MICRO-EPSILON colorSENSOR CFO Operating Instructions Manual page 14

Functional Principle, Technical Data
The system can be set to the distance models Sphere (∆E), Cylinder (∆L; ∆ab), Box (cuboid, ∆L; ∆a; ∆b) and
Classify. These models form a tolerance space around the learned colors.
Fig. 2 Tolerance space Sphere
C
1
C
m
For an evaluation of color deviations, the color tolerance parameters should be based on the perception
thresholds for color differences. In the Lab color space, a tolerance threshold of ∆E > 1 is frequently used for
perceptible color differences.
Influencing factors for setting color tolerance parameters:
- Required accuracy for color recognition
- Tolerance for reading variations.
colorSENSOR CFO
2E
L
C
1
C
m
b
a
= learned color 1
= detected color
2a b
L
C
1
C
m
b
Fig. 3 Tolerance space Cylinder
L
2a
C
1
C
m
a
Fig. 4 Tolerance space Box
b
a
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