3.4.2.1 Smooth Filter

The smooth filter is a spatial filter that applies a 2D Gaussian function to compute weighted average about the square kernel centered about a given pixel. The effect of the Gaussian function is smoothing of high-frequency elements (for example, sharp spatial changes), such as speckle noise. It is equally important to note that the actual scene may contain high-frequency structural elements, such as edges, will be smoothed by this filter also. The property, sigma, specifies how much smoothing is applied—the larger the value, the more smooth (and blurry). Generally the smooth filter is applied to the phase map.

Figure 19. Smooth Filter Property