The process of any movement of real object can be recorded and displayed by a multiplex holographic stereogram. An embossing multiplex holographic stereogram and a multiplex rainbow holographic stereogram have been made by us, the multiplex rainbow holographic stereogram reconstructs the dynamic 2D line drawing of speech organs, the embossing multiplex holographic stereogram reconstructs the process of an old man drinking water. In this paper, we studied the visual result of an embossing multiplex holographic stereogram made with 80 films of 2-D pictures. Forty-eight persons of aged from 13 to 67 were asked to see the hologram and then to answer some questions about the feeling of viewing. The results indicate that this kind of holograms could be accepted by human visual sense organ without any problem. This paper also discusses visual effect of the multiplex holography stereograms base on visual perceptual psychology. It is open out that the planar multiplex holograms can be recorded and present the movement of real animal and object. Not only have the human visual perceptual constancy for shape, just as that size,
color, etc... but also have visual perceptual constancy for binocular parallax.
Repositing a single exposure hologram to its original place precisely and real-time measuring the phase distribution of the deformed object wave are the foundation of real-time holographic interferometry. In general, phase distribution of the under testing object wave must be determined by measuring the corresponding intensity distribution of several phase shift interferograms. An digital method is introduced in this paper, it greatly simplify the process of determination for the phase distribution of the under testing object wave by using only one interferogram and reduce the precise requirement of the real-time hologram reposition. Some experimental examples are also given in the paper.
In a previous paper we have described that some dark shadow areas appeared among the interference fringes in real-time
holographic interferometry and we pointed that the appearing of these dark shadow regions are the phenomena of caustic in
Geometry Optics. These dark shadow region bears certain relation with the interference fringes. The quantitative relation
between caustics and real-time holographic interferometry in the experiments of mode I crack and mode III crack were
studied in detail. The quantitative relation introduced theoretically in this paper and compare with mode II crack. Based on
these relations, holographic method and caustic method can be combined together in interferometry and it can be used as a
powerful tool for scientific study and might lead to a wide application in many fields.
A wedge-adjusted Talbot interferometer is presented to change the inscribed Bragg wavelength of fiber Bragg gratings. In this system, the grating is written by UV interference stripes of 193 nm derived from two combined mirrors, where a phase mask is used as a beamsplitter of ±1 order of diffraction light. It is noteworthy that the adjustor transforms the shift of wedge into the rotation of the two mirrors, and alters the mutual angle of two interfering beams in writing fiber Bragg gratings.
To determine the phase distribution of the under testing object wave from the interferogram is the foundation of holographic interferometry. A digital image processing method for deleting the background noise and obtaining the phase distribution precisely is proposed by the authors and the example is also presented in this paper.
The principle of holographic CT measurement is introduced briefly, and the possibility of measuring 3D variation of the refractive index from the intensity distribution of a real-time holographic interferogram is proven theoretically. Based on this method, simulated study on calculating the variation of refractive index of an axis symmetry media is made by computer and the example of application is also presented in this paper.
In a series of the experiments of real-time holographic interferometry, some dark shadow areas appear among the interference fringes. The appearing of the dark shadow area plays a very important role in the fracture process. We find that the appearing of these dark shadow regions are the phenomena of caustic in Fracture Mechanics. The shadow region is so called shadow spot in Fracture Mechanics and the factor of stress intensity can be calculated by measuring the size of the correosponding length of the shadow spot and the strain field can be calculated by traditional holographic method. Therefore, holographic method and caustic method can be combined together in holographic interferometry and it will lead to a wide application in Experimental Mechanics.
on the theoretic analysis, this paper reports a new two-step color reflection holography and has made some holograms successfully. Comparing with making Denisyuk hologram, this new two-step recording method can adjust the ratio of reference light and object light, and the reconstructing image can be in any location in holographic recording plate.
In order to decrease the phase shift error, this paper presented a new object phase shifting method by using fringe stabilizing device to stabilize the interference fringe. The experimental result shows the fringe drift is less than ?/20 in five minutes , and the phase shifting precision is more than 0.004 ? , furthermore the system is very simple, performance reliable and operating convenience, it will take an important role for improving the measure precision of 3-D phase profilometry, more strong practicality and popularly application prospect.
Six novel methods in real-time holographic interferometry recently worked out by the authors of this paper. They are: the one for recording a real-time hologram with high contrast interference fringes and high brightness of the testing optics field, the one for measuring the phase modulation of a thin-phase hologram, the one for controlling the phase modulation in making a real-time hologram, the one for measuring in the 'reference wave field', the one for fast predicting the direction of displacement, and the one for avoiding the light reflected from the surfaces of collimation lens. All these methods are helpful to holographers in pursuit of high precision and efficiency in real-time holographic interferometry.
In this paper the physical process of real-time holographic interferometry is simulated by the computer calculations based on scalar diffraction theorem and the deformation field of the specimen is calculated by the inverse calculation of the diffraction from the interference fringes. The application the study of micro-crack nucleation process leads to interesting result in good agreement with experiments.
The fracture process of uniformity solid is simulated by a series of transparent specimen in this study in order to discover relationships between the micro-crack nucleation process and the surrounding stress field. A real-time holographic interferometry is used to record the stress fields and its variations in the specimen while the wave-forms of ultrasonic emission stimulated by the micro-cracks are recorded by a transient automatic wave- form recorder to determine the time, location and intensity of the micro-cracks. The development process of fracture can be visualized clearly by this real-time holographic interferometry. The initial experimental study has brought some phenomena worthy of study. This method provides a powerful new approach for experimental mechanics and seismological research.
In this paper, the holographic recording materials is thought as a scattering object, while a laser beam illuminates to the materials, the scattering light must be emerged. For the reconstructing hologram, the scattering light is thought as the scattering noise, it comes from the scattering particles. By using a narrow laser beam illuminates to the recording plate and measures the scattering and diffraction light intensity and the size of diffraction ring, the scattering noise and the size of the particle of the recording materials can be measured respectively. As the size of the particle of the recording materials determines the resolving power of holographic plate, the resolving power determines the quality of hologram, so the measurement of the size of the particle of the recording materials is very important. This paper also presents some new methods to measure the quality of holographic plate, model plate, model plate and PET materials by using the diffraction pattern of a narrow laser beam. The experimental results shows these new methods with wide measuring range, high precision and short measuring time are very practical.
The holographic information transferred from photoresist master to replica is the relief groove depth. Many properties of the replica are related to groove depth of master, so to control the groove depth of photoresist master is important. In this paper, a novel method is adopted to obtain the value of the phase modulation by measuring diffraction light intensity of the photoresist master, since there is a certain relationship between groove depth and phase modulation, so the groove depth can be obtained indirectly.
Some new methods in real-time holographic interferometry are presented in this paper, such as how to obtain a high contrast of interference fringes in real-time holographic interferometry at the stage of recording or reconstruction; how to predict the deformation direction of an object by a simple and reliable method etc. These techniques are helpful for holographers to improve the precision and efficiency in real-time holographic interferometry.
To evaluate a hologram by measuring its optical density D, diffraction efficiency (tau) and signal-noise ratio SNR is a conventional method in holography. In this paper, a novel method is proposed for evaluation of a thin, phase holograms by testing phase modulation together with D, (tau) and SNR. Many properties of the thin, phase holograms are related to phase modulation, so that to control the value of phase modulation in making a thin, phase hologram is important. The value of the phase modulation of a hologram can be obtained by measuring the irradiance of its zero and first- order diffraction and calculating their ratio. This method will help holographers to obtain a perfect understanding of a thin, phase hologram and help them to choose the optimum parameters of exposure so as to obtain an expectation result. The theoretical analysis of this method are given and some applications are also introduced.
The slit image of a rainbow hologram is analyzed for the case of a narrow laser beam normal to the hologram. The slit image on the screen is found to be of the shape of hyperbola or circle curve. The analytical expressions for the hyperbola or circle curve shown on the screen by a narrow laser beam is derived in this paper. The results agree with the experiments. Some important parameters of a rainbow hologram -- such as the angle between reference and object wave, the width and the length of the slit, and the viewing angle of the hologram -- can be determined by this reconstruction method. It is helpful for holographers to get a better understanding if they are interested in some holograms made by others and they can learn more from them.
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