Analysis and interpretation of the Seidel aberration coefficients in digital holography

Peer reviewedPublisher PD

Dynamical hologram generation for high speed optical trapping of smart droplet microtools

This paper demonstrates spatially selective sampling of the plasma membrane by the implementation of time-multiplexed holographic optical tweezers for Smart Droplet Microtools (SDMs). High speed (>1000fps) dynamical hologram generation was computed on the graphics processing unit of a standard display card and controlled by a user friendly LabView interface. Time multiplexed binary holograms were displayed in real time and mirrored to a ferroelectric Spatial Light Modulator. SDMs were manufactured with both liquid cores (as previously described) and solid cores, which confer significant advantages in terms of stability, polydispersity and ease of use. These were coated with a number of detergents, the most successful based upon lipids doped with transfection reagents. In order to validate these, trapped SDMs were maneuvered up to the plasma membrane of giant vesicles containing Nile Red and human biliary epithelial (BE) colon cancer cells with green fluorescent labeled protein (GFP)-labeled CAAX (a motif belonging to the Ras protein). Bright field and fluorescence images showed that successful trapping and manipulation of multiple SDMs in x, y, z was achieved with success rates of 30-50% and that subsequent membrane-SDM interactions led to the uptake of Nile Red or GFP-CAAX into the SDM

Using Commodity Graphics Hardware for Real-Time Digital Hologram View-Reconstruction

View-reconstruction and display is an important part of many applications in digital holography such as computer vision and microscopy. Thus far, this has been an offline procedure for megapixel sized holograms. This paper introduces an implementation of real-time view-reconstruction using programmable graphics hardware. The theory of Fresnel-based view-reconstruction is introduced, after which an implementation using stream programming is presented. Two different fast Fourier transform (FFT)-based reconstruction methods are implemented, as well as two different FFT strategies. The efficiency of the methods is evaluated and compared to a CPU-based implementation, providing over 100 times speedup for a hologram size of 2048 x 2048

Using Commodity Graphics Hardware for Real-Time Digital Hologram View-Reconstruction

View-reconstruction and display is an important part of many applications in digital holography such as computer vision and microscopy. Thus far, this has been an offline procedure for megapixel sized holograms. This paper introduces an implementation of real-time view-reconstruction using programmable graphics hardware. The theory of Fresnel-based view-reconstruction is introduced, after which an implementation using stream programming is presented. Two different fast Fourier transform (FFT)-based reconstruction methods are implemented, as well as two different FFT strategies. The efficiency of the methods is evaluated and compared to a CPU-based implementation, providing over 100 times speedup for a hologram size of 2048 x 2048

Methods for transform, analysis and rendering of complete light representations

Recent advances in digital holography, optical engineering and computer graphics have opened up the possibility of full parallax, three dimensional displays. The premises of these rendering systems are however somewhat different from traditional imaging and video systems. Instead of rendering an image of the scene, the complete light distribution must be computed. In this thesis we discuss some different methods regarding processing and rendering of two well known full light representations: the light field and the hologram. A light field transform approach, based on matrix optics operators, is introduced. Thereafter we discuss the relationship between the light field and the hologram representations. The final part of the thesis is concerned with hologram and wave field synthesis. We present two different methods. First, a GPU accelerated approach to rendering point-based models is introduced. Thereafter, we develop a Fourier rendering approach capable of generating angular spectra of triangular mesh models.Aktuelle Fortschritte in den Bereichen der digitalen Holographie, optischen Technik und Computergrafik ermöglichen die Entwicklung von vollwertigen 3D-Displays. Diese Systeme sind allerdings auf Eingangsdaten angewiesen, die sich von denen traditioneller Videosysteme unterscheiden. Anstatt für die Visualisierung ein zweidimensionales Abbild einer Szene zu erstellen, muss die vollständige Verteilung des Lichts berechnet werden. In dieser Dissertation betrachten wir verschiedene Methoden, um dies für zwei verschiedene gebräuchliche Darstellungen der Lichtverteilung zu erreichen: Lichtfeld und Hologramm. Wir stellen dafür zunächst eine Methode vor, die Operatoren der Strahlenoptik auf Lichtfelder anzuwenden, und diskutieren daraufhin, wie die Darstellung als Lichtfeld mit der Darstellung als Hologramm zusammenhängt. Abschliessend wird die praktische Berechnung von Hologrammen und Wellenfeldern behandelt, wobei wir zwei verschiedene Ansätze untersuchen. Im ersten Ansatz werden Wellenfelder aus punktbasierten Modellen von Objekten erzeugt, unter Einsatz moderner Grafikhardware zur Optimierung der Rechenzeit. Der zweite Ansatz, Fourier-Rendering, ermöglicht die Generierung von Hologrammen aus Oberflächen, die durch Dreiecksnetze beschrieben sind