Using RT-SLAM

Configuration

There are no configuration files yet. All the constant variables in capital letters defined at the beginning of the file $JAFAR_DIR/modules/rtslam/demo_suite/demo_slam.cpp are open to tuning. Some important ones are described with more details below.

Camera calibration

You have to modify the following lines in order to setup the camera calibration:

   1 const unsigned IMG_WIDTH = 640;
   2 const unsigned IMG_HEIGHT = 480;
   3 const double INTRINSIC[4] = { 306.2969,   264.7741,   499.9177,   494.4829 };
   4 const double DISTORTION[3] = { -0.2293129, 0.08793152, -0.01349877 };

Running the demo

   1 cd $JAFAR_DIR/build/modules/rtslam
   2 demo_suite/<platform>/demo_slam <options>

Control options:

• --disp-2d=0/1 use 2D display

• --disp-3d=0/1 use 3D display

• --render-all=0/1 (needs --replay 1)

• --data-path=/mnt/ram/rtslam

• --replay=0/1 (needs --data-path and having dumped here an online demo first)

• --dump=0/1 dump the images (--replay=0) or the rendered views (--replay=1) (needs --data-path). If --replay=0, --data-path should be in a ram disk.

• --log=0/1 log result in text file

• --rand-seed=0/1/n. 0=generate new one, 1=in replay use the saved one, n=use seed n

• --pause=0/n. 0=don't, n=pause for frames>n (needs --replay 1)

• --verbose=0/1/2/3/4/5. Off/Trace/Warning/Debug/VerboseDebug/VeryVerboseDebug (if compiled in debug only)

• --help

• --usage

Slam options:

• --robot 0=constant vel, 1=inertial

• --trigger 0=internal, 1=external with MTI control, 2=external without control

• --simu 0/1

• --freq camera frequency in double Hz (with trigger==0/1)

• --shutter shutter time in double seconds (with trigger==1)

Controlling the demo

When doing a replay, you can control how slam is running by interacting with the 2D viewer:

• Press "[space]" to switch between play and pause mode.

• Press "N" to process one image when in pause mode.

• Press "F" to switch between render-all mode and fast mode.

• Press "Q" to quit.

• Click on an observation to get textual and visual information about the observation and associated landmark.

• Click on an empty part of the image to get information about the sensor and the associated robot.

Interpreting the demo

Color code:

• magenta: InitialParametrization landmarks that were observed this frame

• dark red: InitialParametrization landmarks that were not observed this frame

• cyan: ConvergedParametrization landmarks that were observed this frame

• dark blue: ConvergedParametrization landmarks that were not observed this frame

2D landmark representation:

• a colored + cross: the predicted position of the landmark

• a colored ellipse: the 3-sigma prediction uncertainty

• an orange x cross: the measured position of the landmark

• a colored label: the id of the landmark, followed by the matching score (/100)

Reasons for a landmark not being observed:

• outside of the sensor frame (you can still see them in the 3D view)
• matching failed (you can see the matching score that is below the threshold)
• the observation was inconsistent (the measure is out of the uncertainty ellipse)
• too many landmarks are in the sensor frame and we didn't try to observe some of them (no matching score is present)