USING SHADE FRACTION IMAGE SEGMENTATION TO EVALUATE DEFORESTATION IN LANDSAT THEMATIC MAPPER IMAGES OF THE AMAZON REGION

Image segmentation based on the shade fraction of a Landsat TM image w as effective in measuring the areal extent of Amazonian deforestation. The shade fraction image derived from spectral mixture models was rel ated to the forest canopy structure. Dense tropical forests have a med ium proportion of shade within their canopy while deforested areas (ba re soil, pasture, and/or regrowth) have a comparatively small proporti on. Comparison of image segmentation results with conventional techniq ues showed visual agreement. Even though additional tests are necessar y to validate this approach for large areas, the technical soundness o f the approach has been demonstrated.