Warm-Started Reinforcement Learning for Iterative 3D/2D Liver Registration

Fuente: arXiv
Saved in:
Bibliographic Details
Main Authors: Zhang, Hanyuan, He, Lucas, Cheng, Zijie, Kadkhodamohammadi, Abdolrahim, Stoyanov, Danail, Davidson, Brian R., Mazomenos, Evangelos B., Clarkson, Matthew. J
Format: Preprint
Published: 2026
Subjects:
Online Access:
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1866916029836296192
author Zhang, Hanyuan
He, Lucas
Cheng, Zijie
Kadkhodamohammadi, Abdolrahim
Stoyanov, Danail
Davidson, Brian R.
Mazomenos, Evangelos B.
Clarkson, Matthew. J
author_facet Zhang, Hanyuan
He, Lucas
Cheng, Zijie
Kadkhodamohammadi, Abdolrahim
Stoyanov, Danail
Davidson, Brian R.
Mazomenos, Evangelos B.
Clarkson, Matthew. J
contents Registration between preoperative CT and intraoperative laparoscopic video plays a crucial role in augmented reality (AR) guidance for minimally invasive surgery. Learning-based methods have recently achieved registration errors comparable to optimization-based approaches while offering faster inference. However, many supervised methods produce coarse alignments that rely on additional optimization-based refinement, thereby increasing inference time. We present a discrete-action reinforcement learning (RL) framework that formulates CT-to-video registration as a sequential decision-making process. A shared feature encoder, warm-started from a supervised pose estimation network to provide stable geometric features and faster convergence, extracts representations from CT renderings and laparoscopic frames, while an RL policy head learns to choose rigid transformations along six degrees of freedom and to decide when to stop the iteration. Experiments on a public laparoscopic dataset demonstrated that our method achieved an average target registration error (TRE) of 15.70 mm, comparable to supervised approaches with optimization, while achieving faster convergence. The proposed RL-based formulation enables automated, efficient iterative registration without manually tuned step sizes or stopping criteria. This discrete framework provides a practical foundation for future continuous-action and deformable registration models in surgical AR applications.
format Preprint
id arxiv_https___arxiv_org_abs_2604_10245
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Warm-Started Reinforcement Learning for Iterative 3D/2D Liver Registration
Zhang, Hanyuan
He, Lucas
Cheng, Zijie
Kadkhodamohammadi, Abdolrahim
Stoyanov, Danail
Davidson, Brian R.
Mazomenos, Evangelos B.
Clarkson, Matthew. J
Computer Vision and Pattern Recognition
Medical Physics
Registration between preoperative CT and intraoperative laparoscopic video plays a crucial role in augmented reality (AR) guidance for minimally invasive surgery. Learning-based methods have recently achieved registration errors comparable to optimization-based approaches while offering faster inference. However, many supervised methods produce coarse alignments that rely on additional optimization-based refinement, thereby increasing inference time. We present a discrete-action reinforcement learning (RL) framework that formulates CT-to-video registration as a sequential decision-making process. A shared feature encoder, warm-started from a supervised pose estimation network to provide stable geometric features and faster convergence, extracts representations from CT renderings and laparoscopic frames, while an RL policy head learns to choose rigid transformations along six degrees of freedom and to decide when to stop the iteration. Experiments on a public laparoscopic dataset demonstrated that our method achieved an average target registration error (TRE) of 15.70 mm, comparable to supervised approaches with optimization, while achieving faster convergence. The proposed RL-based formulation enables automated, efficient iterative registration without manually tuned step sizes or stopping criteria. This discrete framework provides a practical foundation for future continuous-action and deformable registration models in surgical AR applications.
title Warm-Started Reinforcement Learning for Iterative 3D/2D Liver Registration
topic Computer Vision and Pattern Recognition
Medical Physics
url https://arxiv.org/abs/2604.10245