Tracking Object Positions in Reinforcement Learning: A Metric for Keypoint Detection (extended version)

Fuente: arXiv
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Main Authors: Cramer, Emma, Reiher, Jonas, Trimpe, Sebastian
Format: Preprint
Published: 2023
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author Cramer, Emma
Reiher, Jonas
Trimpe, Sebastian
author_facet Cramer, Emma
Reiher, Jonas
Trimpe, Sebastian
contents Reinforcement learning (RL) for robot control typically requires a detailed representation of the environment state, including information about task-relevant objects not directly measurable. Keypoint detectors, such as spatial autoencoders (SAEs), are a common approach to extracting a low-dimensional representation from high-dimensional image data. SAEs aim at spatial features such as object positions, which are often useful representations in robotic RL. However, whether an SAE is actually able to track objects in the scene and thus yields a spatial state representation well suited for RL tasks has rarely been examined due to a lack of established metrics. In this paper, we propose to assess the performance of an SAE instance by measuring how well keypoints track ground truth objects in images. We present a computationally lightweight metric and use it to evaluate common baseline SAE architectures on image data from a simulated robot task. We find that common SAEs differ substantially in their spatial extraction capability. Furthermore, we validate that SAEs that perform well in our metric achieve superior performance when used in downstream RL. Thus, our metric is an effective and lightweight indicator of RL performance before executing expensive RL training. Building on these insights, we identify three key modifications of SAE architectures to improve tracking performance.
format Preprint
id arxiv_https___arxiv_org_abs_2312_00592
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Tracking Object Positions in Reinforcement Learning: A Metric for Keypoint Detection (extended version)
Cramer, Emma
Reiher, Jonas
Trimpe, Sebastian
Machine Learning
Computer Vision and Pattern Recognition
Robotics
Reinforcement learning (RL) for robot control typically requires a detailed representation of the environment state, including information about task-relevant objects not directly measurable. Keypoint detectors, such as spatial autoencoders (SAEs), are a common approach to extracting a low-dimensional representation from high-dimensional image data. SAEs aim at spatial features such as object positions, which are often useful representations in robotic RL. However, whether an SAE is actually able to track objects in the scene and thus yields a spatial state representation well suited for RL tasks has rarely been examined due to a lack of established metrics. In this paper, we propose to assess the performance of an SAE instance by measuring how well keypoints track ground truth objects in images. We present a computationally lightweight metric and use it to evaluate common baseline SAE architectures on image data from a simulated robot task. We find that common SAEs differ substantially in their spatial extraction capability. Furthermore, we validate that SAEs that perform well in our metric achieve superior performance when used in downstream RL. Thus, our metric is an effective and lightweight indicator of RL performance before executing expensive RL training. Building on these insights, we identify three key modifications of SAE architectures to improve tracking performance.
title Tracking Object Positions in Reinforcement Learning: A Metric for Keypoint Detection (extended version)
topic Machine Learning
Computer Vision and Pattern Recognition
Robotics
url https://arxiv.org/abs/2312.00592