Stochastic digital holography for visualizing inside strongly refracting transparent objects

Desse, Jean-Michel; Picart, Pascal

doi:10.1364/ao.54.0000a1

Cited by 18 publications

(4 citation statements)

References 63 publications

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“…n 1 and n 2 describe the refractive index distribution before and after its change, often realized without and with the transparent object to be measured placed in the holographic arrangement. The object, whose refractive index distribution should be determined, can be a gas, a plasma, a liquid or a solid [3], [17]. Such measurements of integrated refractive index changes along a multitude of optical paths through the transparent object to be measured can be the base of a computerized tomography approach for the determination of the 3D refractive index field.…”

Section: Digital Holographic Refractive Index Measurementmentioning

confidence: 99%

Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Kreis

2016

IEEE Trans. Ind. Inf.

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Holography and holographic interferometry as means for nondestructive testing as well as a metrologic tool in engineering, biology, and other fields has got significant momentum by the introduction of digital holography and furtheron by the employment of numerical processing power, which became available due to the increase in speed and data capacity of modern computers. In this review paper we present the basics of holography, holographic interferometry and digital holography and give examples from such diverse fields as deformation analysis, form determination, refractive index measurement, and wave front reconstruction by shearographic differential interference contrast microscopy.Index Terms-Digital holography, holographic interferometry, nondestructive testing, deformation measurement, strain and stress measurement, shearography, fiber testing. ✦ 1551-3203 (c)

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Section: Digital Holographic Refractive Index Measurementmentioning

confidence: 99%

Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Kreis

2016

IEEE Trans. Ind. Inf.

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“…In the past, DHI has been extensively used for many applications such as measurement of temperature [49][50][51][52][53][54][55][56][57][58][67][68][69], heat transfer from surface of heated objects [52,54], diffusion coefficient [70,71], flow field analysis [72], observation of decomposition of crude oil under dispersant fluid [73], refractive index of liquids [74], heat conduction in glass [75], solution concentration variation in protein crystallization process [76], visualization of thermal gradients in bulb [77], and human skin temperature [78].…”

Section: Introductionmentioning

confidence: 99%

Applications of Digital Holographic Interferometry in Heat Transfer Measurements from Heated Industrial Objects

Kumar¹,

Shakher²

2023

Holography - Recent Advances and Applications

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Digital holographic interferometry (DHI) is used worldwide for many scientific and industrial applications. In DHI, two digital holograms; one in the reference/ambient state of the object and another in changed state of object are recorded by electronic imaging sensors (such as CCD/CMOS) as reference holograms and object holograms, respectively. Phase of object wavefronts in different states of the object is numerically reconstructed from digital holograms. The interference phase is reconstructed by subtracting the phase of reference hologram from the phase of object hologram, without performing any phase-shifting interferometry. Thus, no extra effort is needed in DHI for calculating the interference phase. Apart from direct reconstruction of interference phase from two digital holograms, the recent development, availability of recording devices at video rate, and high-performance computers make the measurements faster, reliable, robust, and even real-time. In this chapter, DHI is presented for the investigation of temperature distribution and heat transfer parameters such as natural convective heat transfer coefficient and local heat flux around the surface of industrial heated objects such as cylindrical wires and heat sinks.

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“…Use of lens in the optical path of object beam in digital holographic setups [11][12][13] can affect quality of reconstructed image as lens changes the propagation distance for reconstruction (sensor plane to image plane) by creating image of the object. The lens-based digital holographic setup has several applications such as particle image velocimetry [14], vibration analysis [15], visualization and measurement of refractive index variation, thermal gradients, and convection currents inside strongly refracting transparent objects [16], specular object detection [17], digital holographic imaging [18] and many NDT applications [19]. Lenses in digital holographic setups are generally used to record a large size object e.g., Schnars et al [11] and Mundt et al [12] used concave lens-based setups to reduce the spatial frequency of large size object by creating its virtual image of reduced size.…”

Section: Introductionmentioning

confidence: 99%

Effect of displacement in object plane on reconstructed image in lens-based digital holography

2021

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Optical properties of lenses play significant role in digital holographic setups to increase their applications in several fields of imaging and non-destructive testing. In present work, we investigate the effect of introduction of lenses on quality of reconstructed images when they are placed between the object and the image sensor in digital holography. We define a range of propagation distance suitable for recording digital holograms using different off-axis digital holographic setups. The reconstruction results of conventional off-axis digital holographic setup are taken as reference to compare them with lens-based digital holographic setups. Three different digital holographic setups are realised using lenses i.e. concave lens-based setup, convex lens-based setup, and combined concave and convex lenses-based setup. The quality of the reconstructed image is measured by calculating their structural similarity index measure (SSIM) values. These values compare the reconstructed image obtained in the experiment with a reference image of the object obtained through its computer generated hologram (CGH). Performance of these digital holographic setups is compared on the basis of SSIM values of reconstructed images calculated for different separation between object to sensor. On the basis of SSIM values, a range of distances suitable for recording digital holograms for each setup is obtained as 220 mm to 400 mm for the concave lens-based setup, 560 mm to 800 mm for convex lens-based setup, and 220 mm to 600 mm for the concave-convex lens-based setup using concave lens of 50 mm focal length and a convex lens of 80 mm focal length in the experiments.

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Stochastic digital holography for visualizing inside strongly refracting transparent objects

Cited by 18 publications

References 63 publications

Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Application of Digital Holography for Nondestructive Testing and Metrology: A Review

Applications of Digital Holographic Interferometry in Heat Transfer Measurements from Heated Industrial Objects

Effect of displacement in object plane on reconstructed image in lens-based digital holography

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