The Tracking panel

From frame ... to ...: Restricts tracking to the range defined.

Restrict tracking to labelled region: Select a region from the labels already defined (see Label editor, About labels). Using this option results in faster tracking speed as only the labelled region is processed). A labelled region is useful to exclude an area within the field of view that would potentially occlude worms.

Tracking Parameters

ClosedUse back tracking

WormLab performs tracking backwards, which allows worms with no predecessor—those suddenly appearing in the field of view—to be tracked backwards in time. Tracks generated by worms tracked through back tracking are connected to other worm tracks later.

ClosedTrack worms at the edge of the image

Avoid using if you are interested in worm shape, length or area as worms at the edge of the image can be modeled with an inaccurate length.

ClosedMax tracked hypotheses

Sets the maximum number of hypotheses for a worm location. The fastest speed is achieved with a setting of 1. Multiple hypotheses can help disambiguate, or resolve conflicts, between worms when they are interacting. The hypotheses are tracked over several frames, and only the most likely hypothesis is used to determine the worm track.

For best results, set the maximum number to 4 or 5 when you are tracking multiple worms in complex overlap or interaction scenarios.

ClosedTracking mode

Select Crawling for worms on a dry plate, or Swimming for worms in a liquid solution.

Each mode uses its own model that takes into account locomotion differences.

Advanced

ClosedFrames worms can touch boundary

Number of frames in which WormLab tracks a worm at the edge of the image. If the worm remains at the edge after the specified number of frames, it is dropped from tracking. This is useful for instances where a worm is at the edge for a few frames only.

ClosedFrames worms can overlap

Number of frames in which WormLab tracks overlapping worms. This option is used for faster tracking, limiting the amount of time (in frames) during which WormLab seeks to resolve worm overlaps.

Lower this parameter if tracking becomes unstable while WormLab tracks interacting worms over an extended period of time.
If WormLab drops interacting tracks for no apparent reason, we recommend that you increase this number to resolve this issue.

ClosedPosition tolerance

Percentage of a position shift (as a fraction of body length) tolerated over consecutive frames to continue a track. If the worm position is outside this value, WormLab generates a new worm track.

ClosedShape tolerance

Percentage of a shape difference (length, width) tolerated over consecutive frames to continue a track. If the worm shape is outside this value, WormLab generates a new worm track.

  • If track length is a priority, raise this value.
  • If detection accuracy is a priority, lower this value.
  • If there is only one or very few worms on the plate, a higher value will help to create a continuous track in the presence of noise.

Track Filtering

Use to filter out short, spurious tracks that can occur in the presence of image noise, a cluttered background, or deep tracks.

  • Check Minimum track duration (frame) and set a value for a minimum number of frames in which a track must appear to be considered valid.

If a worm track exists for fewer frames than the set value, the program deletes the worm track from the data generated by Track Worms Workflow: Analyze Data.