Wavelet denoising method for laser-induced breakdown spectroscopy

Zhang, Bo; Sun, Limin; Huang, Yu; Xin, Yong; Cong, Zhaotong

doi:10.1039/c3ja50239b

Cited by 46 publications

(20 citation statements)

References 39 publications

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“…Zhang et al utilized WTD with double thresholds correction scheme for noise suppression, and the optimal decomposition level was obtained by the white noise testing method [24]. When the decomposition level (DL) is too small, the power compression of the useful signal is not obvious so that the result of noise reduction is not ideal; when DL is too excessive, the obvious power compression of the useful signal causes the loss of useful information and results in the decreased of the SNR and the increased of the mean square error (MSE).…”

Section: Introductionmentioning

confidence: 99%

A method for improving wavelet threshold denoising in laser-induced breakdown spectroscopy

Zhang

Sun

et al. 2015

Spectrochimica Acta Part B: Atomic Spectroscopy

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Section: Introductionmentioning

confidence: 99%

A method for improving wavelet threshold denoising in laser-induced breakdown spectroscopy

Zhang

Sun

et al. 2015

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…Therefore, using the appropriate data processing methods to reduce spectra noise is very desirable, especially for liquid samples. Recently, Schlenke et al (2012) and Zhang et al (2013a) carried out theoretical studies on LIBS data's de-noising using wavelet theory. They have shown significant improvements for LOD and signal-to-noise ratio after data processing.…”

Section: Data Processingmentioning

confidence: 99%

Laser-induced breakdown spectroscopy application in environmental monitoring of water quality: a review

et al. 2014

Environ Monit Assess

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Water quality monitoring is a critical part of environmental management and protection, and to be able to qualitatively and quantitatively determine contamination and impurity levels in water is especially important. Compared to the currently available water quality monitoring methods and techniques, laser-induced breakdown spectroscopy (LIBS) has several advantages, including no need for sample pre-preparation, fast and easy operation, and chemical free during the process. Therefore, it is of great importance to understand the fundamentals of aqueous LIBS analysis and effectively apply this technique to environmental monitoring. This article reviews the research conducted on LIBS analysis for liquid samples, and the article content includes LIBS theory, history and applications, quantitative analysis of metallic species in liquids, LIBS signal enhancement methods and data processing, characteristics of plasma generated by laser in water, and the factors affecting accuracy of analysis results. Although there have been many research works focusing on aqueous LIBS analysis, detection limit and stability of this technique still need to be improved to satisfy the requirements of environmental monitoring standard. In addition, determination of nonmetallic species in liquid by LIBS is equally important and needs immediate attention from the community. This comprehensive review will assist the readers to better understand the aqueous LIBS technique and help to identify current research needs for environmental monitoring of water quality.

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“…Wiens et al used WTD for removing noise and obtained satisfying denoising results; however, they gave no details about the method used to select the optimal DL. Zhang et al constructed double‐threshold optimization models for wavelet denoising, and the model was verified by means of the denoising effect of both the synthetic and observed LIBS signal. When the DL is too small, the power compression of the useful signal is not obvious; thus, the result of noise reduction is not ideal.…”

Section: Spectral Data Preprocessingmentioning

confidence: 99%

Chemometrics in laser‐induced breakdown spectroscopy

Zhang

Tang

2018

Journal of Chemometrics

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Laser-induced breakdown spectroscopy (LIBS) is a new type of elemental analytical technology with the advantages of real-time, online, and noncontact as well as enabling the simultaneous analysis of multiple elements. It has become a frontier analytical technique in spectral analysis. However, the issue of how to improve the accuracy of qualitative and quantitative analyses by extracting useful information from a large amount of complex LIBS data remains the main problem for the LIBS technique. Chemometrics is a chemical subdiscipline of multi-interdisciplinary methods; it offers advantages in data processing, signal analysis, and pattern recognition. It can solve some complicated problems that are difficult for traditional chemical methods. In this paper, we reviewed the research progress of chemometrics methods in LIBS for spectral data preprocessing as well as for qualitative and quantitative analyses in the most recent 5 years (2012-2016). KEYWORDSchemometrics, data preprocessing, laser-induced breakdown spectroscopy, qualitative analysis, quantitative analysis | INTRODUCTIONAs one of the most promising analytical tools in the 21st century, laser-induced breakdown spectroscopy (LIBS) is a novel analytical technique for materials and elements; it is based on atomic emission spectroscopy and a laser as an excitation source. 1-4 In LIBS, a low-energy pulse laser (typically tens to hundreds of millijoules per pulse) generated from a laser device is reflected by a plane mirror and focused by a plano-convex lens onto the sample surface; a laser-induced plasma with high temperature is then generated. The light with different frequencies is radiated during the plasma cooling process, and it is collected by an optical fiber coupled to a spectrometer. The qualitative and quantitative analyses by the LIBS technique can be performed using the wavelength and integrated intensity of the spectral line. A schematic diagram of the LIBS instrument is presented in Figure 1. It consists of Nd:YAG laser, optical part, X-Y-Z manual micrometric stage, optical fiber, spectrometer, Charge coupled device (CCD) camera, and computer.The LIBS technology has benefited from the invention of the ruby crystal laser 5 and was first reported by Brech and Cross. 6 It has become a research focus in the spectral field with the development of laser and optical detection techniques. Compared with conventional analytical tools, LIBS demonstrates some substantial advantages with regards to being rapid, real-time, on-site, and nondestructive while allowing remote detection without complicated sample preparation procedures as well as simultaneous multicomponent analysis. 7-9 Because of these advantages, LIBS technology has been widely used in process analysis and in the control of industrial manufacturing, food supervision, environmental monitoring, historical relic identification, and space exploration. [10][11][12][13] The National Aeronautics and

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Wavelet denoising method for laser-induced breakdown spectroscopy

Cited by 46 publications

References 39 publications

A method for improving wavelet threshold denoising in laser-induced breakdown spectroscopy

A method for improving wavelet threshold denoising in laser-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy application in environmental monitoring of water quality: a review

Chemometrics in laser‐induced breakdown spectroscopy

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