# Geometric Point Light Source Calibration

@inproceedings{Ackermann2013GeometricPL, title={Geometric Point Light Source Calibration}, author={Jens Ackermann and Simon Fuhrmann and Michael Goesele}, booktitle={VMV}, year={2013} }

We present a light position calibration technique based on a general arrangement of at least two reflective spheres in a single image. Contrary to other techniques we do not directly intersect rays for triangulation but instead solve for the optimal light position by evaluating the image-space error of the light highlights reflected from the spheres. This approach has been very successful in the field of Structure-from-Motion estimation. It has not been applied to light source calibration…

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## 27 Citations

Light Structure from Pin Motion: Geometric Point Light Source Calibration

- Computer ScienceInternational Journal of Computer Vision
- 2020

It is shown that shadow observations from a moving calibration target under a fixed light follow the principles of pinhole camera geometry and epipolar geometry, allowing joint recovery of the light position and3D shadow caster positions, equivalent to how conventional structure from motion jointly recovers camera parameters and 3D feature positions from observed 2D features.

Calibrating a Non-isotropic Near Point Light Source Using a Plane

- Computer Science, Physics2014 IEEE Conference on Computer Vision and Pattern Recognition
- 2014

We show that a non-isotropic near point light source rigidly attached to a camera can be calibrated using multiple images of a weakly textured planar scene. We prove that if the radiant intensity…

Light Structure from Pin Motion: Simple and Accurate Point Light Calibration for Physics-Based Modeling

- Computer ScienceECCV
- 2018

It is shown that, given shadow observations from a moving calibration target and a fixed camera, the shadow caster positions and the light position or direction can be simultaneously recovered in a structure from motion framework.

Light Pose Calibration for Camera-light Vision Systems

- Computer ScienceArXiv
- 2020

A novel light calibration approach by taking multi-view and -distance images of a reference plane in order to provide pose information of the employed light sources to the computer vision system by following a physical light propagation approach.

Multiple Point Light Estimation from Low-Quality 3D Reconstructions

- Computer Science2019 International Conference on 3D Vision (3DV)
- 2019

This work develops a more general framework for light source estimation in environments containing multiple, in-scene illuminants, which resembles that found in intrinsic image decomposition and is capable of modeling complex lighting scenarios with high-fidelity.

Indoor Scene Reconstruction Using Near-Light Photometric Stereo

- Mathematics, Computer ScienceIEEE Transactions on Image Processing
- 2017

A novel framework for photometric stereo under low-light conditions using uncalibrated near-light illumination using specular spheres detected with a perspective-correcting Hough transform to robustly triangulate light positions in the presence of outliers via a least-squares approach.

Practical Free-form RTI Acquisition with Local Spot Lights

- Computer ScienceSTAG
- 2016

An automated light calibration pipeline for free-form acquisition of shape and reflectance of objects using common off-the-shelf illuminators that can be placed arbitrarily close to the objects is presented.

Uncalibrated Near-Light Photometric Stereo

- Computer ScienceBMVC
- 2014

This work solves the uncalibrated photometric stereo problem with lights placed near the scene and proposes a solution for reconstructing the normal map, the albedo, the light positions and the light intensities of a scene given only a sequence of near-light images.

A self-calibrated photo-geometric depth camera

- Computer ScienceThe Visual Computer
- 2018

This paper presents a practical 3D imaging system by combining the near-light photometric stereo and the speckle-based stereo matching method, which is compact in structure and suitable for multi-albedo targets.

LED-Based Photometric Stereo: Modeling, Calibration and Numerical Solution

- Computer ScienceJournal of Mathematical Imaging and Vision
- 2017

A provably convergent alternating reweighted least-squares scheme for solving the original system of nonlinear PDEs, which are linearized using image ratios in the case of RGB images is introduced.

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