Real-time quantitative phase reconstruction in off-axis digital holography using multiplexing

Abstract

We present a new approach for obtaining significant speedup in the digital processing of extracting unwrapped phase profiles from off-axis digital holograms. The new technique digitally multiplexes two orthogonal off-axis holograms, where the digital reconstruction, including spatial filtering and two-dimensional phase unwrapping on a decreased number of pixels, can be performed on both holograms together, without redundant operations. Using this technique, we were able to reconstruct, for the first time to our knowledge, unwrapped phase profiles from off-axis holograms with 1 megapixel in more than 30 frames per second using a standard single-core personal computer on a MATLAB platform, without using graphic-processing-unit programming or parallel computing. This new technique is important for real-time quantitative visualization and measurements of highly dynamic samples and is applicable for a wide range of applications, including rapid biological cell imaging and real-time nondestructive testing. After comparing the speedups obtained by the new technique for holograms of various sizes, we present experimental results of real-time quantitative phase visualization of cells flowing rapidly through a microchannel.

One-step reconstruction of assembled 3D holographic scenes

“…(7), a scene containing all objects is obtained. In particular for our example, as individual holograms have the same reconstruction plane, they will all appear in focus at the same time, [21] …”

“…Powerful tools have been developed for processing optical holograms [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In the context of experimental optical encryption of 2D objects a filtering and positioning process were successfully applied for security purposes.…”

“…In a recent paper of Girshovitz et al [21] we found a proposal of a simple method for real-time reconstruction of off-axis digital holograms based on a kind of digital angular multiplexing algorithm. This method realizes the quick synchronous reconstruction of two holograms recorded at different time, thus greatly increases the reconstructing speed, which makes it possible to realize realtime holographic reconstruction with a simple personal computer system.…”

Three-Dimensional Imaging by Self-Reference Single-Channel Digital Incoherent Holography

“…The most recognized advantage of digital holography is its ability to image a three-dimensional (3D) scene with no more than three camera shots [1]. Additionally, hologram recorders of certain types are capable of imaging phase objects [2], [3]. Different types of hologram recorders have been proved to have superior imaging resolution over equivalent ordinary imagers [4], [5].…”

An ultra-compact multiplexed holographic microscope using a multiple-pinhole aperture

“…Multiplexing is one of the alternative solutions to the aforementioned problem which has been extensively studied in holographic data storage [9][10][11], multi-dimensional measurement [12,13], super-resolution imaging system [14][15][16][17], fast reconstruction of off-axis digital hologram [18,19] and other areas [20,21]. In 2010, Larbi's team [22] developed an off-axis imaging system which only uses a single reference wave and two object waves to form a multiplexed hologram.…”