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COMPENDIUM INCLINATION MEASUREMENT
WYLER AG, WINTERTHUR / SWITZERLAND

6.4.5 CLOSURE ERROR CORRECTION ACCORDING TO PHILIPS AND ALIGNMENT METHOD

ACCORDING TO ISO 1101
Introduction to the closure error correction according to “PHILIPS“
The closure error correction according to PHILIPS is used in the WYLER grid flatness measuring method.
At the end of a measurement, the result (flatness of a surface) can be displayed in two versions:
• without correction of the closure error
• with correction of the closure error
When the version without the correction of the closure error is used, all these errors will be seen in nu-
merical and graphical form. The so-called closure error is an indication of the quality of the measurement.

closure error
Definition of the
“CLOSURE ERROR“
The CLOSURE ERROR is the
LARGEST DEVIATION of a
measuring point in an over-deter-
mined grid when the calculation of
the height at this measuring point
is done by using different paths
(see illustration at the right).

Display of a flatness measurement without
correction of the closure error according
to PHILIPS
The correction of the closure error according
to PHILIPS is a mathematical process by which
a closure error of linearly spreading characteris-
tic can be successfully corrected and elimina-
ted.
After the closure error correction a so called
“Index of correction” is an indication of the “suc-
cess” of the mathematical treatment. (the “In-
dex of correction” is the result of the standard
deviations of all the closure error corrections)

THE LARGER THE INDEX OF CORRECTION,
THE LARGER THE MEASURING UNCERTAINTY

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