Gradient-directed Composition of Multi-exposure Images

Neither over-exposure nor under-exposure is good for a photograph. Although current image-correction tools provide multi-exposure composition technique, it is time-consuming and the outcome is less than ideal. Prof. Cham Wai-kuen, Department of Electronic Engineering, and his student Dr. Zhang Wei aim at producing good-looking, well-exposed images by compositing a stack of photos at different exposures taken with a conventional camera. Gradient information is utilized in the proposed technique to accomplish direct exposure composition in both static and dynamic scenes. If the exposure stack is captured in static scenes, the goal is to preserve all present details and make them visible in one image. If the stack is captured in dynamic scenes containing moving objects, there are two goals. Besides preserving details, the influence of moving objects needs to be removed. Compared to conventional high dynamic range (HDR) imaging methods, this technique is more appealing to the public since it is more efficient, easier to use, and the outcome of the retouched photo is also greatly enhanced.

Project Website: http://www.ee.cuhk.edu.hk/~zhangwei/GradComp.html