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Yu X.-H.,CAS Xian Institute of Optics and Precision Mechanic | Yao B.-L.,CAS Xian Institute of Optics and Precision Mechanic | Li X.-Y.,Security Printing Institute of Peoples Bank of China | Liu S.-L.,Security Printing Institute of Peoples Bank of China | And 8 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2015

Upon excitation of high intensity linearly polarized femtosecond laser, a blue-shifted two-photon induced photoproduct named F540 state with permanent photo-induced anisotropy is observed in bacteriorhodopsin (BR) films. Based on the F-state, permanent optical data storage can be realized with spatial field modulation of femtosecond laser. By using a phase-only spatial light modulator to modulate the spatial phase distribution of the incident femtosecond laser beam, we generate spot-patterns in the focal plane of the microscopic objective lens, and the patterns are recorded in the BR film. At the same time, by varying the polarization direction of the excitation laser beam, polarization-multiplexed optical data storage in the BR film is demonstrated, which is applicable to high-density optical data storage and optical information encryption. © 2015 Chinese Physical Society. Source


Jian Z.,Security Printing Institute of Peoples Bank of China | Qin Q.,Security Printing Institute of Peoples Bank of China | Li F.,Security Printing Institute of Peoples Bank of China | Feng Z.,Security Printing Institute of Peoples Bank of China | And 2 more authors.
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

In high-speed banknote sorting system, to real-time deal with massive data and complex algorithm is required. This paper proposes an embedded processing system, which realizing the high-speed image acquisition and real-time processing of banknote image. The system is a customized and flexible architecture consisting of one large scale FPGA and four high performance DSP chips. The five processors have good communication with each other by RapidIO BUS. After evaluating the system-calculating overhead, the data throughput, and the hardware characteristics, we presents the whole processing program systematically running in FPGA and DSPs. In order to make full use of the advantage of FPGA highly parallelism and DSP deeply pipeline, the FPGA is designed for running parallel algorithms with large amount of calculation but low complexity of control flow, and the rest of algorithms are assigned to the four DSPs relatively. Finally, the whole program of image processing at the speed of 40 frames per second is realized on the embedded processing platform. The system has been successfully used in high-speed banknote sorting device, which has showed stable and reliable properties. And it also has excellent performance in processing ability with the verification of large scale operation. © 2013 SPIE. Source


Zhou J.,Beihang University | Ke G.,Security Printing Institute of Peoples Bank of China | Wang B.,Security Printing Institute of Peoples Bank of China | Liu W.,Security Printing Institute of Peoples Bank of China | Li R.,Beihang University
Key Engineering Materials | Year: 2010

The paper reports the methods for making a novel optical device consisted of photo alignment nematic liquid crystal films and polarizers. The color shift of the device depends on not only the viewing angle but also the viewing orientation. The retardation and intensity of the reflected light are theoretically calculated on the basis of Jones Matrix, and a spectral-RGB transition program is introduced to display colorful results directly. The theoretical results show excellent agreement with experimental data. It is an effective method for predicting interference color and optimizing key parameters of the device. The device can be used to protect valuable documents against fraud because of its special optical variable effects which is caused by interference of polarized light. © (2010) Trans Tech Publications. Source


Zhou J.,Beihang University | Zhou J.,Security Printing Institute of Peoples Bank of China | Ke G.,Security Printing Institute of Peoples Bank of China | Wang B.,Security Printing Institute of Peoples Bank of China | And 3 more authors.
Optical Engineering | Year: 2011

A liquid crystal optically variable device (LCOVD) was fabricated by linearly polarized photoalignment technique. The device is composed of a nematic liquid crystal layer on the polyethylene terephthalate (PET) substrate and two parallel polarizers. By continuously changing the polarization direction during photoalignment, the optical axes of the liquid crystal can be variably aligned. We measured the colors and transmission spectra of the LCOVD at different observing angles. The results indicate that the colors of the device distribute continuously. The colors shift to others with the changing of the observing positions, and such color shift phenomenon depends not only on the observing inclination angle but also the azimuth angle. Furthermore, a calculation method based on the Jones matrix for simulating the performance of the LCOVD was established. The theoretical results show good agreement with the experiment. Because of the distinctive optical features, one highly significant application of the LCOVD may be its use for improving document security. © 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). Source


Qin Q.W.,Security Printing Institute of Peoples Bank of China | Zhang J.,Security Printing Institute of Peoples Bank of China | Feng Z.G.,Security Printing Institute of Peoples Bank of China | Feng L.,Security Printing Institute of Peoples Bank of China | Sui J.H.,Security Printing Institute of Peoples Bank of China
Applied Mechanics and Materials | Year: 2013

To the banknote sorting system, application of large-scale high-performance FPGA can help to conduct high speed capture and processing of banknote color images. In line with the detection algorithm, the real-time-captured image upon color-space conversion needs to be compared in the four color channels of LGAB with the template images so as to work out the checking results. With Xilinx soft IP core MPMC, two sets of multiport video interface controllers have been designed, each of which embraces four ways of video data read-write operation; the controller interface parameters can be configured via the DSP interface, with the process flow control based on the image frame synchronizing signal. Tests conducted show that the controllers with flexible configurations boast of reliable performance and now are reputed for proven application to large banknote sorting equipment. © (2013) Trans Tech Publications, Switzerland. Source

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