Tracking deformable objects from videos, in low resolution and clutter, is an open issue in Computer Vision. Our method aims at simultaneously tracking many worms moving in a plate (swimming or crawling), often touching and occluding each other (in contrast to most existing methods that track only a single worm), and extracts the worms' locomotion parameters, both global (such as positions and movement paths) and local (magnitude of inter-frame deformations, shapes, normal and directional speeds, symmetry of deformations etc.), in contrast to commercial programs that can only provide global parameters. In our approach, "tracking" means not only the estimation of the size and position of each worm on the image plane (e.g. bounding box), but also the extraction of the exact shape of each worm. The main advantages of our approach are that enables researchers to collect more locomotion data accurately and automatically, sufficient for statistical analysis, and provides locomotion parameters over time, in terms of both displacements on the image plane (global features) and local deformations (local features).
After tracking, our method is capable of estimating: (a) global motion features, such as: the positions on the image plane, movement paths over time, and distances covered, the number of frames that worms remain static, (b) local locomotion features, such as magnitude ("strength") and shape of inter-frame deformations,& magnitude and symmetry of ("absolute") deformation (compared to the straight line connecting the two ends of a worm), normal and directional speeds of movement, and (c) changes, averages, statistics of the local and global locomotion features.
The aim of our method is to extract motion parameters that can be used for classifying worms according to their motion/swimming ability for behavioral and aging studies.
In the near future, we plan to make the source code of our program available to the research community as a free web-download. The website can be found at:
http://www.research.rutgers.edu/~gabrielt/locoworm.html.