In order to achieve precise pointing and high-resolution imaging, acquisition, tracking and pointing (ATP) system is usually required to stabilize the line-of-sight (LOS) within arc-second or even higher level. In case of ATP system mounted on moving platform, broadband angular disturbance is the most serious factor to prevent the LOS being stabilized. Due to the limited sampling frequency of detectors, the angular disturbance is usually mitigated by incorporating inertial stabilized platform (ISP) and fast steering mirror (FSM) into ATP system. The need for small, inexpensive inertial angular rate sensors(ARSs), which may be employed in these devices to measure angular jitter at sufficiently wide bandwidth, is urgent. However, there is no single angular rate sensor (ARS) currently available that could measure angular jitter from DC to hundreds of hertz while maintaining comparable accuracy. Multi-sensor fusion is a practical solution to broadband angular jitter measurement for the purpose of jitter control. In this paper, the measurements from Magnetohydrodynamics (MHD) ARS and MEMS gyro are blended together using closed-loop fusion (CLF) method. The approach does not rely on accurate models or transfer functions of sensors, and meanwhile, can be easily implemented in real-time system. Experimental results indicate that the measuring bandwidth of CLF method is within overall frequency range covered by MHD ARS and MEMS gyro.
Adaptive kernelized correlation Filter (AKCF) approach is designed to achieve an accurate and stable tracking for the moving target with fast motion and background clutter. The proposed algorithm combines the advantages of adaptive threshold selection method and KCF algorithm. The adaptive threshold selection method can automatically select the appropriate threshold according to the size of the object in the image. The accuracy of KCF algorithm is improved by adaptive threshold selection method. The performance of AKCF is verified by some publicly available benchmark video sequences. The experiment results demonstrate that the proposed approach which has the performance accuracy and stability can effectively realize the stable tracking for fast moving target.
A novel optical accelerometer based on laser self-mixing effect is presented and experimentally demonstrated, which
consists of a mass-loaded elastic-beam assembly and laser self-mixing interferometer. Under external acceleration, an
inertial force is applied to the mass, flexible beams deflect from their equilibrium position. The deflection can be read
out by the self-mixing interferometer. In order to reduce the impact of higher harmonic, wavelet analysis is introduced to
remove singular points. Preliminary results indicate that the resolution is 0.19μg/Hz1/2 within a bandwidth of 100Hz. The
optical accelerometer has the potential to achieve high-precision, compact accelerometers.
A numerical method is investigated to design gradient-index (GRIN) fiber probes. The GRIN fiber probe is composed of
a single mode fiber (SMF), a no-core fiber (NCF), and a GRIN fiber lens. The optical software GLAD is adopted to
simulate the optical performance of the probe. The simulation results show that, given the length of the GRIN fiber lens
0.1mm and the length of the NCF 0.36mm, the working distance is 0.73mm and the focus spot size 33μm, which are well
agreement with the experimental data. As a result, the proposed numerical method is validated to be effective to design
such GRIN fiber probes.
The objective of this paper is to find a method to design an active multichannel silicon microelectrode which is used to measure the neural signal. A circuit model when measuring the neural signal using the silicon microelectrode is proposed based on the structure and fabrication process of the microelectrode. The method of determining the dimensional parameters of the probe shank is discussed in the following three aspects: the structure of pallium and endocranium, efficient, coupled interconnects noise and strength characteristic of neural probe. The design criterion is to minimize the size of the neural probe and increase its stiffness to pierce the endocranium. The on-chip unity-gain bandpass amplifier has an overall gain of 40 over a bandwidth from 60Hz to 10 kHz; an input loadits resistance is designed to be above 30MΩ to guarantee a cutoff frequency below 100 Hz.
Proc. SPIE. 5633, Advanced Materials and Devices for Sensing and Imaging II
KEYWORDS: Mirrors, Beam splitters, Interferometers, Control systems, Artificial neural networks, Control systems design, Systems modeling, Device simulation, Beam controllers, Laser systems engineering
Laser tracking method for space coordinates measurement is a newly developed technique that possesses the characteristics of high accuracy, large measuring range, flexible and dynamic measurement and so on. Laser tracking interferometer system based on this method has become an important measuring tool in many industrial fields. However, the control system sometimes acts nonlinearly because of long-range measurement and various applications. To solve this problem, artificial neural network (ANN) controller is introduced as an advanced adaptive control configuration in laser tracking interferometer system. The reason is that artificial neural network which is an important branch of intelligent control area has great potential ability in dealing with high nonlinearity and indeterminate factors. Then the simulation of tracking control system based on either conventional PID controller or ANN controller is carried out separately and the result of comparison is given.
An on-line operation of micro-spectrometer and liquid drop analyzer is proposed in this paper. Comparing with a full spectral range spectrometer system, a micro-spectrometer has narrow spectral range that results in its inefficiency or inability in qualitative analysis of a mixed liquid since more than one function group of the mixed liquid might cause a peak or valley in the spectrogram at almost the same wavelength. A liquid drop analyzer (LDA) is an instrument that detects the characters of a liquid by monitoring its drop forming process. The LDA gives a fingerprint that is unique for certain liquid due to its specific chemical, physical and mechanical characters. An approach of combining micro-spectrometer with a fiber drop analyzer, by which a virtual 3D liquid fingerprint is formed, is described and it functions like a full range spectrum. The signals obtained from the micro-spectrometer and liquid drop analyzer, the method of on-line operation and database setting up, the experimental device and test results are described and discussed in the paper.