webcam

Create connection to Raspberry Pi web camera

Syntax

wcam = webcam(mypi)

wcam = webcam(mypi, cameraName)

wcam = webcam(mypi, cameraIndex)

wcam = webcam(mypi, cameraName, resolution)

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 specific Raspberry Pi^® hardware board

raspi object

Connection to a specific 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')

Output Arguments

wcam — Connection to Raspberry Pi web camera

camera object

Connection to a Raspberry Pi web camera.

You can use wcam with the following snapshot function.

Properties

Name — Name of your webcam

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

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

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.

Connect the Raspberry Pi to your host computer.

Note

If you have not previously configured your Raspberry Pi, see Install Support for 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.