US Patent 7983501 Noise detection and estimation techniques for picture enhancement

A method of filtering noise from a picture may include determining a set of pixel noise metrics for a set of selected pixels in the picture based solely on information from the set of selected pixels in the picture. The method may also designate as valid a subset of pixel noise metrics in the set of pixel noise metrics those associated pixels are not located at an edge or are not located in a complicated area of the picture. A set of block noise metrics may be calculated from the valid subset of pixel noise metrics, and a global noise metric for the picture may be ascertained from the set of block noise metrics. The picture may be filtered using the global noise metric to generate a filtered picture.