Adrian Leu

A robust markerless vision-based human gait analysis system

In this paper, a novel robust markerless image processing system capable of extracting gait features which can be used for gait analysis is presented. The presented system can deal with images of persons captured in natural indoor scenes. The systems robustness against external influences and different person appearance is achieved by employing the idea of improving the image processing robustness by including feedback control at the image segmentation level. The effectiveness of the proposed system is demonstrated by the comparison of gait features, namely knee angles, extracted automatically with the features directly measured using a goniometer. Also a small database is created to extract the gait pattern of healthy subjects. The obtained data is compared to data from medical literature and is also compared to data obtained from persons having a pathological gait.

Stereo Vision-Based Human Tracking for Robotic Follower

Abstract This paper addresses the problem of real-time vision-based human tracking to enable mobile robots to follow a human co-worker. A novel approach to combine stereo vision-based human detection with human tracking using a modified Kalman filter is presented. Stereo vision-based detection combines features extracted from 2D stereo images with reconstructed 3D object features to detect humans in a robots environment. For human tracking a modified Kalman filter recursively predicts and updates estimates of the 3D coordinates of a human in the robots camera coordinate system. This prediction enables human detection to be performed on the image region of interest contributing to cost effective human tracking. The performance of the presented method was tested within a working scenario of a mobile robot intended to follow a human co-worker in indoor applications as well as in outdoor applications.

Mobile robotic gait rehabilitation system CORBYS - overview and first results on orthosis actuation

In this paper the novel mobile robotic gait rehabilitation system CORBYS is presented. The system consists of a mobile platform and a powered orthosis attached to the platform. Beside the mobility, i.e. overground walking, due to introduced degrees of freedom (DOFs) CORBYS gait rehabilitation system, in contrast to existing gait rehabilitation robotic systems will enable more physiological movements including turning. The focus in the paper is on novel push-pull control (PPC) cables based actuation system of the orthosis. The first results on orthosis actuation obtained in the control experiments with the powered orthosis test-stand are shown. The results prove the advantages of using the push-pull cables for the dislocation of the actuators from the powered orthosis and for providing a flexible power actuation with a bi-directional (pushing and pulling) force transfer.

A novel stereo camera based collision warning system for automotive applications

In collision warning systems for automotive applications the response time of a system is very important, since a precise response is useless if it comes too late. In this paper a fast collision warning system is presented, which uses a stereo camera as a sensor. The used algorithms allow a fast response of the system by making use of parallel processing. The parallel processing algorithms have been implemented and tested using an Nvidia Tesla C1060 GPU, programmed using the Nvidia CUDA API. The processing time comparison between the CPU based and optimized GPU based versions of the algorithms are also presented.

CORBYS cognitive control architecture for robotic follower

In this paper the novel generic cognitive robot control architecture CORBYS is presented. The objective of the CORBYS architecture is the integration of high-level cognitive modules to support robot functioning in dynamic environments including interacting with humans. This paper presents the preliminary integration of the CORBYS architecture to support a robotic follower. Experimental results on high-level empowerment-based trajectory planning have demonstrated the effectiveness of ROS-based communication between distributed modules developed in a multi-site research environment as typical for distributed collaborative projects such as CORBYS.

Robust stereo-vision based 3D modelling of real-world objects for assistive robotic applications

This paper addresses the problem of recognizing and reconstructing real-world objects in cluttered environments to enable service robot to grasp the objects and manipulate them. A novel approach to combine disparity segmentation method with the closed-loop color region based segmentation is presented. Disparity map segmentation leads to definition of object region of interest (ROI) enabling autonomous functioning of robot system in cluttered environments. Closed-loop object region segmentation is robust against variable illumination providing reliable operation of robot system in different lighting conditions. Starting from the segmented object in both stereo images, the 3D contour of the object is generated and the object geometry is recovered from it. The proposed method needs no a-priori knowledge about the object color, its appearance or geometry. The performance of the presented method has been tested within the working scenario of the assistive robotic system FRIEND.

Learning gait by therapist demonstration for natural-like walking with the CORBYS powered orthosis

The number of mechanical degrees of freedom (DoFs) within rehabilitation robots directly influences the scope of the movements that a subject can perform when training walking. Currently, gait rehabilitation robots have a limited number of mechanical DoFs, as a consequence this limits the movements these robots can make possible. In this paper, the novel gait rehabilitation system CORBYS is presented which consists of the mobile platform and a powered orthosis which is attached to the platform. The CORBYS powered orthosis has 16 DoFs enabling more physiological movements, making it a state-of-the-art gait rehabilitation robotic system. With the sufficient number of DoFs to enable natural-like walking, the CORBYS robotic system enables the integration of the “learning gait by therapist demonstration” paradigm. This paper presents the fully integrated functional CORBYS gait rehabilitation system, with the focus on the implementation aspects which enable generation of the reference gait trajectory through learning by therapist demonstration, and the use of the generated trajectory in the robotic therapy session. The results of the initial evaluation of the robotic system obtained in tests with a selected patient are given in the paper.

Robust dazzling detection in a novel visual based dazzling avoidance system

This article presents a novel method of detecting the dazzling effect in a new vision based driving assistance system (ShadeVision) which aims to avoid the dazzling effect caused by strong external light sources. Different from existing systems which only detect the dazzling effect at night, our proposed system can also identify the dazzling effect during the day, particularly in dawn and dusk. To that end, the eye region of the driver and other regions surrounding the eyes, the interior of the vehicle, as well as the background light outside the window are all captured by a high speed camera with 1280×500 resolution and a frame rate of 1000 Hz mounted in the vehicle. Afterwards all these data are synthesized and analyzed to determine the dazzling effect. Moreover, the details of dazzling detection method for nighttime and daytime driving are presented explicitly. The final tests verify the effectiveness of our proposed approaches.

Human-Robot Synergy For Cooperative Robots

This paper presents two human-robot cooperative application scenarios of the project MeRoSy (Human-Robot Synergy) funded by the German Federal Ministry of Education and Research. The first scenario relates to the human-robot cooperation in an industrial application, while the second one refers to the robotic workplace assistance for people with disabilities. The presented scenarios reflect different aspects of human-robot interaction, among others different novel possibilities for human-robot interaction depending on different physical abilities of human co-worker. Beside the consideration of the human-robot cooperative technologies in two MeRoSy scenarios, this paper considers also the identification and classification of the ethical, legal and social implications (ELSI) in the context of human-robot cooperation.

High Speed Stereo Vision Based Automotive Collision Warning System

This chapter presents a high speed, low latency stereo vision based collision warning system for automotive applications. The system uses two high speed cameras running at 100 fps and achieves latency below 0.1s by using an Nvidia Tesla C1060 GPU for accelerating computational expensive algorithms. From each pair of captured stereo images a disparity map is computed using the block matching algorithm, which is afterwards segmented in order to detect different objects in the scene. This segmentation is performed using a novel segmentation method based on the pixels’ intensity value and their connectivity. For each detected object its distance to the front of the vehicle is computed and the degree of danger is estimated by the collision warning module. Extensive experiments show that the presented system delivers reliable results for object detection as well as precise results in terms of estimated distance to the detected objects.