A method and system of calibrating multispectral images from a camera on an aerial vehicle, the method including: capturing multispectral images of an area at a plurality of intervals with a multispectral imaging camera; simultaneously or at an arbitrary time capturing sunlight radiance data for each of the captured images; correlating the images with the sunlight radiance data; and calibrating the multispectral images based on the sunlight radiance data to normalize the multispectral images to one or more previous images of the area.