TARGET FINDING WITH SAM AND BANDMAX Course: Special Topics in Remote Sensing & GIS Mirza Muhammad Waqar Contact: EXT:2257 RG712

Outlines  BandMax 1. Input/Output File Selection 2. Select Targets 3. Select Backgrounds for BandMax Input 4. Calculate the Significant Bands With BandMax 5. Spectral Mapping using Spectral Angle Mapper (SAM) 6. Investigation of Mapping Results  Analysis

BandMax  BandMax allows you to find and use the optimal subset of bands that will maximize the separation of your target from background material.  It also improves the process time.

Step by Step Procedure  1. Input/Output File Selection  2. Select Targets  3. Select Backgrounds for BandMax Input  4. Calculate the Significant Bands With BandMax  5. Spectral Mapping using Spectral Angle Mapper (SAM)  6. Investigation of Mapping Results

1. Input/output file selection  Images should be converted into reflectance through atmospheric correction before being used as input to the wizard  Especially if library spectra or other external spectra are used as targets in the mapping process.  If external spectra are not used in the processing, then  Radiance or even uncalibrated data can be used as input.

2. Target Selection  In this step, you will select your target spectra for analysis.  These targets will be used as the reference spectra in the SAM analysis and the target spectra in the BandMax calculations.  Spectra derived directly from the image data usually produce better results than selecting library targets.

3. Background Selection and Rejection  The BandMax algorithm can help to reduce errors of commission (false positives) that may occur in a SAM analysis.  In this step, you can select as "background" the pixel spectra that were incorrectly identified as targets in a SAM analysis.

3. Background Selection and Rejection  The BandMax algorithm will attempt to identify the bands that are best able to distinguish your targets from these "backgrounds".  By using only these bands when performing the SAM analysis, BandMax attempts to suppress false detection of the "background" without reducing its capability to find targets.

4. SELECT OPTIMAL BANDS  The wizard uses the BandMax algorithm to find the optimal band subset to distinguish your targets from the specified backgrounds.  Each band in the input image has a significance value calculated for it by the BandMax algorithm.  This unitless value ranges from 0 to 1, where a higher value indicates that the band has a higher probability of being able to distinguish target response from background response.

5. Spectral Mapping using Spectral Angle Mapper (SAM)

6. Investigation of Mapping  Investigate the results.  Recalculate results by changing significance value.  Recalculate results by changing angle threshold.  Perform same steps for all material of interests.

Questions & Discussion