Enhanced Detection Sensitivity with Pulsed Laser Digital Signal Integration Algorithm

2006 ◽  
Author(s):  
A.C.T. Quah ◽  
J.C.H. Phang ◽  
L.S. Koh ◽  
S.H. Tan ◽  
C.M. Chua
Keyword(s):  
Fault Localization ◽  
Pulsed Laser ◽  
Digital Signal ◽  
Detection Sensitivity ◽  
Signal Integration ◽  
Laser Operation ◽  
Frequency Range ◽  
Integration Algorithm ◽  
Detection Systems ◽  
Lock In

Abstract This paper describes a pulsed laser induced digital signal integration algorithm for pulsed laser operation that is compatible with existing ac-coupled and dc-coupled detection systems for fault localization. This algorithm enhances laser induced detection sensitivity without a lock-in amplifier. The best detection sensitivity is achieved at a pulsing frequency range between 500 Hz to 1.5 kHz. Within this frequency range, the algorithm is capable of achieving more than 9 times enhancement in detection sensitivity.

Combining Refractive Solid Immersion Lens and Pulsed Laser Induced Techniques for Effective Defect Localization on Microprocessors

2008 ◽  
Author(s):  
A.C.T. Quah ◽  
S.H. Goh ◽  
V.K. Ravikumar ◽  
S.L. Phoa ◽  
V. Narang ◽  
...  
Keyword(s):  
Case Studies ◽  
Spatial Resolution ◽  
Failure Modes ◽  
Pulsed Laser ◽  
Detection Algorithm ◽  
Detection Sensitivity ◽  
Solid Immersion Lens ◽  
Defect Localization ◽  
Lock In

Abstract The spatial resolution and sensitivity of laser induced techniques are significantly enhanced by combining refractive solid immersion lens technology and laser pulsing with lock-in detection algorithm. Laser pulsing and lock-in detection enhances the detection sensitivity and removes the ‘tail’ artifacts due to amplifier ac-coupling response. Three case studies on microprocessor devices with different failure modes are presented to show that the enhancements made a difference between successful and unsuccessful defect localization.

Features of vibroacoustic monitoring of pulsed laser operation

2021 ◽  
Author(s):  
Sergey N. Grigoriev ◽  
Petr M. Pivkin ◽  
Ilya V. Minin ◽  
Thein Maung ◽  
Aleksander A. Zelensky ◽  
...  
Keyword(s):  
Pulsed Laser ◽  
Laser Operation

Lock-in regions of laminar flows over a streamwise oscillating circular cylinder

2018 ◽  
Vol 858 ◽  
pp. 315-351 ◽  
Author(s):  
Ki-Ha Kim ◽  
Jung-Il Choi
Keyword(s):  
Circular Cylinder ◽  
Aerodynamic Force ◽  
Lift Coefficient ◽  
Lower Boundary ◽  
Laminar Flows ◽  
Velocity Range ◽  
Frequency Range ◽  
Vortex Pattern ◽  
Moving Cylinder ◽  
Lock In

In this paper, flow over a streamwise oscillating circular cylinder is numerically simulated to examine the effects of the driving amplitude and frequency on the distribution of the lock-in regions in laminar flows. At $Re=100$, lock-in is categorized according to the spectral features of the lift coefficient as two different lock-in phenomena: harmonic and subharmonic lock-in. These lock-in phenomena are represented as maps on the driving amplitude–frequency plane, which have subharmonic lock-in regions and two harmonic lock-in regions. The frequency range of the subharmonic region is shifted to lower frequencies with increasing amplitude, and the lower boundary of this subharmonic region is successfully predicted. A symmetric harmonic region with a symmetric vortex pattern is observed in a certain velocity range for a moving cylinder. Aerodynamic features induced by different flow patterns in each region are presented on the driving amplitude–frequency plane. The lock-in region and aerodynamic features at $Re=200$ and $40$ are compared with the results for $Re=100$. A subharmonic region and two harmonic regions are observed at $Re=200$, and these show the same features as for $Re=100$ at a low driving amplitude. Lock-in at $Re=40$ also shows one subharmonic region and two harmonic regions. However, compared with the $Re=100$ case, the symmetric harmonic lock-in is dominant. The features of aerodynamic force at $Re=200$ and $40$ are represented on a force map, which shows similar characteristics in corresponding regions for the $Re=100$ case.

Establishing a Detection Threshold for Acoustic-Based External Leak Detection Systems

2020 ◽  
Author(s):  
Mathew Bussière ◽  
Mark Stephens ◽  
Marzie Derakhshesh ◽  
Yue Cheng ◽  
Lorne Daniels
Keyword(s):  
Sensitivity Analysis ◽  
Detection Threshold ◽  
Leak Detection ◽  
Detection Sensitivity ◽  
Sensitivity Threshold ◽  
Detection Systems ◽  
Threshold Measure ◽  
Full Scale Tests ◽  
Parameter Values ◽  
Very High

Abstract A better understanding of the sensitivity threshold of external leak detection systems can assist pipeline operators in predicting detection performance for a range of possible leak scenarios, thereby helping them to make more informed decisions regarding procurement and deployment of such systems. The analysis approach described herein was developed to characterize the leak detection sensitivity of select fiber optic cable-based systems that employ Distributed Acoustic Sensing (DAS). The detection sensitivity analysis consisted of two steps. The first step involved identifying a suitable release parameter capable of providing a defensible basis for defining detection sensitivity; the second step involved the application of logistic regression analysis to characterize detection sensitivity as a function of the chosen release parameter. The detection sensitivity analysis described herein provides a means by which to quantitatively determine the leak detection sensitivity threshold for each technology and sensor deployment position evaluated in a set of full-scale tests. The chosen sensitivity threshold measure was the release parameter value associated with release events having a 90% probability of being detected. Thresholds associated with a higher probability level of 95% were also established for comparison purposes. The calculated sensitivity thresholds can be interpreted to mean that release events associated with release parameter values above the sensitivity threshold have a very high likelihood (either 90 or 95%) of being detected.

Waveform digitizer based lock in amplifier using GPU digital signal processing

2019 ◽  
Author(s):  
Alexandre Castonguay ◽  
Romain Deterre ◽  
Muneeb Khalid
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Digital Signal ◽  
Lock In

Rao-Blackwellized Unscented Particle Filter for a Handheld Unexploded Ordnance Geolocation System using IMU/GPS

2011 ◽  
Vol 64 (2) ◽  
pp. 327-340 ◽  
Author(s):  
Jong Ki Lee ◽  
Christopher Jekeli
Keyword(s):  
Particle Filter ◽  
Discrimination Performance ◽  
Sensor Technology ◽  
Unexploded Ordnance ◽  
Integration Algorithm ◽  
Detection Systems ◽  
Positioning Errors ◽  
Unscented Particle Filter ◽  
Electro Magnetic ◽  
Non Gaussian

The existence of Unexploded Ordnance (UXO) is a serious environmental hazard, especially in areas being converted from military to civilian use. The detection and discrimination performance of UXO detectors depends on the sensor technology as well as on the processing methodology that inverts the data to infer UXO. The detection systems, typically electro-magnetic induction (EMI) devices, require very accurate positioning (or geolocation) in order to discriminate candidate UXO from non-hazardous items. For this paper, a hand-held geolocation system based on a tactical-grade IMU, such as the HG1900, was tested in the laboratory over a small, metre-square area in sweep and swing modes. A camera position system was used to emulate GPS or alternative ground-based external ranging systems that control positioning errors. The proposed integration algorithm is a combination of linear filtering (Extended Kalman Filter) and nonlinear, also non-Gaussian filtering (Unscented Particle Filter) in the form of the Rao-Blackwellized Particle Filter (RBPF). The test results show that the position accuracy was improved by applying nonlinear filter-based smoothing techniques in both the straight and curved sections of the sweep and swing trajectories.

Heterodyne Digital Control of a High-Frequency Micromechanical Oscillator

2005 ◽  
Vol 128 (3) ◽  
pp. 577-583 ◽  
Author(s):  
Thomas E. Kriewall ◽  
Joseph L. Garbini ◽  
John A. Sidles ◽  
Jonathan P. Jacky
Keyword(s):  
High Frequency ◽  
Digital Control ◽  
Narrow Band ◽  
Band System ◽  
Digital Signal ◽  
Computational Effort ◽  
Pass Band ◽  
Magnetic Resonance Force Microscopy ◽  
Force Microscopy ◽  
Lock In

In this paper we present heterodyne control as a technique for digital feedback control of a high-frequency, narrowband micromechanical oscillator. In this technique, isolated and synchronized hardware downconversion and upconversion components are used in conjunction with digital signal processing (DSP) to control the oscillator. Heterodyne control offers reduced computational effort for the digital control of high-frequency, narrow band system, the reduction of noise outside the pass-band, and the generation of lock-in amplifier signals. We present heterodyne control with design criteria in the context of magnetic resonance force microscopy (MRFM) cantilever control. Finally, we present experimental results of heterodyne control applied to an emulated radio-frequency microcantilever system.

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