Automatic three-dimensional localization of micro-particles using digital holographic microscopy

摘要

We present a numerical technique for automatic extended focused imaging and three-dimensional analysis of microparticle field observed in a digital holographic microscope working in transmission. We use Fourier method for the extraction of complex amplitude from the single exposition digital holograms. We create a synthetic extended focused image (EFI) using the focus plane determination method based on the integrated amplitude modulus. We apply the refocusing criterion locally for each pixel, using small overlapping windows, in order to obtain a depth map and a synthetic image in which all objects are refocused independent from their refocusing distance. The obtained synthetic EFI allows us to perform image segmentation and object detection. We improve the accuracy of vertical localization using an additional refining procedure in which each particle is treated separately. A successful application of this technique in the analysis of microgravity particle flow experiment is presented.