CSPS topology_v0.2

Overview

Streams are the central concept of CSPS library and are managed through the other central concept of modules. The CSPS topology translate the way streams are used to link modules and their related devices. This pages gives a presentation of topology edition standards as expected by the library parser.

Topology edition

Topology are given to CSPS library in a simple formated text file. First of all, devices engaged in the topology have to be given befor editing links between modules. Considering a camera device, the definition line waited by the parser is as follow :

device cam 
    model EYESIS4PI 
    tag eyesis4pi
    block 1024
end

The device keyword indicates device definition. The device type is then given, here with cam parameter. The model keyword precede camera model. To deal with ambiguities, devices are referenced with a tag. The next keyword are used to specify device parameters. In this example, the block keyword gives the buffer size used for data importation.

For module link edition, initial streams are engaged through extraction modules. Those modules are device specific and are called in the following form :

module cam-mod-DSIDE 
    eyesis4pi 
end

The module keyword indicates a module call. The called module name has to be given as next parameter. Then, the device tag of the considered device has to be given. Because this example shows extraction module call, input stream are implicitly known.

The stream modules have to consider input streams and a typical call is illustrated here :

module imu-mod-IFETI
    adis16375 
    mod-SGNDN 
    mod-IOISA
end

As extraction module call, the module name is given just after module keyword. Then a list of device tag is given according to module expectations. The modules names that initiated stream considered as input are then provided.

Topology example

An example of a simple CSPS topology is provided here. It considers three devices that are a camera, a GPS reciever and an IMU sensor. The topology example file content is given by :

device cam 
    model EYESIS4PI 
    tag eyesis4pi
    block 1024
end

device gps 
    model LS20031   
    tag ls20031   
    block 1024
end

module cam-mod-DSIDE 
    eyesis4pi 
end

module gps-mod-DSIDE 
    ls20031 
end

module gps-mod-SGNQF 
    ls20031
    mod-DSIDE
end

The devices are initially declared with their specific options. Then the extraction module is called for the camera and the gps reciever. After that, the gps-mod-SGNQF GPS related module is called at end of the example topology.

Topology results

The following image gives a three dimensional illustration of the results provided by the example topology. The earth-attached position are given in yellow when orientations are provided by the red-green-blue frame attached to each camera record :

On the previous image, an Eyesis4Pi camera device was mounted on a car. Two whole turns around a building located at Geneva where performed during this record.