High Accuracy Disbond Thickness Estimation Scheme Employing Multiple-Frequency Near-Field Microwave Measurements

2006 ◽  
Author(s):  
M. A. Abou-Khousa ◽  
R. Zoughi
Keyword(s):  
Near Field ◽  
High Accuracy ◽  
Microwave Measurements ◽  
Multiple Frequency ◽  
Thickness Estimation ◽  
Estimation Scheme

scholarly journals High-accuracy Photonics-assisted Frequency Measurement With Rough-accurate Compensation Based on Mach-Zehnder Interfering and Power Cancellation

2021 ◽  
Author(s):  
Lanfeng Huang ◽  
Yongjun Li ◽  
Shanghong Zhao ◽  
Tao Lin ◽  
Guodong Wang ◽  
...  
Keyword(s):  
Frequency Estimation ◽  
Frequency Measurement ◽  
High Accuracy ◽  
Optical Field ◽  
Comparison Function ◽  
Multiple Frequency ◽  
Frequency Identification ◽  
Mach Zehnder Modulator ◽  
Rf Signal ◽  
Polarization Division Multiplexing

Abstract A high-accuracy photonics-assisted frequency measurement with rough-accurate compensation based on Mach-Zehnder interfering and power cancellation is proposed. A polarization division multiplexing dual-parallel Mach–Zehnder modulator (PDM-DPMZM) is employed to mix the unknown RF signal and sweep signal to optical field. The rough measurement is firstly performed by the interference of a Mach-Zehnder interferometer (MZI) to realize fast frequency estimation. Then, based on the rough measurement result, the accurate measurement based on power cancellation is implemented in a much narrower range, which greatly improves the efficiency of frequency measurement. The simulation results show that the amplitude comparison function (ACF) established by interference can achieve a measurement error of less than 0.3 GHz over 0.5 ~39 GHz. Moreover, thanks to the rough-accurate compensation, the accuracy can be further improved to 4 MHz. Additionally, the multiple frequency identification with a resolution of 10 MHz can also be achieved based on this system.

Body-Segment Orientation Estimation in Rider-Bicycle Interactions With an Un-Calibrated Monocular Camera and Wearable Gyroscopes

2013 ◽  
Author(s):  
Xiang Lu ◽  
Yizhai Zhang ◽  
Kaiyan Yu ◽  
Jingang Yi ◽  
Jingtai Liu
Keyword(s):  
Low Cost ◽  
High Accuracy ◽  
Human Anatomy ◽  
Upper Limbs ◽  
Body Segment ◽  
Orientation Estimation ◽  
Monocular Camera ◽  
Estimation Scheme ◽  
Inertial Measurements ◽  
Segment Orientation

We present a real-time human body-segment (e.g., upper limbs) orientation estimation scheme in rider-bicycle interactions. The estimation scheme is built on the fusion of measurements of an un-calibrated monocular camera on the bicycle and a set of small wearable gyroscopes attached to rider’s upper limbs. The known optical features are conveniently collocated with the gyroscopes. The design of an extended Kalman filter (EKF) to fuse the vision/inertial measurements compensates for the drifting errors by directly integrating gyroscope measurements. The characteristic and constraints from human anatomy and the rider-bicycle interactions are used to enhance the EKF performance. We demonstrate the effectiveness of the estimation design through bicycle riding experiments. The attractive properties of the proposed pose estimation in human-machine interactions include low-cost, high-accuracy, and wearable configurations for outdoor personal activities. Although we only present the application for rider-bicycle interactions, the proposed estimation scheme is readily extended and used for other types of human-machine interactions.

An Improved High-Accuracy CORDIC Algorithm for DSC in Endoscopic Ultrasonography System

2011 ◽  
Vol 130-134 ◽  
pp. 37-40
Author(s):  
Yan Li ◽  
Yun Xia Hao ◽  
Ming Li ◽  
Yi Wang ◽  
Xiao Dong Chen ◽  
...  
Keyword(s):  
Endoscopic Ultrasonography ◽  
Near Field ◽  
Optimization Methods ◽  
High Accuracy ◽  
Cordic Algorithm ◽  
Logic Element ◽  
Imaging Experiment ◽  
Coordinate Rotation ◽  
Coordinate Conversion ◽  
Scan Conversion

An Improved High-Accuracy CORDIC (COordinate Rotation Digital Computer) algorithm for digital scan conversion is presented in this paper to enhance the accuracy and speed of coordinate conversion for Endoscopic Ultrasonography. Several optimization methods are carried out to make coordinate conversion implemented more exactly with fewer resources of FPGA. In the paper, the Cartesian coordinates are re-demarcated to save LE (Logic Element) resources of FPGA. The bit width of data, the scale factor correction and the convergence range are all optimized to improve the accuracy of the algorithm. Further more, a special processing for the near-field data is carried out to reduce the errors of digital scan conversion. With a full pipeline structure implemented on FPGA, the Improved High-Accuracy CORDIC algorithm is validated by both simulation and real-time ultrasound imaging experiment, making the accuracy enhanced and the image quality improved.

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