetation Indices. The OSAVI algorithm uses a canopy background adjustment factor of 0.16 to account for this visible soil in your survey.
This is a variation of the standard Soil Adjusted Vegetation Index offered for RGNIR data. Because of the difference in the canopy adjustment factor the OSAVI algorithm demonstrates increased sensitivity to vegetation cover greater than 50%.
OSAVI= (NIR-Red)/ (NIR+Red+0.16)
The expected values from this algorithm will be -1 to 1. This index is best used in areas with relatively sparse vegetation where soil is visible through the canopy.
Reference: Rondeaux, G., M. Steven, and F. Baret. "Optimization of Soil-Adjusted Vegetation Indices." Remote Sensing of Environment 55 (1996): 95-107.