Edge enhancement
Introduction
Filtering can also be used to emphasize local differences in DN values by increasing local contrast, for example for linear features such as roads, canals and geological faults. This is done using an edge enhancing filter, which amplifies the difference between the central pixel and its neighbours. This is implemented using negative values for the non-central kernel elements. An example of an edge enhancement filter is given in Figure below.
| -1 | -1 | -1 |
| -1 | 16 | -1 |
| -1 | -1 | -1 |
The gain is calculated as: 1 ∕ (16 - 8) = 1 ∕ 8 = 0.125. An example of using an edge enhancement is shown in Figure 2.
Prior knowledge
Outgoing relations
- Edge enhancement is a kind of Filtering