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.
Citations
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05 Jul 2011
TL;DR: In this article, a novel approach for numerical wavefront reconstruction in arbitrary phase step digital holography is presented, which can be used for the 3D reconstruction of micro-structure images.
Abstract: In this work, a novel approach for numerical wave-front reconstruction in arbitrary phase step digital holography is
presented. We present a simple and effective approach for digital holography microscopy that can be used for the 3D
reconstruction of micro-structure images. The experimental results demonstrate that only two digital holograms and a
simple estimation are required for the twin-image suppression and numerical reconstruction. The advantages of this
approach are its simplicity, in that only one estimate equation need be applied, and its effectiveness, in that the exact
phase profile of a micro lens array is presented, without blurring due to numerical reconstruction or aberration caused by
the quadratic phase micro objective lens.
TL;DR: In this article , a three-pack frequency-selective incoherent holography (FSH) method was proposed to remove conjugate and DC terms along with the interception of the object wave.
Abstract: We propose a new, to the best of our knowledge, method of incoherent optical frequency selection called three-pack frequency-selective incoherent holography. Compressed holography is reconstructed using phase shift intercepts and spatial transfer function convolution in the form of separation without loss of magnification or resolution. The frequency-selective reconstruction process removes the conjugate and DC terms along with the interception of the object wave. This work attempts three-dimensional reconstruction and selected-frequency phase extraction of axial slices in submicron steps, and the experimental results show the potential of the proposed method in areas such as compressed holography, extended field of view, and slice tomography.
05 Oct 2018
TL;DR: In this article, a fast and simple numerical method for automatically compensating the phase curvature from the wrapped phase gradient of the reconstructed hologram is presented, which does not require prior knowledge of the object or the setup.
Abstract: espanolLa mayoria de los montajes experimentales utilizados en microscopia holografica digital introducen un objetivo de microscopio en el brazo objeto del miro-interferometro con el objetivo de aumentar la resolucion lateral; sin embargo, como consecuencia, aparece una aberracion de fase esferica que debe corregirse para acceder al retardo de fase que experimenta es especimen microscopico bajo estudio. En este trabajo se presenta un metodo rapido y simple para corregir numericamente la curvatura de fase a partir del gradiente del mapa de fase envuelto del holograma reconstruido. Dado que no se requiere el empleo de metodos de desenvolvimiento de fase, los costos computacionales son notablemente reducidos. Adicionalmente, no se precisa del registro de hologramas adicionales, ni del conocimiento previo del objeto bajo estudio o del arreglo experimental. El metodo se demuestra experimentalmente a partir del holograma de una microalga del genero Pediastrum. EnglishMost digital holographic microscopy architectures introduce a microscope objective in the object arm of the micro-interferometer in order to increase lateral resolution but, as a consequence, a spherical phase aberration arises. The phase distortion must be corrected to achieve reliable phase information linked to the microscopic object under study. In this work, we present a fast and simple numerical method for automatically compensate the phase curvature from the wrapped phase gradient of the reconstructed hologram. Since non-unwrapping methods are required, computational cost is significantly reduced. Furthermore, no additional holograms recording is needed and it does not require prior knowledge of the object or the setup. The method is experimentally demonstrated by a phase contrast imaging of a Pediastrum cell
19 Jun 2011
TL;DR: In this paper, a unified spatial light modulator (SLM) based lensless configuration is used to overcome the geometrical bounds of super resolution. But the SLM is not suitable for super resolution applications.
Abstract: In the field of super resolution researchers are trying to overcome both the diffraction as well as the geometrical bounds of an imaging system. In this paper we present a recently developed approach that aims to overcome the geometrical bounds while using a unified spatial light modulator (SLM) based lensless configuration.
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