can be mapped with a drone in a few minutes. but first the data from the drone has to be processed at the university s institute of medicine. from a jigsaw puzzle of single images a very accurate overall picture of the test area is produced. that s followed by a complex image analysis. and classification into weeds crop plants and soil for example where we re growing sugar beet is done with a pixel density measurement using an image analysis program. we measure the number of green pixels between the rows. it works like a we test. if the number of green pixels exceeds a certain threshold these areas are marked red and we know it s weeds.