Tracking Errors And Flags - Northern Digital Polaris Vicra User Manual

5.2

Tracking Errors and Flags

Many of the following errors and flags are displayed in NDI ToolBox. They are all returned with the
TX and BX commands (using reply options 0x0001 and 0x0002).
System status flags
System Communication Synchronization Error indicates communication problems between internal
sub-components of the system.
Diagnostic Pending Indicates a change in any of the alerts flags. The flag is persistent until the alerts
parameter are read. Reading the alerts parameter automatically clears the flag. By default
transformation data is not returned when this flag is set.
Temperature System is out of specified operating temperature range or not yet warmed up. By
default transformation data is not returned when this flag is set. The flag will automatically be
cleared as soon as the system is back in the specified operating temperature range.
Port status flags
Out of Volume The out of volume flag is set for a marker or tool that is completely outside of the
characterized measurement volume, but can still be detected by the system. The flag is set regardless
of whether the reply option 0x0800 for the TX or BX command is used. (Reply option 0x0800
enables the reporting of the positions of tools and markers that are outside of the characterized
measurement volume. See the "Polaris Application Program Interface Guide" for details.)
Partially Out of Volume The partially out of volume flag is set for a tool if less than the minimum
number of markers are inside the characterized measurement volume, and at least one marker on the
tool is inside the characterized measurement volume. See
for a description of the minimum number of markers parameter.
Algorithm Limitations Indicates that during parts of the algorithm used for 2D/3D/6D calculations a
limitation has been detected (for example buffer full). This does not mean that an error occurred or
that the tools will not track properly.
If the flag is transient, i.e. it comes on for only a few frames during the beginning of tracking or
during a disruption of the scene (blocking/unblocking), no actions need to be taken.
If the flag persists and the tool does not track, changing the scene (removing tools and/or markers)
or simply re-arranging the scene should resolve the problem.
IR Interference Indicates that one of the sensors has detected an object that is bright enough to be
considered a marker but is too large. (For example, this flag can be triggered by two passive sphere
markers being close together.) This may not affect tracking in which case it can be ignored. If one or
more tools do not track and the flag persists the scene should be examined for the root cause of the
flag (for example by taking a video capture with NDI ToolBox).
Processing Exception Indicates that an exception has been detected in the firmware. Transformation
data will be invalid as long as the flag persists. The system may self-recover from this condition,
depending on the scene. The flag typically comes on when the system is overloaded, ie it cannot
handle the scene. Remove some tools and/or markers from the scene to prevent this flag from being
triggered.
Polaris Vicra User Guide - Revision 2
Error Flags and Codes
"Tool Tracking Parameters" on page 31
49