Nano Series GigE Vision Camera Operational Reference • 115
Offset/Gain Control Details (Sony 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: The gain function is a linear multiplier control in 0.01 steps
within the sensor hardware (range is “1-251”, which is a +48dB maximum gain).
• Gain: Sensor gain is applied first by an analog amplifier (multiplier range of “1-15.85”,
i.e. +24dB) and then continues automatically via a digital amplifier as shown in the graphic
below.
• Important: Digital noise increases linearly and quickly with higher gain values. Users
should evaluate image quality with added gain.
• Gain (Raw): Provides an alternative method to control sensor gain, where values entered
are in 0.1dB increments. Therefore the range is 0 to 480 which controls a 0 to 48dB gain
range.
• Gain Selector = Digital: The gain function controls the post sensor digital amplifier
(available only on some models of Nano cameras). This gain factor is independent of any
sensor gain set. This setting is a linear multiplying number of 1 to 4, in 0.1 steps).
• Black Level: This offset variable exists within the sensor. The Sony sensors allow an offset
range between 0 and 511 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.
Sony Sensors Gain Stage Diagram
Sensor Gain Control
Post Digital Gain Control
Sony Sensor Gain Stages
Analog Digital
Black Level
Control
Digital
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