FlowCam® - Flow Imaging Microscopy Blog

Lew Brown

Recent Posts

The Difference Between Real (Optical) Images and Synthetic (Computed) Images

I guess you could call me a die-hard when it comes to what I consider to be a real image. For me, it comes down to whether a real optical image was formed or whether the image itself was generated from some other source, signal or phenomenon. Sure, some will argue that this is all semantics, but in a very real way, the difference is as significant to me as Direct versus Indirect Particle Size Measurement. Part of it has to do with my personal background: I got into this field first as a photographer (who realized it was going to be very hard making a living in that field... a separate topic in and of itself!), then studied Imaging Science in college, followed by many years working in the digital image processing industry.

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Topics: FlowCam Technology

What's Under the Curve? Particle Imaging can Answer!

I've been using the simple question above, "What's Under the Curve", for many years now as a very basic way of illustrating the principle difference between imaging particle analysis and the bulk of automated particle analysis systems. Automated particle analysis has been around for quite a long time, beginning in the 1950's with the availability of Coulter (electrozone) Counters. Many people are familiar with these and other systems which are "volumetric" in nature: basically these systems measure something that is relative to particle volume and convert it to a single number, Equivalent Spherical Diameter (ESD), based upon an assumption that all particles are spherical in shape (see also the post entitled "Direct versus Indirect Particle Size Measurement").

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Topics: FlowCam Technology

How many particles is “enough”?

Another great discussion going on over a the LinkedIn Particle Size & Counting Analysis Group, this one is about sample size requirements for statistical confidence in particle analysis (link), more specifically particle size distributions (PSD’s). Duncan Griffiths from NanoSight started it off by asking if we really need a million particles for reproducibility. This number (10^6) is one I’ve also heard bandied about in my travels, and I always wondered where it came from!

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Topics: FlowCam Technology