Spatial enhancement of satellite imagery was the focus of Module 6 Lab. The enhancement of remotely sensed imagery enables viewers to extract more information from the imagery than originally expected. Enhancements can be used to emphasize particular aspects or features in the imagery or to correct errors resulting from sensor issues. ArcMap and ERDAS complement each other in the application of spatial enhancements.
After practicing the application of various enhancements to other imagery, the final exercise in this lab involved applying image enhancements to a Landsat 7 image. The purpose of the enhancements was to improve the image quality by reducing the visual impact of the "striping" effect of a sensor malfunction. The specific goal was to minimize the striping while maintaining the highest degree of detail as possible. Enhancements that were applied to the imagery to complete this map included Fourier Transform, 3x3 Sharpen Filter, Haze Reduction, Noise Reduction, Contrast Adjustment, and Brightness Adjustment.
This exercise also served as a reminder of how finicky software can be. For undetermined reasons, both ArcMap and ERDAS required multiple attempts at completing some processes either because they resulted in completely unanticipated results or because they would not run at all. In one case, closing completely out of eDesktop and attempting the process again after re-starting resolved the issue. Other processes were unsuccessful primarily because of lack of experience in how to use them optimally. This was especially true with histogram adjustment. Additional practice will be beneficial in learning the ins and outs of spatial enhancement.
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| Landsat 7 Imagery after the application of several spatial enhancements. |
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