Recent advances in holographic 3D particle tracking

Abstract

Particle tracking is a fundamental technique for investigating a variety of biophysical processes, from intracellular dynamics to the characterization of cell motility and migration. However, observing three-dimensional (3D) trajectories of particles is in general a challenging task in classical microscopy owing to the limited imaging depth of field of commercial optical microscopes, which represents a serious drawback for the analysis of time-lapse microscopy image data. Therefore, numerous automated particle-tracking approaches have been developed by many research groups around the world. Recently, digital holography (DH) in microscopy has rapidly gained credit as one of the elective techniques for these applications, mainly due to the uniqueness of the DH to provide a posteriori quantitative multiple refocusing capability and phase-contrast imaging. Starting from this paradigm, a huge amount of 3D holographic tracking approaches have been conceived and investigated for applications in various branches of science, including optofluids, microfluidics, biomedical microscopy, cell mechano-trasduction, and cell migration. Since a wider community of readers could be interested in such a review, i.e., not only scientists working in the fields of optics and photonics but also users of particle-tracking tools, it should be very beneficial to provide a complete review of state-of-the-art holographic 3D particle-tracking methods and their applications in bio-microfluidics

Axial localization with modulated-illumination extended-depth-of-field microscopy

“…Such a microscope could be used to characterize the fast dynamics of samples distributed in three dimensions, including bacteria in natural environments [1][2][3], tracer molecules [4,5], or neuronal activity in brains [6][7][8]. Standard techniques for volumetric imaging are generally limited in speed, requiring the acquisition of image stacks, as in laser scanning [9] or light sheet microscopy [10,11].…”

Compressive holographic video

“…The use of a CCD camera to digitally record holographic interference patterns has made digital holography (DH) an emerging technology with a variety of imaging applications, such as particle imaging, tracking in biomedical microscopy [8][9][10][11][12] and physical process profiling and measuring [13][14][15][16][17]. Digital Gabor/in-line holography (DIH) is a simple, lensless, yet effective setup for capturing holograms.…”

“…small and fast-moving objects [19][20][21]. The tracking of fast movements usually entails multiple exposures [8,10,15,16,22,23]. Temporal resolution is usually limited to the 10-100 millisecond range and little research has been conducted on temporal compression.…”

Fast Refocusing Based on the Phase in the Fourier Domain in Multispectral Digital Holographic Microscopy

“…Numerous refocusing methods were developed, mostly based on metrics in the spatial domain [4]. These require to reconstruct the image in every plane where the criterion is computed.…”

“…To overcome this issue and avoid reconstructions, a solution is the use of a criterion working in the Fourier domain [5]. Moreover, most of criteria are applicable either for pure amplitude objects, or for pure phase objects, while only a few criteria apply for both types of objects [4].…”