# PVI

From OTBWiki

**PVI (Perpendicular Vegetation Index)**

**Calculation:**

- <math>PVI = sin(a) * NIR - cos(a) * R</math>

- with a = angle between soil line and NIR axis

** Alternative calculation:**

- <math> PVI = \frac{NIR - a*R-b}{\sqrt{a^2 + 1}}</math>

- with a = soil line slope,

- b = soil line intercept.

**Characteristics:**

- perpendicular index,
- limited range: -1<PVI<1,
- highly sensitive to atmospheric variations

**Reference:**

- Richardson A.J., Wiegand C.L., 1977. Distinguishing vegetation from soil background information. Photogramm Eng Rem S 43-1541-1552