Linear displacement measurement with a grating and speckle pattern illumination

Perez-Quintián, Fernando; Lutenberg, Ariel; Rebollo, María Antonia Paz

doi:10.1364/ao.45.004821

Cited by 13 publications

(9 citation statements)

References 6 publications

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“…(2) we obtain the characteristic function of the roughness for high roughness limit, /r x ð Þr Ã ðxuÞS ¼ expðÀ9xÀxu9=T 0 Þ, being T 0 the optical correlation length of the field after the grating [7]. This parameter for a decreasing exponential function is related to the roughness by means of T 0 ¼T/(2ks) 2 , [9]. The statistical parameters, T and s, ablation occurred.…”

Section: Theoretical Fundamentalsmentioning

confidence: 99%

Use of steel substrates in diffractive optics: Near field of high surface quality steel tape gratings

Salgado-Remacha

Torcal-Milla

Sanchez‐Brea

et al. 2011

Optics and Lasers in Engineering

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a b s t r a c tSteel tape is used in optical applications due to its mechanical properties. However, roughness of steel surfaces affects to wave propagation. The effect can be observed using diffraction gratings with low periods. In such a case, self-images of the grating appear at certain periodic distances from the grating (Talbot planes). When standard steel is used, the contrast of Talbot self-images strongly decreases with the distance from the grating. In this work, we prove that controlling the surface quality of steel, it is possible to improve its optical behavior and, as a consequence, high quality surface steel represents a good choice for diffractive optics when the use of chrome-on-glass masks is not indicated. As an example, we have manufactured a diffraction grating over a high quality steel surface by means of an ablation process with a nanosecond pulsed laser. The contrast of the self-images for these gratings decreases very slowly with the distance, in comparison with the self-images obtained with standard steel tape gratings.

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Section: Theoretical Fundamentalsmentioning

confidence: 99%

Use of steel substrates in diffractive optics: Near field of high surface quality steel tape gratings

Salgado-Remacha

Torcal-Milla

Sanchez‐Brea

et al. 2011

Optics and Lasers in Engineering

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“…Deformable registration techniques have been previously applied to quantify tissue strain. 2,12,17,23,25,27,30 Patterns of intensity used to spatially align images provide a method of back calculating tissue strain in both bone and soft tissues. This investigation aims to characterize the biomechanical response of rat-tail vertebrae to axial compressive loading through image-based strain measurement.…”

Section: Introductionmentioning

confidence: 99%

Image Registration Demonstrates the Growth Plate has a Variable Affect on Vertebral Strain

et al. 2010

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Characterizing the biomechanical behavior of the vertebrae is important in understanding the impact of structural and material changes on spinal growth and fracture risk. The growth plate is critical for the normal development of the skeleton, with abnormalities leading to uneven maturation. Little is known about how growth plates affect the stress and strain experienced by the surrounding bone. Concentrated strain within the growth plate may influence mechanical cell signaling during development, lead to increased fracture risk at this site and may influence average bone strain measures. It is hypothesized that the growth plates and adjacent bony areas will take up a large amount of the strain within rat-tail vertebrae under axial compressive loading, leading to increased average bone strain measures. The sixth caudal vertebrae of 8 rnu/rnu rats were muCT scanned in both loaded (20-32 N axial compression) and unloaded configurations. Image registration was used to calculate strain in the bone due to the applied load by finding a spatial mapping between the two scans. In seven of the eight rats, the majority of the strain measured within their vertebrae was concentrated in the growth plates. Five of the specimens had growth plates that demonstrated rigid behavior in contrast to compliant growth plate behavior seen in the other three rats. The presence of a compliant growth plate led to higher average (-0.03 vs. -0.01) and maximum (-0.13 vs. -0.02) strains. The strain within the growth plate is important to consider when interpreting apparent tissue level biomechanical data commonly reported in the literature as this study suggests strains are not uniformly distributed with high concentrations in and around the growth plate. This strain distribution may provide insight into the mechanical signals that cells experience during the formation of new bone, with the higher strains near the growth plate signaling cells to lay down more bone, while also leading to increased risk of fracture in this region.

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“…allow an analytical integration of the equations involved [13][14][15][16]. In this work we have used the decreasing exponential model…”

mentioning

confidence: 99%

“…Using this high roughness approach, g Ͼ Ͼ 1, we can relate the field correlation length T 0 with the roughness parameters, resulting in [16] …”

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confidence: 99%

Talbot effect with rough reflection gratings

2007

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The Talbot effect is analyzed when steel tape gratings are used. These gratings are made on a steel substrate, and, because of the manufacture process, both levels of the grating are rough with different roughness parameters. A theoretical analysis based on Fresnel regime, which considers the statistical properties of roughness, is developed. Analytical formulas that show a decreasing exponential dependence on the intensity in terms of the distance between the grating and the observation plane are obtained, and an experimental verification is also performed.

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Linear displacement measurement with a grating and speckle pattern illumination

Cited by 13 publications

References 6 publications

Use of steel substrates in diffractive optics: Near field of high surface quality steel tape gratings

Use of steel substrates in diffractive optics: Near field of high surface quality steel tape gratings

Image Registration Demonstrates the Growth Plate has a Variable Affect on Vertebral Strain

Talbot effect with rough reflection gratings

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