ОЦЕНКА СИСТЕМ КООРДИНАТНЫХ МЕТОК С ИСПОЛЬЗОВАНИЕМ БОРТОВОЙ КАМЕРЫ МОБИЛЬНОГО РОБОТА «СЕРВОСИЛА ИНЖЕНЕР» В УСЛОВИЯХ ЗАКРЫТЫХ ПОМЕЩЕНИЙ

Abstract

Modern tasks of special areas of robotics, including search and rescue operations in urbanareas, face a number of obstacles to mobile robotics, where the automatic performance of various functionsby mobile robots remains a key task. One of the important requirements for the algorithms andsoftware of the robot is the possibility of autonomous decision-making and automatic performance bythe robot of various functions, both low and high levels based on the embedded algorithms and informationreceived from the on-board sensors of the robot. To date, the most common on-board robot sensorsare cameras of various types, due to their technical capabilities and lower cost relative to lidarsand other sensors that provide visual information in the form of digital images. Camera calibration is anecessary process for extracting accurate information from digital images. This process is necessary toobtain an exact correspondence between the three-dimensional object space and the pixel space of theimage, for the possibility of subsequent use of computer vision algorithms, aggregation, and informationprocessing. Calibration of digital cameras is an integral part of a number of practical tasks of machinevision such as navigation of mobile robotic systems, medicine, reconstruction of dense and sparse threedimensionalmaps of the environment, video surveillance and visual inspection, visual simultaneouslocalization and mapping, etc. The urgency of the problem of camera calibration is defined by the presenceof many different methods of calibration and calibration templates. Each individual solution issuitable only for special conditions, e.g., lack of lighting, bad weather conditions, the presence of thirdpartyobjects blocking visibility, etc. In most cases, each calibration method uses a specific calibrationpattern. Camera calibration is usually associated with the use of special calibration templates. Theyallow to achieve the most accurate results due to a previously known geometric structure. Currently, theprocedure for camera calibrating of robotic systems is carried out in laboratory conditions using theclassic “chessboard” method. In addition, there are only a few alternative approaches that are in their infancy state both in Russia and abroad. On the other hand, research into camera calibration methodscontinues and new alternatives for camera calibration are emerging. One of the new directions is theuse of fiducial marker systems as a reference object. A variety of parameters such as the size of the calibrationtemplate, the dimension of the calibration data set, the distribution of distances from the camerato objects on the stage, etc. creates a vast area for experimental testing of optimal camera calibrationparameters. This paper presents a research of automatic camera calibration using fiducial marker systems(FMS), which are located on the surface of the robot. Based on the results of virtual experimentswith FMS in the Gazebo simulation environment of the robotic operating system ROS, two differenttypes of FMS were selected that are optimal relative to other types of FMS covered by our previousstudies in terms of the resistance of FMS to systematic occlusion of the marker area and the effect ofmarker size on quality of its recognition. The selected FMS were tested using the onboard camera of theRussian mobile robot Servosila Engineer in indoor settings to assess the correlation of results in virtualand real environments.