Compressed holographic particle tracking velocimetry for microflow measurements

We have established a holographic particle tracking velocimetry (HPTV) technique based on compressed sensing (CS) for measurement of the velocity field of microflows in this study. In conventional HPTV, where the scattered light field is reconstructed via backpropagation calculations, the particle image spreads greatly in the depth direction and it is then difficult to perform three-dimensional three-component (3D3C) measurements with high accuracy. In the proposed method, CS is applied based on the spatial sparseness of the particle distribution and highly accurate 3D3C measurements are made possible by direct reconstruction of the particle distribution. In this paper, we explain the principle of HPTV based on CS and report the results of evaluation of the velocity vector distribution measurement of a micro linear channel. The experimental results indicate that the proposed method is effective for 3D3C measurements of microflows. Measurement of the velocity field of microflows is becoming increasingly important in the development of microfluidic devices and in the understanding of biological mechanisms. The proposed method is expected to provide an effective technique for use in these applications.