27
Increments are in ¼ LSB (8 bit).
The formula for gain and offset setting is:
Y`= GxY+0
7.5
Lookup tables (LUT)
The camera provides support for up to 63 user-defined LUTs. An additional lookup table
is used for implementing gamma correction. The lookup tables convert the 12 bits from
the digitizer to 8 bits.
The use of LUTs allows you to store any function in the form Output = F (Input) in the
RAM of the camera and to use it on the individual pixels of the frame at run-time.
These make it possible to carry out complex calculations at a suitable point in time and
to use the results while operating the camera in real time. The values of functions are
calculated within a specific range and the input value is used as an index in the table.
The AVT Dolphin can temporarily store up to 64 LUTs in the camera. One example of
such an LUT is the gamma LUT.
Gamma
0
128
256
384
512
640
768
896
1024
0
512 1024 1536 2048 2560 3072 3584 4096
Gamma
Figure 25 Gamma LUT
L
The input value is a 12-bit value from the digitizer. The output value is a value of
10 bits. (8 bit is generated during readout of memory).
L
Because gamma correction is also internally implemented via a lookup table and
only one lookup table can be active at the same time, it is not possible to use a
different LUT when gamma correction is switched on.