XIIMUS 1024CTI User Manual page 48

The data byte for this command can range from 0 to 63 (decimal). 0 corresponds to –2 dB
input stage gain and 63 equals +10 dB gain. The default setting for this register is +4 dB,
which equals 31 decimal.
Decimal
Range
0-10
10-21
21-31
31-42
42-53
53-63
Increasing preamp gain can be useful in low light applications as it improves overall signal to
noise ratio. It is first recommended to increase the preamp gain setting and then increase the
analog gains if there still isn't enough signal. Setting the preamp gain too low can cause the
digital output to never reach saturation even though the CCD itself is in saturated state.
3.13. Dark level (addresses 217 to 222)
The input clamp circuit of each channel removes the CCD's optical black offset to maximise
system headroom and the effect of gain change on the black level. The dark level register
can be used to set the positive offset in the output data, if desired. If this parameter is set, the
dark level of channel in question will have an offset equal to the dark level setting.
Function
Dark Level, Infrared odd
channel
Dark Level, Infrared even
channel
Dark Level, Red odd
channel
Dark Level, Red even
channel
Dark Level, Bluegreen
odd channel
Dark Level, Bluegreen
even channel
The data byte of this command has 8-bit range from 0 to 255 (decimal).
3.14. Offset register (addresses 223 to 228)
The offset can be digitally removed by sending a value to the respective address. This value
is subtracted from all the pixel values prior to sending them out. The offset value is any
number between 0 and 1023. The MSB contains the topmost 8 bits and the LSB the bottom
most two bits of the 10-bit offset range. Offset is subtracted from the original 12-bit pixel
values.
Offset should be set by first sending the most significant byte of the channel and then
sending the least significant byte to the channel in question. The offset will not be updated if
only the MSB or the LSB byte of the desired offset setting is sent.
© TVI Vision, 18 October 2006
XIIMUS R-GB-IR CL User Manual.
Range in
decibels
-2 to 0
0 to 2
2 to 4
4 to 6
6 to 8
8 to 10
decimal
217
218
219
220
221
222
hexadecimal
D9
DA
DB
DC
DD
DE
Version 1.2
binary
1101 1001
1101 1010
1101 1011
1101 1100
1101 1101
1101 1110
page 48 ( 57 )