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5 Vision Functions SIPLACE 80S-20/F4/F4-6/F5 User’s Manual 5.5 Teach Fiducial Edition 03/98 from Software Version SR.404.xx 5 - 60 Line engine er 5.5.5 Cont rast S ensitiv ity Menu The Contrast sens itivity menu provid e…

SIPLACE 80S-20/F4/F4-6/F5 User’s Manual 5 Vision Functions

Edition 03/98 from Software Version SR.404.xx 5.5 Teach Fiducial

Line engineer 5 - 59

Fig. 5.5.12 Teach fiducial menu, Teach search area video image

Use the arrow keys to change the camera position. You can specify the step width by entering a number in

the range 1 - 6.

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 Tab key you can toggle the

field step width between 1 pixel and 10 pixels.

Press Return to launch the teaching process.

The uniqueness value appears as the measurement results. This may vary between 0 (= unsatisfactory) and

100 (= very good) differentiation capability.

Practice shows that a uniqueness value of at least 60 must be achieved for fiducials and ink dots.

Repeat the teaching process a number of times with changed field sizes. In this way you can optimize the

uniqueness value.

Press Esc to quit this option.

NOTE

However, 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 ’Test Option’, Page 5 - 67.)

If the quality is bad as well, it would be better to select another fiducial (see ’Criteria for Creating Fiducials’

in Section 5.2.5 from Page 5 - 23.

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 -

5 Vision Functions SIPLACE 80S-20/F4/F4-6/F5 User’s Manual

5.5 Teach Fiducial Edition 03/98 from Software Version SR.404.xx

5 - 60 Line engineer

5.5.5

Contrast Sensitivity

The Contrast sensitivity menu provides options for optimizing the contrast between the fiducial and its sur-

roundings.

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 Fiducial display field.

If you have not loaded a fiducial you will only be able to selected the Program transform 5 option.

Fig. 5.5.13 Contrast sensitivity menu, options

Each pixel of the video camera contains one unit of 8-bit gray-scale information. The significance of the val-

ues is as follows:

0 = black and

255 = white

SIPLACE 80S-20/F4/F4-6/F5 User’s Manual 5 Vision Functions

Edition 03/98 from Software Version SR.404.xx 5.5 Teach Fiducial

Line engineer 5 - 61

To make it easier for you to assess the range of brightness or the contrast these gray-scale values have been

converted with the help of transformation tables into color as is shown below:

NOTE

In order to achieve a good uniqueness value the contrast difference between the fiducial and its surroundings

should be at least 75. For example, if the background is green the fiducial should be orange.

If the contrast is unsatisfactory you can select in the menu between five pre-programmed transformation

tables in order to obtain a color image which is capable of supplying the necessary information. In addition,

you can also program a transformation table yourself.

NOTE

When the color presentation is changed the fiducial will be taught at the same time.

Gray scale Allocated color

0black

30 violet

50 blue

77 blue-green

100 green

127 brown

150 red

175 orange

200 yellow

255 white

Tab. 5.5.1 Gray-scale to color conversion table