BOBCAT HD-SDI
Hardware User’s Manual
Imperx, Inc.
Rev. 1.4
6421 Congress Ave.
6/2/2014
Boca Raton, FL 33487
+1 (561) 989-0006
68 of 175
Input signal
O
ut
put
s
ignal
O
rig
in
al
T
F
Ne
w T
F
X1
Y1
Figure 3.4 – Single point TF correction.
3.2.2.2.
Multi Point Correction
If the image brightness is weighted towards two particular region – dark
and bright, and in the same time mid region has a low dynamic range a
multi point correction will produce much better results compare to the
single point correction. The range of the correction is determined by the
location of a pair of the break point (X1, Y1) and (X2, Y2) – Figure
3.5a. The camera transfer function is divided into three regions (three
lines), which allows multiple grayscale regions to be corrected
independent of each other. If the angle is less than 45
O
degrees, the
grayscale range will be suppressed, if the angle is 45
O
degrees, the gray
scale will not change. If the angle is more than 45
O
degrees, the
grayscale range will be enhanced. The user can set the optimum (X1,
Y1) and (X2, Y2) values, note that X2 > X1. Figure 3.5b shows some
of the most typical correction curves. If the angle in the mid range
(between X1 and X2) is negative, the grayscale range will be reversed.
Curve TF 1 enhances the dark image regions and suppresses the bright
ones. TF 2 – suppresses the dark and bright image parts and enhances
the mid range. TF 3 – enhances the bright image regions and suppresses
the dark ones. TF 4 – enhances the bright and dark image parts and
suppresses the mid range.
