SVS-Vistek EXO Series, Manual

Page: 59 / 144

SVS-VISTEK
Feature-Set 59
When DVAL signal is enabled only every third pixel in horizontal direction
is grabbed.
Figure 32: Illustration of 2x2 binning
7.1.15 Burst Mode
The hardware interface (GigE, USB3 etc) of your camera very often will
limit the maximum framerate of the camera to the maximum framerate of
the interface of the camera. Inside the camera, the sensor speed (internal
framerate) might be higher than the external interface’s speed (e.g. GigE).
In triggered mode though, trigger frequency might be higher than the
external interface’s speed. The triggered images will stay in the internal
memory buffer and will be delivered one after the other with interface
speed. If trigger frequency is higher than interface max fps frequency,
more and more images will stick in the internal image buffer. As soon as
the buffer is filled up, frames will be dropped.
This internal-save-images and deliver-later thing is called Burst Mode.
Due to internal restriction in the image request process of the camera, on
USB cameras the maximum sensor speed is limited to the maximum
interface speed. This means the maximum trigger frequency cannot be
higher than camera freerun frequency. The image buffer will protect
against breaking datarates of the USB line, though.
Usage of Burst Mode
Burst Mode has 2 main purposes:
> If transfer speed breaks down (e.g. Ethernet transfer rate due to
high network load), tolerate low speed transfer for a short time
and deliver frames later on (buffering low speed interface
performance for a short time)
>
For several frames (up to full internal memory) images can be
taken with higher frame rate than camera specs are suggesting
(as soon as there is enough time later on to deliver the images)
(not applicable to USB cameras)
Please note, as soon as the internal memory buffer is filled up, frames will
be dropped. Due to this reason, SVS-Vistek camers provide up to 512MB
image buffer memory.