This paper presents a novel method to fabricate circular gratings based on binary optics. A smart digital micro-mirror device (DMD) laser writing system is used to fabricate circular gratings. By use of the DMD system, we are capable of making low-cost and useful circular gratings easily. Their levels and radii can be controlled and be suited for many optical systems. Experiment results have been obtained with two and four levels. In this paper, it will also show a method of simulating circular gratings' diffraction. Using the simulation method, we can value and check the diffraction effect of circular gratings to rectify the design parameters.
KEYWORDS: Image processing, Digital holography, Digital image processing, Holography, Image filtering, Binary data, Data storage, 3D image reconstruction, Holographic data storage systems, Image quality
Firstly, this paper introduces the concept of multi-level digital holographic storage. Then, application of digital image processing technology is brought forward in the data restoring process of digital holographic storage. Information in the reconstructed digital images collected from CCD camera is enhanced through digital image processing technology and threshold decision is gone on so as to decreasing bit error ratio of system. Based on above-mentioned ideal, the programming project is designed, which is applicable to binary and multi-level digital holographic storage. Finally, the quality of a binary experimental image is improved through digital image processing program and the accuracy of threshold decision can be improved.
The fracture toughness of high-temperature alloy material under high-temperature is tested with the laser moire interfrometric device. The zero-thickness grating is etched on the surface of test piece by electrochemical method directly, expanding the research space of high-temperature alloy’s moire interferometry. The moire fringe is collected and analyzed by CCD imaging system of computer, the test result that indicates imaging quality and measurement precision of moire interferometry are improved.
KEYWORDS: Digital holography, Holography, Data storage, 3D image reconstruction, Holographic data storage systems, Binary data, Image processing, Image storage, Digital image processing, Remote sensing
This paper brings forward one concept of holographic storage of multi-level digital data at first. It is that each pixel includes more information than 1 bit, which means that a multi-level digital data image provides more information than a binary digital data image with the same pixels. So, the capacity will be increased with this technology. Furthermore, some aspects of holographic storage of multi-level digital data, such as the multi-level coding, storage characters and the quality of the stored image are debated. Finally, we research this holographic storage technology by experiment.
In this paper, the diffractive efficiency in Ce:SBN photorefractive crystal was measured using two-wave coupling light path. The light-induced scattering resistance was gained through observing the transmitted light spot. Furthermore the other holographic storage properties such as the quality of the stored image and preservation time were studied. Finally using Ce:SBN photorefractive crystal as the storage medium, storing and reconstructing the holographic image were realized.
A new technique with a one-step rainbow hologram for recording 2-dimension or 3-dimension images is presented. In this method, not only can we realize to record rainbow hologram in the same recording material with multiplex angles, but also obtain laminated result. The hologram has a low speckle noise and a high diffraction efficiency when it reconstructed with white light.
In this paper, the reconstruction precision of Radon transform iteration based on beam-deflection optical tomography, which is used for 3-D temperature fields, has been studied by computer simulation on the prior knowledge of these fields. As an example, the method has been used to reconstruct the arc temperature fields.
KEYWORDS: Holograms, Signal to noise ratio, Refractive index, Water, Modulators, Image quality, Temperature metrology, Californium, Holography, Signal processing
The experiment has indicated in this paper that dichromated gelatin (DCG) holograms after the first development can be reprocessed. The quality of over exposed of multi-exposed DCG holograms can be improved by reprocessing. This is especially beneficial for the DCG hologram with short developed time in the first development processing.
This paper presents the application of optical epoxy resin as transfer medium to duplicate the relief hologram onto the hard base material. Experiments have been conducted on photo sensitive and thermal sensitive resins in relief hologram duplication. The results have shown that the diffraction efficiency and spatial frequency of the duplicated hologram are approximate to those of the original ones, and its environmental stability is satisfactory. The new one-time transfer duplicating technique, its simple process and low investment offer a practical value in mass-duplicating production.
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