I am working with multispectral data collected with a MicaSense RedEdge 3, providing me 5 bands to work with (Red, Green, Blue, Rededge, NIR). I am able to generate vegetation indexes (VI) such as the NDRE and the NDVI. Because I am working on an experiment with mapping sorghum vegetation, I created classes (with supervised classification polygons) to define elements such as soil reflectance, dead plants, shadows, grain heads, and plant leaves. created each class to a white color (except the 'plant leaves' classification, which was labeled green for visibility). Note: All multispectral indices were created first, and then the classified image was generated.
You can see in the picture that the only elements I wish to work with are the green sections.
My question is this: How do I extract the VI data for only the 'plant leaves' class?
Any help would be much appreciated. Thanks all!