AUTOMATED DATA ANALYSIS FOR CONSECUTIVE IMAGES FROM DROPLET COMBUSTION EXPERIMENTS
DOI:
https://doi.org/10.5566/ias.v31.p137-148Keywords:
conic fitting, droplet combustion, edge detection, ellipse fitting, image analysis, weighted least squaresAbstract
A simple automated image analysis algorithm has been developed that processes consecutive images from high speed, high resolution digital images of burning fuel droplets. The droplets burn under conditions that promote spherical symmetry. The algorithm performs the tasks of edge detection of the droplet’s boundary using a grayscale intensity threshold, and shape fitting either a circle or ellipse to the droplet’s boundary. The results are compared to manual measurements of droplet diameters done with commercial software. Results show that it is possible to automate data analysis for consecutive droplet burning images even in the presence of a significant amount of noise from soot formation. An adaptive grayscale intensity threshold provides the ability to extract droplet diameters for the wide range of noise encountered. In instances where soot blocks portions of the droplet, the algorithm manages to provide accurate measurements if a circle fit is used instead of an ellipse fit, as an ellipse can be too accommodating to the disturbance.
References
Avedisian CT, Yang JC, Wang CH (1998). On Low-Gravity Droplet Combustion. Proceedings of the Royal Society of London A 420:183-200.
Avedisian CT (2000). Recent Advances in Soot Formation from Spherical Droplet Flames at Atmospheric Pressure. Journal of Propulsion and Power 16:628-56.
Bae JH, Avedisian CT (2004). Experimental Study of the Combustion Dynamics of Jet Fuel Droplets with Additives in the Absence of Convection, Combustion and Flame 137: 148-62.
Bae JH, Avedisian CT (2009). Nonane Droplet Combustion With and Without Buoyant Convection: Flame Structure, Burning Rate, and Extinction in Air and Helium. Proceedings of the Combustion Institute 32:2231-8.
Carpenter GC, Duvall D (1983) How-To-Do-It: Motion Picture and Videotape Analysis of Behavior. The American Biology Teacher 45:349-352.
Choi MY, Dryer FL, Haggard, Jr. JB, Brace MH (1988), Further Observations on Microgravity Droplet Combustion in the NASA-Lewis Drop Tower Facilities: A Digital Processing Technique for Droplet Burning Data. AIP Conference Proceedings 197:338-361.
Choi MY (1992). Droplet Combustion Characteristics under Microgravity and Normal-Gravity Conditions, Ph.D Thesis, Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, N.J.
Choi MY, Kyeong-Okk L (1996). Investigation of Sooting in Microgravity Droplet Combustion. Proc. Comb. Inst. 26:1243-9.
CLEMEX intelligent microscopy, .
Dietrich DL, Haggard Jr. JB, Dryer FL, Nayagam V, Shaw
BD, Williams FA (1996). Droplet Combustion Experiments in Spacelab. Proc. Comb. Inst. 26:1201-7.
Fitzgibbon A, Pilu M, Fisher R (1999). Direct Least Squares Fitting of Ellipses. IEEE Trans. Pattern Anal. Mach. Intell. 21:476-80.
Gander W, Golub GH, Strebel R (1994). Least-Squares Fitting of Circles and Ellipses, BIT43:558–78.
Halir R, Flusser J (1998). Numerically Stable Direct Least Squares Fitting of Ellipses. Proc. WSCG’98:125-32.
Hendel T (2010). <http://www.mathworks.com/matlabcentral/fileexchange/22423-ellipse-fit>, 18 May 2010.
Hicks MC, Nayagam V, Williams FA (2010). Methanol droplet extinction in carbon-dioxide-enriched environments in microgravity. Combustion and Flame 157:1439–45.
Image-Pro Plus Version 6.3 for Windows Start-Up Guide (2008). Media Cybernetics, Inc., Bethesda, MD.
ImageWarp, .
Jackson GS, Avedisian CT (1994). The Effect of Initial Diameter in Spherically Symmetric Droplet Combustion of Sooting Fuels. Proceedings of the Royal Society, London A 446:255-76.
Law CK, Williams FA (1972). Kinetics and Convection in the Combustion of Alkane Droplets, Combustion and Flame 19:393-405.
Liu YC, Avedisian CT (2012) A Comparison of the Burning Characteristics of Sub-millimeter Droplets of Binary Mixtures of iso-Octane, n-Heptane and Toluene with a Commercial Unleaded Gasoline, Combustion and Flame 159:770-83.
PAX-it Image Database Software, <http://www.paxit.com/index.asp>.
Pitas I (2006), Digital image processing algorithms and applications, John Wiley & Sons, New York, New York.
SigmaScan, Systat Software Inc., .
Stewart GH, Lynch PR, Gimenez JL (1969). Technical Note: Versatile Technique for the Analysis of Dynamics Multidimensional information. Medical and Biological Engineering and Computing 7:435-8.
Turns SR (2006), An Introduction to Combustion, 2nd edt., McGraw Hill, Boston, M.A., p. 378.
Weisstein EW, "Ellipse." From MathWorld--A Wolfram Web Resource.
