Real-Time Local Contrast Enhancement Algorithm for Video Cameras with Built-in Noise and Artifact Suppression

For real-time imaging with digital video cameras, visibility of details is very important to ensure user confidence. Many complex scenes require local contrast improvements that should bring details to the best possible visibility. However, local enhancement methods mainly suffer from ringing artifacts and over-emphasizing noise. We present a multi-window real-time high-frequency enhancement scheme, in which gain is a non-linear function of the detail energy. Our algorithm controls perceived sharpness, ringing artifacts (contrast) and noise, resulting in a good balance between visibility of details and nondisturbance of artifacts. The new scheme can be successfully applied to any class of video system that would benefit from contrast improvement.