====== Signal Commands Overview ======

Signal commands are used to manipulate signals within the Visual3D pipeline.

===== Signal Math =====

These commands perform mathematical operations using signals.

^ Command ^ Description ^
| [[visual3d:documentation:pipeline:expressions:expressions_overview|Evaluate_Expression]] | Can be used to flexibly define custom mathematical functions. |
| [[visual3d:documentation:pipeline:signal_commands:add_constant_to_signals|Add_Constant_To_Signals]] | Adds a constant to the specified components of a signal(s). |
| [[visual3d:documentation:pipeline:signal_commands:add_random_noise_to_signals|Add_Random_Noise_To_Signals]] | Adds random noise to the specified signal(s). |
| [[visual3d:documentation:pipeline:signal_commands:add_signals|Add_Signals]] | Add the specified signals. Signals must be at the same sampling rate. If your signals are a different rate, you can use the [[Visual3D:Documentation:Pipeline:Expressions:Expressions_Overview|Evaluate_Expression]] command, which determines an appropriate rate automatically.|
| [[visual3d:documentation:pipeline:signal_commands:divide_signals|Divide_Signals]] | This command will divide signals with the first signal being the numerator.|
| [[visual3d:documentation:pipeline:signal_commands:divide_signal_by_constant|Divide_Signal_By_Constant]] | This command will divide a specified components of a signal(s) by a constant. |
| [[visual3d:documentation:pipeline:signal_commands:First_Derivative|First_Derivative]] | Compute the first derivative at each point of a signal. This command is useful for calculating the velocity of targets, landmarks, etc. |
| [[visual3d:documentation:pipeline:signal_commands:Second_Derivative|Second_Derivative]] | Compute the second derivative at each point of a signal. This command is useful for calculating the acceleration of targets, landmarks, etc. |
| [[visual3d:documentation:pipeline:signal_commands:multiply_signals|Multiply_Signals]] | Multiply the components of the specified signals. |
| [[visual3d:documentation:pipeline:signal_commands:multiply_signals_by_constant|Multiply_Signals_By_Constant]] | Multiply signals by a constant value. |
| [[visual3d:documentation:pipeline:signal_commands:indefinite_integral|Indefinite_Integral]] | Compute an indefinite integral from the start event to the stop event.|
| [[visual3d:documentation:pipeline:signal_commands:Signal_magnitude|Signal_Magnitude]] | Calculate the magnitude of a signal according to: <code>Magnitude=Sqrt( x^2+y^2+z^2 )</code> |
| [[visual3d:documentation:pipeline:signal_commands:subtract_constant_from_Signals|Subtract_Constant_From_Signals]] | Subtracts a constant from the specified components of a signal(s). |
| [[visual3d:documentation:pipeline:signal_commands:subtract_signals|Subtract_Signals]] | Subtract the components of the specified signals. |
| [[visual3d:documentation:pipeline:signal_commands:Square_Root|Square_Root]] | Compute the square root of a signal or metric. This command can be used to compute the vector magnitude of a signal. |
| [[visual3d:documentation:pipeline:signal_commands:compute_planar_angle|Compute_Planar_Angle]] | This command computes a planar angle between three or four points. |
| [[visual3d:documentation:pipeline:signal_commands:compute_volume_of_chest_Wall|Compute_Volume_Of_Chest_Wall]] |  |
| [[visual3d:documentation:pipeline:signal_commands:compute_volume_of_a_convex_hull|Compute_Volume_Of_A_Convex_Hull]] | |

===== Signal/Data Management =====

These commands manage signals within the Visual3D workspace.

^ Command ^ Description ^
| [[visual3d:documentation:pipeline:signal_commands:create_target|Create_Target]] | |
| [[visual3d:documentation:pipeline:signal_commands:global_normalized_signal_mean|Global_Normalized_Signal_Mean]] | |
| [[visual3d:documentation:statistics:find_representative_signal|Find_Representative_Signal]] | |
| [[visual3d:documentation:pipeline:signal_commands:merge_data|Merge_Data]] | This command merges data from more than one data name into a single one either by appending one signal to the end of another signal or by treating each original signal as a component of the new signal. |
| [[visual3d:documentation:pipeline:signal_commands:copy_folder|Copy_Folder]] | Makes a copy of an existing folder. If the new folder already exists, select whether these signals should be overwritten (replaced). |
| [[visual3d:documentation:pipeline:signal_commands:rename_folder|Rename_Folder]] | This command renames the specified folder. |
| [[visual3d:documentation:pipeline:signal_commands:delete_folder|Delete_Folder]] | Deletes the specified folder. Note that ORIGINAL folders can not be deleted. |
| [[visual3d:documentation:pipeline:signal_commands:remove_signals|Remove_Signals]] | |
| [[visual3d:documentation:pipeline:signal_commands:rename_signals|Rename_Signals]] | |
| [[visual3d:documentation:pipeline:signal_commands:remove_unlabeled_points|Remove_Unlabeled_Points]] | Vicon Nexus exports unlabeled trajectories identified with an asterisk (*) at the beginning of the filename. |
| [[visual3d:documentation:pipeline:signal_commands:remove_polygon_signals|Remove_Polygon_Signals]] | Remove processed signals generated by Polygon and stored as POINT data in the C3D file. |

===== Signal Filter =====

These commands apply filters to signals within the Visual3D workspace.

^ Command ^ Description ^
| [[visual3d:documentation:pipeline:signal_commands:average_filter|Average_Filter]] | |
| [[visual3d:documentation:pipeline:signal_commands:butterworth_filter|Butterworth_Filter]] | Matlab's FDA tool can be used to [[visual3d:documentation:pipeline:signal_commands:using_the_matlab_fda_tool_for_designing_a_notch_filter|design a notch filter]] using this command. |
| [[visual3d:documentation:pipeline:signal_commands:fft_filter|FFT_Filter]] | |
| [[visual3d:documentation:pipeline:signal_commands:gcvspl|GCVSPL]] | |
| [[visual3d:documentation:pipeline:signal_commands:lowpass_filter|Lowpass Filter]] | |
| [[visual3d:documentation:pipeline:signal_commands:highpass_filter|Highpass Filter]] | |
| [[visual3d:documentation:pipeline:signal_commands:onepass_filter|Onepass_Filter]] | |
| [[visual3d:documentation:pipeline:signal_commands:median_filter|Median_Filter]] | |
| [[visual3d:documentation:pipeline:signal_commands:moving_rms|Moving_RMS]] | |
| [[visual3d:documentation:pipeline:signal_commands:shift_frames|Shift_Frames]] | |
| [[visual3d:documentation:pipeline:signal_commands:teager_kaiser_energy|Teager_Kaiser_Energy]] | The Teager-Kaiser Energy Operator. |

===== Signal Process =====

These commands process signals within the Visual3D workspace. For signal filters see the [[visual3d:documentation:pipeline:signal_commands:signal_commands_overview#Signal_Filters|Signal Filter]] section of this page.

^ Command ^ Description ^
| [[visual3d:documentation:pipeline:signal_commands:interpolate|Interpolate]] | |
| [[visual3d:documentation:pipeline:signal_commands:replace|Replace]] | |
| [[visual3d:documentation:pipeline:signal_commands:set_data_to_new_values|Set_Data_To_New_Values]] | |
| [[visual3d:documentation:pipeline:signal_commands:rectify|Rectify]] | |
| [[visual3d:documentation:pipeline:signal_commands:transform_data_coordinate_system|Transform_Data_Coordinate_System]] | |
| [[visual3d:documentation:pipeline:signal_commands:distance_along_path|Distance_Along_Path]] | |
| [[visual3d:documentation:pipeline:signal_commands:distance_parallel_to_path|Distance_Parallel_To_Path]] | |
| [[visual3d:documentation:pipeline:signal_commands:distance_perpendicular_to_path|Distance_Perpendicular_To_Path]] | |
| [[visual3d:documentation:pipeline:signal_commands:compute_ud_power|Compute_UD_Power]] | |
| [[visual3d:documentation:pipeline:signal_commands:cross_correlation|Cross_Correlation]] | |
| [[visual3d:documentation:pipeline:signal_commands:compute_ik_residuals|Compute_IK_Residuals]] | |

===== Examples =====

This wiki contains examples of how these signal commands can be used to accomplish common analytical tasks.
  - [[visual3d:documentation:pipeline:signal_commands:example_-_intersection_of_two_lines|Compute the intersection of two lines]] (under construction)
  - [[visual3d:documentation:pipeline:signal_commands:example_-_intersection_of_a_line_and_a_plane|Compute the intersection of a line with a plane]] (under construction)

The head fixation point is the intersection between the anterior direction of the head at one frame of time and an another frame of time. The [[visual3d:documentation:pipeline:signal_commands:example_-_computing_the_head_fixation_point|head fixation point can be computed]] using the above example for the intersection of two lines.