webcam

Create connection to Raspberry Pi web camera

Add-On Required: This feature requires the MATLAB Support Package for Raspberry Pi Hardware add-on.

Description

This object represents a connection from the MATLAB^® software to a web camera attached to the Raspberry Pi hardware. To create this object, use the webcam function. To configure the web camera settings, use the object properties listed in Properties. To interact with the web camera, use this object with the functions listed in Object Functions.

Creation

Description

wcam = webcam(mypi) creates a connection, wcam, from the MATLAB software to a web camera that is attached the Raspberry Pi^® hardware. You can capture still images by using wcam with the snapshot function.

wcam = webcam(mypi, cameraName) allows you to select the camera specified by cameraName. Use this syntax when you have more than one camera connected to the Raspberry Pi hardware.

wcam = webcam(mypi, cameraIndex) allows you to select the camera specified by cameraIndex. Use this syntax when you have more than one camera connected to the Raspberry Pi hardware.

wcam = webcam(mypi, cameraName, resolution) allows you to select the dimensions of the image taken by the camera connected to the Raspberry Pi hardware.

Input Arguments

mypi — Connection to Raspberry Pi hardware board

raspi object

Connection to the Raspberry Pi hardware board, specified as a raspi object.

cameraName — Name of the camera attached to hardware

string

Name string of camera. Optional.

cameraIndex — Numerical index of cameras attached to hardware

number

Index of camera. Optional.

resolution — Dimensions of the image taken by camera

string

String of image dimensions. Optional.

If you do not know the resolutions supported by your camera:

1. Create a connection, wcam, using this syntax. The connection displays the supported resolutions in the AvailableResolutions property. Note the resolutions displayed.

   wcam = webcam(mypi)

2. Clear the wcam object.

   clear wcam

3. Recreate the wcam object. Provide any of the noted resolutions as input argument.

   wcam = webcam(mypi, cameraName, '160x120')

Properties

Name — Name of your webcam

Read-only: character vector

This property is read-only.

Name of your webcam, specified as a character vector. It is specific to each camera.

Example: '/dev/video0'

Data Types: char

Resolution — Resolution of captured image

character vector

Resolution of captured image, specified as a character vector.

Example: '320x240'

Data Types: char

AvailableResolutions — Resolutions available on your webcam

Read-only: cell array of character vectors

This property is read-only.

Resolutions available on your webcam, specified as a cell array of character vectors.

Example: {'320x240' '640x480'}

Data Types: cell

Object Functions

snapshot	Capture latest RGB image frame from Camera Board or selected camera on ArduCam Multi Camera Adapter Module
readFrame	Return oldest image frame from board, web, or ArduCam module camera

Examples

Use the Web Camera

You can connect from the MATLAB software to the USB web camera connected to Raspberry Pi board and take a photograph.

Create a connection from the MATLAB to the Raspberry Pi board. If you encounter errors after running the above command, try using additional arguments (as listed in raspi) or refer to Troubleshoot Connecting Issues to Raspberry Pi Hardware.

Create a connection from the MATLAB software to the Raspberry Pi hardware.

mypi = raspi;

Create a connection, wcam, from the MATLAB software to the USB web camera connected to the Raspberry Pi board, and set the image resolution. The connection displays the web camera properties.

wcam = webcam(mypi)

wcam = 

  webcam with properties:

                    Name: "/dev/video0"
              Resolution: "320x240"
    AvailableResolutions: {"320x240"  "640x480"}

Import and display a sequence of 10 snapshots on your host computer.

for ii = 1:10
    img = snapshot(wcam);
    imagesc(img)
    drawnow
end

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The webcam object accepts resolution as a string only if the resolution value specified matches any of these values: '160x120', '320x240', '640x480', '800x600', '1024x768', '1280x720', or'1920x1080'. To set the resolution to any other value, specify the value in the [width height] format, for example, [640 240]. For any run-time error, analyze the associated log file.

• The AvailableWebcams property is a dynamically populated cell array and cannot be used for code generation.

• You can also deploy the webcam object on the Raspberry Pi hardware in MATLAB Online™.

• Using the full version of the Raspberry Pi OS is recommended when deploying webcam on the Raspberry Pi hardware in MATLAB Online.

Version History

Introduced in R2016a