Local Contrast-Based Pixel Ordering for Exact Histogram Specification
Histogram equalization is one of the basic image processing tasks for contrast enhancement, and its generalized version is histogram specification, which accepts arbitrary shapes of target histograms including uniform distributions for histogram equalization. It is well known that strictly ordered p...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-09-01
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| Series: | Journal of Imaging |
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| Online Access: | https://www.mdpi.com/2313-433X/8/9/247 |
| _version_ | 1797486454153150464 |
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| author | Kohei Inoue Naoki Ono Kenji Hara |
| author_facet | Kohei Inoue Naoki Ono Kenji Hara |
| author_sort | Kohei Inoue |
| collection | DOAJ |
| description | Histogram equalization is one of the basic image processing tasks for contrast enhancement, and its generalized version is histogram specification, which accepts arbitrary shapes of target histograms including uniform distributions for histogram equalization. It is well known that strictly ordered pixels in an image can be voted to any target histogram to achieve exact histogram specification. This paper proposes a method for ordering pixels in an image on the basis of the local contrast of each pixel, where a Gaussian filter without approximation is used to avoid the duplication of pixel values that disturbs the strict pixel ordering. The main idea of the proposed method is that the problem of pixel ordering is divided into small subproblems which can be solved separately, and then the results are merged into one sequence of all ordered pixels. Moreover, the proposed method is extended from grayscale images to color ones in a consistent manner. Experimental results show that the state-of-the-art histogram specification method occasionally produces false patterns, which are alleviated by the proposed method. Those results demonstrate the effectiveness of the proposed method for exact histogram specification. |
| first_indexed | 2024-03-09T23:34:25Z |
| format | Article |
| id | doaj.art-ba2d3a00b0554cb6bccacce2a6a4c2b6 |
| institution | Directory Open Access Journal |
| issn | 2313-433X |
| language | English |
| last_indexed | 2024-03-09T23:34:25Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Imaging |
| spelling | doaj.art-ba2d3a00b0554cb6bccacce2a6a4c2b62023-11-23T17:04:44ZengMDPI AGJournal of Imaging2313-433X2022-09-018924710.3390/jimaging8090247Local Contrast-Based Pixel Ordering for Exact Histogram SpecificationKohei Inoue0Naoki Ono1Kenji Hara2Department of Media Design, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minamiku, Fukuoka 815-8540, JapanDepartment of Media Design, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minamiku, Fukuoka 815-8540, JapanDepartment of Media Design, Faculty of Design, Kyushu University, 4-9-1 Shiobaru, Minamiku, Fukuoka 815-8540, JapanHistogram equalization is one of the basic image processing tasks for contrast enhancement, and its generalized version is histogram specification, which accepts arbitrary shapes of target histograms including uniform distributions for histogram equalization. It is well known that strictly ordered pixels in an image can be voted to any target histogram to achieve exact histogram specification. This paper proposes a method for ordering pixels in an image on the basis of the local contrast of each pixel, where a Gaussian filter without approximation is used to avoid the duplication of pixel values that disturbs the strict pixel ordering. The main idea of the proposed method is that the problem of pixel ordering is divided into small subproblems which can be solved separately, and then the results are merged into one sequence of all ordered pixels. Moreover, the proposed method is extended from grayscale images to color ones in a consistent manner. Experimental results show that the state-of-the-art histogram specification method occasionally produces false patterns, which are alleviated by the proposed method. Those results demonstrate the effectiveness of the proposed method for exact histogram specification.https://www.mdpi.com/2313-433X/8/9/247exact histogram equalizationexact histogram specificationGaussian filtercontrast enhancementpixel ordering |
| spellingShingle | Kohei Inoue Naoki Ono Kenji Hara Local Contrast-Based Pixel Ordering for Exact Histogram Specification Journal of Imaging exact histogram equalization exact histogram specification Gaussian filter contrast enhancement pixel ordering |
| title | Local Contrast-Based Pixel Ordering for Exact Histogram Specification |
| title_full | Local Contrast-Based Pixel Ordering for Exact Histogram Specification |
| title_fullStr | Local Contrast-Based Pixel Ordering for Exact Histogram Specification |
| title_full_unstemmed | Local Contrast-Based Pixel Ordering for Exact Histogram Specification |
| title_short | Local Contrast-Based Pixel Ordering for Exact Histogram Specification |
| title_sort | local contrast based pixel ordering for exact histogram specification |
| topic | exact histogram equalization exact histogram specification Gaussian filter contrast enhancement pixel ordering |
| url | https://www.mdpi.com/2313-433X/8/9/247 |
| work_keys_str_mv | AT koheiinoue localcontrastbasedpixelorderingforexacthistogramspecification AT naokiono localcontrastbasedpixelorderingforexacthistogramspecification AT kenjihara localcontrastbasedpixelorderingforexacthistogramspecification |