  Electrical Resistivity Tomography (ERT) has become widely used for
engineering and environmental applications in the last couple of decades due to
(1) the simplification and automating of resistivity meters and (2) the new
generation of inversion software. Although the initial domain of application
remain relevant today, these techniques are increasingly used for deep
investigation and shallow environmental/geotechnical applications. These new
applications involve working with complex resistivity, which can be measured in
the time domain (TDIP: Time Domain Induce Polarization) or frequency domain
(SIP: Spectral Induce Polarization). The new algorithm could process data in
time and frequency domain. The first step is to estimate the no linear
self-potential in order to remove it. Second step is to compute resistivity and
chargeability in time or frequency domain. The results show that the
improvement of the processing is weak for the resistivity and for no noisy data
but we have a better estimation of chargeability. The correlation highlight a
good correlation between calculated out-phasing (in frequency domain) and
chargeability (in time domain).
