An underwater laser vision system for relative 3-D posture estimation to mesh-like targets

Constantinou, Christos C.; Loizou, Savvas G.; Georgiades, George

doi:10.1109/iros.2016.7759320

Cited by 9 publications

(6 citation statements)

References 8 publications

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“…Constantinou et al [142] developed a laser scanner to measure mesh-like objects, like fish nets. The system was calibrated automatically, with the help of a calibration box.…”

Section: Quantitative Analysis Of Current Technologiesmentioning

confidence: 99%

“…Regarding the used viewports, most of the analyzed sensors use flat windows. Nonetheless, some such as Imaki et al [82] and Constantinou et al [142] use hemispherical viewports. Flat viewports are easier to manufacture and mount, but they introduce distortions especially at high incidence angles of the laser beam in the viewport.…”

Section: Quantitative Analysis Of Current Technologiesmentioning

confidence: 99%

“…Moreover, it also involves higher incidence angles on the viewport, which introduces error if a flat viewport is used. The FoV of laser line modules depends on the fan angle induced by the optical elements, and it can range from 30° [143] to 160° [142].…”

Section: Quantitative Analysis Of Current Technologiesmentioning

confidence: 99%

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State of the Art of Underwater Active Optical 3D Scanners

Castillón

Palomer

Forest

et al. 2019

Sensors

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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.

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“…Constantinou et al [142] developed a laser scanner to measure mesh-like objects, like fish nets. The system was calibrated automatically, with the help of a calibration box.…”

Section: Quantitative Analysis Of Current Technologiesmentioning

confidence: 99%

Section: Quantitative Analysis Of Current Technologiesmentioning

confidence: 99%

See 1 more Smart Citation

State of the Art of Underwater Active Optical 3D Scanners

Castillón

Palomer

Forest

et al. 2019

Sensors

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“…Some LLSs [21][22][23][24] do not steer the laser plane, so that its relative pose with respect to the camera is constant. This way, they achieve a robust performance, since the number of parameters to be calibrated is relatively low.…”

Section: A Underwater 3d Laser Scannersmentioning

confidence: 99%

Underwater 3D Scanner Model Using a Biaxial MEMS Mirror

Castillón

Palomer²,

Forest

et al. 2021

IEEE Access

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Underwater 3D laser scanners are an essential type of sensor used by unmanned underwater vehicles (UUVs) for operations such as navigation, inspection and object recognition and manipulation. These sensors need to be able to provide highly accurate 3D data at fast refresh rates in order to accomplish these tasks. Usually, these scanners rely on a rotating mirror actuated by a galvanometer. However, the light planes steered by this type of mirrors are typically deformed into cones due to refraction. In order to produce accurate results, this distortion needs to be taken into account, which increases the computational cost of the 3D reconstruction. A novel approach consisting in using a biaxial MEMS mirror is proposed in this paper. The second rotational degree of freedom of the mirror can be used to project optimally curved light shapes, so that the refraction process transforms them into planes. Being able to model the light surfaces as planes rather than cones can significantly reduce the computation time of the 3D reconstruction. In order to do so, an exhaustive model of the complete light trajectories is presented. To the best of the authors' knowledge, this paper constitutes the first attempt to model and counteract the distortion in the scanning pattern introduced by a biaxial mirror and a double refraction process in the context of underwater robotics.

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“…The main contributions (For contributions 1 and 2 were originally proposed in [4,5] and are presented here in a refined archival-quality form. The filter for mesh-like structures is introduced in the current paper.)…”

Section: Introductionmentioning

confidence: 99%

A Laser Vision System for Relative 3-D Posture Estimation of an Underwater Vehicle with Hemispherical Optics

2021

Self Cite

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This paper describes the development and experimental validation of algorithms for a novel laser vision system (LVS), suitable for measuring the relative posture from both solid and mesh-like targets in underwater environments. The system was developed in the framework of the AQUABOT project, a research project dedicated to the development of an underwater robotic system for inspection of offshore aquaculture installations. In particular, an analytical model for three-medium refraction that takes into account the nonlinear hemispherical optics for image rectification has been developed. The analytical nature of the model allows the online estimation of the refractive index of the external medium. The proposed LVS consists of three line-lasers within the field of view of the underwater robot camera. The algorithms that have been developed in this work provide appropriately filtered point-cloud datasets from each laser, as well as high-level information such as distance and relative orientation of the target with respect to the ROV. In addition, an automatic calibration procedure, along with the accompanying hardware for the underwater laser vision system has been developed to reduce the calibration overhead required by regular maintenance operations for underwater robots operating in seawater. Furthermore, a spatial image filter was developed for discriminating between mesh and non-mesh-like targets in the LVS measurements. Finally, a set of experiments was carried out in a controlled laboratory environment, as well as in real conditions at offshore aquaculture installations demonstrating the performance of the system.

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An underwater laser vision system for relative 3-D posture estimation to mesh-like targets

Cited by 9 publications

References 8 publications

State of the Art of Underwater Active Optical 3D Scanners

State of the Art of Underwater Active Optical 3D Scanners

Underwater 3D Scanner Model Using a Biaxial MEMS Mirror

A Laser Vision System for Relative 3-D Posture Estimation of an Underwater Vehicle with Hemispherical Optics

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