Preharvest Monitoring of Biomass Production - Engineering and Science of Biomass Feedstock Production and Provision - page 75

Fig. 4.13 Ground reference data collection concept scheme

To accomplish close proximity monitoring, there were a couple of sensors
retrofi tted and mounted on gantry for data acquisition including the Agricultural
Digital Camera (ADC) for visible and near-infrared image, USB spectrometer for
crop canopy refl ectance measurement, and SICK LIDAR (Light Detection and
Ranging) scanner for canopy 3D profi le measurement, as illustrated in Fig. 4.13 .
A 6DOF(six-degrees-of-freedom) Inertia Measurement Unit (IMU) from Crossbow
company was mounted on the vehicle where it is close to the SICK LIDAR system
for scanned image corrections in order to avoid the effect of strong vibration when
traveling in uneven terrain fi eld. The red, green, and NIR bands spectral information
can be used for extraction of NDVI, SAVI, and NIR/green ratio. The crop 3D infor-
mation can also be correlated with the biomass yield.

4.8.2 Ground Reference Data Analysis and Results

A SICK LIDAR scanner was mounted beneath the ceiling of the vehicle for the
purpose of drawing a 3D crop height map in the driving direction. The detection
range of LIDAR system was up to 8 m. It only worked while the vehicle was mov-
ing with constant transit speed. Due to the vibration of the generator and the uneven
off-road surface, the result from the SICK LIDAR scanner needs to be corrected
based on the vehicle altitude and vibration in post data processing. The Miscanthus
height distribution from the northeast to northwest of the fi eld is shown in Fig. 4.14 .