Comparing signatures of a feature

Critical to validating the accuracy of the reflectance-correction process is to compare the signatures computed from various pixels in the image (samples) with the library spectra of a similar feature. For example, you can compare the reflectance signature computed from a pixel of a pine tree in an image with the library signature for pine trees. By sampling a variety of features (pixels), you can determine whether the correction you have applied is of suitable quality.

Note: You can use an existing spectral file (.spl) for signature comparison.

To compare signatures of a feature

In the viewer, click a pixel of the feature you want to sample.
For example, to compare a pine tree, click a pixel in the tree.
In the Spectra Reflectance Plot window, click From Spectra File.
The Open Spectra window appears.
In the table, select a feature, and then click Add To Plot.
The feature you selected is added to the table under Displayed spectra.
Repeat steps 1 to 3 for each additional pixel you want to compare with a corresponding feature.