System information

MX Cameras
Vicon MX Hardware System Reference 3-3
Performance Notes:
• Shuttering: The image quality from a shuttered camera is
constant across all frame rates. For an unshuttered camera, which
is more susceptible to background light levels, narrow bandwidth
interference filters are used to provide a signal to noise ratio
performance comparable to the shuttered cameras. Factors such
as strobe illumination, field of view, and depth of field also affect
the image quality. For details of which cameras are shuttered or
not, see Table 3-1 on page 3-2. For further details on how to work
with these factors, see Camera Lenses on page 3-4.
• Monitor Mode: The camera frame rate that monitor mode runs
at is fixed. This mode enables you to use a VGA monitor as a view
finder for the camera; motion capture is not performed in this
mode. For details, see VGA Monitor (MX+ and MX) on page 3-12.
• Increased Frame Rates: You can specify higher frame rates
than those shown in Table 3-1 on page 3-2. However, at higher
frequencies, the MX cameras automatically reduce the image size
(vertical windowing). For details, see Field of View on page 3-4.
You can specify the capture frame rate of each MX camera in the
Vicon software. MX cameras are capable of capturing up to a
maximum of 2,000 fps, but the actual frame rate you can specify
depends on the Vicon application software you are using. For
details, see your software documentation.
• Grayscale Precision: MX cameras evaluate an entire image in
grayscale, rather than applying a black and white threshold. This
provides more information and increases motion measurement
accuracy over an equivalent resolution black and white camera.
The MX cameras perform the majority of data processing. They
generate grayscale blobs for reflections from objects in the cap-
ture volume and then use centroid-fitting algorithms to determine
which of these objects are likely to be markers. MX camera data
is sent to Vicon application software for viewing and further pro-
cessing. For details, see your software documentation.
• Bandwidth: Even with the elimination of background grayscale
through thresholding, MX performance will be limited in real time
by the number of cameras, number of markers, and the frame
rate. MX data capture to disk is limited by the time it takes to write
the data to disk as no buffering outside the host PC is available.
You can configure the buffering of MX data at the time of capture.
You do this in the Vicon software on the host PC. For details, see
MXhardware_Reference.book Page 3 Thursday, September 7, 2006 11:36 AM