Table of Contents
Interpolate
The Interpolate command fills in any gaps in a signal's data using a spline interpolation. This can be useful if there are unreliable data points (residuals < 0).
The interpolation procedure performs a least-squares fit of an nth order polynomial to k data points.
|(x1,t1),...,(xk,tk)|k >= polynomial order + 1|
Pipeline Command
The pipeline command for Interpolate can be found in the Pipeline Workshop within the Signal Process folder as so:
Interpolate /SIGNAL_TYPES= ! /SIGNAL_NAMES= ! /SIGNAL_FOLDER=ORIGINAL ! /RESULT_SUFFIX= ! /RESULT_FOLDER=PROCESSED /MAXIMUM_GAP= ! /NUM_FIT=3 ! /POLYNOMIAL_ORDER=3 ;
Parameters
The parameters that can be used to control the command are as follows:
| Parameter | Description |
|---|---|
| /Signal_Types | The type of signal to be processed. |
| /Signal_Names | The names of the signals to be processed. |
| /Signal_Folder | The name of the signal folder. |
| /Result_Folder | The name of the folder to contain the results. |
| /Result_Suffix | Suffix to be applied to the results. |
| /Num_Fit | The number of frames of data before and after the “gap” that are used to calculate the coefficients of the polynomial. |
| /Polynomial_Order | The order of the polynomial used. |
| /Maximum_Gap | The maximum number of frames of data that can be replaced with interpolated values. |
Dialog
The command can be edited as text or by using the dialog box shown below:
Example: Using an expression
This example shows how you could interpolate for a gap in target data by defining the maximum size of the gap based on the POINT frame rate.
Interpolate /SIGNAL_TYPES=TARGET ! /SIGNAL_FOLDER=ORIGINAL /SIGNAL_NAMES=RASI ! /RESULT_FOLDER=PROCESSED /RESULT_SUFFIX=_INT /MAXIMUM_GAP=0.1*PARAMETERS::POINT::RATE ! /NUM_FIT=3 ! /POLYNOMIAL_ORDER=3 ;
Example: Using Number of Frames
This example shows how missing force plate data can be found via interpolation using a specified number of frames:
Interpolate /SIGNAL_TYPES=FORCE ! /SIGNAL_FOLDER=ORIGINAL /SIGNAL_NAMES=FP2 ! /RESULT_FOLDER=PROCESSED /RESULT_SUFFIX=_INT /MAXIMUM_GAP=30 ! /NUM_FIT=5 ! /POLYNOMIAL_ORDER=3 ;