0000000000675816
AUTHOR
P. Zwaenepoel
Variable rate fertilisation: Measurement of fertilizer granules motion on a centrifugal spreader by image analysis
Although mechanically simple, centrifugal spreaders used for mineral fertilization involve complexphysics that cannot be fully characterized at the present time. We are developing sensors to evaluatethe spatial distribution of the fertilizer on the ground based on the measurement of initial flightconditions of fertilizer granules after their ejection by the spreading disk. The techniques developedare based on the analysis of images of the area around the disk showing the granule ejection. A fastimaging technique developed for this specific purpose is presented in this paper. It allows toautomatically compute the direction of ejection and velocity of each granule observed in the image.
Centrifugal spreading : motion blurred images to determine the three components of fertiliser outlet velocity
In the optical control of centrifugal spreading, the use of a single CCD camera to measure the outlet velocity is not limited to flat discs and 2D motion estimation. Combining the kinetic study of the fertiliser motion on the vane and the geometric analysis of image acquisition, the 3D components of the outlet velocity can be deduced from motion blurred images in the case of a traditional concave disc. The estimation of the horizontal and vertical outlet velocities is useful to predict spread patterns using ballistic flight models. This opens up the possibility to implement simple spreader test tools for quality diagnoses or sensors for feedback loop adjustments.