User Manual - pancroma

The image processing utilities are explained below.Snow and Sand Glare Reduction Group Utility (Grayscale; RGB; Pan)Sometimes areas of an image are close to saturation as a result of intensereflection from snow, sand or clouds. This utility uses a combination of twosliders (which is a common format for many PANCROMA TM image processingutilities). The upper slider selects the clipping threshold. That is all pixels abovethe setting on the slider bar will be affected by the clipping operation. Forexample if the slider is set at 245, then all pixel values of 245 and above will beadjusted.IMPORTANT NOTE: Since all Landsat files have 8 bits of color information, thecolor level can range from 0 – 255 i.e. 256 total levels.The lower slider bar sets the adjustment value, in this case the number by whichall the values above the clipping threshold will be decremented. The result is thatpixel values that are so “overexposed” so that detail is lost can be made lessintense so that detail can be recovered.Haze/Contrast Group Utility (Grayscale; RGB; Pan)This utility allows images that are excessively hazy to be sharpened. The degreeof haze reduction is proportional to the slider position. The lower slider adjustscontrast. Its purpose is to add definition to images lacking contrast.IMPORTANT NOTE: The haze reduction and contrast adjust algorithms canhave unwanted side effects, so attempt small adjustments at first.155