Offset/Gain Control Details (Sony Sensors); Sony Sensors Gain Stage Diagram - Teledyne m640 User Manual

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
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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
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evaluate image quality with added gain.
Gain (Raw): Provides an alternative method to control sensor gain, where values entered are
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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
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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
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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

Analog
Sensor Gain Control
Nano Series GigE Vision Camera
Sony Sensor Gain Stages
Digital
Control
Black Level
Post Digital Gain Control
Digital
Operational Reference • 69