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Journal ArticleDOI

Compensation of the inherent wave front curvature in digital holographic coherent microscopy for quantitative phase-contrast imaging

10 Apr 2003-Applied Optics (Optical Society of America)-Vol. 42, Iss: 11, pp 1938-1946
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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Journal ArticleDOI
TL;DR: The high temporal stability of CRHM is verified in calibration measurements and its application potential demonstrated by a quantitative restoration of the phase resolution target and imaging of biological samples including cheek and sperm cells.
Abstract: This paper proposes an optimized implementation of the double-exposure method with emphasis on the uniformity and minimization of the residual phase imperfections in cross-referenced holographic microscopy (CRHM). The quantitative phase images are restored from single-shot cross-referenced holograms, which are separated in the Fourier space and processed to eliminate effects caused by imperfections of the optical path and sample background. CRHM is implemented in a microscope configuration supplemented by a Sagnac interference module providing splitting and shearing of the sample and reference waves. Utilization of the averaging process, which enhances precision of quantitative phase image (QPI) reconstruction, applicable in the methods with a replicated field of view is also presented. The high temporal stability of CRHM is verified in calibration measurements and its application potential demonstrated by a quantitative restoration of the phase resolution target and imaging of biological samples including cheek and sperm cells.

12 citations

Journal ArticleDOI
Yun Liu1, Zhao Wang1, Jiansu Li1, Jianmin Gao1, Junhui Huang1 
TL;DR: In this paper, the authors proposed a method for the location of the center of the side band based on the unwrapped phase in the spatial frequency domain in the pre-magnification configuration, which can be applied to the phase imaging of the microhole array, phase grating and phase steps.

12 citations

Proceedings ArticleDOI
29 Mar 2010
TL;DR: This work is developing volume reconstruction and object detection algorithms that can speed up considerably by parallel hardware implementation, and put these tasks into operation on a GPU.
Abstract: Using Digital Holographic Microscopy (DHM) we can gather information from a whole volume and thus we can avoid the small depth of field constraint of the conventional microscopes. This way a volume inspection system can be constructed, which is capable to find, segment, collect, and later classify those objects that flow through an inspection chamber. Digital hologram reconstruction and processing, however, require considerable computational resources. We are developing volume reconstruction and object detection algorithms that can speed up considerably by parallel hardware implementation. Therefore, we put these tasks into operation on a GPU. As data transfer of the reconstructed planes would slow down the algorithm, all the reconstruction, object detection processes are to be completed on the parallel hardware, while fine tuning of object reconstruction and classification will be done on a CPU later. The actual speed up of the GPU implemented algorithm comparing to its conventional CPU realization depends on the applied hardware devices. So far we reached a 10 times acceleration value.

12 citations

Journal ArticleDOI
TL;DR: A phase-shifting-free method to improve the resolution of digital holographic microscopy under the structured illumination (SI) and it shows 78% resolution improvement in the experiments.
Abstract: In this paper, we present a phase-shifting-free method to improve the resolution of digital holographic microscopy (DHM) under the structured illumination (SI) The SI used in the system is different from the traditional SI for it is free of the visible structure due to two illumination lights with orthogonal polarization states To separate the recorded information and also retrieve the object phase, two reference beams with different carrier frequencies and orthogonal polarization states are adopted The principle component analysis (PCA) algorithm is introduced in the reconstruction process It is found that the modulated frequency of SI besides the quadratic phases of the imaging system can be easily removed with help of PCA Therefore, phase-shifting is not required both in recording and reconstruction process The simulation is performed to validate our method, while the proposed method is applied to the resolution enhancement for amplitude-contrast and phase-contrast objects imaging in experiments The resolution is doubled in the simulation, and it shows 78% resolution improvement in the experiments

12 citations

Journal ArticleDOI
Liu Huang1, Liping Yan1, Benyong Chen1, Yanjiang Zhou1, Tao Yang1 
TL;DR: In this paper, a numerical phase aberration compensation method with global curve fitting preprocessing and automatic extraction of the background region for microstructure testing is proposed, which can compensate most of the tilt, quadratic and partial high order aberrations and make the profile of the measured object significantly distinguishable.

12 citations

References
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Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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

Journal ArticleDOI
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