Effect of particle concentration and turbidity on particle characterization using digital holography

Rahman, Mohammad Nurur; Rajendran, Arvind; Kariwala, Vinay; Asundi, Anand

doi:10.1016/j.cherd.2013.07.012

Cited by 12 publications

(8 citation statements)

References 21 publications

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“…In addition, dualwavelength DHM can be used to solve the 2p-ambiguity problem in phase unwrapping when DHM is applied to the characterization of high-aspect-ratio samples. Therefore, DHM has been widely used in biomedical imaging (Kemper and von Bally, 2008;M€ older et al, 2008;Popescu et al, 2008;Anand et al, 2014), MEMS dynamic testing (Hegde et al, 2013;Zuo et al, 2014), and particle tracking (Kapfenberger et al, 2013;Rahman et al, 2014;Saglimbeni et al, 2014). The recording plane of the hologram is located around the focused image plane; therefore, the diffraction calculation from the hologram plane to image plane is indispensable.…”

Section: Introductionmentioning

confidence: 99%

Characteristics analysis of digital image‐plane holographic microscopy

et al. 2015

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We utilize digital image-plane holographic microscopy (DIPHM) to achieve the real-time surface profile measurement of microstructure. The impulse response functions of DIPHM and traditional digital holographic microscopy (DHM) are both derived. The theoretical derivations indicate that the differences between the two techniques are caused by the diffraction effect of the recording plane with a finite size. The diffraction effect would introduce an unstable factor to the wavefront reconstruction. Therefore, the DIPHM has the characteristics of totally full field of view and low measuring noise compared to DHM. In addition, we take DIPHM and DHM in dual-wavelength mode as a special example to confirm the points above. From both experimental results and theoretical analysis, DIPHM is demonstrated to be an optimized technique with high-quality imaging, especially benefiting the situation where multi-wavelength measurement is required. This method is robust against environmental noise. SCANNING 38:288-296, 2016. © 2015 Wiley Periodicals, Inc.

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Section: Introductionmentioning

confidence: 99%

Characteristics analysis of digital image‐plane holographic microscopy

et al. 2015

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“…In summary, this thesis has been addressed to find out the practical limitations and applications of the digital inline holographic (DIH) system on particle characterization concerning particle concentration and turbidity effects [43], and to develop some computer algorithms to estimate particle size and shape distribution in population, especially for more complicated particulate systems such as needles and mixed morphologies [44][45]. Further, a theoretical relationship is deduced here between the particle size and the digital image sensor resolution (pixel), both for collimated and diverging illumination, considering DIH system.…”

Section: Discussionmentioning

confidence: 99%

“…And hence, information capacity or particle concentration of DH is much lower. Particle detection procedure is sever adversely affected with high concentration and DH due to the presence of speckle noises in the hologram recording and the reconstruction steps [43]. Today's CCD has sufficient frame rate (frames per second, FPS) which can capture scenes at high temporal resolution.…”

Section: Background and Motivationmentioning

confidence: 99%

“…Since particle size and shape distribution measurement methods using DH are established in literatures [37,[41][42], this thesis has been addressed to find out the practical limitations and applications of the digital inline holographic (DIH) system on particle characterization concerning particle concentration and turbidity effects [43], and to develop some computer algorithms to estimate particle size and shape distribution in population unlike spherical, especially for more complicated particulate systems such as needles and mixed morphologies [44][45]. Single crystal study is also performed.…”

Section: Background and Motivationmentioning

confidence: 99%

“…The effect of particle concentration and turbidity on the number of identified particles and the particle mean size measured using inline transmission based digital holography (DH) is investigated [43]. It is demonstrated that measurement performance can be significantly improved by reducing the sample depth though lower concentration loading is preferred in DH.…”

Section: Contributions Obtained From the Thesismentioning

confidence: 99%

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Digital holographic systems for particulate processes

Rahman¹

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List of Figures 2.1 Limitations of photographic imaging technique. (a) out of focused particle on a photographic image plane; (b) aggregated particles on the image plane. 12 2.2 Geometry of DIH 14 2.3 Schematic representation showing step-wise implementation of DH for micro-objects analysis. 2.4 Diffraction pattern of a particle onto the CCD array. 2.5 Maximum spatial frequency resolved by a CCD array. 2.6 Particle with diverging illumination. 3.1 Materials used for particle concentration and turbidity effects. (a) for concentration effect; (b) for turbidity effect. 3.2 Optical setup of the digital inline holographic microscopy. 3.3 Schematic for the calculation of sample volume imaged onto the camera. 3.4 Effect of particle concentration on detection efficiency. 3.5 Reconstructed images for 10 mm depth. (a) 0.01 v/v% particle concentration; (b) 0.05 v/v% particle concentration showing particle-particle interaction; (c) 0.05 v/v% particle concentration showing size reduction due to the noise (particle outlines at both lower and higher concentrations are shown in the inset for comparison). The green region is the area identified as the particle by the image processing algorithm. 3.6 Holograms and reconstructed images at 0.01 v/v% particle concentration. (a) hologram for 5 mm depth; (b) hologram for 10 mm depth; (c) reconstructed image at 25.55 mm for the hologram shown at (a); (d) reconstructed image at 29.95 mm for the hologram shown at (b). 30 3.7 PSDs and particle sizes at different concentrations. (a) PSDs for 10 mm depth; (b) Errorbar plot of the particle sizes for 10 mm depth; (c) PSDs for 5 mm depth; (d) Errorbar plot of the particle sizes for 5 mm depth. Errorbar plots are drawn based on the means and standard deviations of the distributions.

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Measurement of slurry droplets in coal-fired flue gas after WFGD

Zhao

Zhang

et al. 2014

Environ Geochem Health

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China owns the world's largest capacity of coal-fired power units. By the end of 2012, the capacity of installed national thermal power has been 819.68 million kilowatts. The latest standard requires that newly built power plants emit SO2 in no more than 100 mg/m(3) and the emission of old ones be lower than 200 mg/m(3) while in some key areas the emission should be controlled under 50 mg/m(3). So by the end of 2012, 90% of the active coal-fired units have been equipped with flue gas desulfurization devices. Among the desulfurization methods adopted, limestone-gypsum wet flue gas desulphurization accounts for 92%, causing the problem of fine droplets in the exhaust gas after defogger, which may even form "gypsum rain." At present, sampling methods are widely used at home and abroad, such as magnesium ion tracer method, modified magnesium ion tracer method and chemical analysis. In addition, some scholars use aerodynamic methods, such as ELPI, to measure the diameter distribution and concentration. The methods mentioned above all have their own demerits, such as the inability to on-line, continuous measurements and the need of prolonged measuring time. Thus, in this paper some potential optical on-line methods are presented, such as Fraunhofer diffraction pattern analysis and wavelength-multiplexed laser extinction. Also brought up are their measuring scope and merits. These methods have already been utilized to measure small liquid droplets and their demonstrations and evaluations are as well stated. Finally, a 3D imaging method based on digital holographic microscope is proposed for in-line measurement of size and concentration of slurry droplets. The feasibility of this method is demonstrated by preliminary experimental investigation.

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Effect of particle concentration and turbidity on particle characterization using digital holography

Cited by 12 publications

References 21 publications

Characteristics analysis of digital image‐plane holographic microscopy

Characteristics analysis of digital image‐plane holographic microscopy

Digital holographic systems for particulate processes

Measurement of slurry droplets in coal-fired flue gas after WFGD

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