Exploratory project PERSYVAL-Lab 2016-2017

The Carambole projects initiates a new collaboration between computer scientists from University of Grenoble Alpes and biophysicists from University Paris Diderot. The objectives are to develop hardware and software to help tracking feature points on a leaf of Averrhoa Carambola during its growth with a multi-camera system and to measure their 3D motion. This will be done in 7 successive stages:

  1. Definition of the camera set-up.
  2. Sensor calibration.
  3. Image acquisition.
  4. Virtual 3D model reconstruction at each time step.
  5. Temporal tracking to get a temporally coherent 4D model.
  6. Growth modelling with a compact spatio-temporal model.
  7. Motion measurement.

Averrhoa carambola is of special interest because of the distinctive nutation balancing motion of a leaf during its growth. Other interesting motions are the longitudinal growth of the leaf as well as its rolling out. Total growth lasts about two weeks.


LJK, Univ. Grenoble Alpes

Laboratoire MSC, Univ. Paris Diderot

Preliminary results (2016)



3D mesh model of an Averrhoa Carambola leaf with and without texture.


Left: approximation of the spine of an Averrhoa Carambola leaf for 70 successive time steps. Right: spine for the first and last time steps. The nutation motion is clearly visible.

Feature matching on two successive images of an Averrhoa Carambola leaf.

End-of-project poster (2017)

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