Imaging particle analysis: Difference between revisions

Revision as of 16:22, 28 October 2013

Revision as of 16:23, 28 October 2013

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Imaging particle analysis uses the techniques common to [[image analysis]] or [[image processing]] for the analysis of particles. Particles are defined here per [[particle size analysis]] as particulate solids, and thereby not including atomic or sub-atomic particles. Furthermore, this article is limited to [[real image|real images]] (optically formed), as opposed to "synthetic" (computed) images ([[computed tomography]], [[confocal microscopy]], SIM and other [[super resolution microscopy]] techniques, etc.).

Given the above, the primary method for imaging particle analysis is using optical microscopy. While [[optical microscope|optical microscopes]] have been around and used for particle analysis since the 1600's<ref name="Hogg1887">{{cite book|author=Jabez Hogg|title=The Microscope: Its History, Construction, and Application: Being a Familiar Introduction to the Use of the Instrument, and the Study of Microscopical Science|url=http://books.google.com/books?id=wzM5AAAAMAAJ&pg=PA8|year=1887|publisher=G. Routledge and Sons|pages=8–8}}</ref>, the "analysis" in the past has been accomplished by humans using the human [[visual system]]. As such, much of this analysis is subjective, or qualitative in nature. Even when some sort of qualitative tools are available, such as a measuring [[reticle]] in the microscope, it has still required a human to determine and record those measurements.

Beginning in the late 1800's<ref name="Tissandier1877">{{cite book|author=Gaston Tissandier|title=A History and Handbook of Photography|url=http://books.google.com/books?id=lWo9AAAAYAAJ&pg=PA1|year=1877|publisher=Sampson, Low, Marston, Low, & Searle|pages=1–1}}</ref> with the availability of [[photographic plate|photographic plates]], it became possible to capture microscope images permanently on film or paper, making measurements easier to acquire by simply using a scaled ruler on the hard copy image. While this significantly speeded up the acquisition of particle measurements, it was still a tedious, labor intensive process, which not only made it difficult to measure statistically significant particle populations, but also still introduced some degree of human error to the process.

Finally, beginning roughly in the late 1970's, [[Charge-coupled device|CCD digital sensors]] for capturing images and computers which could process those images, began to revolutionize the process by using [[digital imaging]]. Although the actual algorithms for performing [[digital image processing]] had been around for some time, it was not until the significant computing power needed to perform these analyses became available at reasonable prices that digital imaging techniques could be brought to bear in the mainstream. The first dynamic imaging particle analysis system was patented in 1982 <ref>{{US patent|4338024}}</ref>.