InfoMus Lab
The EyesWeb Trajectory Analysis Library
The EyesWeb Trajectory Analysis Library contains a collection of blocks and patches for extraction of features from trajectories in 2D (real or virtual) spaces. It complements the EyesWeb Space Analysis Library and it can be used in together with the EyesWeb Motion Analysis Library.
Blocks can deal with many trajectories at the same time, for example trajectories of body joints (e.g., head, hands, and feet tracked by means of color tracking techniques - occlusions are not dealt with at this stage) or trajectories of points tracked using the Lucas-Kanade feature tracker available in the Motion Analysis Library.
Features that can be extracted include geometric and kinematics measures. Some of them are listed here:
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Directness index
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Trajectory length
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Trajectory local and average direction
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Velocity
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Acceleration
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Curvature
Descriptive statistic measures can also be computed:
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Along time: for example, average and peak values of features calculated either on running windows or on all the samples between two subsequent commands (e.g., the average velocity of the hand of a dancer during a given motion phase)
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Among trajectories: for example, average velocity of groups of trajectories available at the same time (e.g., the average instantaneous velocity of all the tracked points located on the arm of a dancer).
Trajectories can be real trajectories coming from tracking algorithms in the real world (e.g., the trajectory of the head of a dancer tracked using a tracker included in the EyesWeb Motion Analysis Library) or trajectories in virtual, semantic spaces (e.g., a trajectory representing a gesture in a semantic, expressive space).
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| An EyesWeb application calculating the length (in the graph on the left) and the direction (the green arrow in the display) of a trajectory (the red stripe in the display). Both length and direction are calculated on sliding windows of 10 samples (i.e., 0.4 s). |