getTrackVelocities
Obtain updated track velocities and velocity covariance matrix
Syntax
Description
returns a matrix of track velocities based on tracks and the velocity
selector.velocities
= getTrackVelocities(tracks
,velocitySelector
)
[
also returns the track velocity covariance matrices.velocities
,velocityCovariances
]
= getTrackVelocities(tracks
,velocitySelector
)
Examples
Input Arguments
tracks
— Object tracks
array of objectTrack
objects | array of structures
Object tracks, specified as an array of objectTrack
objects or an
array of structures containing sufficient information to obtain the track
velocity information. At a minimum, these structures must contain a
State
column vector field and a positive-definite
StateCovariance
matrix field. For a sample
track structure, see toStruct
.
Note
If you specify tracks
as an empty objectTrack
object, an
empty cell, or an empty track structure,
velocities
and
velocityCovariances
are returned based on
the second argument (velocitySelector
or
modelName
) as follows.
Second input argument | velocities | velocityCovariances |
---|---|---|
velocitySelector |
|
|
modelName |
|
|
modelName
— Motion model name
"constvel"
| "constacc"
| "singer"
| "constturn"
| "ctrv"
Motion model name, specified as one of these options:
"constvel"
— The function obtains the velocity states based on the state definition in theconstvel
function."constacc"
— The function obtains the velocity states based on the state definition in theconstacc
function."constturn"
— The function obtains the velocity states based on the state definition in theconstturn
function.In R2024b:
"ctrv"
— The function obtains the velocity states based on the state definition in thectrv
function."singer"
— The function obtains the velocity states based on the state definition in thesinger
function. The use ofsinger
model requires the Sensor Fusion and Tracking Toolbox™.
velocitySelector
— Velocity selection matrix
D-by-N real-valued matrix.
Velocity selector, specified as a D-by-N real-valued matrix of ones and zeros. D is the number of dimensions of the tracker. N is the size of the state vector. Using this matrix, the function extracts track velocities from the state vector. Multiply the state vector by velocity selector matrix returns velocities. The same selector is applied to all object tracks.
Output Arguments
velocities
— Velocities of tracked objects
real-valued 1-by-D vector | real-valued M-by-D matrix
Velocities of tracked objects at last update time, returned as a 1-by-D vector or a real-valued M-by-D matrix. D represents the number of velocity elements. M represents the number of tracks.
velocityCovariances
— Velocity covariance matrices of tracked objects
real-valued D-by-D-matrix | real-valued
D-by-D-by-M
array
Velocity covariance matrices of tracked objects, returned as a real-valued D-by-D-matrix or a real-valued D-by-D-by-M array. D represents the number of velocity elements. M represents the number of tracks. Each D-by-D submatrix is a velocity covariance matrix for a track.
More About
Velocity Selector for 2-Dimensional Motion
Show the velocity selection matrix for two-dimensional motion when the state consists of the position and velocity.
Velocity Selector for 3-Dimensional Motion
Show the velocity selection matrix for three-dimensional motion when the state consists of the position and velocity.
Velocity Selector for 3-Dimensional Motion with Acceleration
Show the velocity selection matrix for three-dimensional motion when the state consists of the position, velocity, and acceleration.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
In code generation, if you use the
modelName
input, thetracks
input must be specified as non-empty structures. Use the following if empty structures are unavoidable:if isempty(tracks) % Return the sizes and data types you desire velocities = zeros(0,3,"single"); velocitiesCovariances = zeros(3,3,0,"single"); else [velocities,velocityCovariances] = getTrackVelocities(tracks,"constvel"); end
Version History
Introduced in R2018bR2022b: Obtain velocity and covariance from tracks using motion model name input
You can now obtain velocities and associated covariances of tracks by specifying the motion model name as an input. For example,
[positions,covariances] = getTrackVelocities(tracks,"constvel")
constvel
function.See Also
Functions
Objects
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