Search results for " Vision"
showing 10 items of 2709 documents
Approche multi-critère pour la caractérisation des adventices
2022
The objective of this thesis is to develop a way to detect weeds in a field using multispectral images, in order to determine which weeds should be eliminated during the current crop cycle and more particularly at the early stages. The multi-criteria approach focuses on the spatial arrangement, the spec- tral signature, the morphology and the tex- ture of the plants located in the plots. This work proposes a method for selecting the best criteria for optimal discrimination for a given setup. Prior to the extraction of these crite- ria, a set of methods was developed in order to correct the errors of the acquisition de- vice, to precisely detect the vegetation and then to identify within the…
Robotics for weed control: I-Weed Robot for a specific spraying
2012
International audience; To preserve environment for a sustainable agriculture, we explore the development of a new autonomous robot, called I-Weed Robot (Intelligent Weed Robot), which aims at reducing herbicides in crop fields (maize, sunflower...). Using a high precision positioning signal (RTK) to locate the robot in the field, a Kaman filter and a proportional-integral-derivative controller (PID controller) allow adjusting the orientation of the robot depending on a predefined trajectory. As for the spraying system, a camera in front of the mobile platform detects weed plants thanks to an image processing based on a crop/weed discrimination algorithm (Hough Transform). At the back a spr…
Impression 3D et propriété intellectuelle: Un aperçu français
2019
Technological developments and the expiry of patents in three-dimensional printing are making this technology less and less expensive and with increased performance. Now widespread in the manufacturing industry, 3D printing is about to cross the threshold of our homes. The dematerialization of objects into exchangeable digital files raises many questions about the enforcement of intellectual property rights in French Law.
Photometric Gaussian Mixtures for Direct Virtual Visual Servoing of Omnidirectional Camera
2021
International audience
Temporal-range estimation of multiple objects: evidence for an early bottleneck.
2011
When making parallel time-to-contact (TTC) estimates of two approaching objects, the two respective TTC estimates interfere with one another in an asymmetric fashion. The TTC of the later-arriving object is systematically overestimated, while the estimated TTC for the first-arriving object is as accurate as in a condition presenting only a single object. This asymmetric interference points to a processing bottleneck that could be due to early (e.g., during the estimation of the TTC from the optic flow) or late (e.g., during the timing of the response or the motor execution) constraints in the TTC estimation process. We used a Sperling-like prediction-motion task to differentiate between the…
Multi-Scale Feature Extraction for Vehicle Detection Using Phis-Lbp
2018
International audience; Multi-resolutionobjectdetectionfacesseveraldrawbacksincludingitshighdimensionalityproducedby a richer image representation in different channels or scales. In this paper, we propose a robust and lightweight multi-resolution method for vehicle detection using local binary patterns (LBP) as channel feature. Algorithm acceleration is done using LBP histograms instead of multi-scale feature maps and by extrapolating nearby scales to avoid computing each scale. We produce a feature descriptor capable of reaching a similar precision to other computationally more complex algorithms but reducing its size from 10 to 800 times. Finally, experiments show that our method can obt…
Towards automated and operational forest inventories with T-Lidar
2011
International audience; Forest inventory automation has become a major issue in forestry. The complexity of the segmentation of 3D point cloud is due to mutual occlusion between trees, other vegetation, or branches. That is why, the applications done until now are limited to the estimation of the DBH (Diameter at Breast Height), the tree height and density estimation. Furthermore other parameters could also be detected, such as volume or species of trees (Reulke and Haala) . . . This paper presents an effective approach for automatic detection, isolation of trees and DBH estimation. Tree isolation is achieved using an innovative approach based on a clustering methodology followed by a skele…
A Framework for Mesh Segmentation and Annotation using Ontologies
2015
International audience; Mesh segmentation and annotation using semantics has received an increased interest with the recent democratisation of 3D reconstruction methods. The common approach is to perform this task in two steps, by first segmenting the mesh and then annotating it. However, this approach does not allow one part to take advantage of the other. In image processing, some methods are combining segmentation and annotation, but they are not generic and require implementation adjustments or rewritings for each modification of the expert knowledge. In this work, we describe an original framework that mixes segmen-tation and annotation while minimizing the required geometric analysis …
Depth-of-Field of the Accommodating Eye
2014
Our eyes project information from a three-dimensional world to a basically two-dimensional surface, corresponding to the photoreceptor plane in the retina. In theory, only one plane or surface of world can be in focus at one time. However, the eye exhibits a certain tolerance to out-of-focus images, a feature that is known as depth-of-focus (DOF). The corresponding distance range in which the objects are seen “clearly” is known as depth-of-field (DOFi). Although DOF and DOFi refer to an interval of distances or a dioptric range in the image and object space, respectively, both parameters define a similar concept and are usually interchangeable. This article will mainly refer to DOFi because…
Vecuma ietekme uz Vernjē asumu.
2020
Maģistra darbs ir uzrakstīts angļu valodā uz 36 lapaspusēm, tas satur 19 attēlus, 3 tabulas un atsauces uz 36 literatūras avotiem. Darba mērķis ir noskaidrot, vai Vernjē asumu ietekmē cilvēka novecošanās process kopējā populācijā. Metode. Pētījumā piedalījās 75 netrenēti dalībnieki divās vecuma grupās, lietotjot labāko iespējamo briļļu korekciju. Dalībniekiem nebija zināmu acs patoloģiju, izņemot agrīnu kataraktu. Dalībniekiem 3 reizes tika novērtēts Vernjē asums. Rezultāti. Vernjē asuma sliekšņi ir augstāki vecāku dalībnieku grupā nekā jaunāko dalībnieku grupā. Secinājumi. Pētītajā dalībnieku grupā novecošanās process ietekmēja Vernjē asumu. Pētījumu varētu uzlabot plašāks dalībnieku loks …