Compensation of the inherent wave front curvature in digital holographic coherent microscopy for quantitative phase-contrast imaging
TL;DR: An approach is proposed for removing the wavefront curvature introduced by the microscope imaging objective in digital holography, which otherwise hinders the phase contrast imaging at reconstruction planes and it is shown that a correction effect can be obtained at all reconstruction planes.
Abstract: An approach is proposed for removing the wave front curvature introduced by the microscope imaging objective in digital holography, which otherwise hinders the phase contrast imaging at reconstruction planes. The unwanted curvature is compensated by evaluating a correcting wave front at the hologram plane with no need for knowledge of the optical parameters, focal length of the imaging lens, or distances in the setup. Most importantly it is shown that a correction effect can be obtained at all reconstruction planes. Three different methods have been applied to evaluate the correction wave front and the methods are discussed in detail. The proposed approach is demonstrated by applying digital holography as a method of coherent microscopy for imaging amplitude and phase contrast of microstructures.
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TL;DR: In this paper, a totally automatic and robust phase aberration compensation method is proposed for digital holographic microscopy, where the phase aberrations are modeled with orthogonal polynomials and the coefficients are obtained in an optimization procedure by minimizing the total standard deviation.
8 citations
TL;DR: Instead of using pre-defined aberration models or 2D fitting, the simpler and more flexible 1D fitting is used, which means data across the whole plane could be used and the pure object phase can be obtained for further studies.
Abstract: Digital holography is a well-accepted method for phase imaging. However, the phase of the object is always embedded in aberrations. Here, we present a digital holographic phase imaging with the aberrations fully compensated, including the high order aberrations. Instead of using pre-defined aberration models or 2D fitting, we used the simpler and more flexible 1D fitting. Although it is 1D fitting, data across the whole plane could be used. Theoretically, all types of aberrations can be compensated with this method. Experimental results show that the aberrations have been fully compensated and the pure object phase can be obtained for further studies.
8 citations
TL;DR: This cooperative implementation of two metrics to automatically determine the best focal plane in digital lensless holographic microscopy (DLHM) reduces by at least 11 times the total computational complexity of the auto-focusing method with respect to the MEE method only.
Abstract: The cooperative execution of two metrics to automatically determine the best focal plane in digital lensless holographic microscopy (DLHM) is presented. This proposal is comprised of two stages: first, a quick coarse search over the whole reconstruction range by using Dubois's metric allows the finding of a range in which the best focal plane can be found. In a second stage, the modified enclosed energy (MEE) metric is used within the found range in the former stage to finely determine the best focal plane. While this cooperative implementation keeps the proven effectiveness of the MEE in DLHM, it reduces by at least 11 times the total computational complexity of the auto-focusing method with respect to the MEE method only. This proposal has been validated experimentally with DLHM holograms of a paramecium specimen, polystyrene beads, and the section of the head of a Drosophila melanogaster fly.
8 citations
03 Apr 2003
TL;DR: In this article, the authors report on the application of Digital Holography as metrological tool for the inspection and characterization of the domain structures in bulk Lithium Niobate samples.
Abstract: Ferroelectric domain micro structuring of bulk Lithium Niobate is very useful for optoelectronic applications such as non-linear optics employing Quasi-Phase-Matching for efficient harmonic and parametric conversion processes or for the fabrication route for production of novel MEMS devices, like micro-cantilever beams. Quasi-Phase-Matching based applications require periodically reversed ferroelectric structures with periods of the order of micrometers. Precise control of the surface quality and of the domain structure of the micro structured materials is required such as in the case of optical MEMS applications. We here report on the application of Digital Holography as metrological tool for the inspection and characterization of the domain structures in bulk Lithium Niobate samples. This technique allows reconstructing both the intensity and the phase of the microstructures under test and it allows determining quantitatively the phase distribution. Several examples of application of the Digital Holography technique for the numerical reconstruction of the micro-topography of domain structure are presented and discussed.
8 citations
TL;DR: It is demonstrated that QIM based on this improved phase aberration compensation (PAC) approach realizes high-quality phase imaging from a single interferogram, of great potential for a real-time speedy diagnosis.
Abstract: Single-shot quantitative interferometric microscopy (QIM) needs a high-accuracy and rapid phase retrieval algorithm. Retrieved phase distributions are often influenced by phase aberration background caused by both imaging system and phase retrieval algorithms. Here, we propose an improved phase aberration compensation (PAC) approach in order to eliminate the phase aberrations inherent in the data. With this method, sample-free parts are identified and used to calculate the background phase, reducing phase errors induced in samples and providing high-quality phase images. We now demonstrate that QIM based on this PAC approach realizes high-quality phase imaging from a single interferogram. This is of great potential for a real-time speedy diagnosis.
8 citations
Cites background from "Compensation of the inherent wave f..."
...then a sample phase can be solved by subtracting the background.(9) The aberrations can also be eliminated based on multiwavelength interferometry....
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...phase can be obtained by extrapolation according to the sub-FOV.(9) Self-referencing is also adopted to remove the background phase....
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References
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TL;DR: A new method is proposed in which the distribution of complex amplitude at a plane is measured by phase-shifting interferometry and then Fresnel transformed by a digital computer, which can reconstruct an arbitrary cross section of a three-dimensional object with higher image quality and a wider viewing angle than from conventional digital holography using an off-axis configuration.
Abstract: A new method for three-dimensional image formation is proposed in which the distribution of complex amplitude at a plane is measured by phase-shifting interferometry and then Fresnel transformed by a digital computer. The method can reconstruct an arbitrary cross section of a three-dimensional object with higher image quality and a wider viewing angle than from conventional digital holography using an off-axis configuration. Basic principles and experimental verification are described.
1,813 citations
TL;DR: The principle of recording holograms directly on a CCD target is described and a real image of the object is reconstructed from the digitally sampled hologram by means of numerical methods.
Abstract: The principle of recording holograms directly on a CCD target is described. A real image of the object is reconstructed from the digitally sampled hologram by means of numerical methods.
1,444 citations
TL;DR: A new application of digital holography for phase-contrast imaging and optical metrology and an application to surface profilometry shows excellent agreement with contact-stylus probe measurements.
Abstract: We present a new application of digital holography for phase-contrast imaging and optical metrology. This holographic imaging technique uses a CCD camera for recording of a digital Fresnel off-axis hologram and a numerical method for hologram reconstruction. The method simultaneously provides an amplitude-contrast image and a quantitative phase-contrast image. An application to surface profilometry is presented and shows excellent agreement with contact-stylus probe measurements.
1,202 citations
TL;DR: Off-axis holograms recorded with a magnified image of microscopic objects are numerically reconstructed in amplitude and phase by calculation of scalar diffraction in the Fresnel approximation to show that the transverse resolution is equal to the diffraction limit of the imaging system.
Abstract: We present a digital method for holographic microscopy involving a CCD camera as a recording device. Off-axis holograms recorded with a magnified image of microscopic objects are numerically reconstructed in amplitude and phase by calculation of scalar diffraction in the Fresnel approximation. For phase-contrast imaging the reconstruction method involves the computation of a digital replica of the reference wave. A digital method for the correction of the phase aberrations is presented. We present a detailed description of the reconstruction procedure and show that the transverse resolution is equal to the diffraction limit of the imaging system.
1,174 citations
TL;DR: The principles and major applications of digital recording and numerical reconstruction of holograms (digital holography) are described, which are applied to measure shape and surface deformation of opaque bodies and refractive index fields within transparent media.
Abstract: This article describes the principles and major applications of digital recording and numerical reconstruction of holograms (digital holography). Digital holography became feasible since charged coupled devices (CCDs) with suitable numbers and sizes of pixels and computers with sufficient speed became available. The Fresnel or Fourier holograms are recorded directly by the CCD and stored digitally. No film material involving wet-chemical or other processing is necessary. The reconstruction of the wavefield, which is done optically by illumination of a hologram, is performed by numerical methods. The numerical reconstruction process is based on the Fresnel–Kirchhoff integral, which describes the diffraction of the reconstructing wave at the micro-structure of the hologram. In the numerical reconstruction process not only the intensity, but also the phase distribution of the stored wavefield can be computed from the digital hologram. This offers new possibilities for a variety of applications. Digital holography is applied to measure shape and surface deformation of opaque bodies and refractive index fields within transparent media. Further applications are imaging and microscopy, where it is advantageous to refocus the area under investigation by numerical methods.
1,171 citations