A modified stochastic gradient descent algorithm for view-based SLAM using omnidirectional images

This paper describes an approach to the problem of Simultaneous Localization and Mapping (SLAM) based on Stochastic Gradient Descent (SGD) and using omnidirectional images. In the field of mobile robot applications, SGD techniques have never been evaluated with information gathered by visual sensors. This work proposes a SGD algorithm within a SLAM system which makes use of the beneficial characteristics of a single omnidirectional camera. The nature of the sensor has led to a modified version of the standard SGD to adapt it to omnidirectional geometry. Besides, the angular unscaled observation measurement needs to be considered. This upgraded SGD approach minimizes the non-linear effects which impair and compromise the convergence of traditional estimators. Moreover, we suggest a strategy to improve the convergence speed of the SLAM solution, which inputs several constraints in the SGD algorithm simultaneously, in contrast to former SGD approaches, which process only constraint independently. In particular, we focus on an efficient map model, established by a reduced set of image views. We present a series of experiments obtained with both simulated and real data. We validate the new SGD approach, compare the efficiency versus a standard SGD and demonstrate the suitability and the reliability of the approach to support real applications. (C) 2014 Elsevier Inc. All rights reserved.