We report a new method for automated identification and measurement of primary particles within soot aggregates as well as the sizes of the aggregates and discuss its application to high-resolution transmission electron microscope (TEM) images of the aggregates. The image processing algorithm is based on an optimized Hough transform, applied to the external border of the aggregate. This achieves a significant data reduction by decomposing the particle border into fragments, which are assumed to be spheres in the present application, consistent with the known morphology of soot aggregates. Unlike traditional techniques, which are ultimately reliant on manual (human) measurement of a small sample of primary particles from a subset of aggregates, this method gives a direct measurement of the sizes of the aggregates and the size distributions of the primary particles of which they are composed. The current version of the algorithm allows processing of high-resolution TEM images by a conventional laptop computer at a rate of 1–2 ms per aggregate. The results were validated by comparison with manual image processing, and excellent agreement was found.
© 2012 Optical Society of America
Original Manuscript: June 29, 2011
Revised Manuscript: October 25, 2011
Manuscript Accepted: October 28, 2011
Published: February 8, 2012
Vol. 7, Iss. 4 Virtual Journal for Biomedical Optics
Igor Grishin, Kevin Thomson, Francesca Migliorini, and James J. Sloan, "Application of the Hough transform for the automatic determination of soot aggregate morphology," Appl. Opt. 51, 610-620 (2012)