Feature Extraction and Image Processing

Basic image processing operations 95

This is one of the known properties of median filtering: an ability to reduce noise whilst

retaining feature boundaries. Indeed, there have actually been many other approaches to

speckle filtering; the most popular include direct averaging (Shankar, 1986), median filtering,

adaptive (weighted) median filtering (Loupas, 1987) and unsharp masking (Bamber, 1986).

3.5.4 Comparison of statistical operators

The different image filtering operators are shown by way of comparison in Figure 3.25. All

operators are 5 5 and are applied to the earlier ultrasound image, Figure 3.24(a). Figure

3.25(a), (b), (c), and (d) are the ...