Histogram equalisation

This demo issustrates the use of Histogram equalization, gamma correction matching and Contrast Limited Adaptive Histogram Equalization

Histogram equalisation is used to imporve the contrast in an single-channel grayscale image. It distributes the intensity of the image in a uniform manner. The natural justification for uniformity is that the image has better contrast if the intensity levels of an image span a wide range on the intensity scale. The transformation is based on mapping of cumulative histogram

using ImageContrastAdjustment, TestImages, ImageCore

img = testimage("moonsurface")

Now we will apply Histogram equalisation, gamma correction and Adaptive histogram equalisation method to enhance contrast of the image

hist_equal = adjust_histogram(img, Equalization(nbins = 256))
gamma_correction = adjust_histogram(img, GammaCorrection(gamma = 2))
mosaicview(img, hist_equal, gamma_correction, hist_adapt; nrow = 1)