scholarly journals Underwater High-Precision 3D Reconstruction System Based on Rotating Scanning

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1402
Author(s):  
Qingsheng Xue ◽  
Qian Sun ◽  
Fupeng Wang ◽  
Haoxuan Bai ◽  
Bai Yang ◽  
...  

This paper presents an underwater high-precision line laser three-dimensional (3D) scanning (LLS) system with rotary scanning mode, which is composed of a low illumination underwater camera and a green line laser projector. The underwater 3D data acquisition can be realized in the range of field of view of 50° (vertical) × 360° (horizontal). We compensate the refraction of the 3D reconstruction system to reduce the angle error caused by the refraction of light on different media surfaces and reduce the impact of refraction on the image quality. In order to verify the reconstruction effect of the 3D reconstruction system and the effectiveness of the refraction compensation algorithm, we conducted error experiments on a standard sphere. The results show that the system’s underwater reconstruction error is less than 0.6 mm within the working distance of 140 mm~2500 mm, which meets the design requirements. It can provide reference for the development of low-cost underwater 3D laser scanning system.

2020 ◽  
Vol 23 (3) ◽  
pp. 277-288
Author(s):  
Shahad A. Al-Saqal ◽  
Ali A. Al-Temeemy

Three-dimensional reconstruction of real objects comprises capturing the appearance and the shape for these objects and determining the three-dimensional coordinates for their profiles. This reconstruction process can be accomplished either by using active or passive techniques. In this paper, a new fusion method is proposed for 3D reconstruction. This method exploits the advantages of both stereo-based passive and laser-based active techniques and overcomes their limitations to improve the performance of 3D reconstruction. With this method, a hybrid laser-based structured light scanning system is designed and implemented. This system captures the required information using passive and active techniques and uses the proposed fusion method for 3D reconstruction. The performance of the proposed method and its scanning system were experimentally evaluated. The evaluation results show high reconstruction performance for the proposed fusion method over the traditional 3D reconstruction techniques. The results also show the effectiveness of the hybrid laser scanning system and its ability to scan and reconstruct the shape and the appearance for real objects using the proposed fusion method.


Author(s):  
M. Bleier ◽  
A. Nüchter

In-situ calibration of structured light scanners in underwater environments is time-consuming and complicated. This paper presents a self-calibrating line laser scanning system, which enables the creation of dense 3D models with a single fixed camera and a freely moving hand-held cross line laser projector. The proposed approach exploits geometric constraints, such as coplanarities, to recover the depth information and is applicable without any prior knowledge of the position and orientation of the laser projector. By employing an off-the-shelf underwater camera and a waterproof housing with high power line lasers an affordable 3D scanning solution can be built. In experiments the performance of the proposed technique is studied and compared with 3D reconstruction using explicit calibration. We demonstrate that the scanning system can be applied to above-the-water as well as underwater scenes.


2019 ◽  
Vol 8 (6) ◽  
pp. 285 ◽  
Author(s):  
Balletti ◽  
Ballarin

In recent decades, 3D acquisition by laser scanning or digital photogrammetry has become one of the standard methods of documenting cultural heritage, because it permits one to analyze the shape, geometry, and location of any artefact without necessarily coming into contact with it. The recording of three-dimensional metrical data of an asset allows one to preserve and monitor, but also to understand and explain the history and cultural heritage shared. In essence, it constitutes a digital archive of the state of an artefact, which can be used for various purposes, be remodeled, or kept safely stored. With the introduction of 3D printing, digital data can once again take on material form and become physical objects from the corresponding mathematical models in a relatively short time and often at low cost. This possibility has led to a different consideration of the concept of virtual data, no longer necessarily linked to simple visual fruition. The importance of creating high-resolution physical copies has been reassessed in light of different types of events that increasingly threaten the protection of cultural heritage. The aim of this research is to analyze the critical issues in the production process of the replicas, focusing on potential problems in data acquisition and processing and on the accuracy of the resulting 3D printing. The metric precision of the printed model with 3D technology are fundamental for everything concerning geomatics and must be related to the same characteristics of the digital model obtained through the survey analysis.


2018 ◽  
Vol 18 ◽  
pp. 98-105
Author(s):  
N. V. Pavliuk

The issues related to the introduction of innovative methods, technologies and technological means in the investigation of crimes are considered. It is noted that one of the main directions of the development of Criminalistics is the assimilation of the virtual reality associated with computerization of spheres of life, implementation of modern technologies and their use in law enforcement. Technology use of laser scanning of terrain and objects resulting in 3D model is produced allows several times to increase informative value of data collected at the incident scene, provides a visual and convenient visualization in three-dimensional form. As against photo and video images, 3D model has a stereoscopic image and the ability to freely change the angle while viewing. Besides to scanning results can be stored on any digital media without the possibility of changes or adjustments. Attention is focused on the technological capabilities of 3D-visualization systems on examples of their use in foreign countries as technological means of capturing the situation of the scene and the subsequent of a crime reconstruction. Thus, using a portable three-dimensional imaging system for working with volumetric traces at a crime scene, it is possible to obtain accurate three-dimensional images of traces of protectors or footprints (shoes) on soil and snow. This system is an alternative to traditional methods of fixing evidence: photofixing and making plaster casts. Unlike other systems, new approach does not require the use of lasers. The expediency of expanding the range of 3D laser scanning system use in modern investigative and judicial practice of our state with the aim of increasing the level of provision of pre-trial investigation authorities with technological means and bringing it closer to European standards is argued.


2016 ◽  
Vol 9 (1) ◽  
pp. 114-121
Author(s):  
吕源治 LYU Yuan-zhi ◽  
孙 强 SUN Qiang ◽  
毕国玲 BI Guo-ling

Water ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 2101 ◽  
Author(s):  
Zhang ◽  
Zhao ◽  
Hu ◽  
Wang ◽  
Ai ◽  
...  

Urban drainage pipe networks have complex spatial contributions, andthey are now facing problems such as damage, defects, and aging. A rapid and high-precision pipe inspection strategy is thekey to ensuring thesustainable development of urban water supply and drainage system. In this paper, a three-dimensional (3D) reconstruction pipeline of urban drainage pipes based on multiview image matching using low-cost panoramic video cameras is proposed, which provides an innovative technical approach for pipe inspection. Firstly, we extracted frames from the panoramic video of the pipes andcorrected the geometric distortion using a spherical reprojection to obtain multiview pipe images. Second, the robust feature matching method using support lines and affine-invariant ratios isintroduced to conduct pipe image matching. Finally, the photogrammetric processing, using structure from motion (SfM) and dense reconstruction, wasintroduced to achieve the 3D modeling of drainage pipes. Several typical drainage pipes and shafts of the real scenes were taken for the 3D reconstruction experiments. Theresults show that our strategy can realize high-precision 3D reconstruction of different types of pipes, which can provide effective technical support for rapid and efficient inspection of urban pipes with broad application prospects in the daily management of sustainable urban drainage systems (SUDSs).


Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 893 ◽  
Author(s):  
Carmen Marín-Buzón ◽  
Antonio Pérez-Romero ◽  
Fabio Tucci-Álvarez ◽  
Francisco Manzano-Agugliaro

The accurate assessment of tree crowns is important for agriculture, for example, to adjust spraying rates, to adjust irrigation rates or even to estimate biomass. Among the available methodologies, there are the traditional methods that estimate with a three-dimensional approximation figure, the HDS (High Definition Survey), or TLS (Terrestrial Laser Scanning) based on LiDAR technology, the aerial photogrammetry that has re-emerged with unmanned aerial vehicles (UAVs), as they are considered low cost. There are situations where either the cost or location does not allow for modern methods and prices such as HDS or the use of UAVs. This study proposes, as an alternative methodology, the evaluation of images extracted from Google Maps (GM) for the calculation of tree crown volume. For this purpose, measurements were taken on orange trees in the south of Spain using the four methods mentioned above to evaluate the suitability, accuracy, and limitations of GM. Using the HDS method as a reference, the photogrammetric method with UAV images has shown an average error of 10%, GM has obtained approximately 50%, while the traditional methods, in our case considering ellipsoids, have obtained 100% error. Therefore, the results with GM are encouraging and open new perspectives for the estimation of tree crown volumes at low cost compared to HDS, and without geographical flight restrictions like those of UAVs.


Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 2981 ◽  
Author(s):  
Limei Song ◽  
Xinyao Li ◽  
Yan-gang Yang ◽  
Xinjun Zhu ◽  
Qinghua Guo ◽  
...  

The non-contact three-dimensional measurement and reconstruction techniques have played a significant role in the packaging and transportation of precious cultural relics. This paper develops a structured light based three-dimensional measurement system, with a low-cost for cultural relics packaging. The structured light based system performs rapid measurements and generates 3D point cloud data, which is then denoised, registered and merged to achieve accurate 3D reconstruction for cultural relics. The multi-frequency heterodyne method and the method in this paper are compared. It is shown that the relative accuracy of the proposed low-cost system can reach a level of 1/1000. The high efficiency of the system is demonstrated through experimental results.


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