Development of Stand Alone Tower Remote Sensing for Energy Crops

摘要

Stand alone tower remote sensing platform was developed to monitor energy crops using multispectral imagery. The sensing system was capable of collecting RGB and CIR images of 1920(H)x1080(V) resolution and transferred through wireless networking overthe growing season for Miscanthus, Corn, Prairie grass and Switch grass. A motorized variable lens (8-200mm) was implemented to get the high spatial resolution. The system was rotated 0-355° movement in horizontal plane and tilt ±90° movement on vertical plane from a pan-tilt device which was installed with a multispectral camera of 400-1000 nm wavelength on top of a tower at a height of 38 m from the ground. A digital compass was installed with this system to get yaw and pitch of camera position Analgorithm was developed to control automatic image collection in real time for four experimental plots. The calibration for intrinsic parameters of lens distortion was performed for 18, 50, 100, 15q and 200 mm focal length. The maximum spatial resolution using 200 mm focal length at the underneath of the tower with an 89° tilt was 1 mm per pixel. At the corner edge of the field, 270 m away from the tower with an 8° tilt, the spatial resolution was 10 mm per pixel. The minimum spatial resolutions using 18 mm focal length for the corresponding distances and tilt were 15 mm and 10 cm per pixel. In each of the plots, 20 images were collected to develop a site-specific map for energy crops. A 50 mm focal length was selected with 6-40 mm spatial resolutions based on distances and tilt of camera while rotating on horizontal and vertical plane. The temporal resolution was another great advantage which enabled real time image acquisition as opposed to aerial and satellite imagery.