Consistent relaxation matching for handwritten Chinese character recognition

Due to the complexity in structure and the various distortions (translation, rotation, shifting, and deformation) in different writing styles of Handwritten Chinese Characters(HCCs), it is more suitable to use a structural matching algorithm for computer recognition of HCC. Relaxation matching is a powerful technique which can tolerate considerable distortion. However, most relaxation techniques so far developed for Handwritten Chinese Character Recognition (HCCR) are based on a probabilistic relaxation scheme. In this paper, based on local constraint of relaxation labelling and optimization theory, we apply a new relaxation matching technique to handwritten character recognition. From the properties of the compatibility constraints, several rules are devised to guide the design of the compatibility function, which plays an important role in the relaxation process. By parallel use of local contextual information of geometric relaxationship among strokes of two characters, the ambiguity between them can be relaxed iteratively to achieve optimal consistent matching.published_or_final_versio

A deformable elastic matching model for handwritten Chinesecharacter recognition

Conference Theme: Intelligent Systems for the 21st CenturyThis paper describes a deformable elastic matching approach to handwritten Chinese character recognition (HCCR). Handwritten character is regarded as a kind of deformable object, with elastic property. For the same category of character, we assume that different handwriting variations share the same topological structure, but may differ in shape details. The variations between different handwriting characters are modelled by a set of stroke displacement vectors (SDV). According to the SDV derived, a model character is deformed gradually, in an effort to transform itself much closer to an input character. Experiments show that the proposed elastic matching model can efficiently deal with local shape changes and variations between characters.published_or_final_versio

Holographic fabrication of diamondlike photonic crystal template using two-dimensional diffractive optical elements

This letter demonstrates holographic fabrication of three-dimensional diamondlike photonic crystal templates in SU8 photoresist using a single diffractive optical element. Five coherent laser beams produced by a two-dimensional phase mask were used to construct face-centered-cubic or tetragonal interference patterns. The superposition of two interference patterns through double exposures yields diamondlike photonic crystal templates in SU8. Photonic bandgap calculation reveals a full bandgap in inverse structures based on the template. The utilization of the two-dimensional phase mask simplifies the fabrication configuration in multiple beam holographic lithography for three-dimensional photonic fabrication. © 2008 American Institute of Physics

Development of domestic and international computer forensics

With the increasing of computer crime, instant emergence of new digital product, new computer technology and computer forensics technology is promoted, developed constantly. This paper described basic information/content of computer forensics, and elaborated the development of current computer forensics at domestic and overseas market. The trends of computer forensics are pointed out and recent hot topics of research are introduced. © 2011 IEEE.published_or_final_versionThe 7th International Conference on Intelligent Information Hiding and Multimedia Signal Processing (IIH-MSP 2011), Dalian, China, 14-16 October 2011. In Proceedings of the 7th IIH-MSP, 2011, p. 388-39

Photonic crystals with defect structures fabricated through a combination of holographic lithography and two-photon lithography

This paper presents the capability of direct laser writing of complex defect structures in holographically formed three-dimensional photonic crystals in dipentaerythritol penta/hexaacrylate (DPHPA) monomers mixed with photoinitiators. The three-dimensional photonic crystal template was fabricated through prism-based holographic lithography. Defect structures are fabricated through the two-photon polymerization excited by a femtosecond laser. The strengths of two optical lithographic techniques are combined with holographic lithography providing a rapid and large area microfabrication and two-photon lithography providing flexibility in fabrication of defect structures. The optical fabrication process is simplified in the negative tone DPHPA without prebake and postexposure bake as is required of SU-8 while maintaining a capability for constructing photonic structures with small features. © 2010 American Institute of Physics

Cryogenic fluid level sensors multiplexed by frequency-shifted interferometry

We present a liquid level sensing system for cryogenic fluids based on an array of aluminum-coated fiber Bragg gratings written in high-attenuation fibers (HAFs) interrogated by frequency-shifted interferometry (FSI). The sensors are heated up optically through the absorption of light at the core of the HAF sections. The distinct thermal response of sensors in the liquid from that in the gas provides an unambiguous means to detect the liquid level. FSI allows the sensors to have overlapped spectral response, and, therefore, has the potential of accommodating a larger number of sensors in the array. The measurement of liquid nitrogen level using this system was experimentally demonstrated. The successful combination of aluminum-coated HAF Bragg grating sensors and the FSI technique promises a viable solution for liquid level sensor networks at cryogenic temperatures. © 2010 Optical Society of America

Holographic fabrication of photonic crystals using multidimensional phase masks

This paper reports the experimental approaches to the fabrication of two-layer integrated phase masks and the fabrication of photonic crystal templates using the phase mask based on holographic lithography technique. The photonic crystal template is formed by exposing photoresist mixtures to five-beam interference patterns generated through the phase mask. The fabricated phase mask consists of two layers of orthogonally oriented gratings produced in a liquid crystal and photoresist mixture. A polymerization-induced phase separation preserves the grating structure during the exposure. The vertical spatial separation between two layers of gratings produces a phase difference among diffracted laser beams, which enables the holographic fabrication of diamondlike photonic crystal structures. The fabricated photonic crystal structure is consistent with simulations based on the five-beam interference. The two-layer phase mask opens up an opportunity of direct printing photonic structures. © 2008 American Institute of Physics

Self-heated fiber Bragg grating sensors

This letter demonstrates an approach for tuning fiber Bragg grating sensors with optical energy carried in the same optical fiber. Optical energy carried in the optical fiber was used to heat in-fiber Bragg gratings in order to alter the grating's optical response to surrounding media. The functional enhancement of optically heated Bragg gratings as sensor devices is demonstrated by a dual-function Bragg grating temperature and level sensing array for liquid at room and cryogenic temperatures. © 2005 American Institute of Physics

Five beam holographic lithography for simultaneous fabrication of three dimensional photonic crystal templates and line defects using phase tunable diffractive optical element

This paper demonstrates an approach for laser holographic patterning of three-dimensional photonic lattice structures using a single diffractive optical element. The diffractive optical element is fabricated by recording gratings in a photosensitive polymer using a two-beam interference method and has four diffraction gratings oriented with four-fold symmetry around a central opening. Four first-order diffracted beams from the gratings and one non-diffracted central beam overlap and form a threedimensional interference pattern. The phase of one side beam is delayed by inserting a thin piece of microscope glass slide into the beam. By rotating the glass slide, thus tuning the phase of the side beam, the five beam interference pattern changes from face-center tetragonal symmetry into diamond-like lattice symmetry with an optimal bandgap. Three-dimensional photonic crystal templates are produced in a photoresist and show the phase tuning effect for bandgap optimization. Furthermore, by integrating an amplitude mask in the central opening, line defects are produced within the photonic crystal template. This paper presents the first experimental demonstration on the holographic fabrication approach of three-dimensional photonic crystal templates with functional defects by a single laser exposure using a single optical element. ©2009 Optical Society of America

A tunable three layer phase mask for single laser exposure 3D photonic crystal generations: bandgap simulation and holographic fabrication

Through the use of a multi-layer phase mask to produce five-beam interference, three-dimensional photonic crystals can be formed through single exposure to a photoresist. In these holographically formed structures, the interconnectivity is controlled by the relative phase difference among contributing beams. Photonic band gaps are calculated and the simulation shows a maximum bandgap of 18% of the middle gap frequency when the phase difference is optimized. A three-layer phase mask is fabricated by placing a spacer layer between two orthogonally-orientated gratings. The phase difference is controlled by thermal-tuning of the spacer thickness. Photonic crystal templates are holographically fabricated in a photosensitive polymer using the phase mask