SwisTrack/Multi-Camera Client

Introduction

Abstract

SwisTrack Multi-Camera Client is a client tool to communicate with several SwisTrack instances. It is written in C++ using wxWidgets. Data received by a TCP connection will be merged and synchronized before displaying it on a window. SwisTrack is the server part of the connection and SwisTrack Multi-Camera Client is the client.

Zoom / focus function

You can zoom in and out using the scroll wheel of the mouse. To focus on a specific region click with the right mouse button on that region. The left mouse button is to get several information if clicked on a robot. By clicking the mouse wheel the view will be reset.

Class hierarchy

We have 10 classes, where "ClientFrame" is the mean one.

Name	Explanation
ClientFrame	Defines a new frame type (main class)
CommunicationMessage	Creates new messages that can be send to the robots and the SwisTrack instances.
CommunicationNMEAInterface	Interface to parse incoming messages and send outgoing messages
MapPanel	Responsible for painting the panel
Robot	Creates new robots for communication and painting
RobotSocketManager	Responsible for the communication between the robots and the SwisTrack Multi-Camera Client
SavePosition	If enabled, saves the positions of the robots each separated in a file
STClient	Defines the application type
SwisTrack	Creates new SwisTrack objects for communication and painting the camera areas
SwisTrackSocketManager	Responsible for the communication between the SwisTrack instances and the SwisTrack Multi-Camera Client

Edit Settings

If you select the menu "Edit/Edit settings" a editing window will pop up and you will be able to change the settings. Beware to the syntax, otherwise the program won't run correctly. Lines that begins with "#" are treated like comments.

The proper syntax of the SwisTrack Multi-Camera Client settings is (with example)):

SwisTrack

Type	Adress:port;	Reference point (x,y);	Vector 1 (x,y);	Vector 2 (x,y);	Width, height (w,h);
cam:	localhost:3000;	2,3;	1,0;	0,1;	4,6

Robot

Type	Adress:port;	id
robot:	127.0.0.1:4002;	5

Watch that after a type follows always a ":" and else after every entry follows a ";" except for the last one where nothing follows. Have a look on the screenshots for an real example.

Save tracking positions: file syntax

If desired, the movements of the robots can be saved on a "robotX.txt" file (X is the id of the robot). A line per frame will be used. The syntax is the following:

frame number, position in x, position in y, angle

example: 217,0.669787,8.297836, 6.210000

Camera area definition

As seen above we use a reference point with 2 vectors, a width and height for defining a camera area.

NMEA 0183 protocol

The SwisTrack Multi-Camera Client uses the NMEA 0183 protocol to communicate with the SwisTrack instances and the robots.

SwisTrack

Keep in mind that every command is encapsulated in a message with a message header (command) and a list of arguments according to the specific command. Every command begins with a $ and is in capitals.

Sending commands

Command	Arguments	Description
$START	None	Initiates the SwisTrack instances and sets the current frame number to 0, but doesn't process anything till $STEP is send.
$STOP	None	Stops the current tracking and resets the current frame number to 0.
$STEP	None	Indicates to the SwisTrack instances to process a next image frame.

The program can be paused (not sending $STEP commands any more) and be resumed by the menu commands under "ST controls/Pause tracking" and "ST controls/Resume tracking".

Receiving commands

Command	Arguments	Description
$PARTICLE	int id, double x, double y, double angle	Every robot recognized on a frame is send separately with these parameters
$BEGINFRAME	int frameNb	Indicates that the data that arrives after this command belongs to the frame number send
$ENDFRAME	None	Indicates that the current processing frame is completed and finished

Remark: One or several $PARTICLE commands can only be received between a $BEGINFRAME and a $ENDFRAME command!

Robot

Sending commands

Command	Arguments	Description
$STATUS	None	Get the current status of the robot (for example: tracking, idle, searching).
$POSITION	double position x, double position y	Reset the current position of the robot.

Receiving commands

Command	Arguments	Description
$STATUS	string status	Returns its current status.

Screenshots

Here are some screenshots taken from the SwisTrack Multi-Camera Client: