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User Manual HS-50 6 Vision functions Software Vers ion SR.501.xx 12/99 Issue US 6.5 Teach Fiducial 223 t I I t NOTE 6 If you wish to u se a fi ducial de spite the fac t that it h as a lo w uniquenes s valu e, you s hould…

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6 Vision functions User Manual HS-50
6.5 Teach Fiducial Software Version SR.501.xx 12/99 Issue US
222
t IIt
6.5.4.1 Standard Values Option
When this option is selected 6
– the menu is closed.
– the teaching process is launched.
– the video image is shown with fiducial, fiducial structure field and uniqueness value.
– header and footer with commentary, measurement results, key assignments and command se-
quences will be displayed.
The teaching process will now be launched with the standard values. The result of the teaching
process is the uniqueness value which is shown in the header of the video image. This value pro-
vides information on the differentiation quality of the fiducial with respect to other structures in the
vicinity of the fiducial. The figure displayed may range between 6
0 = unsatisfactory and
100 = very good differentiation capability. 6
Practice shows that a uniqueness value of at least 60 must be achieved for fiducials and ink dots. 6
6
Fig. 6.5 - 14 Teach fiducial menu, Teach with standard values video image
teach
1..6 : x/y step
Fiducial No. = 8 Uniqueness = 70
Ret :
Standard values
x/y step width = ...
: x axis +
: x axis -
: y axis +
: y axis -
User Manual HS-50 6 Vision functions
Software Version SR.501.xx 12/99 Issue US 6.5 Teach Fiducial
223
t IIt
NOTE 6
If you wish to use a fiducial despite the fact that it has a low uniqueness value, you should ensure
that the fiducial has a good quality value (see Section 6.5.6.2
on page ).
If the quality is bad as well, it would be better to select another fiducial (see Criteria for Creating
Fiducials in Section 6.2.5 on page 192).
Å Use the arrow keys to change the camera position. You can vary the step width by entering a
number in the range 1 - 6.
Å Press the Return key to repeat the teaching process.
Å Press Esc to quit the teaching process. The video image disappears and the Teach fiducial
menu is displayed once more.
6.5.4.2 High, Middle and Low Resolution Options
When you select one of these options, 6
– the menu closes,
– the video image is shown with fiducial and search area, and
– header and footer with commentary, measurement results, key assignments and command se-
quences are displayed.
6
Fig. 6.5 - 15 Teach fiducial menu, Change search area video image
Fiducial No. = 8 Uniqueness = 70
Blank: hor./vert.
Tab : field step
Template high res.
1..6 : x/y step
: x axis +
: x axis -
: y axis +
: y axis -
x/y step width = ...Direction = ...
Field step = ...
Ret: teach
- : smaller
+ : larger
6 Vision functions User Manual HS-50
6.5 Teach Fiducial Software Version SR.501.xx 12/99 Issue US
224
t IIt
Å Use the arrow keys to change the camera position. You can specify the step width by entering
a number in the range 1 - 6.
Å Use the + and - keys to move the fiducial boundaries and teach them at the same time. With
the space bar you can toggle between horizontal and vertical directions. With the Tab key you
can toggle the field step width between 1 pixel and 10 pixels.
Å Press Return to launch the teaching process.
The unique value appears on the screen as the measurement result. This may vary between 6
0 = unsatisfactory and
100 = very good differentiation capability. 6
Practice shows that a uniqueness value of at least 60 must be achieved. 6
Å Repeat the teaching process a number of times with changed field sizes. In this way you can
optimize the uniqueness value. Reducing the size of the search area to dimensions which are
less than those of the fiducial itself will increase the uniqueness value since the fiducial ends
will, for example, when wetted with solder-stop lacquer, exhibit poor reflection characteristics.
However, you should not select too small a field as this may impair the uniqueness of the fidu-
cial among other things.
Å Press Esc to quit this option.
NOTE 6
If you wish to use a fiducial despite the fact that it has a low uniqueness value, you should
ensure that the fiducial has a good quality value (see Section 6.5.6.2
on page 237).
If the quality is bad as well, it would be better to select another fiducial (see Criteria for Cre-
ating Fiducials in Section 6.2.5 on page 192). 6
Changing existing fiducials 6
During each teaching process the centering offsets are set to zero. If this is not done, optical cen-
tering with the fiducial structure field boundaries will not be correct; the measurement results
would be distorted. 6
6.5.4.3 Search Area Option
The search area is a freely selectable field within the field of view of the camera. 6
NOTE 6
Å Always select a size for the search area which will still also take into account tolerances in
board positioning.