Portable electronic speckle interferometry device for the damages measurements in veneered wood artworks

Castellini, Paolo; Abaskin, V.; Achimova, E.

doi:10.1016/j.culher.2008.05.002

Cited by 20 publications

(10 citation statements)

References 2 publications

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“…In an ideal case, the methods should be non-destructive, simple, and portable. Spectrometric methods were developed such as infrared or near-infrared spectrometry (Marengo et al 2004;Tsuchikawa et al 2005;Kandemir-Yucel et al 2007;Castellini et al 2008;Desnica et al 2008;Inagaki et al 2008a, b). There is a large progress in this field and in the development of protecting and preserving wooden cultural heritages (Falciai et al 2003;Giorgi et al 2005Giorgi et al , 2009Björdal and Nilsson 2008;Mahltig et al 2008;Bugani et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Aging of wood: Analysis of color changes during natural aging and heat treatment

Matsuo¹,

Yokoyama²,

Umemura³

et al. 2011

Holzforschung

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The color properties of aging wood samples from historical buildings have been compared with those of recent wood samples that were heat treated at temperatures ranging from 90°C to 180°C. The results of kinetic analysis obtained by the time-temperature superposition method showed that the color change during natural aging was mainly due to a slow and mild oxidation process. In other words, heat treatment could accelerate the changes in wood color that occur during aging. In one sample, the color change (ΔE* ab ) after 921 years at ambient temperature was almost equivalent to that of heating (artificial aging) approximately for 6.7 h at 180°C. The results have been interpreted that the aging and the subsequent change in wood color begin at the time of tree harvesting.

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Section: Introductionmentioning

confidence: 99%

Aging of wood: Analysis of color changes during natural aging and heat treatment

Matsuo¹,

Yokoyama²,

Umemura³

et al. 2011

Holzforschung

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“…The portable fiber-optic ESPI set-up based on a He-Ne CW laser and optical fibers has been developed from off-the-shelf components [4,5]. According with our aims by splitting the ESPI set-up into two separate units for illumination and monitoring linked by the optical fiber cables a very flexible usage of the set-up in different environments can be constructed.…”

Section: Optical Espi Set-upmentioning

confidence: 99%

Using the Optical Code for Phase Analysis of the Fiber-Optic ESPI Set-Up

Abaskin¹,

Achimova²,

Rastogi³

et al. 2010

AIP Conference Proceedings

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Shape error analysis for reflective nano focusing optics AIP Conf.Abstract. Reliable information about object properties by applying ESPI (Electron Speckle Pattern Interferometry) method strongly depends on quality of speckle images. Acquisition of information about object is resulted as optical setup performance as digital processing. Digital phase extraction is the sequent step in image processing after optical acquisition. High focus quality, uniform illumination of object and CCD camera chip properties are the important parameters for consequence image processing. "Sharp focus" of speckle image on CCD camera is one of these features that would determine the object region of interest. As a rule the speckle images, speckle correlation distances and consequently unwrapped phase map suffer by distortion and brightness unevenness of image. It leads to cutting the field of credence of ESPI method. The use of ZEMAX's Image Analysis, Illumination and Wavefront Map features for predicting and verifying the performance of optical part of fiber-optic ESPI set-up designs will be discussed. For digital processing of speckle images obtained we made use of a spatial phase shifting method by LabVIEW that permits the quantitative analysis of phase differences. The work results proof that ZEMAX Image Analysis is a valuable tool for ESPI designs and visualizing ESPI performance before a prototype is built. Optical image processing is the cumbersome part of optical system design, but thanks to the optical code we have possibility to simulate optical components performance including optimization.

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“…Thermography allows accurate subsurface delamination imaging, but is limited to millimeterthick laminates, such as veneer overlays, due to the inherent thermal damping of the porous wood microstructure (Meinlschmidt, 2005;Tsuchikawa et al, 2000). The same restrictions apply for optic methods, which are based on the detection of surface deformations (Castellini et al, 2008). X-rays are able to penetrate thick structural members.…”

Section: Introductionmentioning

confidence: 99%

Bonding Defect Imaging in Glulam with Novel Air-Coupled Ultrasound Testing

Sanabria

Furrer

Neuenschwander

et al. 2014

Research Developments in Wood Engineering and Technology

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The objective of this chapter is to provide an overview of novel non-destructive testing methodologies for bonding quality assessment in glued laminated timber developed within a recently completed Swiss National Science Foundation research project (Sanabria, 2012). The focus is set on air-coupled ultrasound testing, which has previously been applied to wood-based panels typically up to 50 mm thick. A novel prototype capable of transmitting ultrasound signals through up to 500 mm thick glulam was developed. A computerized-scanning system allowed imaging of the position and geometry of defects within the bonding planes. A normal transmission setup allows a global assessment of defective bonding planes stacks. Latest results are as well shown for a recently patented slanted lateral transmission setup, which allows separate assessment of individual bonding planes with unlimited beam height and length. The investigations allowed an improved understanding of the wave propagation phenomena in thick laminated timber components through both analytical calculations and finite-difference numerical simulations. An overview of the main findings is as well provided. Future research is planned to combine the developed theoretical and experimental tools in a tomographic inspection method.

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Portable electronic speckle interferometry device for the damages measurements in veneered wood artworks

Cited by 20 publications

References 2 publications

Aging of wood: Analysis of color changes during natural aging and heat treatment

Aging of wood: Analysis of color changes during natural aging and heat treatment

Using the Optical Code for Phase Analysis of the Fiber-Optic ESPI Set-Up

Bonding Defect Imaging in Glulam with Novel Air-Coupled Ultrasound Testing

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