VI User Manual - 第218页
Tools library 7 - 56 Vision 2007 4.10 User Manual Re v 01 Concrete case 1. Go in Expert tab. 2. In Peak threshold (lev el of gray) area enter the threshold value to apply and the peak to use (Y max or Y min). 3. Fill Lim…
Tools library
Vision 2007 4.10 User Manual Rev 01 7 - 55
7.9.4 Expert mode
If all defects are not detected with tolerances algorithm, 3 Global adjustment tool algorithms
are proposed to detect lifted leads:
Peak threshold,
Contrast,
3D analysis.
You can use one or several algorithm. The choice depends of the position and the orientation
of the profile and of the image you obtain.
Expert mode is used when:
Size of lead of component are irregular,
Difficile case, where tolerances algorithm not detect bad leads,
...
For each
Global adjustment tool algorithm selected, the Lead to lead algorithm must be set.
7.9.4.1 Peak threshold
This algorithm can be use:
When you have a difference of lead length between bad and good lead,
When you have a difference of contrast between bad and good lead,
When you have a difference on joint aspect between bad and good lead.
Principle
This algorithm mea-
sures the
length
of
the profile between
2 points which are
determined by the
intersection be-
tween the profile
and a threshold
straight.
Limits are used
to ignore a part of
the profile.
Threshold (in grey level)
Y max
Length
Ignored
part
Ignored
part
Profiler
™
in Custom
Tools library
7 - 56 Vision 2007 4.10 User Manual Rev 01
Concrete case
1. Go in Expert tab.
2. In Peak threshold (level of gray) area enter the threshold value to apply and the
peak to use (Y max or Y min).
3. Fill Limits field to ignore a part of the profile.
4. Define the acceptable limits (Length [µm] field).
In this case, for a lifted lead, result of
Peak threshold al-
gorithm is smaller compared with a joined leads.
Profiler
™
in Custom
Tools library
Vision 2007 4.10 User Manual Rev 01 7 - 57
7.9.4.2 Contrast
This algorithm can be used when you have a difference of lead / joint contrast between
lifted and joined lead.
Principle
This algorithm measures the amplitude of
the gradient peak. This measure can corre-
spond, depending on the profile area posi-
tion, to the contrast of the outline.
Concrete case
Go in Expert tab.
In
Contrast
area enter the minimum and maximum value of distance (the acceptable limits).
For a lack of joint, result of contrast algorithm is bigger
compared with correct joint.
Max peak
Min peak
Max peak
Min peak
Profiler
™
in Custom