Robotic-based therapy is becoming a very popular treatment for the rehabilitation of hand function impairment as a consequence of strokes, due to the high-dimensional and less interpretable nature of superficial electromyography (sEMG) signals. In this context, feature engineering becomes particularly important to estimate the intention of upper limb movements by utilizing machine learning models, specially when a hardware embedded on-board implementation is expected, due to the strong computational, energy and latency constraints. Our work compares the performance achieved by implementing four state-of-the-art feature techniques (random forest, minimum redundancy maximum relevance (MRMR), Davies-Bouldin index, and t-tests), when these are evaluated on a sEMG dataset intended for training hand gesture classifiers. The results of three different machine learning algorithms (neuronal networks, k-nearest neighbors and bagged forest) are used as a reference to validate the analysis. This ongoing research has revealed valuable information on the potential and constraints of these 4 feature generation methods for real gesture recognition embedded applications.

This paper presents the integration of an UAV for the autonomous monitoring of rice crops. The system integrates image processing and machine learning algorithms to analyze multispectral aerial imagery. Our approach calculates 8 vegetation indices from the images at each stage of rice growth: vegetative, reproductive and ripening. Multivariable regressions and artificial neural networks have been implemented to model the relationship of these vegetation indices against two crop variables: biomass accumulation and leaf nitrogen concentration. Comprehensive experimental tests have been conducted to validate the setup. The results indicate that our system is capable of estimating biomass and nitrogen with an average correlation of 80% and 78% respectively.

In this study, the authors propose a new method for transmission tower detection that involves the use of visual features and the linear content of the scene. For this process, they developed a descriptor based on a grid of two‐dimensional feature descriptors that is useful not only for object detection, but also for tracking the area of interest. For the detection and classification, they used a support vector machine. The experiments were conducted with a dataset of real world images from transmission tower videos that were used to validate the strategy by comparing it with the ground truth. The results showed that the obtained method is fast and appropriate for tower detection in video sequences of environments that include rural and urban areas. The detection took less than 50 ms and was faster than other methods.

This paper presents a Fuzzy Control application for a landing task of an Unmanned Aerial Vehicle, using the 3D-position estimation based on visual tracking of piecewise planar objects. This application allows the UAV to land on scenarios in which it is only possible to use visual information to obtain the position of the vehicle. The use of the homography permits a realtime estimation of the UAV's pose with respect to a helipad using a monocular camera. Fuzzy Logic allows the definition of a model-free control system of the UAV. The Fuzzy controller analyzes the visual information to generate altitude commands for the UAV to develop the landing task.

This article presents a real time Unmanned Aerial Vehicles UAVs 3D pose estimation method using planar object tracking, in order to be used on the control system of a UAV. The method explodes the rich information obtained by a projective transformation of planar objects on a calibrated camera. The algorithm obtains the metric and projective components of a reference object (landmark or helipad) with respect to the UAV camera coordinate system, using a robust real time object tracking based on homographies. The algorithm is validated on real flights that compare the estimated data against that obtained by the inertial measurement unit IMU, showing that the proposed method robustly estimates the helicopter's 3D position with respect to a reference landmark, with a high quality on the position and orientation estimation when the aircraft is flying at low altitudes, a situation in which the GPS information is often inaccurate. The obtained results indicate that the proposed algorithm is suitable for complex control tasks, such as autonomous landing, accurate low altitude positioning and dropping of payloads.

In this paper we introduce a real-time trinocular system to control rotary wing Unmanned Aerial Vehicles based on the 3D information extracted by cameras located on the ground. The algorithm is based on key features onboard the UAV to estimate the vehicle's position and orientation. The algorithm is validated against onboard sensors and known 3D positions, showing that the proposed camera configuration robustly estimates the helicopter's position with an adequate resolution, improving the position estimation, especially the height estimation. The obtained results show that the proposed algorithm is suitable to complement or replace the GPS-based position estimation in situations where GPS information is unavailable or where its information is inaccurate, allowing the vehicle to develop tasks at low heights, such as autonomous landing, take-off, and positioning, using the extracted 3D information as a visual feedback to the flight controller.

This paper presents an implementation of two Fuzzy Logic controllers working in parallel for a pan-tilt camera platform on an UAV. This implementation uses a basic Lucas-Kanade tracker algorithm, which sends information about the error between the center of the object to track and the center of the image, to the Fuzzy controller. This information is enough for the controller to follow the object by moving a two axis servo-platform, regardless the UAV vibrations and movements. The two Fuzzy controllers for each axis, work with a rules-base of 49 rules, two inputs and one output with a more significant sector defined to improve the behavior of those controllers. The controllers have shown very good performances in real flights for statics objects, tested on the Colibri prototypes.

UAVs (unmanned aerial vehicles) are becoming more popular for civil task due to their unique flight capabilities. The video shows several capabilities of a platform used as main research testbed of computer vision for unmanned aerial vehicles. Four major research areas are explored in the present work as visual servoing, trajectory planning, power line inspection and stereo-based visual navigation.