Enhanced Dynamic Quadrant Histogram Equalization Plateau Limit for Image Contrast Enhancement

Enhanced Dynamic Quadrant Histogram Equalization Plateau Limit for Image Contrast Enhancement

Authors: Rizwan Khalid, Muhammad Rizwan Ali Kamran

Abstract: Consumer electronic devices require brightness preservation while image enhancement. Many of the
histogram equalization techniques that have been introduced tend to strike out the mean image brightness
while the process of enhancement is carried out. Hence, we suggest a method that enhances the image
while keeping its brightness in a better form as compared to the former methods applied. Firstly, based on
median value, the input image histogram is divided into sub-histogram and this process reprises until we
have derived 8 sub-histograms. Further, the clipping of the histogram is implemented based on the average
pixels in each sub-histogram. Then, each sub-histogram is assigned with a new dynamic range and finally
customary histogram equalization is done independently on each sub-histogram. Proposed method is
tested against conventional methods and results indicate that image mean brightness is preserved better
than other methods while enhancing the image. The proposed method keep the brightness save of the
original image while during the enhancement of the images. Many images has been taken from the SIPI
database and applied the proposed method for the contrast enhancement of the low contrast images and
results are improved. The major problem is to keep the brightness of the low contrast image preserve. The
proposed technique has dealt with brightness preservation of the images.
Keywords: Clipped Histogram Equalization, Sub-histogram Equalization, EDQHEPL, Plateau Limit
Equalization, Dynamic Histogram Equalization, Brightness Perserving Image Enhancement

Download: Rizwan Khalid et al, Afro Asian J SciTech,2017,4(1),024-032