As an efficient image contrast enhancement (CE) tool, adaptive gammacorrection (AGC) was previously proposed by relating gamma parameter withcumulative distribution function (CDF) of the pixel gray levels within animage. ACG deals well with most dimmed images, but fails for globally brightimages and the dimmed images with local bright regions. Such two categories ofbrightness-distorted images are universal in real scenarios, such as improperexposure and white object regions. In order to attenuate such deficiencies,here we propose an improved AGC algorithm. The novel strategy of negativeimages is used to realize CE of the bright images, and the gamma correctionmodulated by truncated CDF is employed to enhance the dimmed ones. As such,local over-enhancement and structure distortion can be alleviated. Bothqualitative and quantitative experimental results show that our proposed methodyields consistently good CE results.
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