Mengkun She | 佘梦坤

Relative Illumination Fields: Learning Medium and Light Independent Underwater Scenes
Mengkun She*, Felix Seegräber*, David Nakath, Patricia Schöntag, Kevin Köser
(*equal contribution)
International Conference on Computer Vision (ICCV), 2025
Project Page / Preprint / Code

We address the challenge of constructing a consistent and photorealistic Neural Radiance Field in inhomogeneously illuminated, scattering environments with unknown, co-moving light sources.

Refractive COLMAP: Refractive Structure-from-Motion Revisited
Mengkun She, Felix Seegräber, David Nakath, Kevin Köser
IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2024 (Oral Presentation)
Preprint / Code

Underwater cameras suffer from geometric distortion induced by refraction of light rays at the water-glass-air interfaces. We integrate the refractive geometry within the COLMAP framework and release it as open-source.

Semihierarchical Reconstruction and Weak-area Revisiting for Robotic Visual Seafloor Mapping
Mengkun She, Yifan Song, David Nakath, Kevin Köser
Journal of Field Robotics

A semi-hierarchical approach which combines the good parts of incremental and global structure-from-motion for large-scale AUV-based monocular camera seafloor reconstruction. Weak-area revisiting helps to mitigate inconsistencies in the reconstructed camera poses and map.

Visual Tomography: Physically Faithful Volumetric Models of Partially Translucent Objects
David Nakath, Xiangyu Weng, Mengkun She, Kevin Köser
International Conference on 3D Vision (3DV), 2024
Preprint / Poster / Supplementary Material / Data

How to establish 3D models of partially translucent organisms? We adapt Differentiable Raytracing to real data to capture Tomography-like internal structure, establish relightable models, immerse models in other media, and exhibit high novel-view stability.

Marine Bubble Flow Quantification Using Wide-baseline Stereo Photogrammetry
Mengkun She, Tim Weiß, Yifan Song, Peter Urban, Jens Greinert, Kevin Köser
ISPRS Journal of Photogrammetry and Remote Sensing

The BubbleBox project aims to develop a high-speed stereo camera system that can be deployed on the seafloor of the deep ocean to measure and quantify the amount of gas released from the seafloor into the water column. Checkout the livestream of the BubbleBox deployment!

Refractive Geometry for Underwater Domes
Mengkun She, David Nakath, Yifan Song, Kevin Köser
ISPRS Journal of Photogrammetry and Remote Sensing

We look more into the refractive geometry properties of underwater dome-port cameras.

Macal-Macro Lens Calibration and the Focus Stack Camera Model
Xiangyu Weng*, Mengkun She*, David Nakath, Kevin Köser
(*equal contribution)
International Conference on 3D Vision (3DV), 2021 (Oral Presentation)
Preprint

We discover that the camera model of a focus stacked image is essentially an affine model. We then propose a macro-lens calibration approach for 3D reconstruction of very tiny objects using such cameras. This technology is used in the TechOceanS project.

In-Situ Joint Light and Medium Estimation for Underwater Color Restoration
David Nakath, Mengkun She, Yifan Song, Kevin Köser
International Conference on Computer Vision Workshops (ICCV), 2021

3D reconstruction using a camera with an active light source creates an uneven and color-distorted texture. We use physically-based differentiable ray-tracing to estimate the light source and then optimize a medium- and light-free texture in the subsequent SfM step.

Adjustment and Calibration of Dome Port Camera Systems for Underwater Vision
Mengkun She, Yifan Song, Jochen Mohrmann, Kevin Köser
41st DAGM German Conference on Pattern Recognition (GCPR), 2019 (Oral Presentation)
Preprint

In this work, we develop an effective method to align a camera with an underwater spherical port (dome-port) for underwater camera systems. This technique is essential for the accurate calibration of our underwater cameras.