This is due to HDR’s features like accurate reproducibility of a scene with its entire spectrum of visible lighting and color depth. The rising demand for high quality display has ensued active research in high dynamic range (HDR) imaging, which has the potential to replace the standard dynamic range imaging. Example applications of linear and nonlinear local contrast enhancement and colour image Daltonisation illustrate the behaviour of the method. In this paper, we show that a version of anisotropic gradient-domain image processing can result from a more general variational formulation through the minimisation of a functional formulated in terms of the eigenvalues of the structure tensor of the differences between the processed gradient and the gradient of the original image. To deal with this, local or anisotropic diffusion has been added as an ad hoc modification of the Poisson equation.

However, this technique in some cases lead to severe haloing artefacts in the resulting image. This is normally done by solving the Poisson equation, most often by means of a finite difference implementation of the gradient descent method. The resulting image is obtained by reintegrating the processed gradient.

Gradient-domain image processing is a technique where, instead of operating directly on the image pixel values, the gradient of the image is computed and processed.

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