Uneven illumination correction of digital images: A survey of the state-of-the-art

The common image related artifacts during image acquisition are noise caused due to external interference and imbalance in illumination. Uneven illumination correction incorporates a penalty term that performs intensity distribution, and transfer between pre-defined uniformly illuminated and non-uniformly illuminated sub-regions of the input scale image. Many methods exist in the literature to address illumination correction. In this study, an overview of illumination models, estimation, unevenly illuminated image processing, non-uniform illumination correction, background correction techniques, and shadow correction are delivered. Various real-life applications, in the field of remote sensing imaging, automatic medical diagnosis of different diseases, underground imaging, and document imaging depend on image quality and illumination conditions. Some of the related work done by different researchers in solving illumination correction is discussed in a sequel. Assessment of correction quality is difficult because of non-availability of unilluminated images. Some of the objective assessment techniques are also discussed in this survey. This study aims at putting forward an all-inclusive discussion on the application of non-uniform image processing by means of various existing correction models in a wide application domain, and their frequently encountered challenges.