Table of contents 1 Why is particle size important?

DYNAMIC IMAGE ANALYSIS
Dynamic image analysis utilizes many of the same steps as static 
image analysis with a few notable exceptions. Sample preparation 
is completely different since the sample itself is moving during 
the measurement. Sample preparation steps could include an 
ionizer to mitigate static interactions between particles thus 
improving flowability or a sample director to specifically orientate
particles through the measurement zone. Many of the same 
image processing steps used for static image analysis are also 
used in dynamic systems, but it is less common that the operator 
actively selects the functions being utilized. A basic diagram of the 
CAMSIZER dynamic image analysis system is shown in Figure 31.
The sample is transported to the measurement zone via a 
vibratory feeder where the particles drop between a backlight and 
two CCD cameras. The projected particle shadows are recorded at 
a rate of more than 60 images (frames) per second and analyzed. 
In this way each particle in the bulk material flow is recorded and
evaluated, making it possible to measure a wide range of particles 
(30 microns to 30 millimeters) with extreme accuracy without needing operator 
involvement to switch lenses or cameras as can be the case with other technologies. 
A great depth of sharpness, and therefore maximum precision across the entire 
measuring range, is obtained with the two-camera system. The zoom camera 
provides maximum resolution down to the fine range, while the basic camera also
records larger particles and guarantees a high statistical certainty in the results. 
Because of the size range measured by dynamic image analysis, this is a popular 
technique for applications historically using sieves. By choosing the appropriate 
size parameters the results can closely match sieve results, while providing the 
benefits of quick, easy analyses with the bonus information about particle shape.
In those cases where matching historic sieve data is required the CAMSIZER 
can be easily configured to “think like a sieve” to ensure the closest possible
correlation. This is made possible by collecting shape information for each particle 
and calculating how that shape would pass through a square mesh of known size. 
Such a function could be used to satisfy existing quality control specifications
while simultaneously measuring the true, non-biased particle size and shape 
distributions for the first time ever.
figure 31
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DYNAMIC IMAGE ANALYSIS

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