ИСПОЛЬЗОВАНИЕ КОМПЛЕКСИРОВАННЫХ ДЕСКРИПТОРОВ В РЕШЕНИИ SLAM-ЗАДАЧИ

Abstract

The actual problem of determining all six coordinates (three linear and three angular) of thecurrent position of a mobile robot (unmanned aerial vehicle) from video rangefinder images of theexternal environment (volumetric colored point clouds) formed by an onboard integrated visionsystem built on the basis of a 3D rangefinder sensor (lidar) and a color video camera while moving(flying) in an unknown environment is considered. An algorithm of video navigation based onthe use of complexed (video-rangefinder) descriptors is proposed, for the description of whichvisual and geometric parameters are used. The rules for the formation of a complex descriptor areformulated, which ensure the allocation of special (central) points of the descriptor using theSobel operator and the calculation of brightness and geometric parameters in its local area. Theaddition of the brightness parameters of the descriptor provided by the video camera with the geometricparameters provided by the rangefinder sensor removes the problem of invariance of thedescriptor to the scale and thereby significantly reduces the complexity of calculations when selectingit. The rules for finding complexed descriptors corresponding to each other in a sequenceof complexed images are described, based on calculating the difference in brightness and geometricparameters of the compared descriptors. The estimation of the error in solving the navigationproblem using the integrated descriptors was performed depending on the error of the sensors ofthe vision system and the geometric dimensions of the descriptor. By constructing histograms ofthe solution of the navigation problem for each coordinate of the control object for all pairs ofdescriptors corresponding to each other, a statistically stable high reliability of the solution of thecomplete navigation problem has been achieved. At the same time, the error in solving the navigationtask turned out to be an order of magnitude smaller than the error in the formation of compleximages by the technical vision system. The use of complex descriptors made it possible, with arelatively small amount of calculations, to solve the complete navigation problem with acceptableaccuracy, which provides a solution to the SLAM problem on the onboard computations at thepace of movement of the control object. The effectiveness of the proposed algorithmic and developedsoftware and hardware is confirmed by field experiments conducted in real conditions ofvarious environments.