Colmap-PCD: An Open-source Tool for Fine Image-to-point cloud Registration

TL;DR

This paper introduces Colmap-PCD, an open-source tool that enables precise registration of images to pre-existing LiDAR point cloud maps without requiring synchronized data, improving scale accuracy in monocular reconstruction.

Contribution

It presents a novel, cost-effective pipeline using a fixed LiDAR map as a constraint, and releases Colmap-PCD, a tool based on Colmap for fine image-to-point cloud registration without synchronized data.

Findings

First method to register images onto point cloud without synchronized capture

Enables flexible reconstruction detail levels across areas

Open-source tool facilitates further research

Abstract

State-of-the-art techniques for monocular camera reconstruction predominantly rely on the Structure from Motion (SfM) pipeline. However, such methods often yield reconstruction outcomes that lack crucial scale information, and over time, accumulation of images leads to inevitable drift issues. In contrast, mapping methods based on LiDAR scans are popular in large-scale urban scene reconstruction due to their precise distance measurements, a capability fundamentally absent in visual-based approaches. Researchers have made attempts to utilize concurrent LiDAR and camera measurements in pursuit of precise scaling and color details within mapping outcomes. However, the outcomes are subject to extrinsic calibration and time synchronization precision. In this paper, we propose a novel cost-effective reconstruction pipeline that utilizes a pre-established LiDAR map as a fixed constraint to effectively address the inherent scale challenges present in monocular camera reconstruction. To our knowledge, our method is the first to register images onto the point cloud map without requiring synchronous capture of camera and LiDAR data, granting us the flexibility to manage reconstruction detail levels across various areas of interest. To facilitate further research in this domain, we have released Colmap-PCD${^{3}}$, an open-source tool leveraging the Colmap algorithm, that enables precise fine-scale registration of images to the point cloud map.