I am using Image J to threshold green crop canopy pixels from background soil pixels. I would like to first transform my image using a colour index based on RGB channels, the Excess Green Index:
ExGreen = 2 * (G/R+G+B) - (R/R+G+B) - (B/B+G+R)
This should create a tonal image with the green channel enhanced so that it becomes easier to threshold.
How do I tell ImageJ to create a new image by using the above equation to calculate new RGB values? Do I need to write a macro?