The feature-based graphical approach to robotic mapping provides a representationally rich and computationally efficient framework for an autonomous agent to learn a model of its environment. However, this formulation does not naturally support long-term autonomy because it lacks a notion of environmental change; in reality, “everything changes and nothing stands still, ” and any mapping and localization system that aims to support truly persistent autonomy must be similarly adaptive. To that end, in this paper we propose a novel feature-based model of environmental evolution over time. Our approach is based upon the development of an expressive probabilistic generative feature persistence model that describes the survival of abstract semi-static environmental features over time. We show that this model admits a recursive Bayesian estimator, the persistence filter, that provides an exact online method for computing, at each moment in time, an explicit Bayesian belief over the persistence of each feature in the environment. By incorporating this feature persistence estimation into current state-of-the-art graphical mapping techniques, we obtain a flexible, computationally efficient, and information-theoretically rigorous framework for lifelong environmental modeling in an ever-changing world.

Object detection and recognition are fundamental capabilities for a mobile robot. Objects are a powerful representation for a variety of tasks including mobile manipulation and inventory tracking. As a result, object-based world representations have seen a great deal of research interest in the last several years. However, these systems usually assume that object recognition is well-solved: they require that accurate recognition be available for every object they might encounter. Despite steady advances, object recognition remains a difficult, open problem. Existing object recognition algorithms rely on high-resolution three-dimensional object models or on extensive hand-labeled training data. The sheer variety of objects that occur in natural environments makes manually training a recognizer for every possible object infeasible. In this work, we present a robotic system for unsupervised object and class discovery, in which objects are first discovered, and then grouped into classes in an unsupervised fashion. At each step, we approach the problem as one of robotics, not disembodied computer vision. On a very large robotic dataset, we discover object classes with 98.7% precision while achieving 71.8% recall. The scale and quality of these results demonstrate the merit of our approach, and prove the practicality of long-term large-scale object discovery. To our knowledge, no other authors have investigated robotic object discovery at this scale, making direct quantitative comparison impossible. We make our implementation and ground-truth labelings available, and evaluate our technique on a very large dataset. As a result, this work is a baseline against which future work can be compared.

After many years, the robotics research community has settled on standard middleware: the Robot Operating System (ROS). This standard presents a great opportunity for educational robotics. This hands-on workshop will engage participants in ROS-based curricula for CS 02 and advanced undergraduates. The workshop will highlight how ROS has simplified, enabled, and expanded flipped robotics curricula in CS 02. Our advanced materials show how ROS enables easy access to the robotics research community, permitting larger and more research-representative projects. This workshop is two long hands-on sessions punctuated with short reports from the presenters' experience. Participants will implement the first two assignments of our CS 2 curriculum. http://www.cs.hmc.edu/dodds/ROSatSIGCSE2013.

Recent years have seen rising interest in robotic mapping algorithms that operate at the level of objects, rather than two- or three-dimensional occupancy. Such “semantic maps” permit higher-level reasoning than occupancy maps, and are useful for any application that involves dealing with objects, including grasping, change detection, and object search. We describe and experimentally verify such a system aboard a mobile robot equipped with a Microsoft Kinect RGB-D sensor. Our representation is object-based, and makes uniquely weak assumptions about the quality of the perceptual data available; in particular, we perform no explicit object recognition. This allows our system to operate in large, dynamic, and uncon-strained environments, where modeling every object that occurs (or might occur) is impractical. Our dataset, which is publicly available, consists of 67 autonomous runs of our robot over a six-week period in a roughly 1600m2office environment. We demonstrate two applications built on our system: semantic querying and change detection.

A useful capability for a mobile robot is the ability to recognize the objects in its environment that move and change (as distinct from background objects, which are largely stationary). This ability can improve the accuracy and reliability of localization and mapping, enhance the ability of the robot to interact with its environment, and facilitate applications such as inventory management and theft detection. Rather than viewing this task as a difficult application of object recognition methods from computer vision, this work is in line with a recent trend in the community towards unsupervised object discovery and tracking that exploits the fundamentally temporal nature of the data acquired by a robot. Unlike earlier approaches, which relied heavily upon computationally intensive techniques from mapping and computer vision, our approach combines visual features and RGB-D data in a simple and effective way to segment objects from robot sensory data. We then use a Dirichlet process to cluster and recognize objects. The performance of our approach is demonstrated in several test domains.

The Microsoft Kinect and Willow Garage's Robot Operating System (ROS) are changing the way robots are developed. Together, these tools can enable today's CS educators to provide richer and more research-representative experiences with robots and perception. This hands-on workshop will introduce ROS and showcase two pilot courses taught using ROS and the Kinect. Four 20-minute talks will intersperse with participants' hands-on development of Python programs on low-cost Kinect-equipped robots and the ARDrone quadcopter. This workshop is intended for all college-level CS educators interested in robotics or embodied AI. First-time ROS/Kinect users are particularly welcome! Laptops and robots will be provided. See http://www.ros.org/wiki/Courses/sigcse2012. Laptops optional.

A textured occupancy grid map is an extremely versatile data structure. It can be used to render human readable views and for laser rangefinder localization algorithms. For camera-based localization, landmark or feature based maps tend to be favored in current research. This may be because of a tacit assumption that working with a textured occupancy grid with a camera would be impractical. We demonstrate that a textured occupancy grid can be combined with an extremely simple monocular localization algorithm to produce a viable localization solution. Our approach is simple, efficient, and produces localization results comparable to laser localization results. A consequence of this result is that a single map representation, the textured occupancy grid, can now be used for humans, robots with laser rangefinders, and robots with just a single camera.