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Installation Guide
24 of 33
Revision 2.00 of 04/11/2009
Detecting the “Start of Blood” Point
Two methods are used to elaborate the readings curves and detect the correct
Start of Blood Point. The two methods are completely independent the one
respect to the other, and are used to have a double security on the reliability
of the readings, in fact if the points calculated by the two methods are
different, a warning is signaled for that result to alert the user that it’s an
“Uncertain result”.
Method 1
In Method 1 first of all the minimum light point is detected on the curve.
Then using the parameter “PERC_FILTER” a limiting filter is applied to
the curve so that all the values below the limit will be set equal to the
limit itself.
The limit value is represented by the green line in the above figures.
Once that limit value has been found, and the curve has been filtered
using this value, the curve is newly analyzed starting from the left-most
point until the first point with light value equal to the filtering limit Value.
Then, starting from this point, going back in a right-to-left direction the
algorithm looks for a step in the curve.
This step is assumed to be the Starting Point of blood.
This Step Point is the blood level in Method 1.
Applying this method for both Reader 1 and Reader 2 the two levels of
blood are detected, and an ESR value is calculated, this ESR is the
“Method 1 ESR value”.
Method 2
Method 2 is based on the first derivative calculation for all the points of
the curve. This calculation generates a new curve, the blue one on the
above figures.
By analyzing this new curve, starting from the left-most point, the
software looks for the first higher-rate falling edge, the point of this
falling edge is assumed to be the Blood Level of Method 2.
Applying this method for both Reader 1 and Reader 2 the two levels of
blood are discovered, and an ESR value is calculated, this ESR is the
“Method 2 ESR value”.
Method 3