Spectral angle mapper (descriptor)

Use spectral angle maps for object classification. See Spectral angle mapper (SAM) guide for more information. Also see Create end members on how to create your own spectral library.

Parameters

Regions

Write in the wavelength range to use. If left empty all wavelengths are included.

Example

460:600;660:800

This will include all wavelengths from w460 to w600 and from w660 to w800

End Members (1-10)

Select files containing End members for each pure sample.

Threshold

Write the threshold angle in radians. The angle is the difference between the end member angle and the angle from the spectrum in each pixel.

Weights

Weights for the importance of the pixels in the objects. The higher the value the more importance they have.

Example

1,2,4

This means that the first pixels at the border have 1/4 of the importance of the pixels in the middle of the objects.

Pretreatments

In button-up applied order ⬆️ , meaning UV is applied first then Center and so on.

• Savitzky-Golay

• Derivative

• SNV (Standard Normal Variate)

• Logarithm

• Center

• UV (Unit Variance) scaling

For more on each type of pretreatment see: Pretreatments

Rule images

Show calculated SAM value rule image for each reference spectrum. Brighter value is closer to the reference spectrum for that pixel

✅ Apply the rule images to all the classes in the library.

⬜ Rule images are not applied.

Smooth

Smooth prediction result using median filter kernel

• None

  • No Smoothing prediction.

• Low

  • Smoothing using median filter kernel with 5x5 pixel box

• Medium

  • Smoothing using median filter kernel with 10x10 pixel box

• High

  • Smoothing using median filter kernel with 15x15 pixel box

Output

• Type

  • This shows the estimated type in the table view.

• Value

  • This shows the calculated value in the table view.