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Inspecting in "Gray Range" Mode
Principle of "Gray Range Mode" of Flaw Detection
If the PV failed to detect any flaw after testing in Differential mode, try to test again after switching to Gray
Range mode.
Gray Range mode is effective to inspect the object with a surface of uneven brightness, but it will take longer
time to process than Differential mode.
Process description
The checker calculates the brightness
(average gray value) of each rectangular
area, which is called cell, created in a certain
size within the inspection area.
The checker groups the cells and calculates
the maximum gray range in the brightness of
the grouped cell. The function calculates
maximum gray range of each group made by
shifting the cells by the setting value for "No.
of Cells per Shift", and then identifies the
cells comprising the group gray range of
which is the value of "Threshold" or more as
a candidate flaw.
The number of grouped cells
The cells are grouped according to the
setting value for "Num. of Cells for Calc.
Range". If the setting value for "Num. of Cells
for Calc. Range" is "4", four cells are grouped
(see the figures shown on the right).
The number of cells per shift
This is the number of shifting cells to group
them from the start point to the end point in
the area. If the setting value for "Num. of
Cells per Shift" is "2", the PV calculates
maximum gray range of each group made by
shifting two cells till the end of the cells. (See
the figures on the right.)
Threshold
As you increase the threshold value, the PV
identifies the cells having larger gray range
as a candidate flaw, whereas you decrease
the threshold value, the PV identifies even
the cells having lower gray range as a
candidate flaw.
The checker judges whether to regard the
candidate flaw as a flaw based on the
number of the cells in the candidate flaw. If
the number of cells in the candidate flaw is
more than the number of cells that have been
set as "Flaw Size", the candidate will be
judged as a flaw.
Image
If flaw size = 3
If flaw size = 10
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