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snapshot

Capture RGB image from Camera

Syntax

img = snapshot(wcam)

Description

example

img = snapshot(wcam) returns a still image from the web camera in RGB format.

Examples

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You can connect from the MATLAB® software to a USB camera connected to an NVIDIA® platform and capture images from this camera.

Create a live hardware connection from the MATLAB software to the NVIDIA hardware by using the jetson function. To create a live hardware connection object, provide the host name or IP address, user name, and password of the target board. For example:

hwobj = jetson('192.168.1.15','ubuntu','ubuntu');

Check the webcamlist property of the hwobj object to find the web camera name.

hwobj.webcamlist
ans =

  1×1 cell array

    {'Microsoft® LifeCam Cinema(TM)'}

If this property is empty, then try re-connecting the USB webcam and run the following command. This command tries to scan the available webcams on the target when there is a addition or deletion.

hwobj.updatePeripheralInfo;

Create a webcam object, wcam using the name or the index number of the webcam list. If no webcam name or the index is specified, then it uses the default webcam.. The wcam object has the following camera properties.

wcam = webcam(hwobj)
wcam = 

  webcam with properties:

                    Name: 'Microsoft® LifeCam Cinema(TM)'
              Resolution: '320x240'
    AvailableResolutions: {1×12 cell}

To display the images captured from webcam in MATLAB, use the following commands.

img = snapshot(wcam);
figure();
imagesc(img);
drawnow;

To change the resolution of the image capture, use the following command.

clear wcam;
wcam = webcam(hwobj,1,[1280 800])

You can use the AvailableResolutions property of the wcam object to get a cell array of the available resolutions for your camera.

Import and display a sequence of 50 snapshots on your host computer.

figure();
for ii = 1:50
    img = snapshot(wcam);
    imagesc(img);
    drawnow;
end

Input Arguments

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Connection to a Webcam, specified as a webcam object.

Use the webcam function to create this connection.

Example: mycam

Output Arguments

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RGB image, returned as an n-by-n-by-3 matrix of values.

Introduced in R2018b