Search results for "Pattern recognition"
showing 10 items of 2301 documents
Evaluating creep in metals by grain boundary extraction using directional wavelets and mathematical morphology
2001
Abstract It is economically important for manufacturers of high-temperature machines to be able to measure creep so that they can predict residual service life more accurately. This paper describes and refines an image analysis method for evaluating creep in laboratory test pieces. It is a preliminary study of how to extract relevant information for creep measurement by cavities counting. Sample preparation for quantification by image analysis is an important step determining the further development of the image analysis technique. Grain boundary extraction, which is directional information, is the major question to be overcome before measurement can be automated. The search for a crest-lin…
Fuzzy predictive controller design using ant colony optimization algorithm
2014
In this paper, an approach for designing an adaptive fuzzy model predictive control (AFMPC) based on the Ant Colony Optimization (ACO) is studied. On-line adaptive fuzzy identification is used to identify the system parameters. These parameters are used to calculate the objective function based on predictive approach and structure of RST control. The optimization problem is solved based on an ACO algorithm, used at the optimization process in AFMPC to calculate a sequence of future RST control actions. The obtained simulation results show that proposed approach provides better results compared with Proportional Integral-Ant Colony Optimization (PI-ACO) controller and adaptive fuzzy model pr…
Linear parameter‐varying modelling and control of an offshore wind turbine with constrained information
2014
This study deals with linear parameter-varying modelling and output-feedback H ∞ control design for an offshore wind turbine. The controller is designed with consideration that not all the information in the feedback loop will be used. This constraint is incorporated into the design procedure. Constrained information means that a special zero-non-zero pattern is forced upon the gain matrix. The constrained controller is obtained based on parameter-dependent Lyapunov functions and formulated in terms of linear-matrix inequalities. Since the functions are dependent on the wind speed and accurate wind speed measurements are rarely available in practice, an extended Kalman filter is used to est…
Vibration control for adjacent structures using local state information
2014
In this paper, a novel strategy for structural vibration control of multi-structure systems is presented. This strategy pays particular attention to mitigating negative interstructure interactions. Moreover, it is based on recent advances in static output–feedback control, which make possible the efficient computation of decentralized velocity-feedback controllers by solving a single-step optimization problem with Linear Matrix Inequality constraints. To illustrate the main ideas, a local velocity-feedback energy-to-peak controller is designed for the seismic protection of a two-building system. This controller is remarkably effective and extremely simple. Moreover, it can also be implement…
Design of a configurable multispectral imaging system based on an AOTF.
2011
In this paper, we present a configurable multispectral imaging system based on an acousto-optic tunable filter (AOTF). Typically, AOTFs are used to filter a single wavelength at a time, but thanks to the use of a versatile sweeping frequency generator implemented with a direct digital synthesizer, the imager may capture a configurable spectral range. Experimental results show a good spectral and imaging response of the system for spectral bandwidth up to a 50 nm.
Hybrid Procedure for Automated Detection of Cracking with 3D Pavement Data
2016
Pavement cracks are considered a major indicator of pavement performance. Because traditional manual crack surveys are dangerous, time consuming, and expensive, technologies have been developed to collect high-speed pavement images, and numerous algorithms have been proposed to detect cracks on pavement surface. The latest PaveVision3D Ultra system (3D Ultra) has been implemented to achieve 30-kHz three-dimensional (3D) scanning rate for 1-mm resolution pavement surface data at highway speed up to 100 km/h (60 mi/h). This paper presents the application of a hybrid procedure for automated crack detection on 3D pavement data collected using 3D Ultra. The procedure combines three different me…
Two-stage procedure based on smoothed ensembles of neural networks applied to weed detection in orange groves
2014
The potential impacts of herbicide utilization compel producers to use new methods of weed control. The problem of how to reduce the amount of herbicide and yet maintain crop production has stimulated many researchers to study selective herbicide application. The key of selective herbicide application is how to discriminate the weed areas efficiently. We introduce a procedure for weed detection in orange groves which consists of two different stages. In the first stage, the main features in an image of the grove are determined (Trees, Trunks, Soil and Sky). In the second, the weeds are detected only in those areas which were determined as Soil in the first stage. Due to the characteristics …
Data-driven design of robust fault detection system for wind turbines
2014
Abstract In this paper, a robust data-driven fault detection approach is proposed with application to a wind turbine benchmark. The main challenges of the wind turbine fault detection lie in its nonlinearity, unknown disturbances as well as significant measurement noise. To overcome these difficulties, a data-driven fault detection scheme is proposed with robust residual generators directly constructed from available process data. A performance index and an optimization criterion are proposed to achieve the robustness of the residual signals related to the disturbances. For the residual evaluation, a proper evaluation approach as well as a suitable decision logic is given to make a correct …
A computer‐aided instrument for pattern recognition of partial discharges
1998
In this paper a new computer‐aided digital system for partial discharge (PD) measurements is presented. The system is able to collect a great number of data, up to a pulse repetition rate of 100kHz, during the acquisition phase, thus allowing an off‐line analysis of PD data. After a description of the instrument, some experimental tests performed on epoxy specimens are here presented in terms of amplitude, phase and energy resolved histograms. Finally, emphasis is given to the very interesting use of the instrument for pattern recognition techniques in the discrimination and classification of discharges in HV components.
Phase imaging via compressive sensing
2013
This communication develops a novel framework for phase imaging at optical wavelength by merging digital lenless phase-shifting holography with single-pixel optical imaging based on compressive sensing.