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Contrast Enhancement using Completely
        
        Illumination pre-processing is an inevitable step for a  real-time automatic  face  recognition system in  solving 
challenges related to lighting variation  for  recognizing  the  face  images. This  paper proposes a  novel  framework  namely 
Completely  Overlapped  Uniformly  Decrementing  Sub-Block  Histogram Equalization  (COUDSHE)  to normalize  or  pre-
process  the  illumination  deficient  images.  COUDSHE  is  based  on  the idea that  efficiency  of  the  pre-processing  technique 
mainly  depends on the  framework  for application of the  technique on the affected image. The  primary  goal of this paper is to 
bring  out  a  new  strategy  for  localizing  a  Global  Histogram  Equalization (GHE) Technique  to  help  it  adapt  to  the  local  light 
condition  of  the image. The  Mean  Squared  Error (MSE),  Histogram  Flatness  Measure,  Absolute  Mean  Brightness  Error 
(AMBE) are  the  objective  measures  used  to  analysis  the  efficiency  of  the  technique. Experimental  Results  reveal  that 
COUDSHE has better performance on Heavy shadow images and half lit image than the existing techniques.    
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[21] Zuo C., Chen Q., and Sui X., “Range Limited Bi- Histogram Equalization for Image Contrast Enhancement,” Optik, vol. 124, no. 5, pp. 425- 443, 2013. 396 The International Arab Journal of Information Technology, Vol. 16, No. 3, May 2019 Shree Devi Ganesan received B.Sc., Mathematics from University of Madras, India and M.C.A from Periyar University, India. After Post graduation she worked as Lecturer in Colleges affiliated to Anna University. She is currently employed as Assistant Professor (Sr. Grade) in Department of Computer Applications, B.S.Abdur Rahman University. and pursuing Ph.D degree in the field of Image Processing. Munir Rabbani M.Sc., B.Ed., M. Phil., PGDCA., MCA., Ph.D is a Professor in School of Computer, Information and Mathematical Sciences, B.S. Abdur Rahman University, India. He received Ph.D degree from Anna University, India. in year 2009. He Posses rich International Experience in the Field of Teaching and Research. He has 21 International journal publications and 22 International Conference proceedings. His research interests include Data Mining, Image processing and Networks.
