Applying Texture Filter
Many images have regions characterized by brightness variations. The texture filter refers to spatial variations in image tones as a scale function. Specially to aerial photos, applying texture filter is recommended.
To the analyst is easy to recognize the texture differences in an image. The quantification through digital processing is more complex because there is not a general definition of texture. Different from spectral characteristic describing the object tone variations. In addition, theses tone variations can be considered as a scale function in which the object is observed.
Select IMAGE PROCESSING → IMAGE PROCESSING → TEXTURE FILTER in the main menu.
Texture Filters: click on the box to choose the filter to be applied on the image.
Use co-occurrence measures filter to apply automatically 8 different texture filter types based on co-occurrence matrix.
The occurrence filter uses gray tones in function of texture value calculation matrix. This matrix is the frequency matrix relative to which the pixel values occur in two neighborhood of the processing window separated by a specific distance and direction. Then it is showed a number of occurrences between a pixel and its specified neighbor.
Texture to Compute: Select needed texture type.
Processing Window: select the option of rows x columns correspondent to considered area (pixels) for texture evaluation.
Bands: click on the box to select to apply to all band or to select one band.
Output Parameters:
Layer Name: enter the name of resulting image.
Click on the OK button.
It will be created a layer to each selected texture filter.
Note: Depending on the filter, there will be different filter types.