Cheetah KAC Camera User Manual | Camera Link (CLF) Interface
October 1, 2019
Page
108
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135
Rev 7.2
Figure 65: A Single Knee Point Demonstrations of the WDR Function.
5.11.3 Initial WDR Setup Recommendations
For initial Wide Dynamic Range (WDR) setup, the scenario below provides one knee point
to get a usable image. It also allows experimentation with various settings.
1.
Set the overall exposure time so the dark portions of the image are visible with
good contrast while other portions of the image are overexposed with no visible
detail.
2.
Set E1 to 90% (or 95%) of the overall exposure time.
3.
Set P1 to 50% then set P2 and P3 to 100%.
4.
Try varying P1 and E1 and observe the impact on the image (and histogram).
Increasing P1 increases the amount of contrast in the dark regions of the image while
decreasing contrast in the bright regions. If the dark regions appear noisy or if the color
reproduction in the dark regions is poor, try increasing P1. Changing E1 changes the
exposure time for the bright areas. For more contrast, try increasing P1. View a histogram
of the output to get a sense of how changes in P1 affect the output.
In a scene with several different intensity levels, two knee points can be helpful. If two
knee points (3 intensity slopes) are required, then both E1 and E2 (E1 is the exposure time
for bright pixels and E2 is the exposure time for the Very Bright pixels.) must be used.
Below is an initial setting for applications that have several areas of varying intensities.
