Image Processing applied to an unsigned 8-bit image: Equalization, Stretching, Light Threshold and Dark Threshold. Example Of Image After Some Common Histogram Operations Equalization The Equalization operation enhances the Input Image by flattening the histogram of the Input Image. Stretching The Stretching operation stretches (increases) the contrast in an image by applying a simple piecewise linear intensity transformation, based on the histogram of the input image. Light Threshold The Light Threshold operation changes each pixel value depending on whether they are less than or greater than the specified threshold.
If an input pixel value is less than the threshold, the corresponding output pixel is set to the minimum acceptable value. Otherwise, it is set to the maximum acceptable value. Dark Threshold The Dark Threshold operation changes each pixel value depending on whether they are less than or greater than the specified threshold. If an input pixel value is less than the threshold, the corresponding output pixel is set to the maximum presentable value. Otherwise, it is set to the minimum acceptable value. ACEUser's Guide, 3.6.x, 18316-000 Rev A Page 521