Noninvasive particle sizing using camera-based diffuse reflectance spectroscopy

Abildgaard, Otto Højager Attermann; Frisvad, Jeppe Revall; Falster, Viggo; Parker, Allan E.; Christensen, Niels Jørgen; Dahl, Anders Bjorholm; Larsen, Rasmus

doi:10.1364/ao.55.003840

Cited by 9 publications

(4 citation statements)

References 25 publications

(38 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Lately, Abildgaard et al. 15 published diffuse reflectance measurements to estimate particle sizes of fat emulsions. Similar to our work, they used a fitting procedure on the reduced scattering coefficient based on Mie theory.…”

Section: Introductionmentioning

confidence: 99%

Broadband Optical Properties of Milk

et al. 2016

View full text Add to dashboard Cite

Dairy products play an important role in our daily nutrition. As a turbid scattering medium with different kinds of particles and droplets, each alteration of these components changes the scattering properties of milk. The goal of this work is the determination of the amount of main scattering components, the fat droplets and the casein micelles, by understanding the light propagation in homogenized milk and in raw milk. To provide the absolute impact of these milk components, the geometrical and optical properties such as the size distribution and the refractive index (RI) of the components have to be examined. We determined the reduced scattering coefficient [Formula: see text] and the absorption coefficient [Formula: see text] from integrating sphere measurements. By use of a collimated transmission setup, the scattering coefficient [Formula: see text] was measured. Size measurements were performed to validate the influence of the fat droplet size on the results of the scattering properties; also, the RI of both components was determined by the said coefficients. These results were used to determine the absolute impact of the milk components on the scattering behavior. By fitting Mie theory calculations on scattering spectra [Formula: see text] and [Formula: see text] from different raw milk samples, it was possible to get reliable values for the concentrations of fat and casein and for the size of the fat droplets. By destroying the casein micelles, it was possible to separate the influence of the different scattering components on scattering behavior.

show abstract

Section: Introductionmentioning

confidence: 99%

Broadband Optical Properties of Milk

et al. 2016

View full text Add to dashboard Cite

show abstract

“…This is important since a separation of these parameters can help measuring the fat concentration of raw milk without any dilution or pre-treatment necessary. In recent years, milk has often been measured by different diffuse reflectance measurements; [31][32][33][34][35] the idea of an oblique illumination has already partly been applied. 36 Our setup differs from these measurements since it is more sensitive to changes in the scattering phase function and the anisotropy factor.…”

Section: Resultsmentioning

confidence: 99%

Spatially Resolved Lateral Transmission Measurements to Characterize Changes in the Scattering Coefficient and the Anisotropy Factor

2018

View full text Add to dashboard Cite

A new setup is described to characterize the scattering coefficient and the scattering phase function of liquid media. The setup utilizes the basic idea of a spatially resolved reflectance measurement combined with a sophisticated illumination geometry. The sample is illuminated parallel and close to the interface of the sample and a glass window to get information from single scattered and multiple scattered light. By illuminating the sample with a fiber orientated with the axis parallel to the glass surface, small distances to the source can be examined unimpeded by the illumination beam. The derived information is, for example, not only sensitive to the concentration of the scatterers but also to the size of the scattering particles. We present the setup including the theory to describe the light propagation in the whole configuration using Monte Carlo simulations. The validation has been done with polystyrene microsphere dispersions with different scattering coefficients. As application for the developed setup, we show measurements of different milk samples which vary in concentration of fat, protein, and in fat droplet size during homogenization process. By measuring milk, we show the ability of the sensor to determine information about the scattering phase function without diluting the sample. For sensors in the dairy industry, a measurement with no pre-processing and no diluting of the sample is worthwhile, because this can be used to determine the fat and protein concentration on-line.

show abstract

“…A large number of techniques have been suggested for measuring the sizes of emulsion drops, including light microscopy [71], endoscopic techniques [72], UV-spectroscopy [73], diffuse reflectance spectroscopy [74] laser diffraction-based techniques [75], coulter counters [76], low-resolution NMR [77,78], nano-particle tracking [79], and flow field fractionation [80,81]. A comprehensive comparison or review of the different methods is available elsewhere [1,82,83] and is beyond the scope of this contribution.…”

Section: Experimental Considerations For Emulsification Experiment-ba...mentioning

confidence: 99%

Experimental Methods for Measuring the Breakup Frequency in Turbulent Emulsification: A Critical Review

Håkansson¹

2020

ChemEngineering

View full text Add to dashboard Cite

The growing interest in using population balance modeling to describe emulsification processes has spurred an interest in experimentally measuring the breakup frequency. This contribution classifies, compares, and critically reviews the different methods that have been suggested for measuring the breakup frequency, applicable to emulsification devices. Two major approaches can be seen in previous studies. The first is ‘single drop breakup experiment’-based studies, which estimate the breakup frequency by observing the fate of individual drops. The second approach involves ‘emulsification experiment’-based studies, which combine measured drop-size distributions with assumptions to allow for estimations of the breakup frequency. This second approach can be further subdivided in three types: Parametric determination, inverse self-similarity-based methods, and direct back-calculation methods. Each of these methods are reviewed in terms of their implementation, reliability, and validity. Suggestions of methodological considerations for future studies are given for each class, together with more general suggestions for further investigations. The overall objective is to provide emulsification researchers with background information when choosing which method to use for measuring the breakup frequency and with support when setting up experiments and data evaluation procedures.

show abstract

Noninvasive particle sizing using camera-based diffuse reflectance spectroscopy

Cited by 9 publications

References 25 publications

Broadband Optical Properties of Milk

Broadband Optical Properties of Milk

Spatially Resolved Lateral Transmission Measurements to Characterize Changes in the Scattering Coefficient and the Anisotropy Factor

Experimental Methods for Measuring the Breakup Frequency in Turbulent Emulsification: A Critical Review

Contact Info

Product

Resources

About