U. Qidwai et Ch. Chen, Blind enhancement for ultrasonic C-scans using recursive 2-D H-infinity-based state estimation and filtering, INSIGHT, 42(11), 2000, pp. 737-741
The main purpose of any image enhancement scheme is to improve the quality
of image in such a way that more information is available for the observer.
Ultrasonic C-scans, which are commonly used in non-destructive evaluation
of material, are a special form of images that suffer from blurring effects
due to the quantisation in the scanning grid, squaring and windowing opera
tions, and additive noise. A software approach is presented in this work wh
ich utilises the 2-D H-infinity Estimation and Filtering theories to enhanc
e the ultrasonic C-scans. The states in the mathematical formulation are se
lected as the neighbouring pixels in an image and the blur components as th
e system matrix coefficients. Repetitive application of estimator and filte
r on successive images results in an overall improved image.