Campy

Known Issues

If ROS is messing up the path for OpenCV, specially when trying to use python3 then do:

source fix_ros # to fix it in current terminal

or

bash fix_ros # to permanently add python3 dist-packages path to PYTHONPATH at boot

Classes

Camera Class

Operates USB cameras using OpenCV library.

__init__ Method

Object constructor.

Args

• device_number: The numerical value associated with the hardware by the OS.

display Method

Displays the frames received from the hardware. This is a blocking function.

capture Method

Starts capturing the frames without displaying them. This is a non-blocking function. It uses multi-threading library for starting a thread that stores the most recent frame.

Args

• device_number: The numerical value associated with the hardware by the OS.

monitor Method

Opens a windows and starts displaying the frames. This is a blocking function. One can think of this method as a combination of capture and display methods.

Args

• device_number: The numerical value associated with the hardware by the OS.

close Method

Destructs the object. Ends all the threads and removes the access to camera hardware.

get Method

Returns the frame as a ndarray.

Args

• blocking: A boolean that indicates if the method should wait for a new frame or return whatever it contains in its buffer.

setSize Method

Sets the width and height of the frame.

Args

• width: An integer value corresponding the number of horizontal pixels.
• height: An integer value corresponding the number of vertical pixels.

Stream Class

This is a subclass of Camera class with added functionality of streaming frames over a connection.

server Method

This method should be called on the server machine to setup the connection. It takes the IP address and port number of the server to establish the connection. It is also possible to not use this method, setup the connection separately, and pass the connection handle to send and receive methods below. It should be noted that the server can either be the sender of camera frames or the receiver.

Args

• ip: IP address of the server.
• port: Port number of server.
• backlog: Connection backlog.

client Method

This method should be called on the client machine to setup the connection. It takes the IP address and port number of the server to establish the connection. It is also possible to not use this method, setup the connection separately, and pass the connection handle to send and receive methods below. It should be noted that the client can either be the sender of camera frames or the receiver.

Args

• ip: IP address of the server.
• port: Port number of server.

send Method

A non-blocking method that starts streaming the frames over the connection. If the connection has been configured using server or client methods, then the connection argument can be left unassigned.

Args

• connection: TCP connection handle.

receive Method

A non-blocking method that starts receiving the frames over the connection. If the connection has been configured using server or client methods, then the connection argument can be left unassigned.

Args

• connection: TCP connection handle.