ImarisTrack is the most powerful commercially available tracking program that rises to the challenge of monitoring temporal changes in biological systems (2D and 3D images over time). Based on a choice of multiple sophisticated automatic tracking algorithms, the ability to manually edit and correct tracks if needed, and the ability to work on extremely large and complex data sets, ImarisTrack allows researchers to answer even the most demanding live-cell imaging questions.
Fully integrated into Imaris, ImarisTrack enables you to leverage the impressive range of 3D and 4D visualization capabilities as well as the image editing and image processing functions of Imaris. ImarisTrack provides automatic and manual track building of the movement-over-time for individually labeled particles, such as cells, molecules, nucleic acids, lipids and many others that have been segmented in Imaris. Tracking can be done on both surface objects and spot objects created with Imaris.
A challenge to any tracking software is that segmented objects at different time points have no relationship between the time points. The job of a good tracking software package is to identify the objects that should be all part of the same track, to accurately join them as part of a track, and to precisely track the objects position even if on occasion the object may disappear and reappear.
ImarisTrack allows selection from a variety of automatic tracking methods to join these independent objects into tracks easily. Sophisticated algorithms of ImarisTrack can handle objects that appear and disappear, can use previous speed and direction of movement of objects for predicting future positions, and can use weighted intensity information to enable the most accurate tracking possible even for complex, busy, and noisy images. If needed, there is always the possibility to manually correct and edit the tracks once the automatic tracking is finished.
In combination with Imaris MeasurementPro, ImarisTrack provides statistical data that is specific to tracking such as straightness and length of tracks; speed, variability and duration tracks; displacement of movement of the object and many more. Because ImarisTrack links independent objects together in a track, users can look at changes in all previously calculated statistical parameters for size, shape, and intensity over time for each set of objects. Like for any other statistical parameter calculated with Imaris MeasurementPro, tracks can be sorted, filtered, classified, selected and grouped with the exact same interface described for Imaris MeasurementPro, but based on these track specific statistics. Likewise, track statistics can be exported to external programs for analysis.
Additionally, ImarisTrack provides a variety of methods to display the tracked results with the original data. This allows for easy verification of the tracking results and the possibility to present the data in a manner that outside observers can quickly understand.
ImarisTrack functionality requires Imaris. For statistical output, ImarisTrack functionality requires Imaris MeasurementPro.
(1) Track Construction – Algorithms
Integrated into the object “Creation Wizard” of Imaris for both “Spot Objects” and “Surface Objects”, ImarisTrack provides an advanced set of algorithms to manually or automatically group segmented objects into tracks over time. All of the tracking methods can be applied to 2D time series or 3D time series (4D) images.
Inspecting or presenting a tracking result visualized as a line connecting all the positions of an object is a natural starting point, but more innovative and flexible options are needed to make sense of images as the X, Y, Z, and t dimensions increase in size, or as the density of objects in the image increases. ImarisTrack not only provides the right variety of tools to clarify complex positional data, but also can map object size, time index, and other statistical information directly to the tracks.
The main point of tracking objects is almost always to measure how they change over time, ImarisTrack, in combination with Imaris MeasurementPro, provides a variety of measurements to facilitate analysis.
ImarisTrack offers a set of tools to modify tracks once they have been created. This feature allows manual creation of tracks, or editing of automatically generated tracks, or for the correction of drift in parts of the image that are moving that should not be.
- All segmented objects (Spots or Surfaces) initially have no relationship to one another between time points
- Tracking links the objects, thus identifying one object as really being the same object at subsequent time points
- Tracks allow the quantification of movements of objects and changes in size, shape, and intensity
Tracking algorithms are used for the creation of tracks for surface or spot objects
Brownian motion algorithm
- Finds the most likely path connection in any direction, within a distance constraint.
Autoregressive motion algorithm
- Utilizes direction and speed information from previous motion of the object to predict future locations to search of an object
- Searchers within a distance constraint around the predicted location
- Excellent of objects that have directed movement
Autoregressive motion expert algorithm
- Utilizes all the parameters of the autoregressive motion algorithm
- Adds the possibility to use object intensity as a criteria for tracking
- Excellent for when objects of varying intensity cross
Connected components algorithm
- Connects objects that would physically overlap if adjacent time points where superimposed on each other
- Good only for extremely high time resolution
- Allows for merge and split of objects
MaxDistance
- The maximum distance that an object moves between two adjacent time points
- Utilized in the Brownian motion and autoregressive algorithms as the distance constraint
MaxGapSize
- The maximum number of time points that the algorithm searchs for an object that disappears
- Utilized in the Brownian motion and autoregressive algorithms
- Prevents two separate tracks being created for one object
- Excellent for object that appear / disappear or turn on /off
Utilizes the Hungarian algorithm of linear assignment of objects which utilizes all objects and all possible connections in the assessment of possible track connections resulting in the most accurate assignment of tracks
Track Path Display
- Display as a line or a cylinder
- Change the diameter of the cylinder or line
- Turn on or off as needs
- Color code the line or cylinder based on time, a single base color, or on any calculated statistics (Requires Imaris MeasurementPro)
- Display the line as a “dragon tail”- the connections for the last X number of time points rather than all time points
Displacement
- An arrow showing the distance and direction between the first and last point of the track
- Turn on or off as needed
- Color and change diamenter as desired
Object Display – As described for Imaris, Spot and Surface objects can be displayed along with the track as a center point representation, the actual segmented object, a scaled down version of the actual segmented object, or can be hidden to show only the original data and the track
Track Specific
- Duration, length, straightness
- Displacement, X, Y, Z, total displacement, squared displacement
- Instantaneous velocity X, Y, Z, velocity, average speed, instantaneous speed, speed variability
- Quality of fit to autoregressive model- per-axis or mean of all axes
Object Specific – Spots or Surfaces
- Changes in size, shape and intensity over time.
- All statistics as described for objects in the MeasurementPro module become linked on a per track basis
- A plot of each objects statistics per time point is graphed when the object is selected. Selection in the graph changes the visualization time point.
Export
- Export for one track, a group of tracks or all tracks
- Exports both track specific and object specific statistics for each track
Uses the Autodepth algorithm for easy selection of tracks or objects in 3D space for editing
Connect and disconnect tracks
- Allows for manual correction of problem areas
- Point and click method is easy to use
Correct object drift
- Select an object or group of objects that should not be moving (after the object has been tracked)
- Shifts the image so that the selected objects no longer move and the movement of the other objects can properly be assessed
Rebuild – The tracking algorithm may be repeated without the need for recreating / re-segmenting the objects
Like surfaces and spots objects, tracks may be filtered as part of the creation wizard based on any of the statistical parameters calculated for those tracks.
Tracks also may be filtered with the filter tab after creation is complete
This video tutorials will help you learn Imaris Track.
Watch this video to learn how to identify, follow 3D-objects over time, display their paths and analyze their movements.
Watch this video to learn how to identify, follow 2D-objects over time, display their paths and analyze their movements.
4D-Tracking with Imaris
Dr. T. Worbs, Prof. R. Förster and, Hannover Medical School, Germany
Automated tracking of T-lymphocyte migration: The present study demonstrates that chemokine receptor CCR7 signaling enhances the motility of CD4+ T cells.
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