Optics and Precision Engineering, Volume. 25, Issue 2, 502(2017)
Local linear enhancement of luminance histogram of color remote sensing image
Aimed at actual problem of low energy of remote sensing image, a local linear image enhancement method of luminance histogram was put forward to improve visual effect of color remote sensing image. Firstly, HSI transformation was performed on color remote sensing image described by RGB model to separate component H, S and I effectively; secondly, traditional histogram equalization was implemented to luminance I component and gained equalized gray level mapping curve; then, by taking image gradient as objective function, the location of optimum linear break point were determined and linear processing was conducted to mapping curve within dynamic range at low side of gray level and gained local linear gray level mapping curve; finally, new gray level mapping curve was adopted to enhance image. Experimental result of Himawari-8 true color image enhancement shows that after local linear enhancement of luminance histogram, level gradient of pixel increases from 73 to 147, and with traditional RGB domain histogram equalization, it only increases to 123, with HSI domain histogram equalization, it increases to 134, and information entropy of image increases from 5.87 to 6.63, so it can be conclusion that the proposed algorithm is superior than other two algorithms in all aspects. The method improves visual effect of color remote sensing image effectively and improves identification capability of image to different objectives.
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CHEN Bo-yang. Local linear enhancement of luminance histogram of color remote sensing image[J]. Optics and Precision Engineering, 2017, 25(2): 502
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Received: Sep. 14, 2016
Accepted: --
Published Online: Mar. 29, 2017
The Author Email: Bo-yang CHEN (chenby@cma.gov.cn)