FIGURE 5-3 With the histogram adjust function the color scale distribution is spread across more of the available color scale. In the top image, a very small amount of the available color scale is used for features in the image. After the "histogram adjust", more of the color scale is used for features in an image. Often, by adjusting the histogram, it is possible to see more structure in an AFM image.

5.1.3 Filtering

Often there is unwanted high and low frequency noise that appears in AFM images. This noise can be removed by filtering. The two types of filtering most commonly used on AFM images are Matrix Filtering and Fourier Filtering.

Matrix Filtering averages 2, 3, 4, 5, 6 adjacent points together in an image. The averaging may be weighted such that the data points directly next to the pixel being calculated has more weight than the others. Matrix filters can be use to sharpen or to blur an image.

Equation 5-1 would be the calculation for a single data point with a weighting value of 1 of each of the surrounding data points.