A survey of agricultural image processing for unmanned aircraft systems

This paper presents a discussion and comparison of the methods used to process images retrieved from a dual sensor system deployed on an unmanned aircraft for agricultural use. A challenge to the broader use of unmanned aircraft systems stems from the FAA imposed maximum flying altitude threshold of 400 feet (120 meters) above ground level. However, additional FAA permission is needed for flights conducted at altitudes greater than 400 feet above ground level. While this low altitude threshold provides an opportunity to collect high-resolution spatial information, it also requires that remotely sensed information be collected as discrete individual sub images. These individual images are then stitched or mosaicked together as a larger image to depict an agricultural crop field. This process requires the use of sensor characteristics along with the amount of sensor overlap during the flight phase. Image processing algorithms were tested to assemble a multitude of separate images into a single image, depicting the field area or target interest. Sensor configuration, geotagged file structure, flight planning, and approaches to processing the remotely sensed information collected during a typical flight operation are presented.