4.5.5 Textural features extraction

Texture features can be extracted with the help of image filters based on texture analysis methods like Haralick and structural feature set (SFS).

Haralick texture features

This application computes Haralick, advanced and higher order texture features on every pixel in the selected channel of the input image. The output image is multi band with a feature per band.

The HaralickTextureExtraction application has the following input parameters:

The available values for -texture with their relevant features are:

The application can be used like this:

otbcli_HaralickTextureExtraction  -in             InputImage  
                                  -channel        1  
                                  -texture        simple  
                                  -parameters.min 0  
                                  -parameters.max 255  
                                  -out            OutputImage

SFS texture extraction

This application computes Structural Feature Set textures on every pixel in the selected channel of the input image. The output image is multi band with a feature per band. The 6 output texture features are SFS’Length, SFS’Width, SFS’PSI, SFS’W-Mean, SFS’Ratio and SFS’SD. They are provided in this exact order in the output image.

It is based on line direction estimation and described in the following publication. Please refer to Xin Huang, Liangpei Zhang and Pingxiang Li publication, Classification and Extraction of Spatial Features in Urban Areas Using High-Resolution Multispectral Imagery. IEEE Geoscience and Remote Sensing Letters, vol. 4, n. 2, 2007, pp 260-264.

The texture is computed for each pixel using its neighborhood. User can set the spatial threshold that is the max line length, the spectral threshold that is the max difference authorized between a pixel of the line and the center pixel of the current neighborhood. The adjustement constant alpha and the ratio Maximum Consideration Number, which describes the shape contour around the central pixel, are used to compute the wmean value.

The SFSTextureExtraction application has the following input parameters:

The application can be used like this:

otbcli_SFSTextureExtraction -in             InputImage  
                            -channel        1  
                            -out            OutputImage