MICRO-EPSILON colorSENSOR CFO Series, Instruction Manual

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Page 56
Operation
colorSENSOR CFO
A change in the color readings for one and the same specimen can have two causes:
- Internal factors. Change in readings due to detector noise, changes in brightness of the light source or
modulated ambient light.
- External factors. Deviations in color or surface texture of specimens or in measuring conditions (distance,
angle).
Define the color distance tolerances so that the tolerance limits are greater than the change in the readings
for acceptable specimens.
During
classification
the current color readings are associated with the closest color value saved in the
color table. In this mode classification is always accomplished regardless of the actual similarity between the
selected colors.
For example, if red is the only color saved in the table, all color readings are associated with this color. The
following diagram shows an example of how the current color reading Cm is associated with the saved color
value C3, see
Fig. 23 . This association is accomplished based on the smallest distance D3 between Cm and
C3.
C3
D1
C2
L*
C1
a*
b*
D2
D3
Cm
Fig. 23 Distance model classification