For my Master Thesis in Ecology I want to calculate an NDVI Index. The tricky part is, that I don't have sattelite pictures with bands and so on, but RGB pictures. The pictures where taken with a normal digital camera and the NIR pictures were taken by using a filter to block the light from 680 nm onwards. The information of the red channel were obtained by extracting this channel out of a normal RGB picture, taken with the same digital camera as the NIR pictures. I stored this extracted channel as a TIF-file.
Now I loaded these two pictures in QGIS, render type "platted". Starting the raster calculator per picture 3 bands appear.
How can I reduce these raster channels in raster calculator to only one raster channel per picture?
Could I combine the information of the 3 bands to one somehow?
Could a simple addition of all three bands per picture help?