| 1. |
- El-Schich, Zahra, et al.
(författare)
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Det digitala holografiska mikroskopet : innovativ teknik för analys av levande celler
- 2010
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Ingår i: Bioingenjøren. - : Norges Ingeniør- og Teknologorganisasjon. ; :9, s. 6-13
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)abstract
- Bakgrund: Digital holografi är en ny teknik som de senaste fem åren använts för att studera levande celler. Tekniken utgör en innovativ, icke-förstörande metod som möjliggör studier av levande celler över tid. Material och metoder: Litteraturen har valts ut genom att söka på redan kända forskargrupper och företag som arbetar både med digital holografi och cellstudier samt PubMed-sökningar. Resultat och sammanfattning: Digital holografi ger kunskap om cellernas brytningsindex, som kan ändras under olika förhållanden. De parametrar som kan mätas ger unik information om cellantal, cellernas area, tjocklek och volym, vilket kan omvandlas till proliferation, viabilitet och celldöd. Tekniken är relativt billig, snabb och enkel att använda.
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| 2. |
- El-Schich, Zahra, et al.
(författare)
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Digital holographic microscopy : innovative and non-destructive analysis of living cells
- 2010
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Ingår i: Microscopy: Science, Technology, Applications and Education. - : Formatex Research Center.
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Digital holography is a novel technique that has been developed recently to study living cells. The technique is an innovative, non-destructive method with possibilities to study living cells over time. We are investigating cell number, growth, viability and death of adherent cells using digital holography, which is a novel, label-free, imaging technique for biological applications. We have recently demonstrated that digital holography is highly comparable to the conventional manual cell counting method using a hemocytometer (Mölder et al., 2008). Digital holography is a method that gives us information about the refractive index of cells, which can change under different circumstances. The technique is cheap, fast and simple to use. The unique measurable parameters are the cell number, cell area, thickness and volume, which can be transformed to proliferation, migration, viability and cell death. The digital holographic images produced can provide both quantitative and qualitative phase information from a single hologram. Future applications can include real-time cell monitoring of various parameters of cells of different diseases in response to clinically relevant compounds.
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| 3. |
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| 4. |
- Gustafsson, Mats, et al.
(författare)
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High-resolution digital transmission microscopy: a Fourier holography approach
- 2004
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Ingår i: Optics and Lasers in Engineering. - 0143-8166. ; 41:3, s. 553-563
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Tidskriftsartikel (refereegranskat)abstract
- A spherical reference field is used to construct a digital holographic system with a demonstrated resolution up to 228 line pairs per mm. The reference field originates from a GRIN lens placed 1 mm from the illuminated object. This allows the use of a standard sensor to record the hologram with the required numerical aperture. The image is determined by evaluation of the Rayleigh–Sommerfeld diffraction integral that relates the object field in the image plane to the object field in the sensor plane. Experimental results are given for two charge coupled device sensors and one complementary metal-oxide-semiconductor active pixel sensor.
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| 5. |
- Gustafsson, Mats, et al.
(författare)
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High resolution digital transmission microscopy : a Fourier holography approach
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A spherical reference field is used to construct a digital holography system with a demonstrated resolution down to 228 line pairs per mm. The reference field origin from a GRIN lens placed 1mm from the illuminated object. This allows the use of a standard sensor to record the hologram with the required numerical aperture. The image is determined by evaluation of the Rayleigh-Sommerfeld diffraction integral that relates the object field in the image plane to the object field in the sensor plane. Experimental results are given for two charge couple device sensors and one complementary metaloxide- semiconductor active pixel sensor.
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| 6. |
- Gustafsson, Mats, et al.
(författare)
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Refractometry of microscopic objects using digital holography
- 2003
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Digital holography has some desirable properties for refractometry of microscopic objects since it gives phase and amplitude information of an object in all depths of focus from one set of exposures. The refractive index of the object can be determined by observation of the movements of the Becke lines between different focus depths. It is also shown that one single phase image provides an independent technique to determine sign of the relief between an object and the surrounding medium.
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| 7. |
- Gustafsson, Mats, et al.
(författare)
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Refractometry of microscopic objects with digital holography
- 2004
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Ingår i: Applied Optics. - 2155-3165. ; 43:25, s. 4796-4801
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Tidskriftsartikel (refereegranskat)abstract
- Digital holography has some desirable properties for refractometry of microscopic objects since it gives phase and amplitude information of an object in all depths of focus from one set of exposures. We show that the amplitude part of the image can be used to observe how the Becke lines move between different depths of focus and hence determine whether an object has a higher or a lower index of refraction than its surrounding medium, i.e., the sign of the relief. It is also shown that one single-phase image provides an independent technique to determine the sign of relief between an object and the surrounding medium.
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| 8. |
- Lenart, Thomas, et al.
(författare)
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Accelerating signal processing algorithms in digital holography using an FPGA platform
- 2003
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Ingår i: Proceedings. 2003 IEEE International Conference on Field-Programmable Technology (FPT). - 0780383206 ; , s. 387-390
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Konferensbidrag (refereegranskat)abstract
- This paper describes the implementation of a custom DSP system to accelerate image processing algorithms used in the field of digital holography. The system, implemented on an FPGA platform, is intended for real-time reconstruction of images captured on a large image sensor. Due to the large amount of processing information, it is not possible to perform a HDL simulation of a complete image reconstruction in reasonable time. Instead, a reconfigurable solution is being used for full scale image reconstruction, exhaustive testing of the functionality and for connecting the accelerator to external components, i.e. the image sensor, monitor output device and high-speed memory banks
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| 9. |
- Mölder, Anna, et al.
(författare)
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Non-invasive, label-free cell counting and quantitative analysis of adherent cells using digital holography
- 2008
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Ingår i: Journal of Microscopy. - : Wiley. - 0022-2720 .- 1365-2818. ; 232:2, s. 240-247
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Tidskriftsartikel (refereegranskat)abstract
- Manual cell counting is time consuming and requires a high degree of skill on behalf of the person performing the count. Here we use a technique that utilizes digital holography, allowing label-free and completely non-invasive cell counting directly in cell culture vessels with adherent viable cells. The images produced can provide both quantitative and qualitative phase information from a single hologram. The recently constructed microscope HolomonitorTM (Phase Holographic Imaging AB, Lund, Sweden) combines the commonly used phase contrast microscope with digital holography, the latter giving us the possibility of achieving quantitative information on cellular shape, area, confluence and optical thickness. This project aimed at determining the accuracy and repeatability of cell counting measurements using digital holography compared to the conventional manual cell counting method using a haemocytometer. The collected datawere also used to determine cell size and cellular optical thickness.Theresults showthat digital holography can be used for non-invasive automatic cell counting as precisely as conventional manual cell counting
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| 10. |
- Sebesta, Mikael, et al.
(författare)
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Object characterization with refractometric digital Fourier holography
- 2005
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Ingår i: Optics Letters. - 0146-9592. ; 30:5, s. 471-473
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a digital holographic method in which two different substances in a blend are discerned. The method requires only one set of exposures and one reconstruction in the plane of focus. The phase is unwrapped by Flynn's discontinuity algorithm to produce an image of the variation of the optical distance of the illuminating wave. Objects with indices of refraction that are higher and lower than the mounting liquid are detected as regions in which the phase is increased and decreased, respectively. We also present a method for calculating the volume distribution of substrates in a sample. The method is experimentally demonstrated with crystals of NaCl and KCl.
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