In ultrasonic nondestructive evaluation (NDE), flaw characterization is inhibited by the effects of the measurement system and by acoustic noise due to non-flaw related scattering of the sound. The Wiener filter can be formulated to optimally remove the effects of the measurement system and suppress the noise; however, prior information must be available about the noise and flaw distributions, respectively. The objective of this research is to develop an approach for the optimal implementation of the Wiener filter given prior noise information but no prior flaw information.