Review of Variable-Rate Sprayer Applications Based on Real- Time Sensor Technologies

Precision variable rate spray is one of the research hotspots in the field of modern agriculture spraying applications. Variable rate spraying of the canopy allows growers to apply adjusted volume rate of pesticides to the target, based on canopy size, and to apply plant protection products in an economical and environmentally sound manner. In the field of pesticide application, knowledge of the geometrical characteristics of plantations will guarantee a better adjustment of the dosage of the agrochemicals applied. This technology is integrated with intelligent real-time sensors, which have a high potential for agricultural precision spray applications. This book chapter presents the foundations and applications in agriculture of the primary systems used for real-time spray target detection of the geometrical characterization of tree plantations. Systems based on infrared, ultrasonic, light detection and ranging (LIDAR), and stereo vision sensors were discussed, respectively, on their performances to detect spray targets. Among them, laser scanners and stereo vision systems are probably the most promising and complementary techniques for achieving three-dimensional (3D) pictures and maps of plants and canopies. The advantages of data fusion applied in real-time target detection and its accuracy in density estimation of the plants were stressed

A Variational Stereo Method for the Three-Dimensional Reconstruction of Ocean Waves

We develop a novel remote sensing technique for the observation of waves on the ocean surface. Our method infers the 3-D waveform and radiance of oceanic sea states via a variational stereo imagery formulation. In this setting, the shape and radiance of the wave surface are given by minimizers of a composite energy functional that combines a photometric matching term along with regularization terms involving the smoothness of the unknowns. The desired ocean surface shape and radiance are the solution of a system of coupled partial differential equations derived from the optimality conditions of the energy functional. The proposed method is naturally extended to study the spatiotemporal dynamics of ocean waves and applied to three sets of stereo video data. Statistical and spectral analysis are carried out. Our results provide evidence that the observed omnidirectional wavenumber spectrum S(k) decays as k-2.5 is in agreement with Zakharov's theory (1999). Furthermore, the 3-D spectrum of the reconstructed wave surface is exploited to estimate wave dispersion and currents

Low-Cost Three-Dimensional Modeling of Crop Plants

Plant modeling can provide a more detailed overview regarding the basis of plant development throughout the life cycle. Three-dimensional processing algorithms are rapidly expanding in plant phenotyping programmes and in decision-making for agronomic management. Several methods have already been tested, but for practical implementations the trade-off between equipment cost, computational resources needed and the fidelity and accuracy in the reconstruction of the end-details needs to be assessed and quantified. This study examined the suitability of two low-cost systems for plant reconstruction. A low-cost Structure from Motion (SfM) technique was used to create 3D models for plant crop reconstruction. In the second method, an acquisition and reconstruction algorithm using an RGB-Depth Kinect v2 sensor was tested following a similar image acquisition procedure. The information was processed to create a dense point cloud, which allowed the creation of a 3D-polygon mesh representing every scanned plant. The selected crop plants corresponded to three different crops (maize, sugar beet and sunflower) that have structural and biological differences. The parameters measured from the model were validated with ground truth data of plant height, leaf area index and plant dry biomass using regression methods. The results showed strong consistency with good correlations between the calculated values in the models and the ground truth information. Although, the values obtained were always accurately estimated, differences between the methods and among the crops were found. The SfM method showed a slightly better result with regard to the reconstruction the end-details and the accuracy of the height estimation. Although the use of the processing algorithm is relatively fast, the use of RGB-D information is faster during the creation of the 3D models. Thus, both methods demonstrated robust results and provided great potential for use in both for indoor and outdoor scenarios. Consequently, these low-cost systems for 3D modeling are suitable for several situations where there is a need for model generation and also provide a favourable time-cost relationship

In situ monitoring of additive manufacturing using digital image correlation: A review

UIDB/00667/2020 POCI-01-0145-FEDER-016414This paper is a critical review of in situ full-field measurements provided by digital image correlation (DIC) for inspecting and enhancing additive manufacturing (AM) processes. The principle of DIC is firstly recalled and its applicability during different AM processes systematically addressed. Relevant customisations of DIC in AM processes are highlighted regarding optical system, lighting and speckled pattern procedures. A perspective is given in view of the impact of in situ monitoring regarding AM processes based on target subjects concerning defect characterisation, evaluation of residual stresses, geometric distortions, strain measurements, numerical modelling validation and material characterisation. Finally, a case study on in situ measurements with DIC for wire and arc additive manufacturing (WAAM) is presented emphasizing opportunities, challenges and solutions.publishersversionpublishe

Application of image processing methodologies for fruit detection and analysis

En aquesta memòria es presenten diversos treballs d'investigació centrats en l’automatització d’operacions agrícoles mitjançant l’aplicació de diverses tècniques de processament d’imatge. En primer lloc es presenta un mètode desenvolupat per detectar i comptar raïms mitjançant la localització de pics d'intensitat en superfícies esfèriques. En segon lloc es desenvolupa un sistema de recol•lecció automàtica de fruita mitjançant la combinació d'una càmera estereoscòpica de baix cost i un braç robòtic. En tercer lloc es proposa una aplicació en què es desenvolupa un mètode basat en l'ús de la informació de color per a la verificació d'una varietat de nectarines de forma automàtica i individual en una línia d’embalatge de fruita. Finalment s’han estudiat les correlacions entre els paràmetres de qualitat de la fruita i el espectre visible de la seva pell amb l’objectiu de controlar la seva qualitat de forma no destructiva durant el seu emmagatzematge.En esta memoria se presentan diversos trabajos de investigación centrados en la automatización de operaciones agrícolas mediante la aplicación de distintas técnicas de procesado de imágenes. En primer lugar se presenta un método desarrollado para detectar y contar uvas rojas mediante la identificación de picos de intensidad en las superficies esféricas. En segundo lugar se desarrolla un sistema de recolección automática de fruta mediante la combinación de una cámara estereoscópica de bajo coste y un brazo robótico. En tercer lugar se propone una aplicación en la que se desarrolla un método de procesamiento de imágenes basado en el uso de la información de color para la verificación de una variedad de nectarinas de forma automática e individual en una línea de envasado de fruta. Finalmente se han estudiado las correlaciones entre los parámetros de calidad de la fruta y el espectro visible de su piel con el fin de controlar su calidad de forma no destructiva durante el almacenamiento.This memory introduces several research works developed to automate agricultural tasks by applying image processing techniques. In the first place a new image processing method is proposed for detecting and counting red grapes by identifying specular reflection peaks from spherical surfaces. The proposal of the second application is to develop an automatic fruit harvesting system by combining a low cost stereovision camera and a robotic arm. The third application proposed is to develop a novel image processing method based on the use of color information to verify an in-line automatic and individual nectarine variety verification in a fruitpacking line. Finally, a study focused on assessing correlations between post-storage fruit quality indices and the visible spectra of the skin of the fruit is proposed in order to control fruit quality in a non-destructive way during the storage

Address-Event Based Stereo Vision with Bio-Inspired Silicon Retina Imagers

Artificial intelligenc

MACHINE VISION RECOGNITION OF THREE-DIMENSIONAL SPECULAR SURFACE FOR GAS TUNGSTEN ARC WELD POOL

Observing the weld pool surface and measuring its geometrical parameters is a key to developing the next-generation intelligent welding machines that can mimic a skilled human welder who observes the weld pool to adjust welding parameters. It also provides us an effective way to improve and validate welding process modeling. Although different techniques have been applied in the past few years, the dynamic specular weld pool surface and the strong weld arc complicate these approaches and make the observation /measurement difficult. In this dissertation, a novel machine vision system to measure three-dimensional gas tungsten arc weld pool surface is proposed, which takes advantage of the specular reflection. In the designed system, a structured laser pattern is projected onto the weld pool surface and its reflection from the specular weld pool surface is imaged on an imaging plane and recorded by a high-speed camera with a narrow band-pass filter. The deformation of the molten weld pool surface distorts the reflected pattern. To derive the deformed surface of the weld pool, an image processing algorithm is firstly developed to detect the reflection points in the reflected laser pattern. The reflection points are then matched with their respective incident rays according to the findings of correspondence simulations. As a result, a set of matched incident ray and reflection point is obtained and an iterative surface reconstruction scheme is proposed to derive the three-dimensional pool surface from this set of data based on the reflection law. The reconstructed results proved the effectiveness of the system. Using the proposed surface measurement (machine vision) system, the fluctuation of weld pool surface parameters has been studied. In addition, analysis has been done to study the measurement error and identify error sources in order to improve the measurement system for better accuracy. The achievements in this dissertation provide a useful guidance for the further studies in on-line pool measurement and welding quality control

Review of Intelligent Control Systems with Robotics

Interactive between human and robot assumes a significant job in improving the productivity of the instrument in mechanical technology. Numerous intricate undertakings are cultivated continuously via self-sufficient versatile robots. Current automated control frameworks have upset the creation business, making them very adaptable and simple to utilize. This paper examines current and up and coming sorts of control frameworks and their execution in mechanical technology, and the job of AI in apply autonomy. It additionally expects to reveal insight into the different issues around the control frameworks and the various approaches to fix them. It additionally proposes the basics of apply autonomy control frameworks and various kinds of mechanical technology control frameworks. Each kind of control framework has its upsides and downsides which are talked about in this paper. Another kind of robot control framework that upgrades and difficulties the pursuit stage is man-made brainpower. A portion of the speculations utilized in man-made reasoning, for example, Artificial Intelligence (AI) such as fuzzy logic, neural network and genetic algorithm, are itemized in this paper. At long last, a portion of the joint efforts between mechanical autonomy, people, and innovation were referenced. Human coordinated effort, for example, Kinect signal acknowledgment utilized in games and versatile upper-arm-based robots utilized in the clinical field for individuals with inabilities. Later on, it is normal that the significance of different sensors will build, accordingly expanding the knowledge and activity of the robot in a modern domai