Stability of the determination of the surface impedance of an obstacle   from the scattering amplitude
  We prove a stability estimate of logarithmic type for the inverse problem consisting in the determination of the surface impedance of an obstacle from the scattering amplitude. We present a simple and direct proof which is essentially based on an elliptic Carleman inequality. 
Mourad Bellassoued, Mourad Choulli (LMAM), Aymen Jbalia
math.AP