User`s manual

Genie HM-HC Series-GigE Vision Camera Operational Reference  39
Gain and Black Level Controls
The Genie HM series of cameras provide gain and black level adjustments in the digital domain for the CMOS
sensor. The gain and black level controls can make small compensations to the acquisition in situations where
lighting varies and the lens iris can not be easily adjusted. The user can evaluate Gain and Black Level by using
CamExpert.
Features and limitations are described below.
 Gain is expressed in decibels (dB). Range from 0dB to +12dB in 0.1dB increments. Gain is a multiplication
factor to the signal. Increasing gain increases the sensor noise proportionately.
Note that a gain of 6dB is a multiplier of 2 (doubles the level).
 Black level offset is expressed as a digital number ranging from 0 to 1023. As an example, if the Genie HM is
used in 10-bit mode and captures a 1024 step gray level (such as the internal ramp test pattern), an offset of 1
would cause the two lowest gray levels to have a value of 0 (i.e. black level units = 1 DN). Note that in the
same way, the peak white level is one less then maximum and the gain adjustment would be used to then get the
full dynamic range. With the Genie HM in 8-bit mode, the offset values would change by 1 for each data entry
of 4 (i.e. black level units = 1/4 DN).
Important: The Genie gain adjustment range and 0dB point is arbitrarily defined by DALSA for the Genie
camera series. The reference setting of 0dB must not be compared to any other product's gain settings when
evaluating the signal to noise specifications of the two products.
Proper comparisons of two products requires identical illumination with identical camera exposure integration
time, then followed by gain control adjustments to produce an identical image gray level.
Gain and Offset Control via Sapera LT or GigE Vision Compliant
Applications
Sapera
Genie Sapera parameters for Gain and Black level:
Gain = Amplification in dB from 0 to 12.0 dB
BlackLevel = DC offset in DN, range from 0 to 1023
(1/4 DN for 8-bit mode, 1 DN for 10-bit mode)
In CamExpert, these parameters are available under the “Sensor” tab.
See "Accessing Features with Sapera++ LT" on page 76.
XML features for Gain and Black level:
GainSelector = Select which gain control {DigitalAll}
GainRaw = multiplier of 1.0 to 3.0
BlackLevelRaw = Black level (offset) in 1/16 of DN
(0 – 4092 with increments of 4 in 10-bit mode and 0 – 1023 with increments of 1 in 8-bit mode)