Twowavelength holography and phaseshifting interferometry are combined to measure aspheric surface contours with variable sensitivity. Computer reconstruction by phaseshifting digital holography. Special phaseshift is introduced in the reference beam by changing code pattern displayed on the lcslm. In this paper we report the potentialities of a new technique for surface contouring by phase shifting realtime holography using the photorefractive bi 12 sio 20 bso crystal. Wyant shows that the interferogram obtained with two wavelengths. Thus, the outofplane displacement can be expressed as follows. The technique is implemented by inserting a phaseshifting array device consisting of array of 2.
Download citation surface shape measurement by phaseshifting digital holography surface contouring by phaseshifting digital holography is proposed that provides surface height from a change. Digital holography for quantitative phasecontrast imaging. Introduction surface shape measurement by means of digital holography is generally known as holographic topography, or holographic contouring when performed with analog holography, and can be performed using multiwavelength digital. The phase shifting is generated by a mechanical motion of a piezoelectric ceramic transducer pzt, and the most common phase shift between images is. It is based on an averaging procedure with shifted images obtained before and after a load is applied. Yokota, surface shape measurement by dualwavelength phaseshifting digital holography, fringe 2005, proc.
Surface height from a reference plane is directly obtained from the phase change. Parallel phaseshifting digital holographic microscopy. Several recording and processing schemes have been developed to assess optical wave characteristics such as amplitude, phase, and polarization state, which make digital holography a very powerful method. A further improvement is the linear conoscopic holography 3, 4, where two crystals, with a specific orientation one with respect to the other, build up the conoscopic module. Microscopic imaging by digital holography has been applied to imaging of microstructures1 and biological systems. Setup for microscopy using phase shifting digital holography without imaging lens onion peels z 17mm, zq itmm, magnification m5. It is widely applied in computer reconstruction for the object image, optelectronic reconstruction and the object information measurement, in which the computer reconstruction is the basis of the others. The method can reconstruct an arbitrary cross section of a threedimensional object with higher image quality and a wider viewing angle than from conventional digital holography. Suppression of the zeroorder and twin images by phaseshifting digital holography allows efficient use of the pixel array 24.
This technique provides the surfaces height from a change of object phase. Digital holography offers a means of measuring optical phase data and typically delivers threedimensional surface or optical thickness images. Measurement of surface shape and deformation by phase. Surface contouring by phaseshifting realtime holography. Dynamic digital holography for recording and reconstruction. Digital holographic measuring systems dhm have the potential for complete 100% and fast quality testing. Holographic contouring using electronic phase measurement. Abstract this work proposes to obtain surface contouring by phaseshifting realtime holography using photorefractive sillenite crystals which provides the surface contouring from a change in phase of wavefront of the object illumination beam. Freeviewpoint images captured using phaseshifting synthetic. Threedimensional vibrometry of the human eardrum with. They are recorded, such as on a digital camera, and are reconstructed numerically.
In this paper we report the potentialities of a new technique for surface contouring by phaseshifting realtime holography using the photorefractive bi 12 sio 20 bso crystal. Superresolution imaging method using phase shifting digital. In the paper, they have presented a new application of digital holography for phasecontrast imaging. Digital recording and numerical reconstruction of holograms. Digital holography dh has emerged as one of the most effective coherent imaging technologies.
Mirror with pzt half mirror phase shift half mirror figure 53. Special section on laser applications in life sciences. Principles and techniques of digital holographic microscopy. Wave front reconstruction by means of phaseshifting digital. Surface shape measurement by phaseshifting digital holography. In speckle projection profilometry, the inplane displacement u measured by the dic method has unit pixels, so the actual physical distance is given by, where m is the magnification of the imaging system. Osa surface shape measurement by phaseshifting digital. This change is obtained by tilting the object illumination beam. Abstract surface contouring by phaseshifting digital holography is proposed that provides surface height from a change of reconstructed object phases due to the tilt of object illumination. Surface contouring by phase shifting digital holography is proposed that derives surface height from the difference of reconstructed object phases for different incident angles at an object. Phaseshifting method with unknown intervals in phase.
Wholefield techniques, second edition provides a comprehensive collection of wholefield optical measurement techniques for engineering applications. Phaseshifting digital holography 151 beam is frequency shifted and an object is scanned by an xy stage under focused illumination. Wave front reconstruction by means of phase shifting digital inline holography. In phaseshifting method, it is often used four steps of phaseshifting for one cycle. A new method for threedimensional 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 simultaneously provides an amplitudecontrast image and a quantitative phasecontrast image. For hologram recording a conventional holographic setup can be used, as long as a phase shifting element is included in the optical path of the reference beam see fig. The numerical reconstruction of the digital holograms was performed using the software holodig. In this configuration, the wavefront reflected by the inspected surface is duplicated by the conoscope, and the resulting wavefronts emerge with a lateral shear between. Surface contouring by phaseshifting digital holography is proposed and verified by experiments and numerical simulations. The authors present a parallel phaseshifting digital holography as a digital imaging technique for recording and reconstruction of threedimensional object.
Introduction digital holography has many versatile applications, including microscopy 1, phase contrast 2, 3d displays 3, tomography 4, and terahertz imaging 5. A number of holograms are optically generated using different wavelengths spaced at regular intervals. Surface contouring by phaseshifting digital holography is proposed that provides surface height from a change of reconstructed phase due to tilting of the object illumination. As nouns the difference between holography and hologram is that holography is physics a technique for recording, and then reconstructing, the amplitude and phase distributions of a coherent wave disturbance. A perpendicularly polarized light beam is emitted from the laser and is split into two beams by a beam splitter. The phase of the averaged product at the object plane provides the shape of the surface, whereas the peak position of the modulus with. Surface contouring by phase shifting digital holography is proposed and verified by experiments and numerical simulations. This paper presents the methods for measurement of not only surface shape but also its distance from a charge. Principles and applications provides a comprehensive overview of the theory, practical considerations, and applications of holography. Optical aberrations, digital image focusing, and numerical compensation for sample tilt and environmental disturbances can be. Digital holograms are recorded before and after mode hopping of a laser diode subject to current tuning, and the difference of the reconstructed phases at each wavelength is computed to deliver surface contours of a diffusely reflecting surface. This technique enables the measurement of both amplitude and phase, useful for quantify. Suppression of the zeroorder and twin images by phase shifting digital holography allows efficient use of the pixel array 24.
Aug 02, 2004 digital holography technique is the numerical version of conventional holography technique. Simultaneous measurement of inplane and outofplane. Its sensitivity depends on the difference of incident angles. Digital holography comes in different flavors, such as offaxis fresnel, fourier, image plane, inline, gabor and phase shifting digital holography, depending on the optical setup. The application of digital holography as a viable solution to 3d capture and display technology is examined.
It directly delivers surface shape without fringe phase analysis. A simple digital holographic apparatus and method allow reconstruction of threedimensional objects with a very narrow depth of focus or high axial resolution. Measurement of surface shape and deformation by phaseshifting digital holography. A new method for threedimensional image formation is proposed in which the distribution of complex amplitude at a plane is measured by phaseshifting interferometry and then fresnel transformed by a digital computer. Contouring surfaces using twowavelength phaseshifting interferometry 1457 the two techniques can be combined to extend the sensitivity of phaseshifting interferometry to the range of twowavelength holography 4. They are very important because noncontacting and wholefield measurements of surface shape with high resolution are required in many fields like biotechnology and engineering the shape determination of surfaces can be done by the holographic interferometry. Freeviewpoint images captured using phase shifting synthetic aperture digital holography tatsuya nakatsuji and kyoji matsushima department of electrical and electronic engineering, kansai university, yamatecho 3335, suita, osaka 5648680, japan corresponding author. Principle of digital holographic microscopy digital holography is based on the classic holographic principle, with the difference that the hologram recording is performed by a digital image sensor, e.
Dynamic digital holography for recording and reconstruction of 3d images using optoelectronic devices. Surface shape measurement by phase shifting digital holography with dual wavelengths. Single shot digital holography using iterative reconstruction. In conventional method, to measure the displacement of an object by an interferometer, the phase of a reference beam should be shifted by every. Superresolution imaging method using phaseshifting digital lensless fourier holography luis granero 1, vicente mico 2, zeev zalevsky 3, and javier garcia 2 1aido technological institute of optics, color and imaging, c nicolas copernico 7, 46980, paterna, spain. Parallel phase shifting digital holographic microscopy ppsdhm figure 1a shows a block diagram of the ppsdhm. Analysis in digital holography under the supervision presented by of b. In digital holography holograms are recorded by a ccd camera and images are reconstructed by a computer. Strategies for reducing speckle noise in digital holography. The technique uses a ccd camera for recording of a digital fresnel offaxis hologram and a numerical method for hologram reconstruction. Surface contour measurement by lcslm digital phase.
And the reconstruction quality of complex amplitude of object wave has been improved greatly. Digital gabor holography, without separate reference. Digital holographic capture and optoelectronic reconstruction. Apr 25, 20 digital holography and 3d imaging dh 21 25 april 20 21 april 20 the fairmont orchid, kohala coast, hawaii united states the digital holography and threedimensional imaging dh topical meeting provides a forum for science, technology, and applications of digital holographic and threedimensional imaging and display methods. This digital approach to holography allows the application of computer based procedures at a level unreached in videomicroscopy.
A simple method for surface contouring by phase shifting digital holography is reported. Surface contouring by phaseshifting digital holography and. Yamamoto, h 1994 fouriertransform speckle profilometry. Chapters 1 and 2, surface contouring chapter 3 and characterization of optical waveguides chapter 4. Us7127109b1 digital interference holographic microscope. Digital holography has been used for this purpose using optoelectronic devices. The first one is based on the method of multiple illumination directions, whereas the second one uses a. In particular the strength of dhm principle allows unique software compensations. The author has spent his career working on different aspects of this subject, and in this book, conveys the foundation for others to use holography and holographic concepts in a variety of important applications. Phaseshifting interferometry is a wellknown technique that has been used with great success in optical profilers. This technique is a complement to the phaseshifting methods. Measurement of surface shape and position by phase.
Phase shifting digital holography 151 beam is frequency shifted and an object is scanned by an xy stage under focused illumination. Surface measurement 101 noncontact 3d optical metrology. Singleshot phaseshifting digital holography based on the spatial carrier interferometry and its tolerance analysis describes how angularly multiplexed phase shifting in a single digital. For these reasons, digital and analog holography, along with their many variations i. Measurement of surface shape and deformation by phaseshifting image digital holography, opt. Determination of the zeroorder fringe position in digital.
Advanced holography metrology and imaging holography. For the given talbot fringe projection system, k is a constant and can be obtained by experimental calibration. A significant constraint of digital holography is the pixel count and resolution of the imaging devices. A method for determining the position of the zeroorder fringe in a metrological experiment with digital speckle pattern interferometry is proposed. Its sensitivity depends on the tilt angle as well as on the initial incident angle. The technological developments of digital sensors and optical elements have made dh. Image formation and measurement of surface shape and. Along with the reorganization of contents, this edition includes a new chapter on optical interference, new material on nondiffracting and singular beams and their applications, and updated bibliography and. Surface contouring by phase shifting digital holography is proposed that provides surface height from a change of reconstructed phase due to tilting of the object illumination.
The application of heterodyne and quasiheterodyne stepwise phase shifting fringe interpolation techniques to contouring for 3d object shape measurement is discussed. Surface contouring by digital phaseshifting holograph system based on the lcslm is proposed in the paper. For surface contouring we calculate the difference of the reconstructed phases before and after small tilt of. Transmission digital holography microscopy applied to the study of coal palynofacies.
One beam illuminates the specimen, and then the scattered light from the specimen is collected by a microscope objective. This extension can be achieved by looking more closely at twh. Contouring aspheric surfaces using twowavelength phase. Surface contouring by phase shifting digital holography is proposed that provides surface height from a change of reconstructed object phases due to the tilt of object illumination. Diffusely reflected light from a coherently illuminated object is recorded by a ccd with coherent inline superposition of a reference beam subject to phase shifting. A setup with two spherical illumination sources for contour fringe generation is described. D distribution of complex amplitude without any filtering operation needed in the off. To ensure that measurements are reliable and independent of the measuring method, the holographic system is configured so that principal components of displacements, d x, d y, d z, can be measured with two different holographic interferometric approaches. Chapter 5 phaseshifting digital holography principles and. In conventional holography, an optical lens is used to focus on an object of interest. Surface shape measurement by phaseshifting digital holography with dual wavelengths authors. Displacement measurement can be performed with high accuracy using phaseshifting method. Widescale surface measurement using white light interferometry and atomic force microscopy. Surface contouring by phaseshifting digital holography.
This technique has been broadly applied in surface contouring and in phaseshifting real time interferometry 8, 9, 10. The interference fringe is deformed since it is modulated by the fluctuation of the tested surface. Digital holography and 3d imaging dh topical meeting. Steps or surface variations up to 10 mm surfaces with roughsteep surfaces vxi option, 0.
Surface shape measurement by phaseshifting digital. Surface contouring by phaseshifting digital holography is proposed that derives surface height from the difference of reconstructed object phases for different incident angles at an object. In order to reconstruct the threedimensional features of objects is broadly used the phase shifting technique in digital holography 31, the images resulting from this process withdraw the zero order term and the conjugated image of the object, that are usually seen in dh. Setup for microscopy using phaseshifting digital holography without imaging lens onion peels z 17mm, zq itmm, magnification m5. Surface contouring by phaseshifting digital holography is proposed that provides surface height from a change of reconstructed object phases due to the tilt of object illumination.