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Institute Talks

"Exploring” Haptics: Human-Machine Interactive Applications from Mid-Air Laser Haptics to Sensorimotor Skill Learning

  • 25 February 2019 • 10:30 11:15
  • Hojin Lee
  • MPI-IS Stuttgart, Heisenbergstr. 3, Room 2P4

Haptic technologies in both kinesthetic and tactile aspects benefit a brand-new opportunity to recent human-machine interactive applications. In this talk, I, who believe in that one of the essential role of a researcher is pioneering new insights and knowledge, will present my previous research topics about haptic technologies and human-machine interactive applications in two branches: laser-based mid-air haptics and sensorimotor skill learning. For the former branch, I will introduce our approach named indirect laser radiation and its application. Indirect laser radiation utilizes a laser and a light-absorbing elastic medium to evoke a tapping-like tactile sensation. For the latter, I will introduce our data-driven approach for both modeling and learning of sensorimotor skills (especially, driving) with kinesthetic assistance and artificial neural networks; I call it human-like haptic assistance. To unify two different branches of my earlier studies for exploring the feasibility of the sensory channel named "touch", I will present a general research paradigm for human-machine interactive applications to which current haptic technologies can aim in future.

Organizers: Katherine J. Kuchenbecker

Virtual Reality Based Needle Insertion Simulation With Haptic Feedback: A Psychophysical Study

  • 25 February 2019 • 11:15 12:00
  • Ravali Gourishetti
  • MPI-IS Stuttgart, Heisenbergstr. 3, Room 2P4

Needle insertion is the most essential skill in medical care; training has to be imparted not only for physicians but also for nurses and paramedics. In most needle insertion procedures, haptic feedback from the needle is the main stimulus that novices are to be trained in. For better patient safety, the classical methods of training the haptic skills have to be replaced with simulators based on new robotic and graphics technologies. The main objective of this work is to develop analytical models of needle insertion (a special case of epidural anesthesia) including the biomechanical and psychophysical concepts that simulate the needle-tissue interaction forces in linear heterogeneous tissues and to validate the model with a series of experiments. The biomechanical and perception models were validated with experiments in two stages: with and without the human intervention. The second stage is the validation using the Turing test with two different experiments: 1) to observe the perceptual difference between the simulated and the physical phantom model, and 2) to verify the effectiveness of perceptual filter between the unfiltered and filtered model response. The results showed that the model could replicate the physical phantom tissues with good accuracy. This can be further extended to a non-linear heterogeneous model. The proposed needle/tissue interaction force models can be used more often in improving realism, performance and enabling future applications in needle simulators in heterogeneous tissue. Needle insertion training simulator was developed with the simulated models using Omni Phantom and clinical trials are conducted for the face validity and construct validity. The face validity results showed that the degree of realism of virtual environments and instruments had the overall lowest mean score and ease of usage and training in hand – eye coordination had the highest mean score. The construct validity results showed that the simulator was able to successfully differentiate force and psychomotor signatures of anesthesiologists with experiences less than 5 years and more than 5 years. For the performance index of the trainees, a novel measure, Just Controllable Difference (JCD) was proposed and a preliminary study on JCD measure is explored using two experiments for the novice. A preliminary study on the use of clinical training simulations, especially needle insertion procedure in virtual environments is emphasized on two objectives: Firstly, measures of force JND with the three fingers and secondly, comparison of these measures in Non-Immersive Virtual Reality (NIVR) to that of the Immersive Virtual Reality (IVR) using psychophysical study with the Force Matching task, Constant Stimuli method, and Isometric Force Probing stimuli. The results showed a better force JND in the IVR compared to that of the NIVR. Also, a simple state observer model was proposed to explain the improvement of force JND in the IVR. This study would quantitatively reinforce the use of the IVR for the design of various medical simulators.

Organizers: Katherine J. Kuchenbecker

Design of functional polymers for biomedical applications

  • 27 February 2019 • 14:00 15:00
  • Dr. Salvador Borrós Gómez
  • Stuttgart 2P4

Functional polymers can be easily tailored for their interaction with living organismes. In our Group, we have worked during the last 15 years in the development of this kind of polymeric materials with different funcionalities, high biocompatibility and in different forms. In this talk, we will describe the synthesis of thermosensitive thin films that can be used to prevent biofilm formation in medical devices, the preparation of biodegradable polymers specially designed for vectors for gene transfection and a new familliy of zwitterionic polymers that are able to cross intestine mucouse for oral delivery applications. The relationship between structure-functionality- applications will be discussed for every example.

Organizers: Metin Sitti

A new path to understanding biological/human vision: theory and experiments

IS Colloquium
  • 11 March 2019 • 14:00 15:00
  • Zhaoping Li
  • MPI-IS lecture hall (N0.002)

Since Hubel and Wiesel's seminal findings in the primary visual cortex (V1) more than 50 years ago, progress in vision science has been very limited along previous frameworks and schools of thoughts on understanding vision. Have we been asking the right questions? I will show observations motivating the new path. First, a drastic information bottleneck forces the brain to process only a tiny fraction of the massive visual input information; this selection is called the attentional selection, how to select this tiny fraction is critical. Second, a large body of evidence has been accumulating to suggest that the primary visual cortex (V1) is where this selection starts, suggesting that the visual cortical areas along the visual pathway beyond V1 must be investigated in light of this selection in V1. Placing attentional selection as the center stage, a new path to understanding vision is proposed (articulated in my book "Understanding vision: theory, models, and data", Oxford University Press 2014). I will show a first example of using this new path, which aims to ask new questions and make fresh progresses. I will relate our insights to artificial vision systems to discuss issues like top-down feedbacks in hierachical processing, analysis-by-synthesis, and image understanding.

Organizers: Timo Bolkart Aamir Ahmad

  • Dr. Yiğit Mengüç
  • Room 3P02 - Stuttgart

Incredible biological capabilities have emerged through evolution. Of special note is the material intelligence that defines the bodies of living things, blurring the line between brain and body. Material robotics research takes the approach of imbuing power, control, sensing, and actuation into all aspects of a (primarily soft) robot body. In this talk, the research topics of material robotics currently underway in the mLab at Oregon State University will be presented. Soft active materials designed and researched in the mLab include liquid metal, biodegradable elastomers, and electroactive fluids. Bioinspired mechanisms include octopus-inspired soft muscles, gecko-inspired adhesives, and snake-like locomotors. Such capabilities, however, introduce new fundamental challenge in making materially-enabled robots. To address these limitation, the mLab is also innovating in techniques to rapidly and scalably manufacture soft materials. Though significant challenges remain to be solved, the development of such soft and materially-enabled components promises to bring robots more and more into our daily lives.

Organizers: Metin Sitti

  • JP Lewis
  • PS Aquarium, 3rd floor, north, MPI-IS

The definition of art has been debated for more than 1000 years, and continues to be a puzzle. While scientific investigations offer hope of resolving this puzzle, machine learning classifiers that discriminate art from non-art images generally do not provide an explicit definition, and brain imaging and psychological theories are at present too coarse to provide a formal characterization. In this work, rather than approaching the problem using a machine learning approach trained on existing artworks, we hypothesize that art can be defined in terms of preexisting properties of the visual cortex. Specifically, we propose that a broad subset of visual art can be defined as patterns that are exciting to a visual brain. Resting on the finding that artificial neural networks trained on visual tasks can provide predictive models of processing in the visual cortex, our definition is operationalized by using a trained deep net as a surrogate “visual brain”, where “exciting” is defined as the activation energy of particular layers of this net. We find that this definition easily discriminates a variety of art from non-art, and further provides a ranking of art genres that is consistent with our subjective notion of ‘visually exciting’. By applying a deep net visualization technique, we can also validate the definition by generating example images that would be classified as art. The images synthesized under our definition resemble visually exciting art such as Op Art and other human- created artistic patterns.

Organizers: Michael Black

Automatic Understanding of the Visual World

  • 26 April 2018 • 11:00 12:00
  • Dr. Cordelia Schmid
  • N3.022

One of the central problems of artificial intelligence is machine perception, i.e., the ability to understand the visual world based on input from sensors such as cameras. In this talk, I will present recent progress with respect to data generation using weak annotations, motion information and synthetic data. I will also discuss our recent results for action recognition, where human tubes and tubelets have shown to be successful. Our tubelets moves away from state-of-the-art frame based approaches and improve classification and localization by relying on joint information from several frames. I also show how to extend this type of method to weakly supervised learning of actions, which allows us to scale to large amounts of data with sparse manual annotation. Furthermore, I discuss several recent extensions, including 3D pose estimation.

Organizers: Ahmed Osman

  • Preeya Khanna
  • Heisenbergstr. 3, Room 2P4

Actions constitute the way we interact with the world, making motor disabilities such as Parkinson’s disease and stroke devastating. The neurological correlates of the injured brain are challenging to study and correct given the adaptation, redundancy, and distributed nature of our motor system. However, recent studies have used increasingly sophisticated technology to sample from this distributed system, improving our understanding of neural patterns that support movement in healthy brains, or compromise movement in injured brains. One approach to translating these findings to into therapies to restore healthy brain patterns is with closed-loop brain-machine interfaces (BMIs). While closed-loop BMIs have been discussed primarily as assistive technologies the underlying techniques may also be useful for rehabilitation.

Organizers: Katherine J. Kuchenbecker

Consistency and minimax rates of random forests

  • 18 April 2018 • 13:30 14:45
  • Erwan Scornet
  • Tübingen, Main seminar room (N0.002)

The recent and ongoing digital world expansion now allows anyone to have access to a tremendous amount of information. However collecting data is not an end in itself and thus techniques must be designed to gain in-depth knowledge from these large data bases.

Organizers: Mara Cascianelli

  • Alexander Mathis
  • Tübingen, Aquarium (N3.022)

Quantifying behavior is crucial for many applications in neuroscience. Videography provides easy methods for the observation and recording of animal behavior in diverse settings, yet extracting particular aspects of a behavior for further analysis can be highly time consuming. In motor control studies, humans or other animals are often marked with reflective markers to assist with computer-based tracking, yet markers are intrusive (especially for smaller animals), and the number and location of the markers must be determined a priori. Here, we present a highly efficient method for markerless tracking based on transfer learning with deep neural networks that achieves excellent results with minimal training data. We demonstrate the versatility of this framework by tracking various body parts in a broad collection of experimental settings: mice odor trail-tracking, egg-laying behavior in drosophila, and mouse hand articulation in a skilled forelimb task. For example, during the skilled reaching behavior, individual joints can be automatically tracked (and a confidence score is reported). Remarkably, even when a small number of frames are labeled (≈200), the algorithm achieves excellent tracking performance on test frames that is comparable to human accuracy.

Organizers: Melanie Feldhofer

Machine Learning for Tactile Manipulation

IS Colloquium
  • 13 April 2018 • 11:00 12:00
  • Jan Peters
  • MPI-IS Stuttgart, Heisenbergstr. 3, Room 2P4

Today’s robots have motor abilities and sensors that exceed those of humans in many ways: They move more accurately and faster; their sensors see more and at a higher precision and in contrast to humans they can accurately measure even the smallest forces and torques. Robot hands with three, four, or five fingers are commercially available, and, so are advanced dexterous arms. Indeed, modern motion-planning methods have rendered grasp trajectory generation a largely solved problem. Still, no robot to date matches the manipulation skills of industrial assembly workers despite that manipulation of mechanical objects remains essential for the industrial assembly of complex products. So, why are current robots still so bad at manipulation and humans so good?

Organizers: Katherine J. Kuchenbecker

BodyNet: Volumetric Inference of 3D Human Body Shapes

  • 10 April 2018 • 16:00 17:00
  • Gül Varol
  • N3.022

Human shape estimation is an important task for video editing, animation and fashion industry. Predicting 3D human body shape from natural images, however, is highly challenging due to factors such as variation in human bodies, clothing and viewpoint. Prior methods addressing this problem typically attempt to fit parametric body models with certain priors on pose and shape. In this work we argue for an alternative representation and propose BodyNet, a neural network for direct inference of volumetric body shape from a single image. BodyNet is an end-to-end trainable network that benefits from (i) a volumetric 3D loss, (ii) a multi-view re-projection loss, and (iii) intermediate supervision of 2D pose, 2D body part segmentation, and 3D pose. Each of them results in performance improvement as demonstrated by our experiments. To evaluate the method, we fit the SMPL model to our network output and show state-of-the-art results on the SURREAL and Unite the People datasets, outperforming recent approaches. Besides achieving state-of-the-art performance, our method also enables volumetric body-part segmentation.

A New Perspective on Usability Applied to Robotics

  • 04 April 2018 • 14:00 15:00
  • Dr. Vincent Berenz
  • Stuttgart 2P4

For many service robots, reactivity to changes in their surroundings is a must. However, developing software suitable for dynamic environments is difficult. Existing robotic middleware allows engineers to design behavior graphs by organizing communication between components. But because these graphs are structurally inflexible, they hardly support the development of complex reactive behavior. To address this limitation, we propose Playful, a software platform that applies reactive programming to the specification of robotic behavior. The front-end of Playful is a scripting language which is simple (only five keywords), yet results in the runtime coordinated activation and deactivation of an arbitrary number of higher-level sensory-motor couplings. When using Playful, developers describe actions of various levels of abstraction via behaviors trees. During runtime an underlying engine applies a mixture of logical constructs to obtain the desired behavior. These constructs include conditional ruling, dynamic prioritization based on resources management and finite state machines. Playful has been successfully used to program an upper-torso humanoid manipulator to perform lively interaction with any human approaching it.

Organizers: Katherine J. Kuchenbecker Mayumi Mohan Alexis Block

  • Omar Costilla Reyes
  • Aquarium @ PS

Human footsteps can provide a unique behavioural pattern for robust biometric systems. Traditionally, security systems have been based on passwords or security access cards. Biometric recognition deals with the design of security systems for automatic identification or verification of a human subject (client) based on physical and behavioural characteristics. In this talk, I will present spatio-temporal raw and processed footstep data representations designed and evaluated on deep machine learning models based on a two-stream resnet architecture, by using the SFootBD database the largest footstep database to date with more than 120 people and almost 20,000 footstep signals. Our models deliver an artificial intelligence capable of effectively differentiating the fine-grained variability of footsteps between legitimate users (clients) and impostor users of the biometric system. We provide experimental results in 3 critical data-driven security scenarios, according to the amount of footstep data available for model training: at airports security checkpoints (smallest training set), workspace environments (medium training set) and home environments (largest training set). In these scenarios we report state-of-the-art footstep recognition rates.

Organizers: Dimitris Tzionas