Erosion and dilating of low-contrast regions

The main problem of the window approach to classification is that the more contrast classes (wood) covers the less contrast (fields) by the amount roughly equal to half of classification window size. To solve this problem there are added two additional steps - erosion and dilating the low-contrast regions. Their implementation allows to define more precisely borders between contrast and low-contrast classes.

Erosion of low-contrast regions is carried out for a complete elimination of hitting the low-contrast regions into high-contrast regions. At the dilating step on border of low-contrast regions the pixels insignificantly different in colour from earlier classified are added.