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Wire & Cable ASIA – September/October 2007 62 Nove ber/De ember 2 12
reference can be stored for further production of this wire
type. Any number of recipes can be stored. Until now the
recipe database is very simple and should include search
functions in future software.
Connection to the line PLC should be possible via
simple digital 24V signals (signal status and device
enable) where fault messages are implemented to the
coil protocol like spark or diameter faults or with a more
complex network communication via TCP/IP to have
access to the recipe database or to support host computer
link.
Figure 9 shows the main screen that includes the most
important information for the line operator. Additional
windows can display more details, like separated
L*/a*/b*-channel measurement, various signal history or
trend information. For later evaluation, a subsample of raw
data is stored on the IPC hard disk. To be independent
of all production lighting conditions, the scan field is
covered and illumination is done by an internal LED light
source (see Figure 10, white arrow). According the higher
luminance variation compared to a* and b*, a modification
of equation (1) should be tested:
While equation (1) represents a circular error distribution,
the modification is an elliptical distribution with enhanced
tolerance in the L* channel (for f > 1).
Technical aspects are almost solved; the main focus is
now the improvement of device interface and handling.
This needs feedback from the wire and cable production
companies. Another point of discussion should be the
combination of stripe and main colour. For example main
colour red with a brown stripe is difficult to separate
eq (2)
for an automatic device as well as for a line operator.
So this is not a problem in colour measurement itself but
a possible improvement of quality control by a simple
redefinition of colour pairs with high ∆E.
References
[1] Edward H Adelson, MIT, 1995
[2]
[3] Joint ISO/CIE Standard: CIE Colorimetry – Part 1-5, ISO 11664-1··5/
CIE S014-1··5/E:2006-2007
[4] Masataka Okabe, Kei Ito (2008-02-15). Color blind barrier free. http://
jfly.iam.u-tokyo.ac.jp/color/
Siebe Engineering GmbH
Industriegebiet Fernthal
53577 Neustadt/Wied,
Germany
Email:
Website
❍
❍ Figure 10: Prototype of Siebe colour measurement system
during test at a customer’s line. Installation between spark test
and lump camera. IPC at the top, below, turn mechanics and
sensor (under light cover)