Holographic Three-Dimensional Tracking of Micro-objects Exploiting Their Morphological Properties Fringe 2013

Digital holographic microscopy [1-8] is a powerful tool for the imaging of micro-objects contained into a three dimensional (3D) volume. Many techniques accomplish the tracking with good detection accuracy of particle, microorganism and cells [9-13]. The most popular approaches adopted in digital holography for the 3D tracking of micro-objects consist into estimate the 3D position dividing the computation process into two parts: the estimation of the coordinate along the optical axis of the imaging systems through automatic focusing on the amplitude reconstruction of the digital holograms, and the estimation of the transverse coordinates on the phase reconstruction of digital holograms computed at distance d equal to the estimated focal plane. About the estimation of the focal plane, several automatic focusing methods were developed in digital holography for pure phase objects. These techniques are based on a suitable image contrast parameters and perform a numerical scanning of the focal plane [14]. The estimated focus distance is typically achieved in their global maximum or minimum. Instead the localization in the plane can be computed through different image segmentation methods. The accuracy of each of these techniques is closely related to the kind of object to be tracked [11].