Definiens Developer 7 - PCI Geomatics

Definiens Developer 7 - Reference Book2 About Rendering a DisplayedImagec min = c' kminc max = c' kmaxInput Range Mapping Function[c min ...c max ] c s = 255*(((c k -c min )/(c max -c min ))^n)You can be modify the exponent of the mapping function by editing the equalizationparameter e. Values of n less than 1 emphasize darker regions of the image, valueslarger than one emphasize darker areas of the image. A value from n=1 represents thelinear case.Histogram EqualizationHistogram equalization is well suited for LANDSAT images but can lead to substantialover-stretching on many normal images. It can be helpful in cases you want to displaydark areas with more contrast.Histogram equalization maps the input range to the available screen intensity range[0...255] by a nonlinear function. Simply said, the mapping is defined by the propertythat each color value of the output image represents the same number of pixels. Therespective algorithm is more complex and can be found in standard image processingliterature.Manual Image Layer EqualizationManual image layer equalization allows you to control equalization in detail. For eachimage layer individually, you can set the equalization method specifying the mappingfunction. Further you can define the input range by setting minimum and maximumvalues.Manual Image LayerEqualization section inUser Guide10