1. Natural Tasking of Robots Based on Human Interaction Cues Brian Scassellati, Bryan Adams, Aaron Edsinger, Matthew Marjanovic MIT Artificial Intelligence Laboratory Locate target Foveate Target Apply Face Filter Software Zoom Feature Extraction 300 msec 66 msec Current Research: Joint Reference and Simple Mimicry Our team at the MIT Artificial Intelligence lab is building robotic systems that use natural social conventions as an interface. We believe that these systems will enable anyone to teach the robot to perform simple tasks. The robot will be usable without special training or programming skills, and will be able to act in unique and dynamic situations. We originally outlined a sequence of behavioral tasks, listed on the chart below, that will allow our robots to learn new tasks from a human instructor. In the chart below, behaviors in bold text have been completed, behaviors in italic text have been partially implemented. Schema Creation Development of Social Interaction Development of Commonsense Knowledge Development of Sequencing Development of Coordinated Body Actions Face Finding Eye Contact Gaze Direction Gaze Following Recognizing Pointing Speech Prosody Intentionality Detector Recognizing Instructor’s Knowledge States Recognizing Beliefs, Desires, and Intentions Arm and Face Gesture Recognition Facial Expression Recognition Familiar Face Recognition Directing Instructor’s Attention Vocal Cue Production Motion Detector Depth Perception Object Saliency Object Segmentation Object Permanence Body Part Segmentation Human Motion Models Long-Term Knowledge Consolidation Expectation-Based Representations Attention System Turn Taking Task-Based Guided Perception Action Sequencing VOR/ OKR Kinesthetic Body Representation Mapping Robot Body to Human Body Self-Motion Models Reaching Around Obstacles Object Manipulation Active Object Exploration Tool Use Robot Teaching Line-of-Sight Reaching Simple Grasping Smooth Pursuit and Vergence Multi-Axis Orientation Social Script Sequencing Instructional Sequencing Goals Future Research Our current research focuses on building the perceptual and motor primitives that will allow the robot to detect and respond to natural social cues. In the past year, we have developed systems that respond to human attention states and that mimic the movement of any animate object by tracing a similar trajectory with the robot’s arm. Gaze Direction Visual Input Animate Objects Face/Eye Finder ToBY Visual Attention Trajectory Formation ffff Pre-attentive filters Arm Primitives Reaching / Pointing Trajectories are selected based on the inherent object saliency, the instructor’s attentional state, and the animacy judgment. These trajectories are mapped from visual coordinates to a set of primitive arm postures. The trajectory can then be used to allow the robot to perform object-centered actions (such as pointing) or process-centered actions (such as repeating the trajectory with its own arm). The attention of the instructor is monitored by a system that finds faces (using a color filter and shape metrics), orients to the instructor, and extracts salient features at a distance of 20 feet. Moving handRolling chair“Animate” chair The “theory of body” module (ToBY) is a set of agents, each of which incorporates a rule of naïve physics. These rules estimate how objects move under natural conditions. In the images Feature Extraction Generate k-best Hypotheses Management (pruning, merging) Delay Generate Predictions Matching  Attention Activation w Saturation w Motion w Habituation w Skin The system operates in a sequence of stages: Visual input is filtered pre-attentively. An attention mechanism selects salient targets in each image frame. Targets are linked together into trajectories by a motion correspondence procedure. The “theory of body” module (ToBY) looks for objects that are self-propelled (animate). Faces are located in animate stimuli. Features such as the eyes and mouth are extracted to provide head orientation. Animate visual trajectories are mapped to arm movements. The attention system produces a set of target points for each frame in the image sequence. These points are connected across time by the multi-hypothesis tracking algorithm developed by Cox and Hingorani. The system maintains multiple hypothesis for each possible trajectory, which allows for ambiguous data to be resolved by further information. Visual input is processed by a set of parallel pre-attentive filters including skin tone, color saturation, motion, and disparity filters. The attention system combines the filtered images using weights that are influenced by high-level task constraints. The attention system also incorporates a habituation mechanism and biases the robot’s attention based on the attention of the instructor. shown above, trajectories that obey these rules are judged to be inanimate (shown in red), while those that display self-propelled movement (like the moving hand or the “animate” chair being pushed with a rod) are judged animate (green). More Complex Mimicry One future direction for our work is to look at more complex forms of social learning. We will both explore a wider range of tasks and ways to sequence together learned actions into more complex behaviors, and we will work on building systems that imitate, that is, they follow the intent of the action, not the form of the action. Understanding Self We will also exploring ideas about how to build representations of the robot’s own body, and the actions that it is capable of performing. The robot should recognize it’s own arm as it moves through the world, and even be able to recognize it’s own movements in a mirror by the temporal correlation. New Head and Hands New Hands