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Alvium USB Cameras User Guide V3.6.4
Specifications
Sensor ADC readout modes for maximum frame rates
If you are using pixel formats that do not require 12-bit sensor ADC readout and
you want to achieve higher frame rates, you can select between readout modes for
12-bit, 10-bit, and 8-bit with some Alvium USB camera models. See your model’s
specifications.
By default, Alvium 1800 U models use the maximum bit depth for
SensorBitdepth
. For selected models,
Adaptive
mode switches automatically
between 12-bit and 10-bit sensor ADC readout, depending on the bit depth of the
selected pixel format. This allows to reduce bandwidth and increase frame rates
when only 10-bit is required.
To enable the 8-bit sensor readout mode, you must switch manually, using
SensorBitdepth
. Please observe that the image brightness changes when you
switch between 8-bit sensor ADC readout mode and the other readout modes.
Exposure time behavior regarding ExposureMode
This section informs about how exposure time behaves in the different exposure
modes.
All Alvium cameras have an exposure time offset. The exposure time offset and the
exposure time increment depend on sensor and camera characteristics. Both, the
exposure time offset and the exposure time increment, can change if
Width
,
PixelFormat
, or
DeviceLinkThroughputLimit
are changed. See
ExposureMode = Timed
For all Alvium cameras, exposure time can be set by
ExposureTime
or
ExposureAuto
. For this,
ExposureMode
is set to
Timed
.
The selected exposure time is extended automatically:
• If the selected exposure time does not match the available increment, the
camera automatically extends the exposure time to the next increment.
• The
exposure time offset is included
in the selected exposure time.
ExposureMode = TriggerWidth or TriggerControlled
In addition, most global shutter (GS) cameras can control exposure time by the
trigger signal, with the
ExposureMode
set to
TriggerWidth
or
TriggerControlled
(using
ExposureStart
and
ExposureStop
).
The trigger controlled exposure time is extended automatically:
Maximum frame rates at different values for SensorBitDepth
When the maximum bandwidth supported by USB interface is reached, reducing
the value for
SensorBitDepth
does not increase the available maximum frame
rate.