YSD_Users_E.pdf - 第251页
5-62 5 Creating the board data 6.6 Pattern matching P attern matching is a function for correcting board dimensional or reference hole errors, positioning errors occurring from the board clamping mechanism, or local dist…
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Creating the board data
7
Check that the mark can be recognized even if it has moved.
Check that the mark can be recognized in any location within the search area.
1. Press the [Move Head] button to open the Move Head window.
2 .Use the arrow buttons to move the mark slightly from the center of the search area.
3. Return to the Mark Adjust window and run the vision test once more.
When no error occurs, the parameter settings are satisfactory. If an error still occurs, press the
[Check] button and readjust the binary level.
Search Area
Center of search area
Final check for mark recognition
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Quit the Mark Adjust mode.
Press the [OK] button to quit the Mark Adjust mode.
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6.6 Pattern matching
Pattern matching is a function for correcting board dimensional or reference hole errors, positioning errors
occurring from the board clamping mechanism, or local distortion of the board. To use this function, the image
of a particular board pattern must be registered as the template. Errors or distortion are corrected by comparing
the template you registered with an actual pattern being recognized. Pattern matching is useful when the
fiducial function cannot be used, for example, if the board has no fiducial marks or the mark does not match
any mark recommended by YAMAHA.
Any pattern can be used, but the pattern image should be smaller than about 1/4th of the monitor and must
meet the following conditions.
• Each pattern clearly contrasts with the board. (It is okay if the outline of each pattern is definite.)
• A pair of patterns are diagonally opposing on the board.
Pattern conditions
Pattern
Pattern
NG
NG
OK
Board Board
OK OK
Low contrast
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CAUTION
Pattern matching requires a longer recognition time than normal mark recognition and its accuracy may drops slightly
when compared to cases using round or square marks. It is not necessary to use pattern matching for marks which
can be correctly recognized with "Algorithm Type" set to “Normal”.
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6.6.1 Pattern registration
To utilize pattern matching, you must register the reference pattern in the template.
1
Decide on the pattern.
Decide which pattern you want to use for pattern matching. Select a pair of patterns
that meet the conditions explained previously.
2
Enter the pattern name in the mark information.
Open the Mark screen and, in the Mark Name column, enter the name that you can
easily identify as a pattern.
3
Set the parameters.
Set the parameters as follows.
1. Set “Mark Type” of the Basic parameters to “Fiducial”.
2. Set “Algorithm Type” of the Vision parameters to “PTRN Outline” or “PTRN GrayLev” or "PTRN Whole".
PTRN Outline:
In most cases, select this parameter for pattern matching. When the outline is definite, the pattern
can be recognized even if uneven brightness portions are present inside the pattern.
PTRN GrayLev :
Selecting this parameter is more effective in recognizing a pattern whose brightness is uniform inside
the pattern. This parameter setting requires a longer time to recognize a pattern than in the “PTRN
Outline” setting and also the data size will be larger.
PTRN Whole:
Selecting this parameter is effective in acquiring details of a pattern image. Since the entire pattern
is recognized and the image is less compressed, this parameter setting requires a longer time than in
the "PTRN GrayLev" setting and also the data size will be even more larger.
Set to "PTRN Outline" or "PTRN GrayLev" or "PTRN Whole".
Entering the pattern name
Enter the pattern name.
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Pattern recognition types
PTRN outline PTRN Graylev
Uneven brightness Uniform brightness
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