Tim Van De Gucht

Development of a High Irradiance LED Configuration for Small Field of View Motion Estimation of Fertilizer Particles

Better characterization of the fertilizer spreading process, especially the fertilizer pattern distribution on the ground, requires an accurate measurement of individual particle properties and dynamics. Both 2D and 3D high speed imaging techniques have been developed for this purpose. To maximize the accuracy of the predictions, a specific illumination level is required. This paper describes the development of a high irradiance LED system for high speed motion estimation of fertilizer particles. A spectral sensitivity factor was used to select the optimal LED in relation to the used camera from a range of commercially available high power LEDs. A multiple objective genetic algorithm was used to find the optimal configuration of LEDs resulting in the most homogeneous irradiance in the target area. Simulations were carried out for different lenses and number of LEDs. The chosen configuration resulted in an average irradiance level of 452 W/m2 with coefficient of variation less than 2%. The algorithm proved superior and more flexible to other approaches reported in the literature and can be used for various other applications.

Automatic cow lameness detection with a pressure mat

The minimum pressure mat length needed to monitor a full gait cycle is determined.The minimum sensor resolution of the pressure mat is determined.Lameness detection performance was not reduced by these sensor changes.Reducing the sensor price should be possible by optimization of sensor dimensions. While previous research has shown the potential of automatic lameness detection by means of a pressure mat, these systems are currently not adopted in practice due to their high cost and low on-farm applicability. Therefore, the aim of this study was to investigate to what level the size (0.614.88m) and resolution (0.01270.0127m) of the pressure mat can be reduced without significant loss in lameness detection performance. To this end, standard gait variables were calculated based on adapted datasets in which the available data had been reduced to simulate the effects of a decreasing mat length and sensor resolution. These extracted gait variables were then used in a linear discriminant analysis to classify cows as non-lame, mildly lame or severely lame. This analysis indicated that the measurement zone length must be at least 3.28m to successfully monitor one complete gait cycle, while the size of each individual sensing element should not be larger than 2.58 103m2 to avoid an increase in the misidentification of imprints. When these limits were taken into account, the obtained overall lameness detection accuracy was not worse than that of the original system.

Development of a Stereovision-Based Technique to Measure the Spread Patterns of Granular Fertilizer Spreaders

Centrifugal fertilizer spreaders are by far the most commonly used granular fertilizer spreader type in Europe. Their spread pattern however is error-prone, potentially leading to an undesired distribution of particles in the field and losses out of the field, which is often caused by poor calibration of the spreader for the specific fertilizer used. Due to the large environmental impact of fertilizer use, it is important to optimize the spreading process and minimize these errors. Spreader calibrations can be performed by using collection trays to determine the (field) spread pattern, but this is very time-consuming and expensive for the farmer and hence not common practice. Therefore, we developed an innovative multi-camera system to predict the spread pattern in a fast and accurate way, independent of the spreader configuration. Using high-speed stereovision, ejection parameters of particles leaving the spreader vanes were determined relative to a coordinate system associated with the spreader. The landing positions and subsequent spread patterns were determined using a ballistic model incorporating the effect of tractor motion and wind. Experiments were conducted with a commercial spreader and showed a high repeatability. The results were transformed to one spatial dimension to enable comparison with transverse spread patterns determined in the field and showed similar results.

Supporting the Development and Adoption of Automatic Lameness Detection Systems in Dairy Cattle: Effect of System Cost and Performance on Potential Market Shares

Simple Summary Most prototypes of systems to automatically detect lameness in dairy cattle are still not available on the market. Estimating their potential adoption rate could support developers in defining development goals towards commercially viable and well-adopted systems. We simulated the potential market shares of such prototypes to assess the effect of altering the system cost and detection performance on the potential adoption rate. We found that system cost and lameness detection performance indeed substantially influence the potential adoption rate. In order for farmers to prefer automatic detection over current visual detection, the usefulness that farmers attach to a system with specific characteristics should be higher than that of visual detection. As such, we concluded that low system costs and high detection performances are required before automatic lameness detection systems become applicable in practice. Abstract Most automatic lameness detection system prototypes have not yet been commercialized, and are hence not yet adopted in practice. Therefore, the objective of this study was to simulate the effect of detection performance (percentage missed lame cows and percentage false alarms) and system cost on the potential market share of three automatic lameness detection systems relative to visual detection: a system attached to the cow, a walkover system, and a camera system. Simulations were done using a utility model derived from survey responses obtained from dairy farmers in Flanders, Belgium. Overall, systems attached to the cow had the largest market potential, but were still not competitive with visual detection. Increasing the detection performance or lowering the system cost led to higher market shares for automatic systems at the expense of visual detection. The willingness to pay for extra performance was €2.57 per % less missed lame cows, €1.65 per % less false alerts, and €12.7 for lame leg indication, respectively. The presented results could be exploited by system designers to determine the effect of adjustments to the technology on a system’s potential adoption rate.

Measuring the dynamic mass flow from a centrifugal fertilizer spreader

Working widths of commercial centrifugal fertilizer spreaders are continuously increasing, increasing the sensitivity of the spread pattern to fertilizer and spreader properties. One very important parameter is the fertilizer mass flow rate from the hopper to the disks, since this determines the application rate on the field and has also an effect on the shape of the distribution pattern. In this study, the dynamic mass flow rate of a commercially available fertilizer spreader was evaluated for three types of fertilizer. Fluctuations of the flow rate were found and illustrate the need to consider the dynamic behavior of the mass flow rate when designing systems or procedures for measuring or simulating spread patterns of centrifugal fertilizer spreaders.

Comparison of different spread pattern determination techniques

Traditionally, the performance of fertilizer spreaders is assessed using a row of collection trays aligned perpendicular to the driving direction of the tractor. For precise calibration of the spreader this technique, however, does not provide adequate insight into the spreading process since particle distributions are measured in only one spatial dimension. In this paper, two different two dimensional spread pattern determination techniques (SPDT) were tested, each consisting of a sampling method and a matching interpolation algorithm. Tests were executed under similar conditions with three commonly used types of fertilizer (CAN, NPK, KCl) with different physical properties. Results were compared with the traditional technique. The differences found illustrate the importance of using an adequate SPDT to compare spread patterns.