"If it can be written, or thought, it can be filmed..." STANLEY KUBRIC

Cross color artefact

From Encyclopedia PRO

Jump to: navigation, search

Cross Color is an artifact produced by the imperfect decoding of composite video. High frequency luma components are incorrectly decoded as chroma signals, causing colorization where there should be none. This colorization can be detected in many types of ”busy” scenes including tiled rooftops, herringbone patterned clothing, leafy scenery, etc. The most common and visible cross color artifacts are flickering that occurs at 15 Hz rate, flashing colors or rainbow patterns. The artifact can be eliminated in still images by using temporal averaging of the chroma signals, the same methodology that is used in a 3-D comb filter. However, this cannot be done wherever there is motion because of the motion artifacts created, just as with deinterlacing using field weaving. Genesis‘s Faroudja-based Cross Color Suppression uses the motion detector to selectively perform the temporal filtering only where there is no motion in the image and to use the already existing frame memory for the chroma storage required. Even cross-color that has been encoded onto a DVD recorded from a composite source can be suppressed using this technology.


Cross Color occurs when the video decoder incorrectly interprets high-frequency luma information (brightness) to be chroma information (color), resulting in color being displayed where it shouldn't.


See also

Views
Personal tools