Perception for detection and grasping

The final publication is available at link.springer.comThis research presents a methodology for the detection of the crawler used in the project AEROARMS. The approach consisted on using a two-step progressive strategy, going from rough detection and tracking, for approximation maneuvers, to an accurate positioning step based on fiducial markers. Two different methods are explained for the first step, one using efficient image segmentation approach; and the second one using Deep Learning techniques to detect the center of the crawler. The fiducial markers are used for precise localization of the crawler in a similar way as explained in earlier chapters. The methods can run in real-time.Peer ReviewedPostprint (author's final draft

Marker based Thermal-Inertial Localization for Aerial Robots in Obscurant Filled Environments

For robotic inspection tasks in known environments fiducial markers provide a reliable and low-cost solution for robot localization. However, detection of such markers relies on the quality of RGB camera data, which degrades significantly in the presence of visual obscurants such as fog and smoke. The ability to navigate known environments in the presence of obscurants can be critical for inspection tasks especially, in the aftermath of a disaster. Addressing such a scenario, this work proposes a method for the design of fiducial markers to be used with thermal cameras for the pose estimation of aerial robots. Our low cost markers are designed to work in the long wave infrared spectrum, which is not affected by the presence of obscurants, and can be affixed to any object that has measurable temperature difference with respect to its surroundings. Furthermore, the estimated pose from the fiducial markers is fused with inertial measurements in an extended Kalman filter to remove high frequency noise and error present in the fiducial pose estimates. The proposed markers and the pose estimation method are experimentally evaluated in an obscurant filled environment using an aerial robot carrying a thermal camera.Comment: 10 pages, 5 figures, Published in International Symposium on Visual Computing 201

A Simple Sheet Bending Recognition for Augmenting a Two-dimensional Marker-based Response Analyzer

2015 International Conference on Informatics, Electronics and Vision (ICIEV), Fukuoka, Japan, June 15, 2015 to June 18, 2015Conventional response analyzers use various student devices such as clickers and mobile devices, which require the additional burdens of charging and managing. Fiducial marker-based response analyzers have been proposed to relieve these burdens. The IDs and rotations of the fiducial markers are used to identify students and their respective answers. The marker-based approach is straightforward, but transferrable data are limited to the ID and the rotations. To enhance the transferrable data, we introduce a method of extracting curves of the marker sheet. Since a paper sheet is flexible, students can control the shape of the sheet intuitively. We have implemented our method by modifying a conventional fiducial marker recognizer and confirmed its effectiveness

An implementation review of occlusion-based interaction in augmented reality environment

Augmented Reality (AR) technology shows some potential in providing new approach of interaction with computer.It shares similar potential in Virtual Reality (VR) but at lower cost.In this paper, an AR application is developed to explore the capability of the interaction approach called Occlusion Based Interaction using low cost device.The implementation of the application is utilizing the ARToolKit library as the main library to handle the AR part while OpenGL and GLUT to handle the graphics manipulation and windows management respectively

Tracking Markerless Augmeted Reality Untuk Design Furniture Room

Metode yang digunakan oleh AR ini adalah menggunakan sistem melacak dan deteksi marker sebagai trigger untuk menampilkan benda virtual melalui media visual (kamera).Marker yang digunakan pada penelitian ini termasuk jenis markerless yang dideteksi menggunakan metode SIFT. Pengujian dilakukan dengan meletakkan markerless yang bertindak sebagai image target yang diletakkan pada sebuah ruangan kemudian kamera akan mengarahkan ke markerless tersebut. Markerless yang bertindak sebagai image target dalam penelitian ini dilakukan dua gambar dengan kedalaman warna berbeda yaitu 8 dan 16 bit.. Parameter yang diuji adalah jumlah keypoint dan matching dengan kondisi jarak,rotasi,sudut pandang ( derajat ) dan kondisi pencahayaan. Berdasarkan pengujian didapat hasil dari jumlah keypoint dan matching, terdeteksi dengan nilai matching dipengaruhi oleh 4 parameter yang juga berpengaruh terhadap terdeteksi atau tidak terdeteksi image target

Comparing fiducial marker systems in the presence of occlusion

© 2017 IEEE. A fiducial marker system is a system of unique 2D (planar) marker, which is placed in an environment and automatically will be detected with a camera with a help of a corresponding detection algorithm. Application areas of these markers include industrial systems, augmented reality, robots navigation, human-robot interaction and others. Marker system designed for such different applications must be robust to such factors as view angles, occlusions, changing distances, etc. This paper compares three existing systems of markers: ARTag, AprilTag, and CALTag. As a benchmark, we use their reliability and detection rate in presence of occlusions of various types and intensity. The paper presents experimental comparison of these markers. The marker detection was performed with a simple inexpensive Web camera

Visual Localization of Mobile Robot Using Artificial Markers

AbstractThe paper presents localization method for mobile robots with use of artificial markers deployed to an environment. A specialty of the markers is that the position and rotation of the camera relative to the marker can be determined from only one marker. Further in the paper, some experiments are described. The results prove that this system can be reliably employed in visual localization of mobile robots

METROLOGICAL CHARACTERIZATION OF A LASER-CAMERA 3D VISION SYSTEM THROUGH PERSPECTIVE-N-POINT POSE COMPUTATION AND MONTE CARLO SIMULATIONS

Abstract. This study focuses on the metrological characterization of a 3D vision system consisting in the fusion of a CMOS camera sensor with a 2D laser scanner for contactless dimensional measurements. The purpose is to obtain an enhanced measurement information as a result of the combination of two different data sources. On one side, we can estimate the pose of the target measurand by solving the well-known Perspective-n-Point (PnP) problem from the calibrated camera. On the other side, the 2D laser scanner generates a discrete point cloud which describes the profile of the intercepted surface of the same target object. This solution allows to estimate the target's geometrical parameters through the application of fit-to-purpose algorithms that see the data acquired by the overall system as their input. The measurement uncertainty is evaluated by applying the Monte Carlo Method (MCM) to estimate the uncertainty deriving from the Probability Distribution Functions (PDF) of the input variables. Through a Design of Experiments (DOE) model the effects of different influence factors were evaluated

ARTag, AprilTag and CALTag fiducial marker systems: Comparison in a presence of partial marker occlusion and rotation

© 2017 by SCITEPRESS - Science and Technology Publications, Lda. All Rights Reserved. Fiducial marker systems consist of patterns that are placed in environment and are automatically detected with a camera using appropriate for the marker detection algorithm. Marker systems are useful for many modern visual applications such as augmented reality, robot navigation and collaboration, industrial and space robotics, and human-robot interaction. A variety of applications demands certain quality assurance for marker properties. Among the most common criteria are resistance to partial occlusion and rotation, sensitivity to lightning conditions, marker size, false positive and false negative rates. This paper compares three types of markers for their resistance to partial occlusion in various types of occlusion and resistance to normal, lateral, and longitudinal rotations. Intensive experimental comparison of tags is presented with analysis. Detection of markers was performed with a common Web camera. Based on our experimental results, we have selected a marker system, which should be preferred for real world applications when only simple inexpensive hardware is available and appearance of rotation and occlusion disturbances are expected in the environment. Our long term goal is to calibrate humanoid robot manipulators in real-world environment applying a pre-calibrated camera of the robot, while the presented in this paper results help selecting a most suitable marker system for further calibration procedures