1. A method, comprising: receiving an input image; performing an edge-preservation enhancement on the input image, wherein performing the edge-preservation enhancement on the input image comprises performing a gradient calculation, bilateral filtering of gradients, and dilation of bilateral filtered gradients in the input image, wherein performing the gradient calculation, bilateral filtering of gradients, and dilation of bilateral filtered gradients in the input image comprises: calculating a gradient for a pixel in the input image; retrieving gradients in a window surrounding this pixel p; doing bilateral filtering for gradients according to weights based on pixel difference and spatial distances; determining a maximal gradient among the bilateral filtered gradients; and replacing the gradient for the pixel with the maximal gradient; performing a local-extrema enhancement on the input image; performing a digital transient improvement (DTi) operation on the input image; performing a gradient-based fusion of an output of the edge-preserving enhancement and an output of the local-extrema enhancement; and performing a transient-based fusion of an output of the gradient-based fusion and an output of the DTi operation.