Basic usage instructions

Basics

Polyora comes with a couple of executables. The most interesting one is: vobj_tracker. It can retrieve, track, and augment planar objects (see Tracking planar objects). QtPolyora is similar, but lower level. Its goal is to provide better visualization of the retrieval process. It can also be used to collect training data.

Both executables rely on trained vector quantization prototypes. Such data can be trained with the procedure described in Training Stage. Alternatively, pre-trained data can be downloaded from Polyora's web site.

• Download: http://www.hvrl.ics.keio.ac.jp/~julien/polyora/polyora-data.zip
• unzip its content in a directory (On Windows, that could be: C:\Program Files\Polyora\bin)
• execute vobj_tracker from this directory

Please note that the pre-trained data might not work well with your configuration. Training your own data is more reliable.

Training Stage

1. Create a directory for your data ("data" for example)
2. Collect point descriptors

   ../qtpolyora/qtpolyora -rp -d descriptors.dat -v visual.db 

3. Build a K-mean tree:

   ../buildtree/buildtree -d descriptors.dat -r 8 -e 64 -v visual.db 

4. Collect tracks of feature points:

   ../qtpolyora/qtpolyora -rt -d tracks.dat -v visual.db 

5. cluster tracks:

   ../cluster_ids/cluster_ids -d tracks.dat -T .1 -v visual.db 

The resulting visual.db should contain the quantization tree for descriptors, and the prototypes for quantizing tracks. Visual objects can also be stored in the same file.

If you have large files (>2 GB), compiling and running these tools in a 64 bits environment might be necessary. Please note also that cluster_ids can require a large amount of memory.

Tracking planar objects

The easiest way to start tracking objects with Polyora is to use the included Visual Object Track (vobj_tracker). The procedure is the following:

1. Either run the training stage described previously or download "visual.db" as described above.
2. Connect a recognized camera.
3. Run the visual object tracker:

   vobj_tracker -v visual.db 

4. Take a frontal view of a planar, textured object and press 'H'.
5. Tracking starts. Repeat (4) as many time as required. Everything is automatically saved in visual.db.