User`s manual

Image Acquisition Control
Basler pioneer 137
10.9 Maximum Allowed Acquisition
Frame Rate
In general, the maximum allowed acquisition frame rate for your camera can be limited by three
factors:
 The amount of time it takes to read the data for an acquired image (known as a frame) from the
image sensor to the frame buffer. This time varies depending on the height of the frame.
Shorter frames take less time to read out of the sensor. The frame height is determined by the
camera’s AOI settings.
 The exposure time for acquired frames. If you use very long exposure times, you can acquire
fewer frames per second.
 The amount of time that it takes to transmit an acquired frame from the camera to your host
PC. The amount of time needed to transmit a frame depends on the bandwidth assigned to the
camera.
To determine the maximum allowed acquisition frame rate with your current camera settings, you
can read the value of the camera’s Resulting Frame Rate parameter. This parameter indicates the
camera’s current maximum allowed frame rate taking the AOI, exposure time, and bandwidth
settings into account.
For more information about AOI settings, see Section 13.5 on page 185.
For more information about the Resulting Frame Rate parameter, see Section 7.1 on page 85.
Increasing the Maximum Allowed Frame Rate
You may find that you would like to acquire frames at a rate higher than the maximum allowed with
the camera’s current settings. In this case, you must first use the three formulas described below
to determine what factor is restricting the maximum frame rate the most. Next, you must try to make
that factor less restrictive:
 You will often find that the sensor readout time is most restrictive factor. Decreasing the AOI
height for the acquired frames will decrease the sensor readout time and will make this factor
less restrictive.
 If you are using normal exposure times and you are using the camera at it’s maximum
resolution, your exposure time will not normally be the most restrictive factor on the frame rate.
However, if you are using long exposure times or small areas of interest, it is quite possible to
find that your exposure time is the most restrictive factor on the frame rate. In this case, you
should lower your exposure time. (You may need to compensate for a lower exposure time by
using a brighter light source or increasing the opening of your lens aperture.)
 The frame transmission time will not normally be a restricting factor. But if you are using
multiple cameras and you have set a small packet size or a large inter-packet delay, you may
find that the transmission time is restricting the maximum allowed rate. In this case, you could
increase the packet size or decrease the inter-packet delay. If you are using several cameras
connected to the host PC via a network switch, you could also use a multiport network adapter
in the PC instead of a switch. This would allow you to increase the Ethernet bandwidth
assigned to the camera and thus decrease the transmission time.