CHEETAH Hardware User’s Manual
Imperx, Inc.
Rev. 6.2
6421 Congress Ave.
7/7/2015
Boca Raton, FL 33487
+1 (561) 989-0006
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Figure 2.9: Dual Slope vs Single Slope Integration
The user can translate pixel data back to linear space by accounting for the different
exposure periods in each of the output partitions. For example, suppose Bright pixel
data is contained between 301 and 1000 of the camera output counts (10 bit system).
By subtracting, 300 from every pixel with a value greater than 300 counts and
multiplying the result by the ratio of the Total Exposure (Texp) period divided by the
Bright pixel exposure period, the Bright pixel data can be properly referenced to the
Dark pixel data.
Bright pixel (Linear) = (Bright pixel counts– Dark pixel max counts) x (Texp /
Bright pixel exposure period)
Another way to view the data partitioning concept is to use view the histogram of the
output data. In Figure 2.10, a histogram is shown with four output partitions. Again,
the user must bear in mind that each data region (Dark, Bright, Very Bright and
Ultra-Bright) has a different exposure time.
Figure 2.10: Output partitioning using Histogram
