Precise Laser-Based Optical 3d Measurement of Welding Seams Under Water

In this study, a laser line auto-scanning system was designed to perform underwater close-range 3D reconstructions with high accuracy and resolution. The system changes the laser plane direction with a galvanometer to perform automatic scanning and obtain continuous laser strips for underwater 3D reconstruction. The system parameters were calibrated with the homography constraints between the target plane and image plane. A cost function was defined to optimize the galvanometer’s rotating axis equation. Compensation was carried out for the refraction of the incident and emitted light at the interface. The accuracy and the spatial measurement capability of the system were tested and analyzed with standard balls under laboratory underwater conditions, and the 3D surface reconstruction for a sealing cover of an underwater instrument was proved to be satisfactory.

Section: Experiments and Resultsmentioning

confidence: 99%

A Laser Line Auto-Scanning System for Underwater 3D Reconstruction

Chi

Xie

Chen

2016

“…Some systems are left out of this analysis because they follow a hybrid approach of combining active and passive light techniques. For instance, some stereo cameras make use of active light projection [113,131,132] in order to ease the feature finding and matching processes. Duda et al [133] use an iterative combination of active light projection with sfm.…”

Section: Quantitative Analysis Of Current Technologiesmentioning

confidence: 99%

State of the Art of Underwater Active Optical 3D Scanners

Castillón

Palomer

Forest

et al. 2019

Underwater inspection, maintenance and repair (IMR) operations are being increasingly robotized in order to reduce safety issues and costs. These robotic systems rely on vision sensors to perform fundamental tasks, such as navigation and object recognition and manipulation. Especially, active optical 3D scanners are commonly used due to the domain-specific challenges of underwater imaging. This paper presents an exhaustive survey on the state of the art of optical 3D underwater scanners. A literature review on light projection and light-sensing technologies is presented. Moreover, quantitative performance comparisons of underwater 3D scanners present in the literature and commercial products are carried out.

“…In [ 153 ], Ekkel et al use a stereo laser profiler (four cameras, two for positioning with targets and two for laser triangulation) using a 640-nm laser. They report an accuracy of

mm in the object plane.…”

Section: Sensors and Technologiesmentioning

confidence: 99%

Optical Sensors and Methods for Underwater 3D Reconstruction

Massot-Campos

Oliver-Codina

2015

138

This paper presents a survey on optical sensors and methods for 3D reconstruction in underwater environments. The techniques to obtain range data have been listed and explained, together with the different sensor hardware that makes them possible. The literature has been reviewed, and a classification has been proposed for the existing solutions. New developments, commercial solutions and previous reviews in this topic have also been gathered and considered.