User Manual - pancroma

79. Tutorial – ENHG with AJISANE Processing_______________________________________________________________It can sometimes be very difficult to produce accurate color tones when pansharpening Landsat images. As discussed in previous articles, the Landsatpanchromatic band sensor is not sensitive to visible blue light. As a result, pansharpened images can exhibit unnatural color tones when the panchromaticband is substituted for the Intensity or other color space band in the pansharpening process. PANCROMA TM provides several algorithms to address thisproblem and these have been previously discussed. However, it may be difficultto achieve desired color tones using even these sophisticated algorithms. It ispossible to combine the PANCROMA TM ENHG algorithm with other pansharpening methods to help overcome such problematic images. The ENHGmethod uses the NDVI vegetation index to enhance the Landsat band 2 (greenband). Although this method can produce improved results and works well byitself, it can also be combined with other methods. This paper outlines atechnique for combining the ENHG with AJISANE.As an introduction, I have compared the results of several PANCROMA TM pansharpening methods using Landsat data setp205r021_7t20000717_z30_nnXX.tif, acquired over Scotland. This image ischaracterized by lots of vegetation in proximity to the ocean and other waterbodies. This combination can prove troublesome as histogram matchingalgorithms can be influenced by such combinations.The first image below is the RGB color composite. This is the standard to whichwe will compare the pan sharpened results.383