Search Results for author: Athanasios Vlontzos

Found 24 papers, 9 papers with code

Benchmarking Counterfactual Image Generation

1 code implementation29 Mar 2024 Thomas Melistas, Nikos Spyrou, Nefeli Gkouti, Pedro Sanchez, Athanasios Vlontzos, Giorgos Papanastasiou, Sotirios A. Tsaftaris

Counterfactual image generation is pivotal for understanding the causal relations of variables, with applications in interpretability and generation of unbiased synthetic data.

Benchmarking Conditional Image Generation +1

Non-parametric identifiability and sensitivity analysis of synthetic control models

no code implementations18 Jan 2023 Jakob Zeitler, Athanasios Vlontzos, Ciaran M. Gilligan-Lee

While identifiability of the causal estimand in such models has been obtained from a range of assumptions, it is widely and implicitly assumed that the underlying assumptions are satisfied for all time periods both pre- and post-intervention.

Causal Inference

Self-Supervised 3D Human Pose Estimation in Static Video Via Neural Rendering

no code implementations10 Oct 2022 Luca Schmidtke, Benjamin Hou, Athanasios Vlontzos, Bernhard Kainz

Inferring 3D human pose from 2D images is a challenging and long-standing problem in the field of computer vision with many applications including motion capture, virtual reality, surveillance or gait analysis for sports and medicine.

3D Human Pose Estimation Neural Rendering

nnOOD: A Framework for Benchmarking Self-supervised Anomaly Localisation Methods

1 code implementation2 Sep 2022 Matthew Baugh, Jeremy Tan, Athanasios Vlontzos, Johanna P. Müller, Bernhard Kainz

It is also difficult to assess whether a task generalises well for universal anomaly detection, as they are often only tested on a limited range of anomalies.

Anomaly Detection Benchmarking

A Review of Causality for Learning Algorithms in Medical Image Analysis

no code implementations11 Jun 2022 Athanasios Vlontzos, Daniel Rueckert, Bernhard Kainz

Medical image analysis is a vibrant research area that offers doctors and medical practitioners invaluable insight and the ability to accurately diagnose and monitor disease.

BIG-bench Machine Learning Translation

Is More Data All You Need? A Causal Exploration

no code implementations6 Jun 2022 Athanasios Vlontzos, Hadrien Reynaud, Bernhard Kainz

Curating a large scale medical imaging dataset for machine learning applications is both time consuming and expensive.

BIG-bench Machine Learning Image Classification

D'ARTAGNAN: Counterfactual Video Generation

1 code implementation3 Jun 2022 Hadrien Reynaud, Athanasios Vlontzos, Mischa Dombrowski, Ciarán Lee, Arian Beqiri, Paul Leeson, Bernhard Kainz

Causally-enabled machine learning frameworks could help clinicians to identify the best course of treatments by answering counterfactual questions.

Anatomy counterfactual +2

Estimating Categorical Counterfactuals via Deep Twin Networks

no code implementations4 Sep 2021 Athanasios Vlontzos, Bernhard Kainz, Ciaran M. Gilligan-Lee

To learn causal mechanisms satisfying these constraints, and perform counterfactual inference with them, we introduce deep twin networks.

counterfactual Counterfactual Inference +2

Video Summarization through Reinforcement Learning with a 3D Spatio-Temporal U-Net

no code implementations19 Jun 2021 Tianrui Liu, Qingjie Meng, Jun-Jie Huang, Athanasios Vlontzos, Daniel Rueckert, Bernhard Kainz

Intelligent video summarization algorithms allow to quickly convey the most relevant information in videos through the identification of the most essential and explanatory content while removing redundant video frames.

reinforcement-learning Reinforcement Learning (RL) +1

Next-Gen Machine Learning Supported Diagnostic Systems for Spacecraft

no code implementations10 Jun 2021 Athanasios Vlontzos, Gabriel Sutherland, Siddha Ganju, Frank Soboczenski

Future short or long-term space missions require a new generation of monitoring and diagnostic systems due to communication impasses as well as limitations in specialized crew and equipment.

BIG-bench Machine Learning

Unsupervised Human Pose Estimation through Transforming Shape Templates

2 code implementations CVPR 2021 Luca Schmidtke, Athanasios Vlontzos, Simon Ellershaw, Anna Lukens, Tomoki Arichi, Bernhard Kainz

Human pose estimation is a major computer vision problem with applications ranging from augmented reality and video capture to surveillance and movement tracking.

Pose Estimation Template Matching +1

Topological Information Retrieval with Dilation-Invariant Bottleneck Comparative Measures

1 code implementation4 Apr 2021 Yueqi Cao, Athanasios Vlontzos, Luca Schmidtke, Bernhard Kainz, Anthea Monod

Appropriately representing elements in a database so that queries may be accurately matched is a central task in information retrieval; recently, this has been achieved by embedding the graphical structure of the database into a manifold in a hierarchy-preserving manner using a variety of metrics.

Information Retrieval Retrieval +1

Causal Future Prediction in a Minkowski Space-Time

no code implementations20 Aug 2020 Athanasios Vlontzos, Henrique Bergallo Rocha, Daniel Rueckert, Bernhard Kainz

In this paper we propose a novel theoretical framework to perform causal future prediction by embedding spatiotemporal information on a Minkowski space-time.

Future prediction Image Generation

3D Probabilistic Segmentation and Volumetry from 2D projection images

no code implementations23 Jun 2020 Athanasios Vlontzos, Samuel Budd, Benjamin Hou, Daniel Rueckert, Bernhard Kainz

X-Ray imaging is quick, cheap and useful for front-line care assessment and intra-operative real-time imaging (e. g., C-Arm Fluoroscopy).

Ultrasound Video Summarization using Deep Reinforcement Learning

1 code implementation19 May 2020 Tianrui Liu, Qingjie Meng, Athanasios Vlontzos, Jeremy Tan, Daniel Rueckert, Bernhard Kainz

We show that our method is superior to alternative video summarization methods and that it preserves essential information required by clinical diagnostic standards.

reinforcement-learning Reinforcement Learning (RL) +1

Correlation of Auroral Dynamics and GNSS Scintillation with an Autoencoder

no code implementations4 Oct 2019 Kara Lamb, Garima Malhotra, Athanasios Vlontzos, Edward Wagstaff, Atılım Günes Baydin, Anahita Bhiwandiwalla, Yarin Gal, Alfredo Kalaitzis, Anthony Reina, Asti Bhatt

High energy particles originating from solar activity travel along the the Earth's magnetic field and interact with the atmosphere around the higher latitudes.

Prediction of GNSS Phase Scintillations: A Machine Learning Approach

no code implementations3 Oct 2019 Kara Lamb, Garima Malhotra, Athanasios Vlontzos, Edward Wagstaff, Atılım Günes Baydin, Anahita Bhiwandiwalla, Yarin Gal, Alfredo Kalaitzis, Anthony Reina, Asti Bhatt

We propose a novel architecture and loss function to predict 1 hour in advance the magnitude of phase scintillations within a time window of plus-minus 5 minutes with state-of-the-art performance.

BIG-bench Machine Learning

Flexible Conditional Image Generation of Missing Data with Learned Mental Maps

no code implementations29 Aug 2019 Benjamin Hou, Athanasios Vlontzos, Amir Alansary, Daniel Rueckert, Bernhard Kainz

Real-world settings often do not allow acquisition of high-resolution volumetric images for accurate morphological assessment and diagnostic.

Anatomy Conditional Image Generation +2

Multiple Landmark Detection using Multi-Agent Reinforcement Learning

1 code implementation30 Jun 2019 Athanasios Vlontzos, Amir Alansary, Konstantinos Kamnitsas, Daniel Rueckert, Bernhard Kainz

We compare our approach with state-of-the-art architectures and achieve significantly better accuracy by reducing the detection error by 50%, while requiring fewer computational resources and time to train compared to the naive approach of training K agents separately.

Anatomy Multi-agent Reinforcement Learning +2

Deep Segmentation and Registration in X-Ray Angiography Video

1 code implementation16 May 2018 Athanasios Vlontzos, Krystian Mikolajczyk

In interventional radiology, short video sequences of vein structure in motion are captured in order to help medical personnel identify vascular issues or plan intervention.

Optical Flow Estimation Position +2

The RNN-ELM Classifier

no code implementations25 Sep 2016 Athanasios Vlontzos

In this paper we examine learning methods combining the Random Neural Network, a biologically inspired neural network and the Extreme Learning Machine that achieve state of the art classification performance while requiring much shorter training time.

General Classification

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