S. Hamidreza Kasaei
University of Aveiro
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Featured researches published by S. Hamidreza Kasaei.
intelligent robots and systems | 2014
Miguel Oliveira; Gi Hyun Lim; Luís Seabra Lopes; S. Hamidreza Kasaei; Ana Maria Tomé; Aneesh Chauhan
This paper addresses the problem of grounding semantic representations in intelligent service robots. In particular, this work contributes to addressing two important aspects, namely the anchoring of object symbols into the perception of the objects and the grounding of object category symbols into the perception of known instances of the categories. The paper discusses memory requirements for storing both semantic and perceptual data and, based on the analysis of these requirements, proposes an approach based on two memory components, namely a semantic memory and a perceptual memory. The perception, memory, learning and interaction capabilities, and the perceptual memory, are the main focus of the paper. Three main design options address the key computational issues involved in processing and storing perception data: a lightweight, NoSQL database, is used to implement the perceptual memory; a thread-based approach with zero copy transport of messages is used in implementing the modules; and a multiplexing scheme, for the processing of the different objects in the scene, enables parallelization. The system is designed to acquire new object categories in an incremental and open-ended way based on user-mediated experiences. The system is fully integrated in a broader robot system comprising low-level control and reactivity to high-level reasoning and learning.
Journal of Intelligent and Robotic Systems | 2015
S. Hamidreza Kasaei; Miguel Oliveira; Gi Hyun Lim; Luís Seabra Lopes; Ana Maria Tomé
Abstract3D object detection and recognition is increasingly used for manipulation and navigation tasks in service robots. It involves segmenting the objects present in a scene, estimating a feature descriptor for the object view and, finally, recognizing the object view by comparing it to the known object categories. This paper presents an efficient approach capable of learning and recognizing object categories in an interactive and open-ended manner. In this paper, “open-ended” implies that the set of object categories to be learned is not known in advance. The training instances are extracted from on-line experiences of a robot, and thus become gradually available over time, rather than at the beginning of the learning process. This paper focuses on two state-of-the-art questions: (1) How to automatically detect, conceptualize and recognize objects in 3D scenes in an open-ended manner? (2) How to acquire and use high-level knowledge obtained from the interaction with human users, namely when they provide category labels, in order to improve the system performance? This approach starts with a pre-processing step to remove irrelevant data and prepare a suitable point cloud for the subsequent processing. Clustering is then applied to detect object candidates, and object views are described based on a 3D shape descriptor called spin-image. Finally, a nearest-neighbor classification rule is used to predict the categories of the detected objects. A leave-one-out cross validation algorithm is used to compute precision and recall, in a classical off-line evaluation setting, for different system parameters. Also, an on-line evaluation protocol is used to assess the performance of the system in an open-ended setting. Results show that the proposed system is able to interact with human users, learning new object categories continuously over time.
Robotics and Autonomous Systems | 2016
Miguel Oliveira; Luís Seabra Lopes; Gi Hyun Lim; S. Hamidreza Kasaei; Ana Maria Tomé; Aneesh Chauhan
This paper describes a 3D object perception and perceptual learning system developed for a complex artificial cognitive agent working in a restaurant scenario. This system, developed within the scope of the European project RACE, integrates detection, tracking, learning and recognition of tabletop objects. Interaction capabilities were also developed to enable a human user to take the role of instructor and teach new object categories. Thus, the system learns in an incremental and open-ended way from user-mediated experiences. Based on the analysis of memory requirements for storing both semantic and perceptual data, a dual memory approach, comprising a semantic memory and a perceptual memory, was adopted. The perceptual memory is the central data structure of the described perception and learning system. The goal of this paper is twofold: on one hand, we provide a thorough description of the developed system, starting with motivations, cognitive considerations and architecture design, then providing details on the developed modules, and finally presenting a detailed evaluation of the system; on the other hand, we emphasize the crucial importance of the Point Cloud Library (PCL) for developing such system.11This paper is a revised and extended version of Oliveira et?al. (2014). We describe an object perception and perceptual learning system.The system is able to detect, track and recognize tabletop objects.The system learns novel object categories in an open-ended fashion.The Point Cloud Library is used in nearly all modules of the system.The system was developed and used in the European project RACE.
robot and human interactive communication | 2014
Gi Hyun Lim; Miguel Oliveira; Vahid Mokhtari; S. Hamidreza Kasaei; Aneesh Chauhan; Luís Seabra Lopes; Ana Maria Tomé
Intelligent service robots should be able to improve their knowledge from accumulated experiences through continuous interaction with the environment, and in particular with humans. A human user may guide the process of experience acquisition, teaching new concepts, or correcting insufficient or erroneous concepts through interaction. This paper reports on work towards interactive learning of objects and robot activities in an incremental and open-ended way. In particular, this paper addresses human-robot interaction and experience gathering. The robots ontology is extended with concepts for representing human-robot interactions as well as the experiences of the robot. The human-robot interaction ontology includes not only instructor teaching activities but also robot activities to support appropriate feedback from the robot. Two simplified interfaces are implemented for the different types of instructions including the teach instruction, which triggers the robot to extract experiences. These experiences, both in the robot activity domain and in the perceptual domain, are extracted and stored in memory, and they are used as input for learning methods. The functionalities described above are completely integrated in a robot architecture, and are demonstrated in a PR2 robot.
Pattern Recognition Letters | 2016
S. Hamidreza Kasaei; Ana Maria Tomé; Luís Seabra Lopes; Miguel Oliveira
Abstract Object representation is one of the most challenging tasks in robotics because it must provide reliable information in real-time to enable the robot to physically interact with the objects in its environment. To ensure robustness, a global object descriptor must be computed based on a unique and repeatable object reference frame. Moreover, the descriptor should contain enough information enabling to recognize the same or similar objects seen from different perspectives. This paper presents a new object descriptor named Global Orthographic Object Descriptor (GOOD) designed to be robust, descriptive and efficient to compute and use. We propose a novel sign disambiguation method, for computing a unique reference frame from the eigenvectors obtained through Principal Component Analysis of the point cloud of the target object view captured by a 3D sensor. Three principal orthographic projections and their distribution matrices are computed by exploiting the object reference frame. The descriptor is finally obtained by concatenating the distribution matrices in a sequence determined by entropy and variance features of the projections. Experimental results show that the overall classification performance obtained with GOOD is comparable to the best performances obtained with the state-of-the-art descriptors. Concerning memory and computation time, GOOD clearly outperforms the other descriptors. Therefore, GOOD is especially suited for real-time applications. The estimated object’s pose is precise enough for real-time object manipulation tasks.
ieee international conference on autonomous robot systems and competitions | 2014
S. Hamidreza Kasaei; Miguel Oliveira; Gi Hyun Lim; Luís Seabra Lopes; Ana Maria Tomé
Three-dimensional object detection and recognition is increasingly in manipulation and navigation applications in autonomous service robots. It involves clustering points of the point cloud from an unstructured scene into objects candidates and estimating features to recognize the objects under different circumstances such as occlusions and clutter. This paper presents an efficient approach capable of learning and recognizing object categories in an interactive and open-ended manner. In this paper, “open-ended” implies that the set of object categories to be learned is not known in advance. The training instances are extracted from actual experiences of a robot, and thus become gradually available, rather than being available at the beginning of the learning process. This paper focuses on two state-of-the-art questions: (1) How to automatically detect, conceptualize and recognize objects in 3D unstructured scenes in an open-ended manner? (2) How to acquire and utilize high-level knowledge obtained from the user (e.g. category label) to improve the system performance? This approach starts with a pre-processing phase to remove unnecessary information and prepare a suitable point cloud. Clustering is then applied to detect object candidates. Subsequently, all object candidates are described based on a 3D shape descriptor called spin-image. Finally, a nearest-neighbor classification rule is used to assign category labels to the detected objects. To examine the performance of the proposed approach, a leave-one-out cross validation algorithm is utilized to compute precision and recall. The experimental results show the fulfilling performance of this approach on different types of objects.
intelligent robots and systems | 2015
Miguel Oliveira; Luís Seabra Lopes; Gi Hyun Lim; S. Hamidreza Kasaei; Angel Domingo Sappa; Ana Maria Tomé
In open-ended domains, robots must continuously learn new object categories. When the training sets are created offline, it is not possible to ensure their representativeness with respect to the object categories and features the system will find when operating online. In the Bag of Words model, visual codebooks are usually constructed from training sets created offline. This might lead to non-discriminative visual words and, as a consequence, to poor recognition performance. This paper proposes a visual object recognition system which concurrently learns in an incremental and online fashion both the visual object category representations as well as the codebook words used to encode them. The codebook is defined using Gaussian Mixture Models which are updated using new object views. The approach contains similarities with the human visual object recognition system: evidence suggests that the development of recognition capabilities occurs on multiple levels and is sustained over large periods of time. Results show that the proposed system with concurrent learning of object categories and codebooks is capable of learning more categories, requiring less examples, and with similar accuracies, when compared to the classical Bag of Words approach using codebooks constructed offline.
intelligent robots and systems | 2016
Nima Shafii; S. Hamidreza Kasaei; Luís Seabra Lopes
Robots are still not able to grasp all unforeseen objects. Finding a proper grasp configuration, i.e. the position and orientation of the arm relative to the object, is still challenging. One approach for grasping unforeseen objects is to recognize an appropriate grasp configuration from previous grasp demonstrations. The underlying assumption in this approach is that new objects that are similar to known ones (i.e. they are familiar) can be grasped in a similar way. However finding a grasp representation and a grasp similarity metric is still the main challenge in developing an approach for grasping familiar objects. In this paper, interactive object view learning and recognition capabilities are integrated in the process of learning and recognizing grasps. The object view recognition module uses an interactive incremental learning approach to recognize object view labels. The grasp pose learning approach uses local and global visual features of a demonstrated grasp to learn a grasp template associated with the recognized object view. A grasp distance measure based on Mahalanobis distance is used in a grasp template matching approach to recognize an appropriate grasp pose. The experimental results demonstrate the high reliability of the developed template matching approach in recognizing the grasp poses. Experimental results also show how the robot can incrementally improve its performance in grasping familiar objects.
intelligent robots and systems | 2016
S. Hamidreza Kasaei; Luís Seabra Lopes; Ana Maria Tomé; Miguel Oliveira
Object representation is one of the most challenging tasks in robotics because it must provide reliable information in real-time to enable the robot to physically interact with the objects in its environment. To ensure reliability, a global object descriptor must be computed based on a unique and repeatable object reference frame. Moreover, the descriptor should contain enough information enabling to recognize the same or similar objects seen from different perspectives. This paper presents a new object descriptor named Global Orthographic Object Descriptor (GOOD) designed to be robust, descriptive and efficient to compute and use. The performance of the proposed object descriptor is compared with the main state-of-the-art descriptors. Experimental results show that the overall classification performance obtained with GOOD is comparable to the best performances obtained with the state-of-the-art descriptors. Concerning memory and computation time, GOOD clearly outperforms the other descriptors. Therefore, GOOD is especially suited for real-time applications.
ieee international conference on autonomous robot systems and competitions | 2015
S. Hamidreza Kasaei; Miguel Oliveira; Gi Hyun Lim; Luís Seabra Lopes; Ana Maria Tomé
Cognitive robotics looks at human cognition as a source of inspiration for automatic perception capabilities that will allow robots to learn and reason out how to behave in response to complex goals. For instance, humans learn to recognize object categories ceaselessly over time. This ability to refine knowledge from the set of accumulated experiences facilitates the adaptation to new environments. Inspired by such abilities, this paper proposes an efficient approach towards 3D object category learning and recognition in an interactive and open-ended manner. To achieve this goal, this paper focuses on two state-of-the-art questions: (i) How to use unsupervised object exploration to construct a dictionary of visual words for representing objects in a highly compact and distinctive way. (ii) How to learn incrementally probabilistic models of object categories to achieve adaptability. To examine the performance of the proposed approach, a quantitative evaluation and a qualitative analysis are used. The experimental results showed the fulfilling performance of this approach on different types of objects. The proposed system is able to interact with human users and learn new object categories over time.