Characterizing weld pool surfaces from polarization state of thermal emissions

Coniglio, N.; Mathieu, Alexandre; Aubreton, Olivier; Stolz, Christophe

doi:10.1364/ol.38.002086

Cited by 19 publications

(10 citation statements)

References 15 publications

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“…In the past decades, a lot of research [1]- [7] has been conducted to measure its shape. In [1] and [2], radiography is used to sense the weld pool by the phenomenon that the radiation of the received x-ray increases with the depression depth of the weld pool.…”

Section: Introductionmentioning

confidence: 99%

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Automatic Segmentation of Fuzzy Laser Lines with Sub-Pixel Accuracy from the Uneven Background During Robotic Arc Welding

Wang¹

2016

2016 7th International Conference on Intelligent Systems, Modelling and Simulation (ISMS)

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Abstract-Robust and automatic segmentation of the reflected laser lines from the arc light modified background is prerequisite for the subsequent measurement of the weld pool shape which is of great importance for monitoring robotic arc welding. In this paper, the two dimensional intensity distribution caused by the arc light in the captured image is modeled. Based on the model, we propose an efficient and effective method that comprises three parts: (1), spline enhancement to achieve sub-pixel accuracy; (2), a gradient detection filter to eliminate the uneven background; (3), an effective threshold selection method. Experimental results verified that the proposed method is significantly superior to other state of art methods in segmentation accuracy.

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Section: Introductionmentioning

confidence: 99%

“…In [6], grating image instead of laser dots was used to estimate the weld pool shape. In [7], the authors made use of the thermal emission to estimate the weld pool shape. Among all these state of art methods, only [5] yields a closed form solution and achieves accurate measurement of gas tungsten arc welding (GTAW) weld pool shape.…”

Section: Introductionmentioning

confidence: 99%

Automatic Segmentation of Fuzzy Laser Lines with Sub-Pixel Accuracy from the Uneven Background During Robotic Arc Welding

Wang¹

2016

2016 7th International Conference on Intelligent Systems, Modelling and Simulation (ISMS)

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“…It is very important for developing the next generation intelligent welding machines. Additionally, estimating the weld joint penetration in automatic welding is very interesting [7,8]. Therefore, in this paper, the images of front-side free surface and back-side width of the weld pool are synchronously sensed by two different CCD cameras are welding process using the laser vision, and then the 3D weld pool surface can be reconstructed utilized our proposed algorithm [9].…”

Section: Introductionmentioning

confidence: 99%

3D Reconstruction Algorithm of Weld Pool Surface Based on Computer Vision Technology

Zhang¹

2015

TOPEJ

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Abstract:As is well known that sensing and measuring the weld pool surface is very important to design intelligent welding machines which is able to imitate a skilled human welder who can choose suitable welding parameters. Therefore, in this paper, we concentrate the problem of weld pool surface 3D reconstruction, which is a key issue in intelligent welding machines development. Firstly, the framework of the weld pool surface 3D reconstruction system is described. The weld pool surface 3D reconstruction system uses a single camera stereo vision system to extract original data from weld pool, and then the left and right image are collected. Afterwards, we utilize Pixel difference square and matching algorithm and Stereo matching algorithm to process images. Next, the 3D reconstruction of weld pool surface is constructed using the point cloud data. Secondly, stereo matching based weld pool surface 3D reconstruction algorithm is illustrated. In this algorithm, the matching cost function is computed through the Markov random field, and then the weighted matching cost is calculated via the guided filter. Thirdly, to test the performance of our proposed algorithm, we develop an experimental platform to measure weld pool width, length, convexity and the previous inputs based on a linear model predictive controller. Experimental results demonstrate that the proposed 3D reconstruction algorithm of weld pool surface can achieve high quality under both current disturbance and speed disturbance.

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“…However, polarization has not been as extensively investigated for imaging applications, although some exciting applications are starting to be explored. [6], and the search for biological activity on other planets [7]. There are even some animals, such as the mantis shrimp, that have evolved sophisticated polarimetric visual systems to obtain valuable information from their environment, and are sensitive to all the polarization components of light [8].…”

mentioning

confidence: 99%

“…However, polarization has not been as extensively investigated for imaging applications, although some exciting applications are starting to be explored. Polarimeters can be used in such diverse areas as passive remote sensing [1] for the detection of improvised explosive devices [2], characterization of aerosol particles in the Earth atmosphere [3], extra-solar planet detection [4], remote mapping of planetary magnetospheres [5], quality control for welding [6], and the search for biological activity on other planets [7]. There are even some animals, such as the mantis shrimp, that have evolved sophisticated polarimetric visual systems to obtain valuable information from their environment, and are sensitive to all the polarization components of light [8].…”

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confidence: 99%

Triple Wollaston-prism complete-Stokes imaging polarimeter

Perreault

2013

Opt. Lett.

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Imaging polarimetry is emerging as a powerful tool for remote sensing in space science, Earth science, biology, defense, national security, and industry. Polarimetry provides complementary information about a scene in the visible and infrared wavelengths. For example, surface texture, material composition, and molecular structure will affect the polarization state of reflected, scattered, or emitted light. We demonstrate an imaging polarimeter design that uses three Wollaston prisms, addressing several technical challenges associated with moving remote-sensing platforms. This compact design has no moving polarization elements and separates the polarization components in the pupil (or Fourier) plane, analogous to the way a grating spectrometer works. In addition, this concept enables simultaneous characterization of unpolarized, linear, and circular components of optical polarization. The results from a visible-wavelength prototype of this imaging polarimeter are presented, demonstrating remote sensitivity to material properties. Light has several physical properties that are useful for remote sensing applications in space science, Earth science, biology, defense, national security, and industry. The intensity and wavelength of light has been used widely to gain spatial and spectral information from a scene. However, polarization has not been as extensively investigated for imaging applications, although some exciting applications are starting to be explored. [6], and the search for biological activity on other planets [7]. There are even some animals, such as the mantis shrimp, that have evolved sophisticated polarimetric visual systems to obtain valuable information from their environment, and are sensitive to all the polarization components of light [8]. These applications stem from the basic interaction of light with a solid surface, liquid surface, or gas. The lightmatter interactions alter the amplitude and phase of polarization states in a way that depends on material properties. For example, conductive materials have a complex index of refraction that will cause a phase-shift between orthogonal polarization states, generating elliptically polarized light [9]. This effect can provide contrast between conductive and nonconductive matter, enabling material discrimination and artificial object detection. The total degree of polarization is also affected by the texture and topology of a surface, and requires complete knowledge of all the polarized and unpolarized components for unambiguous characterization. In addition, all known biological systems have evolved to prefer a particular chirality (or handedness) of organic molecules. This asymmetry in the occurrence of stereoisomers can lead to a unique polarization signal through circular dichroism or optical activity [7,10]. In order to exploit these phenomena one needs to build a polarimeter that can measure both linear and circular polarization, using a robust design that is suitable for a moving platform. In this Letter we put forth a new scanning-polarimet...

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Characterizing weld pool surfaces from polarization state of thermal emissions

Cited by 19 publications

References 15 publications

Automatic Segmentation of Fuzzy Laser Lines with Sub-Pixel Accuracy from the Uneven Background During Robotic Arc Welding

Automatic Segmentation of Fuzzy Laser Lines with Sub-Pixel Accuracy from the Uneven Background During Robotic Arc Welding

3D Reconstruction Algorithm of Weld Pool Surface Based on Computer Vision Technology

Triple Wollaston-prism complete-Stokes imaging polarimeter

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