Recently, bio-robotics based on biology and robotics,and neuro-robotics based on neuroscience and robotics have been developed very fast.In this field, a lot of studies on experimental animals behavior especially rodents behavior like "open-field" experiment setup was developed to analysis the active and immobility time,region interesting and exploring behavior of rodents.This paper makes use of a Poisson PDE multi-grid solver to compute distance transform.We show how this idea extends naturally to the feature points extracting from shape of experiment animals.Solution of Poisson equation results in a good distance transforming method that body and limbs of a shape will be separated apart to different level totally.With this distance information,algorithm is induced to extract head point, tail point of experiment animals like mice and rats.For noise and jitter reason in captured images, we put a Kalman filter to get more steady track of feature points.This approach also has a good computational performance in practice.