Video camera exposure is set too high - as with interfering objects, if your graphs
seem to be "spiky" or form a line, the video may be saturated in various places causing
color artifacts. Some video cameras show saturated areas with striped lines.
Video cameras set themselves to an average level, via an "automatic gain control",
which may result in some areas being beyond the dynamic range of the cameras. This
is best for a picture, but for our purposes, it is best not to have any saturation
in a field-of-view. If your viewfinder, for example, shows white in the middle of
a red object, it has probably reached saturation and the exposure should be turned
down. Find the "exposure control" setting, and set it for a shorter exposure (the
viewfinder should look darker afterwards).
Less than ideal lighting conditions - the automatic gain on most video cameras adjusts
to low-light levels. Sometimes, however, under fluorescent lights that produce very
little red, it may be hard to get good data. In this case, add incandescent clamp
lights to shine on the red objects.
Camera(s) set to "progressive scan" mode - progressive scan mode takes a new image
only thirty times per second rather than the normal sixty times per second. This
option can cause problems with Motion Visualizer 3D video levels and should be disabled.
Camera(s) set to output status information - Some video cameras include status information, such as date/time, in their video output. Status information can interfere with obtaining a clean video signal so this option should be disabled. You can check this by viewing the cameras' video output on an external monitor.