Inverse problems are ubiquitous in image processing and applied science in general. Such problems describe the challenge of computing the parameters that characterize a system from the outcomes. While this might seem easy at first for simple systems, many inverse problems share a property that makes them much more intricate: they are ill-posed. This means that either the problem does not have a unique solution or this solution does not depend continuously on the outcomes of the system. Bayesian statistics provides a framework that allows to treat such problems in a systematic way. The missing piece of information is encoded as a prior distribution on the space of possible solutions. In this talk, we will study probabilistic image models as priors for statistical inversion. In particular, we will give a probabilistic interpretation of the classical TV-prior and discuss how this interpretation can be used as a starting point for more complex models. We will see that many important auxiliary quantities such as edges and regions can be incorporated into the model in the form of latent variables. This leads to the conjecture that many image processing tasks, such as denoising and segmentation, should not be considered separately, but instead be treated together.
The detection and characterization of planets orbiting other stars than the Sun, i.e., so-called extrasolar planets, is one of the fastest growing and most vibrant research fields in modern astrophysics. In the last 25 years, more than 5400 extrasolar planets and planet candidates were revealed, but the vast majority of these objects was detected with indirect techniques, where the existence of the planet is inferred from periodic changes in the light coming from the central star. No photons from the planets themselves are detected. In this talk, however, I will focus on the direct detection of extrasolar planets. On the one hand I will describe the main challenges that have to be overcome in order to image planets around other stars. In addition to using the world’s largest telescopes and optimized cameras it was realized in last few years that by applying advanced image processing techniques significant sensitivity gains can be achieved. On the other hand I will demonstrate what can be learned if one is successful in “taking a picture” of an extrasolar planet. After all, there must be good scientific reasons and a strong motivation why the direct detection of extrasolar planets is one of the key science drivers for current and future projects on major ground- and space-based telescopes.
Organizers: Diana Rebmann
In general Helga Griffiths is a Multi-Sense-Artist working on the intersection of science and art. She has been working for over 20 years on the integration of various sensory stimuli into her “multi-sense” installations. Typical for her work is to produce a sensory experience to transcend conventional boundaries of perception.
Organizers: Emma-Jayne Holderness
Bayesian optimization is a powerful tool that has been successfully used to automatically optimize the parameters of a fixed control policy. It has many desirable properties, such as data-efficiently and being able to handle noisy measurements. However, standard Bayesian optimization does not consider any constraints imposed by the real system, which limits its applications to highly controlled environments. In this talk, I will introduce an extension of this framework, which additionally considers multiple safety constraints during the optimization process. This method enables safe parameter optimization by only evaluating parameters that fulfill all safety constraints with high probability. I will show several experiments on a quadrotor vehicle which demonstrate the method. Lastly, I will briefly talk about how the ideas behind safe Bayesian optimization can be used to safely explore unknown environments (MDPs).
Organizers: Sebastian Trimpe
Our research questions are centred on a basic characteristic of human brains: variability in their behaviour and their underlying meaning for cognitive mechanisms. Such variability is emerging as a key ingredient in understanding biological principles (Faisal, Selen & Wolpert, 2008, Nature Rev Neurosci) and yet lacks adequate quantitative and computational methods for description and analysis. Crucially, we find that biological and behavioural variability contains important information that our brain and our technology can make us of (instead of just averaging it away): Using advanced body sensor networks, we measured eye-movements, full-body and hand kinematics of humans living in a studio flat and are going to present some insightful results on motor control and visual attention that suggest that the control of behaviour "in-the-wild" is predictably different ways than what we measure "in-the-lab". The results have implications for robotics, prosthetics and neuroscience.
Organizers: Matthias Hohmann
Beginning with a seminal paper of Diaconis (1988), the aim of so-called "probabilistic numerics" is to compute probabilistic solutions to deterministic problems arising in numerical analysis by casting them as statistical inference problems. For example, numerical integration of a deterministic function can be seen as the integration of an unknown/random function, with evaluations of the integrand at the integration nodes proving partial information about the integrand. Advantages offered by this viewpoint include: access to the Bayesian representation of prior and posterior uncertainties; better propagation of uncertainty through hierarchical systems than simple worst-case error bounds; and appropriate accounting for numerical truncation and round-off error in inverse problems, so that the replicability of deterministic simulations is not confused with their accuracy, thereby yielding an inappropriately concentrated Bayesian posterior. This talk will describe recent work on probabilistic numerical solvers for ordinary and partial differential equations, including their theoretical construction, convergence rates, and applications to forward and inverse problems. Joint work with Andrew Stuart (Warwick).
Organizers: Philipp Hennig
Understanding the principles of natural movement generation has been and continues to be one of the most interesting and important open problems in the fields of robotics and neural control of movement. In this talk, I introduce an overview of our previous work on the control of dynamic movements in robotic systems towards the goal of control design principles and understanding of motion generation. Our research has focused in the fields of dynamical systems theory, adaptive and optimal control and statistical learning, and their application to robotics towards achieving dynamically dexterous behavior in robotic systems. First, our studies on dynamical systems based task encoding in robot brachiation, movement primitives for imitation learning, and oscillator based biped locomotion control will be presented. Then, our recent work on optimal control of robotic systems with variable stiffness actuation will be introduced towards the aim of achieving highly dynamic movements by exploiting the natural dynamics of the system. Finally, our new humanoid robot H-1 at TUM-ICS will be introduced.
Organizers: Ludovic Righetti
The current performance gap between legged animals and legged robots is large. Animals can reach high locomotion speed in complex terrain, or run at a low cost of transport. They are able to rapidly sense their environment, process sensor data, learn and plan locomotion strategies, and execute feedforward and feedback controlled locomotion patterns fluently on the fly. Animals use hardware that has, compared to the latest man-made actuators, electronics, and processors, relatively low bandwidth, medium power density, and low speed. The most common approach to legged robot locomotion is still assuming rigid linkage hardware, high torque actuators, and model based control algorithms with high bandwidth and high gain feedback mechanisms. State of the art robotic demonstrations such as the 2015 DARPA challenge showed that seemingly trivial locomotion tasks such as level walking, or walking over soft sand still stops most of our biped and quadruped robots. This talk focuses on an alternative class of legged robots and control algorithms designed and implemented on several quadruped and biped platforms, for a new generation of legged robotic systems. Biomechanical blueprints inspired by nature, and mechanisms from locomotion neurocontrol were designed, tested, and can be compared to their biological counterparts. We focus on hardware and controllers that allow comparably cheap robotics, in terms of computation, control, and mechanical complexity. Our goal are highly dynamic, robust legged systems with low weight and inertia, relatively low mechanical complexity and cost of transport, and little computational demands for standard locomotion tasks. Ideally, such system can also be used as testing platforms to explain not yet understood biomechanical and neurocontrol aspects of animals.
Organizers: Ludovic Righetti
More than half of the persons with spinal cord injuries (SCI) are suffering from impairments of both hands, which results in a tremendous decrease of quality of life and represents a major barrier for inclusion in society. Functional restoration is possible with neuroprostheses (NPs) based on functional electrical stimulation (FES). A Brain-Computer Interface provides a means of control for such neuroprosthetics since users have limited abilities to use traditional assistive devices. This talk presents our early research on BCI-based NP control based on motor imagery, discusses hybrid BCI solutions and shows our work and effort on movement trajectory decoding. An outlook to future BCI applications will conclude this talk.
Organizers: Moritz Grosse-Wentrup
Programming robots remains notoriously difficult. Equipping robots with the ability to learn would by-pass the need for what often ends up being time-consuming task specific programming. In this talk I will describe the ideas behind two promising types of robot learning: First I will discuss apprenticeship learning, in which robots learn from human demonstrations, and which has enabled autonomous helicopter aerobatics, knot tying, basic suturing, and cloth manipulation. Then I will discuss deep reinforcement learning, in which robots learn through their own trial and error, and which has enabled learning locomotion as well as a range of assembly and manipulation tasks.
Organizers: Stefan Schaal