Optical setup is based on phaseshifting digital holography with multiple lasers. Principles and techniques of digital holographic microscopy. Measurement of surface shape and deformation by phase. Employing the virtuallab software to carry out the simulations, we first prove that, for cells with different nuclei structures, their wrapped phase distributions indeed. Uncertaintymanaged phaseshifting digital holography joonku hahn1 and hwi kim2, 1school of electronics engineering, kyungpook national university, bukgu sankyukdong, daegu 702701, south korea 2department of electronics and information engineering, college of science and technology, korea university, sejong campus, sejongro 2511, sejong 339700, south korea. One beam illuminates the specimen, and then the scattered light from the specimen is collected by a microscope objective. The best known example is phaseshifting digital holography, where generally at least 3 exposures are needed to unambiguously retrieve the complex amplitudes cf. With the phaseshifting of the reference beam inline holograms for three wavelengths emitted from a hecd laser are recorded simultaneously to derive the. Pdf digital holographic microscopy with phaseshiftfree. Phaseshifting digital holography has been used for the study of vibrating objects. When structured illumination is used in digital holographic microscopy dhm, each direction of the illumination fringe is required to be shifted at least three times to perform the phase shifting reconstruction. More exposures can be taken to improve noise robustness. Also, the interferometric principle is adopted to extract the phase with the numerical wave propagation and 2.
Digital holography comes in different flavors, such as offaxis fresnel, fourier, image plane, inline, gabor and phaseshifting digital holography, 2 depending on the optical setup. Digital inline holographic microscopy jorge garciasucerquia, wenbo xu, stephan k. The phaseshifting or phasestepped digital holography process entails capturing multiple interferograms that each indicate the optical phase relationships between light returned from all points on the illuminated object and a controlled reference beam of light. This method requires no mechanical movement and provides a flexible display and quantitative evaluation of the reconstructed. The global digital holography market size is expected to. In phaseshifting method, it is often used four steps of phaseshifting for one cycle.
Threedimensional microscopy with phaseshifting digital. Phaseshifting method with unknown intervals in phase. Phaseshifting digital holography psdh is a very effective method of removing these terms, introduced by i. Signal processing challenges for digital holographic video. In conventional method, to measure the displacement of an object by an interferometer, the phase of a reference beam should be shifted by every. Multiwavelength digital holographic microscopy dhm has been used to improve phase reconstructions of digital holograms by reducing 2. Multiexposure methods on the other hand, consist of taking several measurements in succession. Digital recording and numerical reconstruction of holograms. As a side effect, the zeroorder term and the twin image can be eliminated in the reconstructed image. In phase shifting digital holography employing an inline setup complex amplitude at a ccd plane is directly detected by stepwise phase shifting of the reference beam. No phase shifting required thus removing the need for piezo stages.
Phaseshifting digital holography psdh,14 was proposed as a. Singleshot twostep gouy phaseshifting digital holography. The difference of the reconstructed phases before and after tilt of the object illumination beam provides the contour lines of the surface height, while before and after object deformation delivers. A perpendicularly polarized light beam is emitted from the laser and is split into two beams by a beam splitter. Fourstep phaseshifting digital holography simultaneously sensing. The optical phase of the reference beam is shifted. By digital holography the intensity and the phase of electromagnetic wave. Digital holography technique allows recording and reconstruction of. To perform phaseshifting digital holography psdh, several holograms have to. It can finish deformation measurement very well because of the phaseshifting algorithm. Freeviewpoint images captured using phaseshifting synthetic aperture digital holography tatsuya nakatsuji and kyoji matsushima department of electrical and electronic engineering, kansai university, yamatecho 3335, suita, osaka 5648680, japan. Mextsupported program for the strategic research foundation at private.
Yamaguchi presented the inline phaseshifting digital holography. The phase shift image is unique for digital holographic microscopy and gives quantifiable information about optical distance. Phase shifting digital holography was also applied to color holography by using a multiline laser and a color ccd shown in fig. Twowavelength holography and phaseshifting interferometry are combined to measure aspheric surface contours with variable sensitivity.
Digital image encryption and watermarking by phase. Figure 1 illustrates the schematic diagram of tpddh in microscopy. Mextsupported program for the strategic research foun dation at private. The dhm technology generates, in true realtime, high resolution 3d digital images of a sample using the principle of holography. These holograms contain amplitude and phase information of the optical radiation diffracted by the object, in the sensor plane. In transmission, the phase image reveals the phase shift induced by a. Uncertaintymanaged phaseshifting digital holography.
A significant constraint of digital holography is the pixel count and resolution of the imaging devices. In pdm, wavelengthmultiplexed phaseshifted holograms are recorded, and. We applied phaseshifting digital holography to microscopy by deriving the complex amplitude of light scattered from microscopic threedimensional objects through a microscope objective by video camera recording, phaseshifting analysis, and computer reconstruction. Technology principle and history of digital holography patented technology use a. Phaseshifting inline digital holography on a digital. Wavelengthselective phaseshifting digital holography is a technique to obtain multiwavelength threedimensional 3d images with a full spacebandwidth product of an image sensor from wavelengthmultiplexed phaseshifted holograms and has been proposed since 20. The phase of the averaged product at the object plane provides the shape of the surface, whereas the peak position of the modulus with.
Its main limitation that is caused by much lower resolution of ccds than photographic materials has been substantially overcome by phaseshifting digital holography that reduces the spatial frequency of hologram by employing the inline setup and directly evaluates complex amplitude at the ccd plane to eliminate the conjugate and zeroth order. 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. Quantitative phase imaging without staining of cells. Digital holography as well as transmitted led bright field observation. The phaseshifting interferometry psi is a well established and widely used technique. Suppression of the zeroorder and twin images by phaseshifting digital holography. 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. Measurement of shape and deformation of diffusely reflecting surfaces by phaseshifting digital holography is presented that uses an imaging setup. Suppression of the zeroorder and twin images by phaseshifting digital holography allows efficient use of the pixel array 24. 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. In this paper, we propose a scheme for spatial resolution enhancement of dhm by using the structured illumination but without phase shifting. With phaseshifting holography, it is possible to obtain the two quadratures of the field even though the conjugate image alias and the true image overlap, because aliases can be removed by taking image differences. Phase shift images besides the ordinary brightfield image, a phase shift image is created as well.
Superresolution imaging method using phase shifting. Holograms are generated by combining a coherent reference wave with the wave received from a specimen. Twostep phase shifting differentialrecording digital. Fourstep phaseshifting digital holography simultaneously sensing dual wavelength information using a monochromatic image sensor. The dhm proprietary software computes the complete wavefront emanating from.
A microscope objective projects a laterally magnified image of the object with a sufficiently in terms of the sensor pixel pitch high. It is a transmission type inverted digital holography microscope with balanced afocal configuration that uses infinity corrected plan achromatic objectives in both reference and object beams. Hodhmit01 is an inverted type digital holography microscope which can be used for the quantitative phase imaging for live cells. Fiberoptic displacement sensor to detect the vibration of the thinned usection by fac. The timeaveraged complex amplitude of fresnel diffracted field due to a vibrating object was obtained by using.
In reflection dhm, the phase shift image forms a topography image of the object transparent objects, like living biological cells, are traditionally viewed in a phase. A dualchannel interferometer was employed to monitor the gouy phaseshifting between two orthogonal polarized references which was introduced by two confocal lenses. Multiwavelength digital holography and phaseshifting. The authors present a parallel phaseshifting digital holography as a digital imaging technique for recording and reconstruction of threedimensional object. In this study we apply 3wavelength offaxis dhm to swimming protozoa. Yamaguchi, where the complex field at the hologram is obtained by phaseshifting interferometry 1.
Parallel phaseshifting digital holographic microscopy. Digital gabor holography, without separate reference. Digital holographic microscopy with phaseshiftfree structured illumination. Digital holography wikimili, the free encyclopedia. Displacement measurement can be performed with high accuracy using phaseshifting method. Fourstep phaseshifting digital holography simultaneously sensing dualwavelength information using a monochromatic image sensor. Parallel phaseshifting digital holographic microscopy ppsdhm figure 1a shows a block diagram of the ppsdhm. The optical phase of the reference beam is shifted from one sampled interferogram to the next. The interferograms on the two ccd cameras are shifted for a phase. The best known example is phase shifting digital holography, where generally at least 3 exposures are needed to unambiguously retrieve the complex amplitudes cf. Multiwavelength digital holographic imaging and phase. Chapter 5 phaseshifting digital holography principles and. In phase shifting digital holography employing an inline setup complex amplitude at a ccd plane is directly detected by stepwise phaseshifting of the reference beam.
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. Singleshot phaseshifting incoherent digital holography doi. Phaseshifting digital holography was also applied to color holography by using a multiline laser and a color ccd shown in fig. Abstract we demonstrated a singleshot quasionaxis digital holography which is capable of simultaneously capturing twostep phaseshifting interferences. After passing through the sample, the object wave was magnified by a telescope system comprised of a microscopic. Measurement of surface shape and position by phase. The phaseshifting or phasestepped digital holography process entails capturing multiple interferograms that each indicate the optical phase relationships. We propose and demonstrate lightinflight recording by parallel phaseshifting digital holography to obtain a motion picture of ultrashort light pulse propagation free from unwanted images, which are a zerothorder diffraction image and a conjugate image, by.
However, they have the fundamental limitations of the measurement. Digital holography has become an important and popular imaging technology with applications in biomedicine, metrology and 3d displays. Education kit edk jd955b the jd955b education kit edk is an lcos, slmbased system that provides indepth, handson optical training via a series of ten experiments. Digital holography for quantitative phasecontrast imaging. Strategies for reducing speckle noise in digital holography.
Twostep phase shifting differentialrecording digital holographic. However, most samples used as test images have been solid or adhered to a surface, making it easy to determine focal planes and correct for chromatic aberration. Optics students and engineering professionals will be able to learn optics fundamentals quickly and easily with the edk. Osa digital holographic microscopy with phaseshiftfree. Edk application software by jasper display national. Twostep phase shifting differentialrecording digital holographic microscopy.
With the phase shifting of the reference beam inline holograms for three wavelengths emitted from a hecd laser are recorded simultaneously to derive the. Dynamic digital holography for recording and reconstruction of 3d. To measure both the amplitude and the phase of a light wave after the passage of a semitransparent specimen, the amplitude of the superposition of the object wave o with a reference wave r fig. Parallel phaseshifting digital holographic microscopy ncbi. In the path of object wave, a test specimen, such as a microlens array, is placed in the front focal plane of microscope objective mo. Noninvasive timedependent cytometry monitoring by digital. Clemson university, clemsonmusc bioengineering program, charleston. Phaseshifting digital holography is widely used to determine the phase as well as the amplitude of the objects wave 1, 2. They are recorded by a video camera and transmitted to a computer for realtime numerical reconstruction.
1488 204 1461 1297 1173 1110 573 1555 419 563 1197 844 1231 557 1517 657 116 123 909 328 1184 698 251 14 483 652 165 750 64 650 33 333 1245 877 791 978 1324 850 1404 883 277 558