Basler A102K, User Manual, Page: 51 / 133

Operation and Features
BASLER A102
k
3-15
DRAFT
3.6 Gain and Offset
The major components in the
A102
k
electronics include:
a CCD sensor, one VGC (Variable Gain Control), and
one ADC (Analog to Digital Converter). The pixels in
the CCD sensor output voltage signals when they are
exposed to light. These voltages are amplified by the
VGC and transferred to the ADC which converts the
voltages to digital output signals.
Two parameters, gain and offset are associated with
the VGC. As shown in Figures
3-11 and 3-12 ,
increasing or decreasing the gain increases or
decreases the amplitude of the signal that is input to
the ADC. Increasing or decreasing the offset moves the
signal up or down the measurement scale but does not
change the signal amplitude.
For most applications, black should have a gray value
of 1 and white should have a gray value of 255 (in 8 bit
output mode) or 1023 (in 10 bit output mode). Attempt
to achieve this by varying exposure and illumination
rather than changing the camera’s gain. The default
gain is the optimal operating point (minimum noise) and
should be used if possible.
You can set the gain and offset using either the Camera Configuration Tool Plus (see Section 4.1
and the configuration tool’s on-line help) or binary commands (see Section 4.2 ).
With the configuration tool, you use the Gain setting in the Gain & Offset group to adjust the gain,
and the Offset setting in the Gain & Offset group to adjust the offset.
With binary commands, you must use the Gain binary command to set the gain and the Offset
binary command to set the offset (see Sections
4.2.4.10 and 4.2.4.11 ).
L
Because increasing gain increases both signal and noise, the signal to noise ratio
does not change significantly when gain is increased.
Figure 3-11: Gain
Figure 3-12: Offset