Cheetah KAC Camera User Manual | Camera Link (CLF) Interface
October 1, 2019
Page
106
of
135
Rev 7.2
5.11.2 Wide Dynamic Range Controls
The wide dynamic range (WDR) function is available only in global shutter mode. You have
the option of enabling or disabling wide dynamic range. When disabled, all pixels within
the array integrate charge for the full exposure time as defined by the exposure control
settings. After activating WDR, the exposure time for each pixel varies based on the
following user-defined settings:
Dark Pixels:
The normal camera exposure controls set the exposure time, and dark pixels
integrate for the full exposure period (Texp) as if WDR mode is disabled. The amount of
the camera output allocated to dark pixels is set by parameter P1, and dark pixel data is
contained between 0% of camera output to the P1 percentage level. P1 can range from
15% of the camera output to 100% (Table 24). If P1 is set to 100%, the entire output is
allocated to Dark Pixels and WDR is effectively disabled.
Table 24: Camera Output Allocation (%).
Bright Pixels
: The exposure time for bright pixels is set by parameter E1. The Bright pixel
exposure time is defined as the Total Exposure Period (Texp) minus E1. For example, if
Texp (Dark Pixel Exposure time) is 50ms and you want to set the Bright pixel exposure
time to 5ms, then you must set E1 to 45ms (50ms – 45ms = 5ms).
Tb (Bright) = Texp – E1
E1 is a value in microseconds and must be some fraction of the overall exposure time
(usually 90% of Texp or more). The minimum value for E1 is 2 microseconds. Bright pixel
data is partitioned between the P1 and P2 output settings. Like P1, parameter P2 can have
values ranging from 15% to 100% of the camera output (16 steps) and must be greater
than P1. If P2 is set to 100%, then the camera output is partitioned into two zones: Dark
Pixel data (0% to P1) and Bright pixel data (P1 to 100%).
Very Bright Pixels:
The exposure time for the Very Bright pixels is set by parameter E2.
The Very Bright pixel exposure time is defined as the Total Exposure Period (Texp) minus
E2. For example, if Texp (Dark Pixel Exposure time) is 50.0ms and it is desired to set the
Very Bright pixel exposure time to 0.5ms, then E2 must be set to 49.5ms. (50.0ms –
49.5ms = 0.5ms).
Tvb (Very Bright) = Texp – E2
E2 is a value in microseconds and must have a value between the E1 exposure time and
Texp. The minimum E2 value is 2 microseconds. The amount of camera output allocated
