Biospeckle laser spectral analysis under Inertia Moment, Entropy and Cross-Spectrum methods

Nobre, C.M.B.; Braga, Roberto A.; Costa, Anderson Gomide; Cardoso, Rafael; Silva, Washington Luis Santos; Sáfadi, Thelma

doi:10.1016/j.optcom.2009.02.061

Cited by 37 publications

(15 citation statements)

References 9 publications

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“…It is due to scatterer's movement, changes in optical paths due changes in refractive index, changes in the configuration or combinations of both. Those situations usually occur in samples with biological activity, then in the literature the phenomenon is known as biospeckle [6]. Besides, a similar phenomenon is also present in some industrial processes.…”

Section: Principle Of Dynamical Specklementioning

confidence: 99%

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Improved inertia moment method of dynamic speckle analysis and its application

et al. 2009

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The aim of this paper is to present a novel inertia moment algorithm meanwhile use it to investigate the stress corrosion initiation stage of an aluminum alloy. The specimens are Al-2A12 alloy with thickness of 2mm which are immersed in the 3.5% sodium chloride solution. Three-point bending system is employed under displacement loading mode. The center displacement is 2mm, 2.5mm and 4mm, respectively. Meanwhile in order to observe the stress corrosion process, the solution temperature increases from 20.9 to 61.3 degrees centigrade. Average intensity method is recommended to contrast due to its validity for corrosion analysis. The results show at room temperature, the material is not prone to stress corrosion. General electrochemical corrosion is a major role and the process is comparatively moderate. Stress corrosion appears when the temperature has increased. It is a phenomenon of localized corrosion and exhibits asymmetric property. Accompanied with the corrosion process developed, this kind of asymmetric property is increasingly apparent from three-dimensional results.

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Section: Principle Of Dynamical Specklementioning

confidence: 99%

“…Besides, a similar phenomenon is also present in some industrial processes. Many efforts have been devoted to assign numbers to characterize the activity and correlate favorably with measurements of interest of experimenter [6][7][8][9]. These methods were applied to some extent to transient phenomena, i.e.…”

Section: Principle Of Dynamical Specklementioning

confidence: 99%

Improved inertia moment method of dynamic speckle analysis and its application

et al. 2009

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“…Being optical non-contact pattern the important aspects of speckles are determining the activity quantity from the materials under study (Braga et al, 2011). The time varying speckle pattern also plays an important role in many physical phenomena like in measurement of dynamic object (Semenov et al, 2010), metrological and stress corrosion analysis (Chiang & Kin, 1982;Lu & Zou, 2010), surface deformation and roughness measurement (Ling et al, 1986), bio-speckle study in seed analysis (Nobre et al, 2009) besides smoothing of the laser beam (Veron et al, 1988).…”

Section: Experiments Laser Beam Smoothing Study Using 2 Mw He-ne Lasermentioning

confidence: 99%

Laser produced thin metallic planar mini-flyer generation using fiber optic plate

et al. 2013

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Laser produced planar mini flyer generation has widely gained importance owing to its wide ranging applications in the field of condensed matter, astrophysics, material research, shock phenomenon, etc. Flattop smooth laser beam profile as driver is the primary requirement for planar flyer generation besides special multilayered target geometry. We present here laser produced thin metallic planar mini-flyer generation using a fiber optic plate (FOP) of 8 mm thickness and about 6 μm fiber dimension. This technique is unique in the sense that it doesn't require large length as compared to optical fiber. A Gaussian shape laser beam from a laser oscillator was allowed to fall on the FOP generating a speckle pattern. This pattern was relayed and amplified using lenses and laser amplifiers to achieve energy of about 400 mJ. The beam was focused on a substrate (fused silica) based multilayered target on which flyer disks of different materials such as Al. Cu, Br, and Ta were attached. Velocities as high as 400 m/s was measured for Al flyer of 1.5 mm diameter and thickness 50 μm. Flyer disks were completely recovered after the laser shot. We also present a theoretical analysis along with experimental results of the laser beam smoothing technique using a He-Ne laser and FOP. Each channel of the FOP acts as a small single mode optical fiber. The basic idea was to divide the incoming coherent beam into many beam-lets introducing random distribution in length or/and diameter of optical fibers of FOP. The individual FOP channel acts as a diverging source because of single mode fiber with natural divergence λ/d. However, due to the small randomness in length or diameter, the individual diffraction sources are not in phase. This results in the generation of speckles in both near (Fresnel) and far field (Fraunhoffer) destroys the spatial coherence of the beam.

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“…The main features of the proposed test are associated to its non-destructive character, non-subjectivity and automation capability. Although there are many optical techniques that can be used with automation capability, the proposed technique in this research work is biospeckle, whose physical principle is the interference phenomenon that occurs when a coherent [9][10][11][12], frequency responses and absolute value of the differences (AVD) [13], normalization of co-occurrence matrix [14]. Recently, cross-correlation coefficient has been used for the analysis of fruit quality [15,16].…”

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confidence: 99%

“…The results showed that for the same water content, it is possible to differentiate living seeds from seeds having reduced potential due to the formation of water crystals. According to Nobre et al [11], the MI value characterizes the activity by assigning a number to its state. The authors evaluated the spectral components of the STS by means of the MI, as well as the entropy expressed through wavelet and cross-spectrum analysis.…”

mentioning

confidence: 99%

Determination of the Optimum Moisture Content of Purple Ipê (Handroanthus heptaphyllus) Seeds for Biospeckle Tests

Fracarolli¹,

Enes²,

Fabbro³

et al. 2016

JAST-A

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Abstract:Handroanthus heptaphyllus (botany synonymy Tabebuia heptaphylla) is considered to have very important economical, ornamental and medicinal value. It is included in the Bignoniaceae botanical family, whose multiplication is quite solely carried by seeds. Forest dispersion elements, i.e., the seeds, deserve a deep understanding on their physiological performance. The objective of this research work was to determine the optimum seed moisture content for laser interaction in biospeckle tests, which is based on laser interferometry. Seeds were hydrated to the level of 69% and then divided into four subsamples, i.e., (1) seeds without teguments, (2) seeds with tegument, (3) seeds without teguments frozen at 0 °C and (4) seeds with teguments frozen at 0 °C. The four subsamples were then separated into five moisture level groups (28%, 35%, 54%, 63% and 69%) and exposed to the laser. The biospeckle phenomenon quantification was carried out by means of the moment of inertia (MI) approach. A positive correlation between MI and seed moisture content was obtained. It was also verified that seed moisture content between 28% and 54% showed better interaction with the laser. The results are important for the application of the biospeckle technique as a possible tool to assess the quality of purple ipê seeds.

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Biospeckle laser spectral analysis under Inertia Moment, Entropy and Cross-Spectrum methods

Cited by 37 publications

References 9 publications

Improved inertia moment method of dynamic speckle analysis and its application

Improved inertia moment method of dynamic speckle analysis and its application

Laser produced thin metallic planar mini-flyer generation using fiber optic plate

Determination of the Optimum Moisture Content of Purple Ipê (Handroanthus heptaphyllus) Seeds for Biospeckle Tests

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