| 摘要 |
The invention relates to a method and an arrangement to emphasize edges appearing in a video picture. The arrangement according to the invention comprises an edge detection means (ED) which processes a video signal formed by samples corresponding to pixels, and which at each sample detects the occurrence of an edge and the direction of the edge when it occurs. The arrangement is characterized in that it further comprises for different directions a set (FB) of unidimensional edge emphasizing filters (F1, F2, F3, F4) which represent all possible directions. A control signal (SEL) from the edge detection means (ED), which corresponds to the occurrence of an edge and the direction of the edge, as a response causes a means (SW3) to select from this set that edge emphasizing filter (F1, F2, F3, F4) which has a direction which is closest to the perpendicular direction of the detected edge, and then the selected filter performs the filtering. The solution according to the invention, in which the edge emphasizing is made by unidimensional filtering only when an edge occurs, and in the direction closest to the perpendicular direction of the detected edge, provides a simple edge emphasizing (peaking) process which almost evenly emphasizes all edges, irrespective of their direction. Motion detection and noise reduction by an averaging spatial-temporal algorithm can be added to the edge emphasizing process according to the invention in a case when no edge or motion is detected. <IMAGE> |
