Module: Analyze Tracks ()

Description:

This module computes several values from tracks (Temporal Spatial Graph) and creates a new track data object as an output with several data columns attached containing the measurements. Three categories of measures computed on steps, segments, and tracks are available.

Glossary:

		The current time step in a segment.
		The number of time steps in a segment.
		The position of step of a segment.
		The time stamp of step .
		The physical time difference between the previous and current element.
		The steps in a segment.

Measures on steps:

• Displacement vector: The vector joining the previous step and the current step.
  
• Step length: The Euclidean distance between the current time step and the previous one.
  
• Instantaneous velocity: The rate of change of the position between the previous step and the current step.
  
• Instantaneous speed: The magnitude of instantaneous velocity.
  
• Instantaneous acceleration vector: The rate of change of the velocity between the current step and the next step.
  
• Instantaneous acceleration: The magnitude of the instantaneous acceleration vector.
  
• Orientation Theta: The azimuthal angle of the segment's orientation in spherical coordinates. Theta is the angle in the xy plane, measured from the x-axis towards to the projected vector to the y-axis in range [-180, 180] degrees. The orientation is calculated using the vector joining the previous step and the current step.
  With the x and y coordinates of the displacement vector:
  
  
  
• Orientation Phi: The polar angle for the segment's orientation in spherical coordinates. Phi represents the angle formed with the z-axis and varies in the range [0, 180] degrees. The orientation is calculated using the vector joining the previous step and the current step.
  With z being the coordinate of the displacement vector and r the radius (the length of dispalacement vector):
  
• Directional change Theta: The angular difference between previous orientation Theta and current orientation Theta.
  
• Directional change Phi: The angular difference between previous orientation Phi and current orientation Phi.
  
• Total distance traveled: The curvilinear distance to the beginning of the segment.
  
• Net distance traveled: The Euclidean distance to the beginning of the segment.
  
• Tortuosity: The tortuosity characterizes the complexity of the path from the beginning of the segment to the current step.
  

Measures on segments:

• Duration: The entire time duration that the segment exists.
  
• Length: The curvilinear distance to the segment.
  
• Diffusion Coefficient: The diffusion coefficient is computed from the mean square displacement using equation 1. It can be used to characterize the mode of motion of the corresponding object.
  
• Displacement vector: The vector joining the extremities of the segment.
  
• Euclidean distance: The Euclidean distance of the segment.
  
• Tortuosity: The tortuosity characterizes the complexity of the segment.
  
• Bounding box: The box with sides parallel to the coordinates system just large enough for the entire segment to fit inside.
• Mean velocity: The mean of the instantaneous velocities of all steps in the segment.
  
• Average speed: The average of velocity magnitudes of all steps in the segment.
  
• Mean straight-line speed: The speed of the object if it would have travelled along a straight line.
  
• Rank: The number of bifurcation between the beginning of the track and the current segment.

Measures on tracks:

• Duration: The duration between the first appearance of a step to the last disappearance of a step on the track.
• Bounding box: The box with sides parallel to the coordinates system just large enough for the entire track to fit inside.
• Max rank: The number of segment of the longest path.

Tips: The Extract Spreadsheet module allows extracting a sub-group of measures from a category.

Note: Once the computation has started, it cannot be interrupted until it is finalized.

Connections:

Data [required]
The Temporal Spatial Graph on which the measures will be computed.

Label Image Series [optional]
This port is linked to the Time Series of Label Fields corresponding to the segmentation of the Time Series of gray images.

Intensity Image Series [optional]
This port is linked to the Time Series of gray images.

Measures Group [required]
Select the measure group of Label Analysis that will be computed on the Time Series of Label Fields and attached to the Steps of the output Temporal Spatial Graph.

Ports:

Measures Type

This port aims to select which type of measures can be selected for computation. It takes its values between:

• Steps measures: With this value it is possible to select which steps measures can be selected for computation in port Steps Related Measures which will be visible
• Segments measures: With this value it is possible to select which segments measures can be selected for computation in port Segments Related Measures which will be visible
• Tracks measures: With this value it is possible to select which tracks measures can be selected for computation in port Tracks Related Measures which will be visible

Steps Related Measures

All Steps measures that are selected in this port will be computed. Selectable items are:

• Displacement X
• Displacement Y
• Displacement Z
• Step Length
• Velocity X
• Velocity Y
• Velocity Z
• Speed
• Acceleration X
• Acceleration Y
• Acceleration Z
• Acceleration
• Orientation Theta
• Orientation Phi
• Orientation Theta Diff
• Orientation Phi Diff
• Total Distance
• Euclidian Distance
• Tortuosity

Segments Related Measures

All segments measures that are selected in this port will be computed. Selectable items are:

• Duration
• Curvilinear Length
• Displacement Vector X
• Displacement Vector Y
• Displacement Vector Z
• Displacement Length
• SegmentTortuosity
• Bounding Box Xmin
• Bounding Box Ymin
• Bounding Box Zmin
• Bounding Box Xmax
• Bounding Box Ymax
• Bounding Box Zmax
• Mean Velocity X
• Mean Velocity Y
• Mean Velocity Z
• Mean Straight Line Speed
• Mean Speed
• Linearity Of Forward Progression
• Rank

Tracks Related Measures

All tracks measures that are selected in this port will be computed. Selectable items are:

• Max Rank
• Bounding Box Xmin
• Bounding Box Ymin
• Bounding Box Zmin
• Bounding Box Xmax
• Bounding Box Ymax
• Bounding Box Zmax