Basler A102K, Руководство пользователя, Страница: 57 / 133

Operation and Features
BASLER A102
k
3-21
DRAFT
Shift Twice
When the camera is set to shift twice, the
output from the camera will include bit 9
through bit 0 from the ADC along with two
zeros as LSBs.
The result of shifting twice is that the
output of the camera is effectively
multiplied by four. For example, assume
that the camera is set for no shift, that it is
viewing a uniform white target, and that
under these conditions the reading for the
brightest pixel is 100. If you changed the
digital shift setting to shift twice, the reading would increase to 400.
Shift Three Times
When the camera is set to shift three
times, the output from the camera will
include bit 8 through bit 0 from the
ADC along with three zeros as LSBs.
The result of shifting three times is that
the output of the camera is effectively
multiplied by eight. For example,
assume that the camera is set for no
shift, that it is viewing a uniform white
target, and that under these conditions
the reading for the brightest pixel is
100. If you changed the digital shift setting to shift three times, the reading would increase to 800.
L
Note that if bit 11 or bit 10 is set to 1, all of the other bits will automatically be set to
1. This means that you should only use the shift twice setting when your pixel read-
ings in 12 bit mode with no digital shift are all below 1024.
Since the shift once setting requires that the two least significant bits (LSBs) always
be “0“, only gray values divisible by 4 can be represented. The gray value scale will
only include gray values of 4, 8, 12 and so forth. The absence of some gray values
is commonly called “Missing Codes“.
L
Note that if bit 11, bit 10 or bit 9 is set to 1, all of the other bits will automatically be
set to 1. This means that you should only use the shift three times setting when your
pixel readings in 12 bit mode with no digital shift are all below 512.
Since the shift once setting requires that the three least significant bits (LSBs) al-
ways be “0“, only gray values divisible by 8 can be represented. The gray value
scale will only include gray values of 8, 16, 24 and so forth. The absence of some
gray values is commonly called “Missing Codes“.
bit
9
bit
8
bit
7
bit
6
bit
5
bit
4
bit
3
bit
2
bit
1
bit
0
ADC
bit
11 bit
10
M
S
B
L
S
B
Shifted Twice
“0” “0”
bit
9
bit
8
bit
7
bit
6
bit
5
bit
4
bit
3
bit
2
bit
1
bit
0
ADC
bit
11 bit
10
M
S
B
L
S
B
Shifted 3 Times
“0” “0” “0”