A True Wiener Filter Implementation for Improving Signal to Noise and Resolution in Acoustic Images

The use of ultrasonic imaging for the detection of flaws is a common non-destructive evaluation (NDE) technique. However, like most imaging techniques, ultrasonic images are degraded by blurring due to practical limitations of the ultrasound system. Consequently, while detection of a flaw may be simple, the characterization of the flaw may be quite difficult. In addition, even the detection of flaws may be challenging because of the presence of correlated noise. Correlated spatial noise is generally the result of inherent structure present in the material and could be more appropriately referred to as ‘unwanted signal’. However, since this is the most dominant image feature which restricts the ability to detect low reflectivity flaws, this unwanted signal will be referred to as ‘noise’.