visual3d:documentation:pipeline:signal_commands:first_derivative
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visual3d:documentation:pipeline:signal_commands:first_derivative [2024/06/14 17:30] – created sgranger | visual3d:documentation:pipeline:signal_commands:first_derivative [2024/11/11 14:05] (current) – wikisysop | ||
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- | |**Language: | + | ====== |
- | + | ||
- | |===== Contents =====\\ \\ \\ \\ * [[# | + | |
Compute the first derivative at each point of a signal. | Compute the first derivative at each point of a signal. | ||
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The command can be edited via text editor or via a dialog. The details on the command and the dialog are found below: | The command can be edited via text editor or via a dialog. The details on the command and the dialog are found below: | ||
- | |[[File: | + | {{:First_Derivative.png}} |
+ | |||
+ | < | ||
+ | First_Derivative | ||
+ | / | ||
+ | / | ||
+ | / | ||
+ | / | ||
+ | / | ||
+ | / | ||
+ | / | ||
+ | </ | ||
The first and last data points become DATA_NOT_FOUND (identified in the C3D file as a POINT Reliability value of –1). | The first and last data points become DATA_NOT_FOUND (identified in the C3D file as a POINT Reliability value of –1). | ||
- | ===== Calculation Method | + | ==== Calculation Method ==== |
Derivatives are calculated using Finite Difference Algorithms. | Derivatives are calculated using Finite Difference Algorithms. | ||
+ | < | ||
Given the signal: | Given the signal: | ||
- | |||
x(ti) for i=1, 2, ..., n | x(ti) for i=1, 2, ..., n | ||
- | The first derivative is calculated using: | ||
+ | The first derivative is calculated using: | ||
xDot(ti)= (x(ti+1)-x(ti-1))/ | xDot(ti)= (x(ti+1)-x(ti-1))/ | ||
- | ===== Example: Velocity of the Centre of Mass ===== | + | </ |
+ | |||
+ | ==== Example: Velocity of the Centre of Mass ==== | ||
The First_Derivative command is useful for calculating the velocity of targets, landmarks, etc. since velocity is the first derivative of position. The following example calculates the velocity of the center of mass using the First_Derivative command. | The First_Derivative command is useful for calculating the velocity of targets, landmarks, etc. since velocity is the first derivative of position. The following example calculates the velocity of the center of mass using the First_Derivative command. | ||
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</ | </ | ||
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- | Retrieved from "" | ||
visual3d/documentation/pipeline/signal_commands/first_derivative.1718386207.txt.gz · Last modified: 2024/06/14 17:30 by sgranger