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116 • Operational Reference Nano Series GigE Vision Camera
Offset/Gain Control Details (On-Semi Python sensors)
The Gain and Black level functions are applied at the sensor and/or on the digital image values
output by the sensor, as described below.
• Gain Selector = Sensor Analog: The gain function is a linear multiplier control in 0.01
steps within the sensor hardware (Gain range is “1-8”, which is a +18dB gain).
•
Gain Selector = Sensor Digital: The gain function is a linear multiplier control in 0.01
steps within the sensor hardware (Gain range is “1-31.99”, which is +30dB gain).
•
Important: Digital noise increases linearly and quickly with higher gain values. Users
should evaluate image quality with added gain.
•
Gain (Raw): Shows the raw sensor control for each gain stage or an alternative method to
control sensor gain.
•
Black Level: This offset variable exists within the sensor. The On-Semi sensors allow an
offset range between 0 and 255 DN. The factory settings default value for each sensor used
by various Nano models, is recommended as per the sensor manufacturer design
specifications.
Note: With the factory default offset, testing a camera’s black output in 8-bit mode may
show a 2 DN value difference across the image. Changing the Black Level value up or down
will push sensor noise (present at the sensors native bits per pixel) to fall within one 8-bit
value, thus the noise becomes hidden.
On-Semi Python Sensors Gain Stage Diagram
Analog Gain Control
Post Digital Gain Control
On-Semi Sensor Gain Stages
Analog
Black Level
Control
Digital Digital
Digital Gain Control