Looking for Single Image HDR Algorithm

Question

Is there any open source implementation or algorithm for single Image HDR?

Answer 1

That PS feature is not high dynamic range anything, which would require multiple images of the scene acquired with different exposure settings. The PS feature is a well tuned local contrast enhancement algorithm, for which there are plenty of google results.

Here is a solid tutorial on how to do this with any C++ image framework: http://www.cromwell-intl.com/3d/histogram/

Answer 2

You may start with implementing "Unsharp Mask" based on Gaussian Blur. Pseudo HDR effects could be achieved by applying unsharp mask with large radius.

Combining it with "Shadow / Highlight" filter yields something similar to what you linked to.

Answer 3

The Photoshop plug in doesn't actually have a special algorithm. It just combines a number of different filters to create an image that displays similar characteristics with HDR images.

You can do the same thing with GIMP, following this Instructable. You might also play with a light edge-glow effect as well.