A Concept for Deployment and Evaluation of Unsupervised Domain Adaptation in Cognitive Perception Systems

Jüngste Entwicklungen im Bereich des tiefen Lernens ermöglichen Perzeptionssystemen datengetrieben Wissen über einen vordefinierten Betriebsbereich, eine sogenannte Domäne, zu gewinnen. Diese Verfahren des überwachten Lernens werden durch das Aufkommen groß angelegter annotierter Datensätze und immer leistungsfähigerer Prozessoren vorangetrieben und zeigen unübertroffene Performanz bei Perzeptionsaufgaben in einer Vielzahl von Anwendungsbereichen.Jedoch sind überwacht-trainierte neuronale Netze durch die Menge an verfügbaren annotierten Daten limitiert und dies wiederum findet in einem begrenzten Betriebsbereich Ausdruck. Dabei beruht überwachtes Lernen stark auf manuell durchzuführender Datenannotation. Insbesondere durch die ständig steigende Verfügbarkeit von nicht annotierten großen Datenmengen ist der Gebrauch von unüberwachter Domänenanpassung entscheidend. Verfahren zur unüberwachten Domänenanpassung sind meist nicht geeignet, um eine notwendige Inbetriebnahme des neuronalen Netzes in einer zusätzlichen Domäne zu gewährleisten. Darüber hinaus sind vorhandene Metriken häufig unzureichend für eine auf die Anwendung der domänenangepassten neuronalen Netzen ausgerichtete Validierung. Der Hauptbeitrag der vorliegenden Dissertation besteht aus neuen Konzepten zur unüberwachten Domänenanpassung. Basierend auf einer Kategorisierung von Domänenübergängen und a priori verfügbaren Wissensrepräsentationen durch ein überwacht-trainiertes neuronales Netz wird eine unüberwachte Domänenanpassung auf nicht annotierten Daten ermöglicht. Um die kontinuierliche Bereitstellung von neuronalen Netzen für die Anwendung in der Perzeption zu adressieren, wurden neuartige Verfahren speziell für die unüberwachte Erweiterung des Betriebsbereichs eines neuronalen Netzes entwickelt. Beispielhafte Anwendungsfälle des Fahrzeugsehens zeigen, wie die neuartigen Verfahren kombiniert mit neu entwickelten Metriken zur kontinuierlichen Inbetriebnahme von neuronalen Netzen auf nicht annotierten Daten beitragen. Außerdem werden die Implementierungen aller entwickelten Verfahren und Algorithmen dargestellt und öffentlich zugänglich gemacht. Insbesondere wurden die neuartigen Verfahren erfolgreich auf die unüberwachte Domänenanpassung, ausgehend von der Tag- auf die Nachtobjekterkennung im Bereich des Fahrzeugsehens angewendet

Defensive Perception: Estimation and Monitoring of Neural Network Performance under Deployment

In this paper, we propose a method for addressing the issue of unnoticed catastrophic deployment and domain shift in neural networks for semantic segmentation in autonomous driving. Our approach is based on the idea that deep learning-based perception for autonomous driving is uncertain and best represented as a probability distribution. As autonomous vehicles' safety is paramount, it is crucial for perception systems to recognize when the vehicle is leaving its operational design domain, anticipate hazardous uncertainty, and reduce the performance of the perception system. To address this, we propose to encapsulate the neural network under deployment within an uncertainty estimation envelope that is based on the epistemic uncertainty estimation through the Monte Carlo Dropout approach. This approach does not require modification of the deployed neural network and guarantees expected model performance. Our defensive perception envelope has the capability to estimate a neural network's performance, enabling monitoring and notification of entering domains of reduced neural network performance under deployment. Furthermore, our envelope is extended by novel methods to improve the application in deployment settings, including reducing compute expenses and confining estimation noise. Finally, we demonstrate the applicability of our method for multiple different potential deployment shifts relevant to autonomous driving, such as transitions into the night, rainy, or snowy domain. Overall, our approach shows great potential for application in deployment settings and enables operational design domain recognition via uncertainty, which allows for defensive perception, safe state triggers, warning notifications, and feedback for testing or development and adaptation of the perception stack

Automated Annotator Variability Inspection for Biomedical Image Segmentation

Supervised deep learning approaches for automated diagnosis support require datasets annotated by experts. Intra-annotator variability of a single annotator and inter-annotator variability between annotators can affect the quality of the diagnosis support. As medical experts will always differ in annotation details, quantitative studies concerning the annotation quality are of particular interest. A consistent and noise-free annotation of large-scale datasets by, for example, dermatologists or pathologists is a current challenge. Hence, methods are needed to automatically inspect annotations in datasets. In this paper, we categorize annotation noise in image segmentation tasks, present methods to simulate annotation noise, and examine the impact on the segmentation quality. Two novel automated methods to identify intra-annotator and inter-annotator inconsistencies based on uncertainty-aware deep neural networks are proposed. We demonstrate the benefits of our automated inspection methods such as focused re-inspection of noisy annotations or the detection of generally different annotation styles using the biomedical ISIC 2017 Melanoma image segmentation dataset

Defensive Perception: Neural Network Performance Estimation and Monitoring under Continuous Deployment

Our approach shows great potential for application in deployment settings, enabling operational design domain recognition via uncertainty, which allows for defensive driving, safe state triggers, warning notifications, and feedback for testing or development and adaption of the perception stack

Night-to-day: Online image-to-image translation for object detection within autonomous driving by night

Object detectors are central to autonomous driving and widely used in driver assistance systems. Object detectors are trained on a finite amount of data, within a specific domain. This hampers detection performance when applying object detectors to samples from other domains during inference, an effect known as domain gap. Domain gap is a concern for data-driven applications, evoking repetitive retraining of networks when the applications unfold into other domains. With object detectors that have been trained on day images only, domain gap can be clearly observed in object detection by night. Training object detectors on night images is critical due to the enormous effort required to generate an adequate amount of diversely labeled data, and existing data sets often tend to overfit specific domain characteristics. This work proposes, for the first time, adapting domains by online image-to-image translation to expand an object detector's domain of operation. The domain gap is decreased without additional labeling effort, and without having to retrain the object detector, while unfolding into the target domain. The approach follows the concept of domain adaptation, shifting the samples of the target domain into the domain known to the object detector (source domain). Firstly, the UNIT network is trained for domain adaptation and subsequently cast into an online domain adaptation module, which narrows down the domain gap. Domain adaptation capabilities are evaluated qualitatively by displaying translated samples, as well as by visualizing the domain shift through the 2D tSNE algorithm. We quantitatively benchmark the influence of the domain adaptation on a state-of-the-art object detector, and on a retrained object detector, with respect to mean average precision, mean recall and the resulting F1 score. Applying online domain adaptation, our approach achieves a F1 score improvement of 5.27 %, within object detection by night. The evaluation is executed on the BDD100K benchmark data set

BackboneAnalysis: Structured Insights into Compute Platforms from CNN Inference Latency

Customization of a convolutional neural network (CNN) to a specific compute platform involves finding an optimal pareto state between computational complexity of the CNN and resulting throughput in operations per second on the compute platform. However, existing inference performance benchmarks compare complete backbones that entail many differences between their CNN configurations, which do not provide insights in how fine-grade layer design choices affect this balance.We present BackboneAnalysis, a methodology for extracting structured insights into the trade-off for a chosen target compute platform. Within a one-factor-at-a-time analysis setup, CNN architectures are systematically varied and evaluated based on throughput and latency measurements irrespective of model accuracy. Thereby, we investigate the configuration factors input shape, batch size, kernel size and convolutional layer type.In our experiments, we deploy BackboneAnalysis on a Xavier iGPU and a Coral Edge TPU accelerator. The analysis reveals that the general assumption from optimal Roofline performance that higher operation density in CNNs leads to higher throughput does not always hold. These results highlight the importance for a neural network architect to be aware of platform-specific latency and throughput behavior in order to derive sensible configuration decisions for a custom CNN

Machine Learning Methods for Automated Quantification of Ventricular Dimensions

Machine learning methods for automated quantification of ventricular dimensions (for further details see Wiki below or take a closer look at our paper: https://www.liebertpub.com/doi/10.1089/zeb.2019.1754 )

BackboneAnalysis: Structured Insights into Compute Platforms from CNN Inference Latency

Customization of a convolutional neural network (CNN) to a specific compute platform involves finding an optimal pareto state between computational complexity of the CNN and resulting throughput in operations per second on the compute platform. However, existing inference performance benchmarks compare complete backbones that entail many differences between their CNN configurations, which do not provide insights in how fine-grade layer design choices affect this balance.We present BackboneAnalysis, a methodology for extracting structured insights into the trade-off for a chosen target compute platform. Within a one-factor-at-a-time analysis setup, CNN architectures are systematically varied and evaluated based on throughput and latency measurements irrespective of model accuracy. Thereby, we investigate the configuration factors input shape, batch size, kernel size and convolutional layer type.In our experiments, we deploy BackboneAnalysis on a Xavier iGPU and a Coral Edge TPU accelerator. The analysis reveals that the general assumption from optimal Roofline performance that higher operation density in CNNs leads to higher throughput does not always hold. These results highlight the importance for a neural network architect to be aware of platform-specific latency and throughput behavior in order to derive sensible configuration decisions for a custom CNN.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Vehicle