Dalsa 1M28-SA User Manual page 14

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illumination conditions or high intra-scene contrasts where a high pixel response is needed.
Welding and traffic management are two application examples best suited for the LinLog
response.
LinLog values are set using the PFRemote configuration tool. See chapter 3 for details on using the
PFRemote.
To compensate for the heavy compression of the intensity values in the area around the transition
point— a characteristic not desired in every application—LinLog technology uses three values.
The first threshold value sets the strong LinLog compression LL1, the second threshold value sets
the weak LinLog compression LL2, and an additional parameter called COMP defines the ratio
between strong and weak compression. Figure 7 shows the characteristic curves of a LinLog
sensor.
Figure 7: LinLog2 Response Curve (Photo Current I
Transition points
Optimisation of the Sensor Characteristic Curve
When determining the LinLog values to use, a picture needs to first be taken with the LinLog
parameters set to LL1 = LL2 = 0 and COMP = 0. This picture is useful in detecting any
overexposed areas. You can then set the three parameters LL1, LL2 and COMP step by step. After
this coarse adjustment, you should redo the black adjustment in order to make use of the full range
of the A/D converter. Alternating modifications of each parameter can be done to achieve an
optimal result. A family of measured characteristic curves is shown in Figure 8. The COMP ratio
has a strong influence on the resulting signal. Figure 10: Parameter adjustment procedure for LL2
shows a flowchart for help with optimization.
03-32-00525-04
PRELIMINARY
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Linear response
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1M28, 1M75, and 1M150 User's Manual
vs. Light Intensity I)
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Linlog weak compression
LL2
Resulting response
LinLog strong compression
LL1
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DALSA