In this paper, a local tone mapping operator is proposed. It is based on the theory of sprays introduced in the Random Sprays Retinex algorithm, a white balance algorithm dealing with the locality of color perception. This tone mapping implementation compresses high dynamic range images by using three types of computations on sprays. These operations are carefully chosen so that the result of their convex combination is a low dynamic image with a high level of detail in all its parts regardless of the original luminance values that may span over large dynamic ranges. Furthermore, a simple local formulation of the Naka-Rushton equation based on random sprays is given. The experimental results are presented and discussed.Index Terms-High dynamic range images, tone mapping, Naka-Rushton equation, Retinex This work was supported by the Croatian Science Foundation under Grant DOK-01-2018. own preference. Additionally, a local formulation of the Naka-Rushton equation based on sprays is proposed. This ensures that all TM calculations of the proposed TMO are entirely performed on local regions represented as sprays.
Images taken outdoors are often degraded by atmospheric conditions such as fog and haze. These degradations can reduce contrast, blur edges, and reduce saturation of images. In this paper we propose a new method for single image dehazing. The method is based on an idea from color constancy called the gray world assumption. This assumption states that the average values of each channel in a picture are the same. Using this assumption and a haze degradation model we can quickly and accurately estimate the haze thickness and recover a haze free image. The proposed method is validated on a synthetic and natural image dataset and compared to other methods. The experimental results have shown that the proposed method provides comparable results to other dehazing methods.
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