Panasonic PV-500, User Manual, Page: 144 / 494

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Inspecting in “Differential” Mode
Principle of “Differential Mode” of Flaw Detection
Process description Image
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.
If the calculated average brightness of the
cells is more than the “threshold value” you
will set later, the PV extracts the cell as a
candidate flaw (see the figure shown on the
right).
As you increase the threshold value, the PV
regards the area of larger difference in
brightness as a candidate flaw, whereas as
you decrease the threshold value, the PV
regards even an area having slight
difference in brightness 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. If flaw size = 3
If flaw size = 5
Setting Procedure
1.
Select "Search Method" in “Flaw Detection”
setting window.
2.
Select “Differential” for “Detect Mode”.
3.
Set “Threshold” and “Min. Flaw Size in Cells”.
Threshold (1 - 255)
The minimum value of brightness to extract the cells comprising a candidate flaw. The checker extracts the
cells with larger gray range than this setting value.
Min. Flaw Size in Cells (1 - 256)
Flaw size in cell unit.
Set the minimum number of the cells in a candidate flaw. The checker decides a candidate flaw consisting
of the more than the minimum number of cells you have set here as a flaw.
4.
After setting is completed, press the CANCEL key.