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User Manual HS-50 6 Vision functions Software-Version 5.01Edition 01/99 6.5 Teach Fiducial 223 The uniquen ess va lue app ears as the meas urement r esults. This may va ry betwee n 0 (= un sat- isfactory ) and 100 (= ver…
6 Vision functions User Manual HS-50
6.5 Teach Fiducial Software-Version 5.01 Edition 01/99
222
Å Make sure that there are no other structures within the search area. Otherwise, fiducial identi-
fication could be made unnecessarily more difficult.
Å Repeat the tests with different search area sizes. It may also be appropriate to optimize the
uniqueness value.
When you select the 6HDUFKDUHDoption
– the menu closes,
– the teaching process is launched,
– 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.
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 structure boundaries and teach them at the same
time. With the space bar you can toggle between horizontal and vertical directions. With the
7DEkey you can toggle the field step width between 1 pixel and 10 pixels.
Å Press 5HWXUQ to launch the teaching process.
Fiducial No. = 8 Uniqueness = 70
Blank: hor./vert.
Tab : step width
Change search area
1..6 : x/y step
: y axis +
: y axis -
x/y step width = ...Direction = ...Field step = ...
Ret: teach
- : smaller
+ : larger
: x axis +
: x axis -
User Manual HS-50 6 Vision functions
Software-Version 5.01Edition 01/99 6.5 Teach Fiducial
223
The uniqueness value appears as the measurement results. This may vary between 0 (= unsat-
isfactory) and 100 (= very good) differentiation capability.
Practice shows that a uniqueness value of at least 60 must be achieved for fiducials and ink dots.
Å Repeat the teaching process a number of times with changed field sizes. In this way you can
optimize the uniqueness value.
Å Press (VF to quit this option.
NOTE
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 6 - 231).
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 6 - 190).
6 Vision functions User Manual HS-50
6.5 Teach Fiducial Software-Version 5.01 Edition 01/99
224
&RQWUDVW6HQVLWLYLW\0HQX
The &RQWUDVWVHQVLWLYLW\ menu provides options for optimizing the contrast between the fiducial
and its surroundings.
NOTE
All of the options in this menu are only accessible if you have loaded a fiducial beforehand. If you
have done so, this will be indicated by the text on the button being black (rather than grayed out).
The fiducial number and fiducial name are displayed in the )LGXFLDO display field.
If you have not loaded a fiducial you will only be able to select the 3URJU DP WUDQVIRU P option.
Each pixel of the video camera contains one unit of 8-bit gray-scale information. The significance
of the values is as follows:
0 = black and
255 = white