3D Simulation with virtual stereo rig for optimizing centrifugal fertilizer spreading

Stereovision can be used to characterize of the fertilizer centrifugal spreading process and to control the spreading fertilizer distribution pattern on the ground reference. Fertilizer grains, however, resemble each other and the grain images contain little information on texture. Therefore, the accuracy of stereo matching algorithms in literature cannot be used as a reference for stereo images of fertilizer grains. In order to evaluate stereo matching algorithms applied to images of grains a generator of synthetic stereo particle images is presented in this paper. The particle stereo image generator consists of two main parts: the particle 3D position generator and the virtual stereo rig. The particle 3D position generator uses a simple ballistic flight model and the disc characteristics to simulate the ejection and the displacement of grains. The virtual stereo rig simUlates the stereo acquisition system and generates stereo images, a disparity map and an occlusion map. The results are satisfying and present an accurate reference to evaluate stereo particles matching algorithms

The Use of High-Speed Imaging Systems for Applications in Precision Agriculture

UB Dijon EcolDurInternational audienceThe book "New Technologies - Trends, Innovations and Research" presents contributions made by researchers from the entire world and from some modern fields of technology, serving as a valuable tool for scientists, researchers, graduate students and professionals. Some practical applications in particular areas are presented, offering the capability to solve problems resulted from economic needs and to perform specific functions. The book will make possible for scientists and engineers to get familiar with the ideas from researchers from some modern fields of activity. It will provide interesting examples of practical applications of knowledge, assist in the designing process, as well as bring changes to their research areas. A collection of techniques, that combine scientific resources, is provided to make necessary products with the desired quality criteria. Strong mathematical and scientific concepts were used in the applications. They meet the requirements of utility, usability and safety. Technological applications presented in the book have appropriate functions and they may be exploited with competitive advantages. The book has 17 chapters, covering the following subjects: manufacturing technologies, nanotechnologies, robotics, telecommunications, physics, dental medical technologies, smart homes, speech technologies, agriculture technologies and management

High Speed Stereovision Setup for Position and Motion Estimation of Fertilizer Particles Leaving a Centrifugal Spreader

A 3D imaging technique using a high speed binocular stereovision system was developed in combination with corresponding image processing algorithms for accurate determination of the parameters of particles leaving the spinning disks of centrifugal fertilizer spreaders. Validation of the stereo-matching algorithm using a virtual 3D stereovision simulator indicated an error of less than 2 pixels for 90% of the particles. The setup was validated using the cylindrical spread pattern of an experimental spreader. A 2D correlation coefficient of 90% and a Relative Error of 27% was found between the experimental results and the (simulated) spread pattern obtained with the developed setup. In combination with a ballistic flight model, the developed image acquisition and processing algorithms can enable fast determination and evaluation of the spread pattern which can be used as a tool for spreader design and precise machine calibration

Development of a 3D image acquisition system and image processing algorithms for the characterization of the ejection parameters of fertilizer granules

The characterization of the fertilizer centrifugal spreading has become an important agriculture scientific issue in order to help farmers having a higher fertilization precision hence higher production efficiency. The ejected fertilizer grains are comparable to projectiles; hence, by using a ballistic flight model, predicting the spread pattern on the ground relies on an estimation of the trajectories and velocities of ejected grains. To estimate those parameters two approaches were proposed. First a two-steps zero mean normalized cross-correlation based algorithm for motion estimation was used to determine the displacement of the grains in the 2D images. The efficiency of this algorithm was evaluated by the mean of a grain images’ simulator. The results showed a high accuracy with an error of less than 0.2 pixels for 90% of the estimated velocities. However, the vertical ejection angle cannot be determined. This limits the use of the technique to spreaders equipped with flat disks where the trajectories of the grains will mostly be in a horizontal plane. This restriction was handled by the second approach. It is based on a 3D stereovision imaging system. A region based stereo matching algorithm with uniqueness and ordering constraints was introduced. It was validated using a grains’ stereo images simulator. 90% of the disparities were estimated with errors less than 2 pixels (around 1%). Moreover a 3D motion estimation algorithm was developed. It is based on an improvement of the previous 2D motion estimation algorithm combined with the estimated 3D coordinates. The efficiency of the whole system was approved via a comparison of its results and a real distribution obtained from a developed cylindrical collector

Development of 3D image acquisition system and image processing algorithms for the characterization of the ejection parameters of the fertilizer granules

L’objectif de cette thèse de doctorat était de concevoir et développer un système permettant de caractériser les épandeurs et de prédire la répartition d’engrais au sol. Nous avons proposé deux approches basées respectivement sur l’imagerie 2D et 3D.Le système 2D a permis de déterminer les déplacements dans les images avec une très haute précision où 90% des estimations ont uniquement moins de 0,2 pixels d’erreur. Cependant cette précision n’était applicable que dans le cas d’un épandeur équipé de disques plats pour lequel la plupart des engrais est éjectée dans le plan horizontal parallèle au plan d’image de la camera. Par conséquent nous avons proposé un système d’imagerie 3D qui a permis de déterminer le mouvement 3D des engrais. Ainsi il peut être appliqué sur des épandeurs équipés de disque concave.Ce nouveau système peut : Caractériser les épandeurs dans un hall avec des conditions contrôlées ;Evaluer les effets de différents réglages des épandeurs ;Etudier le comportement des granulés et améliorer le modèle de vol balistique.Un tel système, moyennant quelques modifications, est envisagé à long terme sur un épandeur, permettant une gestion en temps réel de l’épandage et une rétroaction potentielle sur le fonctionnement de l’épandeur. [extrait du résumé]The characterization of the fertilizer centrifugal spreading has become an important agriculture scientific issue in order to help farmers having a higher fertilization precision hence higher production efficiency. The ejected fertilizer grains are comparable to projectiles; hence, by using a ballistic flight model, predicting the spread pattern on the ground relies on an estimation of the trajectories and velocities of ejected grains. To estimate those parameters two approaches were proposed. First a two-steps zero mean normalized cross-correlation based algorithm for motion estimation was used to determine the displacement of the grains in the 2D images. The efficiency of this algorithm was evaluated by the mean of a grain images’ simulator. The results showed a high accuracy with an error of less than 0.2 pixels for 90% of the estimated velocities. However, the vertical ejection angle cannot be determined. This limits the use of the technique to spreaders equipped with flat disks where the trajectories of the grains will mostly be in a horizontal plane. This restriction was handled by the second approach. It is based on a 3D stereovision imaging system. A region based stereo matching algorithm with uniqueness and ordering constraints was introduced. It was validated using a grains’ stereo images simulator. 90% of the disparities were estimated with errors less than 2 pixels (around 1%). Moreover a 3D motion estimation algorithm was developed. It is based on an improvement of the previous 2D motion estimation algorithm combined with the estimated 3D coordinates. The efficiency of the whole system was approved via a comparison of its results and a real distribution obtained from a developed cylindrical collector

A 3-D stereovision system for fertilizer granule characterization

Machine vision evolved considerably in the last decade. The positive price evolution and robustness of the cameras combined with the high accuracy have led to their widespread use in different agricultural sectors. Our consortium presented different image based methods to measure the speed and direction of fertiliser grains. Currently, a first attempt to extract 3D-information with an image acquisition system based on stereoscopy is presented. The system uses previously developed and tested 2-D techniques. Depending on the imposed vertical angle, the first stereovision system showed an average error between 0,1% and 2,2% for measuring distance and height difference between grains. The second set-up showed promising results when comparing the measured values to the imposed velocity. Preliminary tests indicated that the designed stereovision system is capable of performing high speed 3D measurements on grains. More tests and research are necessary to further develop this first approach to a useful tool for spreading

Development of 3D image acquisition system and image processing algorithms for the characterization of the ejection parameters of the fertilizer granules

L objectif de cette thèse de doctorat était de concevoir et développer un système permettant de caractériser les épandeurs et de prédire la répartition d engrais au sol. Nous avons proposé deux approches basées respectivement sur l imagerie 2D et 3D.Le système 2D a permis de déterminer les déplacements dans les images avec une très haute précision où 90% des estimations ont uniquement moins de 0,2 pixels d erreur. Cependant cette précision n était applicable que dans le cas d un épandeur équipé de disques plats pour lequel la plupart des engrais est éjectée dans le plan horizontal parallèle au plan d image de la camera. Par conséquent nous avons proposé un système d imagerie 3D qui a permis de déterminer le mouvement 3D des engrais. Ainsi il peut être appliqué sur des épandeurs équipés de disque concave.Ce nouveau système peut : Caractériser les épandeurs dans un hall avec des conditions contrôlées ;Evaluer les effets de différents réglages des épandeurs ;Etudier le comportement des granulés et améliorer le modèle de vol balistique.Un tel système, moyennant quelques modifications, est envisagé à long terme sur un épandeur, permettant une gestion en temps réel de l épandage et une rétroaction potentielle sur le fonctionnement de l épandeur. [extrait du résumé]The characterization of the fertilizer centrifugal spreading has become an important agriculture scientific issue in order to help farmers having a higher fertilization precision hence higher production efficiency. The ejected fertilizer grains are comparable to projectiles; hence, by using a ballistic flight model, predicting the spread pattern on the ground relies on an estimation of the trajectories and velocities of ejected grains. To estimate those parameters two approaches were proposed. First a two-steps zero mean normalized cross-correlation based algorithm for motion estimation was used to determine the displacement of the grains in the 2D images. The efficiency of this algorithm was evaluated by the mean of a grain images simulator. The results showed a high accuracy with an error of less than 0.2 pixels for 90% of the estimated velocities. However, the vertical ejection angle cannot be determined. This limits the use of the technique to spreaders equipped with flat disks where the trajectories of the grains will mostly be in a horizontal plane. This restriction was handled by the second approach. It is based on a 3D stereovision imaging system. A region based stereo matching algorithm with uniqueness and ordering constraints was introduced. It was validated using a grains stereo images simulator. 90% of the disparities were estimated with errors less than 2 pixels (around 1%). Moreover a 3D motion estimation algorithm was developed. It is based on an improvement of the previous 2D motion estimation algorithm combined with the estimated 3D coordinates. The efficiency of the whole system was approved via a comparison of its results and a real distribution obtained from a developed cylindrical collector.DIJON-BU Doc.électronique (212319901) / SudocSudocFranceF

Dispositif d'éclairage stroboscopique haute cadence avec large plage d’uniformité lumineuse à base de LEDs de puissance

La présente invention appartient au domaine des dispositifs d'éclairage. Plus particulièrement la présente invention concerne un dispositif d'éclairage permettant d'éclairer uniformément une large surface avec une consommation électrique faible. La présente invention concerne également les techniques d'imageries utilisant le dispositif selon l'invention