The literature in computer vision is rich of works where different types of activities -- single actions, two persons interactions or ego-centric activities, to name a few -- have been analyzed. However, traditional methods treat such types of activities separately, while in real settings detecting and recognizing different types of activities simultaneously is necessary. We first design a new unified descriptor, called Relation History Image (RHI), which can be extracted from all the activity types we are interested in. We then formulate an optimization procedure to detect and recognize activities of different types. We assess our approach on a new dataset recorded from a robot-centric perspective as well as on publicly available datasets, and evaluate its quality compared to multiple baselines.

We present a framework and algorithm to analyze first person RGBD videos captured from the robot while physically interacting with humans. Specifically, we explore reactions and interactions of persons facing a mobile robot from a robot centric view. This new perspective offers social awareness to the robots, enabling interesting applications. As far as we know, there is no public 3D dataset for this problem. Therefore, we record two multi-modal first-person RGBD datasets that reflect the setting we are analyzing. We use a humanoid and a non-humanoid robot equipped with a Kinect. Notably, the videos contain a high percentage of ego-motion due to the robot self-exploration as well as its reactions to the persons' interactions. We show that separating the descriptors extracted from ego-motion and independent motion areas, and using them both, allows us to achieve superior recognition results. Experiments show that our algorithm recognizes the activities effectively and outperforms other state-of-the-art methods on related tasks.

We present a novel method for three-finger precision grasp and its implementation in a complete grasping tool-chain. We start from binocular vision to recover the partial 3D structure of unknown objects. We then process the incomplete 3D point clouds searching for good triplets according to a function that accounts for both the feasibility and the stability of the solution. In particular, while stability is determined using the classical force-closure approach, feasibility is evaluated according to a new measure that includes information about the possible configuration shapes of the hand as well as the hand's inverse kinematics. We finally extensively assess the proposed method using the stereo vision and the kinematics of the iCub robot.

Cooperation1is at the core of human social life. In this context, two major challenges face research on humanrobot interaction: the first is to understand the underlying structure of cooperation, and the second is to build, based on this understanding, artificial agents that can successfully and safely interact with humans. Here we take a psychologically grounded and human-centered approach that addresses these two challenges. We test the hypothesis that optimal cooperation between a naïve human and a robot requires that the robot can acquire and execute a joint plan, and that it communicates this joint plan through ecologically valid modalities including spoken language, gesture and gaze. We developed a cognitive system that comprises the human-like control of social actions, the ability to acquire and express shared plans and a spoken language stage. In order to test the psychological validity of our approach we tested 12 naïve subjects in a cooperative task with the robot. We experimentally manipulated the presence of a joint plan (vs. a solo plan), the use of task-oriented gaze and gestures, and the use of language accompanying the unfolding plan. The quality of cooperation was analyzed in terms of proper turn taking, collisions and cognitive errors. Results showed that while successful turn taking could take place in the absence of the explicit use of a joint plan, its presence yielded significantly greater success. One advantage of the solo plan was that the robot would always be ready to generate actions, and could thus adapt if the human intervened at the wrong time, whereas in the joint plan the robot expected the human to take his/her turn. Interestingly, when the robot represented the action as involving a joint plan, gaze provided a highly potent nonverbal cue that facilitated successful collaboration and reduced errors in the absence of verbal communication. These results support the cooperative stance in human social cognition, and suggest that cooperative robots should employ joint plans, fully communicate them in order to sustain effective collaboration while being ready to adapt if the human makes a midstream mistake.