Line Tracker Plugin
Line Track will create points along a line between the current selected model
point and the previous point. It does this by filtering with a collection of
elongated kernels at a range of orientations.
This Plugin also has a Contour Copying function which will copy the current
contour onto an adjacent section (the section being displayed) then adjust the
position of the contour to match the image on that section. It uses kernels
that are shaped like the contour.
Image data are always analyzed as 8-bit bytes, even when they have been loaded
into the program as 16-bit integers. In the latter case, the current setting
of the Low and High sliders in
the Information window determines how data are
scaled to bytes. For best results, be sure that the Low
and High sliders are set so that images have a good contrast with a
fairly wide range between the Black and White sliders.
- Space bar to add points between the last and the current point
- [Ctrl]-Space or [Shift]-Space to track from the current point and close the
- Apostrophe to copy contour to current section
- U or Semicolon to undo last modeling action
- 0 Light, 1 Dark Lines: Set to 0 or 1 to follow bright or dark
- Offset from line: Amount to offset model points from the center
of the line. Set positive for a positive offset when modeling to the right.
- Sigma (Line width): Sigma is actually the half-width of the
central part of the kernel, but should be set to somewhat more than half the
width of the lines you are trying to track.
- H (half-length): The half-length of the kernel in its elongated
- Kernel Half-size: Should be at least H and 3 * Sigma but could
be reduced to run faster.
- Reduction Tolerance: After finding a path, the program will
remove any points that are within this distance of lines between the remaining
- Copy Tolerance: Maximum distance that the program will search
for best position when copying a contour to a new section.
- Copy Pooling: Number of points that will be considered together
when trying to shift a particular point. Bigger numbers will give more
smoothing. With a positive value, the point being shifted will be given the
most weight; with a negative value, all points will be given equal weight,
resulting in even more smoothing.
- Copy Smoothing: Number of points to fit to in the final
smoothing of the contour (0 for no smoothing, higher values for more smoothing).
- Number of Kernels: Could be reduced to run faster.
- Step Size: Size of step to move between points; could be reduced
to run faster.