In order to explore the key factors of the SPR effect, such as sensitive material, thickness of sensitive metal film, incident angle and wavelength, especially the affection of the incident light wavelength on the modulated reflectivity, calculations and analyses are carried out in this paper. Simulation results show that Ag has the lowest reflectivity when the incident light with shorter wavelength in visible wave band, Au has the lowest reflectivity with red light, and Cu has the best effect from 600 nm to infrared band. The ranges of thickness measurement for thin films can be obtained when the light source wavelength and incidence angle are fixed with the adopted metal sensitive material. Moreover, there is a special range of incidence angle that can put up a significant SPR effect phenomenon when there are definite metal films and wavelength of incident light.
A guided-wave surface plasmon resonance based sensor using graphene layer for detect the biomolecules has been analyzed. The use of waveguide layer between the gold film and graphene significantly improves the penetration depth and increases the sensitivity, then graphene layer is used to enhance the adsorption of the biomolecules. The thickness and materials of waveguide layer along with the number of graphene layer have been optimized to achieve the best performance of the sensor in terms of sensitivity. The highest sensitivity with 228.8°/RIU is obtained for visible wavelength with optimized thickness of gold and waveguide layer as 45nm and 10nm respectively while the materials of waveguide layer is chosen as zinc oxide and the optimum number of graphene layers is 2.We believe that this sensor could find potential applications in biological detection.
In this paper, the impacts of surface plasmon resonance (SPR) on the angular spin splitting of light are investigated theoretically. The expression for the angular spin splitting shifts is derived, and the angular shifts as the function of the angle of incidence under different metal film thicknesses are calculated. The simulation results manifest that the angular spin splitting is significantly enhanced when surface plasmons are strongly excited. Under the optimal parameter conditions, the largest angular shift is up to 4.493×10-5 rad. It is also found that the directions of spatial propagation of photons in the out-of-plane can be switched by adjusting the angle of incidence under certain conditions. These findings may provide a new way for photon manipulation and open another possibility for the development of new nano-photonic devices.
Several light incisions brought up when the large size workpiece was scanned along the cross-section
by laser light structure sensors. Since discrete points of each light incision were fitted to elliptic curve, 3D
coordinates of the center of the light incision plane could be attained. With the space line fitting and error
examination algorithm, the large cross-section workpiece straightness was gained, and the geometry of
cross-section could be calculated. This paper brought forward the method and mathematics model of straightness
measurement of the large-size workpiece by laser vision, and experiment result was also given out.
KEYWORDS: Digital signal processing, System identification, Image processing, Sensors, Fingerprint recognition, Biometrics, Signal processing, Imaging systems, Data acquisition, Embedded systems
The paper presents an optimized design method for a flexible and economical embedded DSP system that can implement complex processing algorithms as biometric recognition, real-time image processing, etc. It consists of a floating-point DSP, 512 Kbytes data RAM, 1 Mbytes FLASH program memory, a CPLD for achieving flexible logic control of input channel and a RS-485 transceiver for local network communication. Because of employing a high performance-price ratio DSP TMS320C6712 and a large FLASH in the design, this system permits loading and performing complex algorithms with little algorithm optimization and code reduction. The CPLD provides flexible logic control for the whole DSP board, especially in input channel, and allows convenient interface between different sensors and DSP system. The transceiver circuit can transfer data between DSP and host computer. In the paper, some key technologies are also introduced which make the whole system work efficiently. Because of the characters referred above, the hardware is a perfect flat for multi-channel data collection, image processing, and other signal processing with high performance and adaptability. The application section of this paper presents how this hardware is adapted for the biometric identification system with high identification precision. The result reveals that this hardware is easy to interface with a CMOS imager and is capable of carrying out complex biometric identification algorithms, which require real-time process.
The paper presents a new embedded sensor method of non-contact automatic route-finding and route-tracing for stepped robot. The final system is designed and integrated into a single hardware PCB with size of 30x30x15 mm3. A line scanning charge couple device (CCD) with 1024 pixels is used to obtain the plane scene of route, and a pair of infrared LED is employed to provide the illumination of the route-finder. Moreover, this route-finder still includes a micro lens, CCD driver, instrumentation pre-amplifier, edge extracting circuit, FPGA circuit for position measure and logic control, direction and state display of the route-finder by LED, moving direction control pins output and power manage circuits. The router-finder for stepped robot has the advantages of simple and fast operation, easy assembly with robot, small volume, high sensitivity and precision for route-finding and tracing. The paper outlines in detail the principle of the route-finding and tracing by edge extraction and edge position measure using a CCD image sensor with a micro lens assisted by infrared illumination and a FPGA circuit. Some relational edge extraction and measure algorithms suitable for embedded system with FPGA are introduced in the paper too. Finally, the actual experiment results are given.
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