CHEETAH Hardware User’s Manual
Imperx, Inc.
Rev. 6.2
6421 Congress Ave.
7/7/2015
Boca Raton, FL 33487
+1 (561) 989-0006
57 of 152
2.11.2 Wide Dynamic Range Controls
Extended Dynamic Range feature is only available in global shutter mode. The user
has the option of enabling or disabling extended dynamic range. When disabled, all
pixels within the array integrate charge for the full exposure period as defined by the
exposure control settings. When wide dynamic range is activated, the exposure
period for each pixel varies based on the following user defined settings:
‘Dark’ Pixels:
Exposure period is set by the normal camera exposure controls and
dark pixels integrate for the full exposure period (Texp), just as if the WDR mode
were 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% as shown
in Table 2.6c. If P1 is set to 100%, then the entire output is allocated to Dark Pixels
and WDR is effectively disabled.
Table 2.6c: Camera output allocation (%)
‘Bright’ Pixels:
The exposure period for ‘bright’ pixels is set by parameter E1.The
Bright pixel exposure period is defined as the Total Exposure Period (Texp) minus
E1. For example, if Texp (Dark Pixel Exposure time) is 50ms and it is desired to set
the Bright pixel exposure period to 5ms, then E1 must be set to 45ms. (50ms – 45ms
= 5ms).
Tb (Bright) = Texp – E1;
E1 is a value in microseconds and must be some fraction of the overall exposure
period (usually 90% of Texp or more). The minimum value for E1 is 2 micro-
seconds. Bright pixel data is partitioned between the P1 and P2 output settings. Like
P1, parameter P2 which can have values ranging from 15% to 100% of the camera
output (16 steps) and
must be
greater than P1. See Table 2.6c. 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%)
