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Enhancing Luminance

Two images, one before, the other after processing with this programme:

In her Ph.D. thesis, Laurence Meylan writes:

"Tone mapping is an essential step for the reproduction of \nice looking" images. It provides the mapping between the luminances of the original scene to the output device's display values. When the dynamic range of the captured scene is smaller or larger than that of the display device, tone mapping expands or compresses the luminance ratios."

The problem is to do this without introducing computational artifacts or greying of bright areas. It is also necessary to keep colours constant as far as possible in all areas, thus simulating the adaptation ability in human vision. Below, two images of the same scene show how details emerge from the darkness while at the same time, the bright sea background visible through the windows on the bridge of a ship still retains much of its colour and appearance.