February 23, 2021

Krishna Murthy Jatavallabhula, Robotics&Embodied AI Lab

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Building Differentiable Models of the 3D World

Modern machine learning has created exciting new opportunities for the design of intelligent robots. In particular, gradient-based learning methods have tremendously While modern learning-based scene understanding systems have shown experimentally promising results in simulated scenarios, they fail in unpredictable and unintuitive ways when deployed in real-world applications. Classical systems, on the other hand, offer guarantees and bounds on performance and generalization, but often require heavy handcrafting and oversight. My research aims to deeply integrate classical and learning-based techniques to bring the best of both worlds, by building “differentiable models of the 3D world”. I will talk about two particular recent efforts along these directions. improved 3D scene understanding in terms of perception, reasoning, and action. However, these advancements have undermined many “classical” techniques developed over the last few decades. I postulate that a flexible blend of “classical” and learned methods is the most promising path to developing flexible, interpretable, and actionable models of the world: a necessity for intelligent embodied agents. 1. gradSLAM – a fully differentiable dense SLAM system that can be plugged as a “layer” into neural nets 2. gradSim – a differentiable simulator comprising a physics engine and a renderer, to enable physical parameter estimation and visuomotor control from the video.

February 16, 2021

Nasrin Rahimi, KUIS AI Fellow

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Perceptual Video Super-Resolution

Perceptual video processing is a challenging task, mostly due to the lack of effective measures of temporal consistency and naturalness of motion in processed videos. In this talk, we first explain the successful video restoration and super-resolution network EDVR (Enhanced Deformable Convolutional Networks), and the role of deformable convolution in its architecture. Then, we present our recent work which is an extension of EDVR for perceptual video super-resolution in two ways: i) including a texture discriminator network and adversarial texture loss in order to improve the naturalness of texture, and ii) including l2 flow loss, a flow discriminator network and adversarial flow loss to ensure motion naturalness. We observe that adding only adversarial texture loss yields more natural texture in each frame, but not necessarily a smooth natural motion. Perceptual motion improves significantly when using both l2 motion loss and adversarial texture and flow losses in addition to l2 texture loss. Finally, we discuss the perceptual performance metrics and evaluation of the results.

February 9, 2021

Onur Keleş, KUIS AI Fellow

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Self-Organizing Operational Neural Networks and Image Super-Resolution

It has become a standard practice to use convolutional networks in image restoration and super-resolution. Although the universal approximation theorem states that a multi-layer neural network can approximate any non-linear function with the desired precision, it does not reveal the best network architecture to do so. Recently, operational neural networks that choose the best non-linearity from a set of alternatives, and their “self-organized” variants that approximate any non-linearity via Taylor series have been proposed to address the well-known limitations and drawbacks of conventional ConvNets such as network homogeneity using only the McCulloch-Pitts neuron model. In this talk, I first briefly mention the operational neural networks (ONNs) and self-organized operational neural networks (Self-ONNs). Then I introduce the concept of self-organized operational residual (SOR) blocks, and present hybrid network architectures combining regular residual and SOR blocks to strike a balance between the benefits of stronger non-linearity and the overall number of parameters. The experimental results on the super-resolution task demonstrate that the proposed architectures yield performance improvements in both PSNR and perceptual metrics.

February 2, 2021

Michael Gygli (Google Research)

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Towards More Reusable and Adaptive Models for Visual Recognition

In this talk, I will go over our recent efforts to make neural networks more reusable and adaptive. First, I will present “Towards Reusable Network Components by Learning Compatible Representations”, published at AAAI 2021. This work studies how components of different networks can be made compatible so that they can be re-assembled into new networks easily. This unlocks improvements in several different applications. Secondly, I will discuss “Continuous Adaptation for Interactive Object Segmentation by Learning from Corrections”, published at ECCV 2020. There, we show the benefits of learning from interactions of a user with an interactive segmentation model: Such a model becomes self-adaptive, which enables it to successfully transfer to new distributions and domains. Due to this, our model achieves state-of-the-art results on several datasets. Finally, I will briefly discuss other important efforts in our team, such as the OpenImages dataset and Localized Narratives.