Particle Detection in Microfluidic Systems

Digital holographic microscopy is a useful tool to obtain three-dimensional information in a small volume range. Its capability to achieve sharp numeric focussing over an extended depth makes it very interesting for microscopic imaging systems, e.g. for lab-on-a-chip applications. Combined with optical particle manipulation systems (optical tweezer) digital holography enables the monitoring of particle manipulation and the examination of the spatial distribution and movements of a dense cloud of particles with an extended depth. We demonstrate an approach for three-dimensional corpuscle detection using a single beam in-line holographic setup. Our evaluation approach for numerical particle detection is split into three steps 1. adapted filtering of the hologramm to prepare 2. the rough/global reconstruction and 3. the local reconstruction Particle detection criteria are discussed and the estimation of grain distribution as well as particle movement are presented.