TY - JOUR
T1 - Characterization of digital waveforms using thermodynamic analogs
T2 - Applications to detection of materials defects
AU - Hughes, Michael S.
AU - Marsh, Jon N.
AU - Hall, Christopher S.
AU - Savéry, David
AU - Lanza, Gregory M.
AU - Wickline, Samuel A.
N1 - Funding Information:
The data used for the materials characterization study was acquired at the Center for Nondestructive Evaluation at Iowa State University (ISU) as part of a project that was funded by the Institute for Physical Research and Technology, also at ISU.
PY - 2005/9
Y1 - 2005/9
N2 - We describe characterization of digital signals using analogs of thermodynamic quantities: the topological entropy, Shannon entropy, thermodynamic energy, partition function, specific heat at constant volume, and an idealized version of Shannon entropy in the limit of digitizing with infinite dynamic range and sampling rate. We show that analysis based on these quantities is capable of detecting differences between digital signals that are undetectable by conventional methods of characterization based on peak-to-peak amplitude or signal energy. We report the results of applying thermodynamic quantities to a problem from nondestructive materials evaluation: detection of foreign objects (FO) embedded near the surface of thin graphite/epoxy laminates using backscattered waveforms obtained by C-scanning the laminate. The characterization problem was to distinguish waveforms acquired from the region containing the FO from those acquired outside. In all cases the thermodynamic analogs exhibit significant increases (up to 20-fold) in contrast and for certain types of FO materials permit detection when energy or amplitude methods fail altogether.
AB - We describe characterization of digital signals using analogs of thermodynamic quantities: the topological entropy, Shannon entropy, thermodynamic energy, partition function, specific heat at constant volume, and an idealized version of Shannon entropy in the limit of digitizing with infinite dynamic range and sampling rate. We show that analysis based on these quantities is capable of detecting differences between digital signals that are undetectable by conventional methods of characterization based on peak-to-peak amplitude or signal energy. We report the results of applying thermodynamic quantities to a problem from nondestructive materials evaluation: detection of foreign objects (FO) embedded near the surface of thin graphite/epoxy laminates using backscattered waveforms obtained by C-scanning the laminate. The characterization problem was to distinguish waveforms acquired from the region containing the FO from those acquired outside. In all cases the thermodynamic analogs exhibit significant increases (up to 20-fold) in contrast and for certain types of FO materials permit detection when energy or amplitude methods fail altogether.
UR - http://www.scopus.com/inward/record.url?scp=27644496167&partnerID=8YFLogxK
U2 - 10.1109/TUFFC.2005.1516028
DO - 10.1109/TUFFC.2005.1516028
M3 - Article
C2 - 16285454
AN - SCOPUS:27644496167
SN - 0885-3010
VL - 52
SP - 1555
EP - 1564
JO - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
JF - IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
IS - 9
ER -