User Manual - pancroma

Use the checked image processing utilities to get the best match that you canbetween the Adjust image and the Reference image. After several iterations oftrial and error, I ended up with the image shown below, which I saved as filePROCESS10.jpg:The following settings are typical in achieving an acceptable manual match:IMPORTANT NOTE: When you select ‘Gap Fill | Gap Fill ETM+ from the menuthe Image Processing Data Input box will again appear. DO NOT ADJUST ANYOF THE SETTINGS. The idea is to adjust each of the bands equally so not toupset the color balance in the processed image.Compute Running AverageIt is convenient to have an estimate of the average pixel values of the Adjust andReference images in order to adjust the brightness of the Adjust image to bettermatch that of the Reference image. Although PANCROMA TM computes theaverage pixel values for the entire Adjust and Reference images, these are notvery useful as the image includes many zero-value border pixels. Snow, cloudsand ocean may further skew the average. As a result, it is more useful tointerrogate the image at areas of interest only, compute the average for theseregions, and then apply an brightness adjustment based on the differencebetween the two averages.You can either interrogate the images one at a time or after they are filled. Tointerrogate them singly, select ‘File | Open’ and then open a single file, the Adjustimage for example. Select ‘Display Files’. When the grayscale image isdisplayed, select ‘Display Files’ | ‘Compute Running Average’. Now place thecursor over the first area of interest and left click the mouse. The average value(current pixel value) will be displayed in the lower right corner of the mainwindow. (You can reset the computation at any time by selecting the ‘ResetAverage’ button.Now move your cursor to a different location and click again. The average of thetwo pixels will be displayed. Continue in this fashion, querying as many pixels inas many different locations as you wish. When you are done, write down orremember the average value for the image. Now select ‘File’ | ‘Close GraphicsWindows and Reset’. Repeat the above procedure for the Reference image.Compute the difference between the two averages. This is the adjustment factorthat you will use to increase or decrease the brightness of the Adjust image in thegap filling process. When you are finished, select ‘File’ | ‘Close GraphicsWindows and Reset’. You are now ready to start the gap filling process asdescribed above.Alternatively, you can estimate the averages during the gap filling process itself.To do this, open the Reference and Adjust images as described in the gap filling350