Brightness Preserving Enhancement for Dental Digital X-ray Images Based on Entropy and Histogram Analysis

Enhancing dental x-ray images could be of great importance in helping the dentist for proper diagnosis. Image enhancement by histogram equalization, log transform, gamma correction for multiple gamma values, and contrast limited adaptive histogram equalization (CLAHE) were considered. Matlab 2015 wa...

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Bibliographic Details
Published in淡江理工學刊 Vol. 22; no. 1; pp. 187 - 194
Main Authors Hassan M. Qassim, Nasseer M. Basheer, Mazin N. Farhan
Format Journal Article
LanguageEnglish
Published 淡江大學 01.01.2019
Subjects
Histogram Equalization
CLAHE
Dental X-ray Enhancement
Image Entropy
Periapical Image
Gamma Correction
Log Transform
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Summary:Enhancing dental x-ray images could be of great importance in helping the dentist for proper diagnosis. Image enhancement by histogram equalization, log transform, gamma correction for multiple gamma values, and contrast limited adaptive histogram equalization (CLAHE) were considered. Matlab 2015 was used to perform all the enhancement tasks. Dental x-rays images (periapical images) were obtained from a dataset published on the internet. It is preferred to preserve the x-ray images brightness so that the dentist can still use it for diagnosis with gray levels as close as possible to the originals. The CLAHE image enhancement, with eight rows and eight columns with clip limit of 0.01, proves to be the best. Two metrics were used for deciding the best enhancement, the entropy, looking for the highest obtained entropy, and the flatness of the resulted histogram. Eye inspection agrees with the metrics used.
ISSN:2708-9967
DOI:10.6180/jase.201903_22(1).0019