Basler Vision Technologies A202k, Руководство пользователя

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Operation and Features
BASLER A202
k
3-15
DRAFT
3.5.2 Balancing the Left Side and Right Side Gain
As described on page 3-13 , gain alignment between the channels, combined with offset
alignment, is important to maintain uniform output data with minimal gray value differences
between the left side and the right side of the image.
In some applications, multiple cameras are used, for example, when two area scan cameras are
used next to each other to form one large image. In some cases, a camera in an existing
application must be replaced. In these situations, it is also necessary to balance the gains
between cameras.
To meet the goals of balanced channels and comparable output between cameras, each Basler
camera is calibrated before it leaves the factory. This calibration procedure has the following
effects:
• The factory gain settings for the left side and the right side channels are aligned so that they
equally amplify the signal and a uniform output is achieved on both channels. In addition,
they are set to a low gain value to obtain an optimal operating point (low noise, good left side/
right side channel match).
• All cameras have default gain settings and reference gain values which match the output of a
factory master camera of the same type. This output is referred to as 0 dB. So if a camera’s
gain is set to 2 dB, this means 2 dB more than the gain of the master camera.
• The reference gain values are stored in the camera. These stored values can be used to cal-
culate higher or lower gain settings that will keep the left side and right side channels in bal-
ance and comparable to other cameras of the same type.
If you use the Camera Configuration Tool Plus (see Section 4.1 and the configuration tool’s on-
line help) to set the gain on your camera, the camera will automatically use the stored reference
values to keep the channels in balance. In addition, you can use the Gain Balance setting in the
CCT+ to manually adjust the gain balance.
If you use binary commands (see Section 4.2 ) to set the gain, you can use the reference values
to calculate gain settings that will keep the channels in balance. Section 3.5.2.1 describes the
method for using the reference values when changing the gain with binary commands.
L
In normal operation, gain settings lower than 288 (0x0120) should not be used. With
gain settings lower than 288, the sensor output signal mapped to the input of the
ADCs will not be linear.