{"title":"Generalized Differential Gray-level Histogram Equalization","authors":"Hideaki Tanaka, A. Taguchi","doi":"10.1109/ISPACS48206.2019.8986331","DOIUrl":null,"url":null,"abstract":"Histogram equalization (HE) is a simple and effective method for contrast enhancement as it can automatically define the gray-level transformation function based on the distribution of gray-level included in the image. HE fails to produce satisfactory results for broad range of low-contrast images because the HE does not use a spatial feature included in the input image. The differential gray-level histogram which is contained edge information of the input image, were defined. Furthermore, the differential gray-level histogram equalization (DHE) has been proposed. The DHE shows better enhancement results compared to the HE results for many kinds of images. In this paper, we propose a generalized DHE (GDHE) method. In GDHE, histograms are created using powers of gradients. If the power is set as 0, GHE is equivalent to HE, and if the power is set as 1, GHE is equivalent to DHE. That is, GDHE includes HE and DHE. GHE can preserve the mean brightness of the input image perfectly by setting the power appropriately and shows good contrast enhancement results at the same time.","PeriodicalId":6765,"journal":{"name":"2019 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS)","volume":"35 1","pages":"1-2"},"PeriodicalIF":0.0000,"publicationDate":"2019-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"2019 International Symposium on Intelligent Signal Processing and Communication Systems (ISPACS)","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1109/ISPACS48206.2019.8986331","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
Abstract
Histogram equalization (HE) is a simple and effective method for contrast enhancement as it can automatically define the gray-level transformation function based on the distribution of gray-level included in the image. HE fails to produce satisfactory results for broad range of low-contrast images because the HE does not use a spatial feature included in the input image. The differential gray-level histogram which is contained edge information of the input image, were defined. Furthermore, the differential gray-level histogram equalization (DHE) has been proposed. The DHE shows better enhancement results compared to the HE results for many kinds of images. In this paper, we propose a generalized DHE (GDHE) method. In GDHE, histograms are created using powers of gradients. If the power is set as 0, GHE is equivalent to HE, and if the power is set as 1, GHE is equivalent to DHE. That is, GDHE includes HE and DHE. GHE can preserve the mean brightness of the input image perfectly by setting the power appropriately and shows good contrast enhancement results at the same time.