Target Geolocation for Agricultural Applications via an Octorotor

In this paper, an orthographic projection based Kalman filter is designed to estimate the location of identified targets for use in disease detection applications for strawberry trees or other shallow crops. The process model and measurement model are formulated, relating the global target position to its corresponding image pixel, taking into account assumptions pertinent to a typical strawberry orchard. An octorotor is custom-designed and built, and expected to carry a spectral camera in hover flight. The camera producing the images of the target is stabilized by a gimbal. An orthographic projection model is adopted here because of the shallow depth of the crop when compared to the camera altitude. This projection approach leads to a Kalman filter design. Firstly, the approach is tested through simulation. Secondly, it is validated in an ad-hoc experiment using a recorded video taken by the octorotor.