Subsurface Diagnosis With Time-Lapse GPR Slices and Change Detection Algorithms

Detection and determination of groundwater contamination plume using time-lapse electrical resistivity tomography (ERT) method

Protection of water resources from contamination and detection of the contaminants and their treatments are among the essential issues in the management of water resources. In this work, the time-lapse electrical resistivity tomography (ERT) surveys were conducted along 7 longitudinal lines in the downstream of the Latian dam in Jajrood (Iran), in order to detect the contamination resulting fro...

Time-lapse travel time change of multiply scattered acoustic waves

Existing techniques in correlation spectroscopy, such as coda wave interferometry and diffusing acoustic wave spectroscopy, determine the average motion of scatterers or change in the propagation velocity from the temporal change of multiply scattered sound. However, neither of them gives an indication of the spatial extent of the change in the medium. This study is an extension of the techniqu...

Nasopharyngeal carcinoma---time lapse before diagnosis and treatment.

This is a descriptive study of 168 patients with nasopharyngeal carcinoma who were referred to public oncology departments for primary treatment between July and September 1996. The mean duration from the onset of the symptoms to histological diagnosis was 5.0 months; the duration ranged from 6.1 months (for patients presenting with nasal symptoms) to 1.8 months (for those with cranial nerve dy...

Change Detection Algorithms

GPR based soil electromagnetic parameters determination for subsurface imaging

The problem of estimating the dielectric permittivity and the electric conductivity of the soil starting from GPR measurements is addressed. A new estimation procedure is proposed and checked against synthetic data generated by a FDTD forward solver. A two-dimensional geometry and a two-layered background medium are considered.