High throughput holographic imaging-in-flow for the analysis of a wide plankton size range

Abstract

We developed a Digital Holographic Microscope (DHM) working with a partial coherent source specifically adapted to perform high throughput recording of holograms of plankton organisms in-flow, in a size range of 3µm-300µm, which is of importance for this kind of applications. This wide size range is achieved with the same flow cell and with the same microscope magnification. The DHM configuration combines a high magnification with a large field of view and provides high-resolution intensity and quantitative phase images refocusing on high sample flow rate. Specific algorithms were developed to detect and extract automatically the particles and organisms present in the samples in order to build holograms of each one that are used for holographic refocusing and quantitative phase contrast imaging. Experimental results are shown and discussed.

Quantitative analysis of platelets aggregates in 3D by digital holographic microscopy

“…This section describes the off-axis DHM with a source of partially spatial coherence light to record the holographic information [14]. The configuration is shown in Fig.…”

“…The recorded fluctuations are then used to establish the accuracy of the phase measurements. The detection processing that we used is identical to the one described in reference [14]. It is based on a high-pass filtering of the is almost constant in this region and the high-pass filtering process gives complex amplitude with very low module values that are eliminated by a simple threshold operation.…”

“…To avoid border effects on the high-pass filter, we implemented, as in reference [14], an inverse Gaussian filter ( ) , H u v defined by:…”

“…However, these limitations can be overcome by using holographic technology. Indeed, the Digital Holographic Microscopy (DHM) is a technology that allows quantitative phase contrast imaging and digital refocusing from a single recorded hologram [12][13][14]. Recently, the DHM has been used to determine the 3D morphometry of human Red Blood Cells (RBC) [15,16].…”

“…In this work, we develop a novel method able to characterize the 3D aggregate characteristics such as aggregates surface, height and volume by using the quantitative phase contrast imaging capability of DHM. In order to reduce as far as possible the influence of defects and aberrations, we use a correction strategy similar to the one described in [14].…”