Spatial and Time Patterns Extraction of Eddy Current Pulsed Thermography Using Blind Source Separation

Eddy current pulsed thermography (ECPT), a new emerging nondestructive testing and evaluation (NDT&E) technique, has been applied for a wide range of conductive materials. The acquired image sequences contain valuable information in both spatial and time domain. ECPT techniques mainly use a specific frame to detect and quantify the defects. However, selection of specific frame from transient thermal image video to maximize the contrast of thermal variation and defect pattern from complex geometrical samples remain a challenge. In order to accurately find anomalous patterns from the transient thermal pattern for defect detection and further quantitative NDE, this paper employs a single channel blind source separation algorithm. This method enables spatial and time patterns to be extracted according to the whole transient response behavior without any training knowledge. In this paper, both mathematical and physical models are discussed, and the basis of the proper selection of contrast image is given. In addition, the artificial slot and thermal fatigue natural crack are applied to validate the proposed method.

[1]  Beate Oswald-Tranta,et al.  Thermo-Inductive Surface Crack Detection in Metallic Materials , 2006 .

[2]  Te-Won Lee,et al.  A Maximum Likelihood Approach to Single-channel Source Separation , 2003, J. Mach. Learn. Res..

[3]  W. L. Woo,et al.  Single-Channel Source Separation Using EMD-Subband Variable Regularized Sparse Features , 2011, IEEE Transactions on Audio, Speech, and Language Processing.

[4]  James Demmel,et al.  Accurate Singular Values of Bidiagonal Matrices , 1990, SIAM J. Sci. Comput..

[5]  Krishnendu Chatterjee,et al.  Image Enhancement in Transient Lock-In Thermography Through Time Series Reconstruction and Spatial Slope Correction , 2012, IEEE Transactions on Instrumentation and Measurement.

[6]  P. Cawley,et al.  Eddy-current induced thermography—probability of detection study of small fatigue cracks in steel, titanium and nickel-based superalloy , 2012 .

[7]  Lichun Feng,et al.  Specified value based defect depth prediction using pulsed thermography , 2012 .

[8]  D. Almond,et al.  Transient thermography in the assessment of defects of aircraft composites , 2003 .

[9]  Gui Yun Tian,et al.  Modelling and evaluation of eddy current stimulated thermography , 2010 .

[10]  Takahide Sakagami,et al.  Development of a New Crack Identification Technique Based on Near-Tip Singular Electrothermal Field Measured by Lock-in Infrared Thermography , 2001 .

[11]  W. L. Woo,et al.  Physical interpretation and separation of eddy current pulsed thermography , 2013 .

[12]  Nik Rajic,et al.  Principal component thermography for flaw contrast enhancement and flaw depth characterisation in composite structures , 2002 .

[13]  Gui Yun Tian,et al.  Stress Measurement Using Pulsed Eddy Current Thermography , 2012 .

[14]  Ermanno G. Grinzato,et al.  Statistical analysis of IR thermographic sequences by PCA , 2004 .

[15]  Feilu Luo,et al.  Defect characterisation based on heat diffusion using induction thermography testing. , 2012, The Review of scientific instruments.

[16]  G. Tian,et al.  Surface Crack Detection for Carbon Fiber Reinforced Plastic (CFRP) Materials Using Pulsed Eddy Current Thermography , 2011, IEEE Sensors Journal.

[17]  Erkki Oja,et al.  Independent Component Analysis , 2001 .

[18]  Otwin Breitenstein,et al.  Localization of gate oxide integrity defects in silicon metal-oxide-semiconductor structures with lock-in IR thermography , 2000 .

[19]  S. Marinetti,et al.  Pulse phase infrared thermography , 1996 .

[20]  N. Ganesan,et al.  Simultaneous Estimation of Electrical and Thermal Properties of Isotropic Material from the Tone-Burst Eddy Current Thermography (TBET) Time–Temperature Data , 2011, IEEE Transactions on Magnetics.

[21]  Ravibabu Mulaveesala,et al.  Three-Dimensional Pulse Compression for Infrared Nondestructive Testing , 2009 .

[22]  J.I. Mars,et al.  A Source Separation Technique for Processing of Thermometric Data From Fiber-Optic DTS Measurements for Water Leakage Identification in Dikes , 2008, IEEE Sensors Journal.

[23]  W. Arnold,et al.  MECHANISMS AND MODELS FOR CRACK DETECTION WITH INDUCTION THERMOGRAPHY , 2008 .

[24]  C. Meola.  Nondestructive Evaluation of Materials With Rear Heating Lock-In Thermography , 2007, IEEE Sensors Journal.

[25]  Wilhelm Satzger,et al.  Thermographic crack detection by eddy current excitation , 2007 .

[26]  Gui Yun Tian,et al.  PEC thermography for imaging multiple cracks from rolling contact fatigue , 2011 .

[27]  M.E. Davies,et al.  Source separation using single channel ICA , 2007, Signal Process..