In Step 3 of the Target Detection Wizard, select the spectra to use as the desired target signatures in the target detection analysis.

To perform Orthogonal Subspace Projection (OSP), Target-Constrained Interference-Minimized Filter (TCIMF), and Mixture Tuned Target-Constrained Interference-Minimized Filter (MTTCIMF) target detection analysis, you need to select more than one target spectra and you need to select non-target spectra in the next step in the Wizard.

  1. Enter target spectra from spectral libraries, individual spectral plots, text files, ROIs, or statistics files. See Importing Spectra for details.
  2. Note: If using radiance or uncalibrated data as input, or if you applied an atmospheric correction that gives relative reflectance, spectra derived directly from the image data usually produce better results than selecting library targets. The image spectra more accurately account for any errors in calibration or atmospheric correction, the scales of mixing that occur in your data, and sensor response effects.

    Note: If you are importing ROIs as targets, the average calculated from each region is used as the target spectrum.

  3. When importing spectra is complete, choose the spectra to use by selecting one or more rows in the table, or by clicking Select All. ENVI uses only the spectra you select for target detection processing. If you do not select any rows, ENVI uses all spectra.
  4. Note: If you select only one target spectrum and do not specify non-target spectra in the next step, the OSP, TCIMF, and MTTCIMF target detection methods will not be available as target detection methods in a later step.

  5. Click Next in the Wizard. The Select Non-Target Spectra panel appears.