play

Play video from camera data object

Since R2024b

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Syntax

play(camData)
play(camData,Name=Value)
axesHandle = play(___)

Description

Add-On Required: This feature requires the Scenario Builder for Automated Driving Toolbox add-on.

play(camData) plays the image frames from the camera data object camData.

example

play(camData,Name=Value) specifies options using one or more name-value arguments. For example, WaitTime=0.5 plays the image frames with a 0.5 second delay between image frames.

example

axesHandle = play(___) returns a figure handle as an Axes object using any combination of input arguments from previous syntaxes.

Examples

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This example uses:

Open Live Script

Specify a sequence of image filenames.

images = {'Frame01.png','Frame02.png','Frame03.png','Frame04.png','Frame05.png', ...
    'Frame06.png','Frame07.png','Frame08.png','Frame09.png','Frame10.png'}';

Specify timestamps for each image frame.

timestamps = (0.1:0.1:1)';

Create an empty camera data object.

camData = scenariobuilder.CameraData
camData = 
  CameraData with properties:

                Name: ''

          NumSamples: 0
            Duration: 0
          SampleRate: 0
          SampleTime: 0
          Timestamps: []

              Frames: []
    SensorParameters: []

          Attributes: []

Add data samples to the camera data object.

add(camData,timestamps,images)

Play the camera data object.

play(camData)

This example uses:

Open Live Script

Specify the path of an image that contains lanes.

filePath = fullfile(toolboxdir("vision"),"visiondata","highway.png");

Create an image datastore that contains two copies of the image.

imds = imageDatastore([filePath filePath]);

Specify timestamps for each image frame.

timestamps = (1:2)';

Create a camera data object using the specified timestamps and image datastore.

camData = scenariobuilder.CameraData(timestamps,imds)
camData = 
  CameraData with properties:

                Name: ''

          NumSamples: 2
            Duration: 1
          SampleRate: 2
          SampleTime: 1
          Timestamps: [2×1 double]

              Frames: {2×1 cell}
    SensorParameters: []

          Attributes: []

Initialize a laneBoundaryDetector object.

detector = laneBoundaryDetector;

Create a datastore from the camera data object.

ds = datastore(camData);

Detect the lane boundary points in the image by using the detect object function of the laneBoundaryDetector object.

laneDets = detect(detector,ds,ROI=120,ExecutionEnvironment="cpu")
laneDets=2×1 cell array
    {1×3 cell}
    {1×3 cell}

Add the lane detections as optional camera attributes to the camera data object.

camData.Attributes = laneDets;

Overlay the lane detections on the image frames, and play the camera data object.

play(camData,PlotFcn=@helperPlotLaneDetections)

% The helperPlotLaneDetections helper function overlays the lane detections as
% colored markers on the image frames.
function imgOut = helperPlotLaneDetections(~,imgIn,idx,obj)
laneDets = obj.Attributes{idx};
for i = 1:numel(laneDets)
    imgOut = insertMarker(imgIn,laneDets{1,i}(:,1:2),"o",Color="g",Size=3);
end
end

Input Arguments

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Camera data, specified as a CameraData object.

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Example: play(camData,WaitTime=0.5) plays the image frames with a 0.5 second delay between image frames.

Parent figure, specified as an Axes object. If you do not specify Parent, the function plays the camera data in a new figure.

Delay between playing image frames, specified as a nonnegative scalar. Units are in seconds.

Custom plot function, specified as a function handle.

The function must support this syntax:

imgOut = plotFunction(axesHandle,imgIn,idx,obj),
where:

  • axesHandle — Figure handle of the axes on which to plot the image frames.

  • imgIn — Input image frame, specified as a P-by-Q-by-R array. P, Q, and R are the height, width, and the number of color channels of the image, respectively.

  • idx — Index of the input image frame, specified as an integer.

  • obj — Camera data, specified as a CameraData object.

The imgOut output argument returns the processed input image, returned as an image the same size as the input image imgIn.

Output Arguments

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Figure handle, returned as an Axes object.

Version History

Introduced in R2024b

See Also

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