Maximum Velocity Error for New Paths
Maximum Velocity Error for New Paths
For particles which do not have any previous velocity history (ie.
particles which are new to the tracking process), we must predict their
behaviour in order to make reasonable matches at the next time step. This
prediction process is governed by [N New particle behaviour]. However, such
predictions will never be precise (if they were there would be no point in
tracking the particles); this option allows the setting of error bounds on
the predicted velocity or predicted particle position. The error limit
affects the costs of any matches to a particle without a velocity history
by discounting any associations with that particle to a degree governed by
the maximum velocity error (the cost for a prediction error equal to this
value is set equal to the cost for a lost particle where the velocity
history is known).
Specify maximum new paths error as a Velocity or Pixel separation ?
The maximum allowable error in the predicted velocity may be expressed
either as an error velocity (<V>) in world units per second, or as a
maximum positional error (<P>) in pixels.
{If specifying error as a velocity}
Maximum x velocity error for new paths (world units per second) ?
This entry specifies the maximum error in the new particles velocity
prediction in the x direction. The velocity error is in world units per
second. By giving this error as a velocity it should not be necessary to
change it for different sample spacings. The final maximum error is
elliptical. The major and minor axes of the elipse are aligned with the x
and y axes.
{If specifying error as a velocity}
Maximum y velocity error for new paths (world units per second) ?
This entry specifies the maximum error in the new particles velocity
prediction in the y direction. The velocity error is in world units per
second. By giving this error as a velocity it should not be necessary to
change it for different sample spacings. The final maximum error is
elliptical. The major and minor axes of the elipse are aligned with the x
and y axes.
{If specifying error as pixels displacement}
Maximum x position error for new paths (Pixels error) ?
This entry specifies the maximum horizontal distance, given in pixels,
between the predicted position of a particle of unknown velocity and the
position of any matched particle.
{If specifying error as pixels displacement}
Maximum y position error for new paths (Pixels error) ?
This entry specifies the maximum vertical distance, given in horizontal
pixels (to give an isotropic measure), between the predicted position of a
particle of unknown velocity and the position of any matched particle.
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DigImage User Documentation
Stuart Dalziel,
last page update: 19 February 1996