| 摘要 |
With the new plasma display panel technology new kinds of artefacts can occur in video pictures. These artefacts are commonly described as "dynamic false contour effect", since they correspond to disturbances of grey levels and colours in the form of an apparition of coloured edges in the picture, when the observation point on the PDP screen moves. With the present invention, a solution able to eliminate the false contour artefact while keeping a good picture quality is proposed. This solution does without motion estimators. The basic idea of the invention is to form a new code for sub-field encoding, which permits to achieve p grey levels (typically p = 256) among 2<n> different sub-field arrangements, to select m grey levels (with m < p). These specific grey levels, which correspond to specific sub-field arrangements and thus sub-field code words, are chosen in such a way that the sub-field code words of similar grey levels will have similar sub-field arrangements, in order to reduce the false contour artefacts. One important rule how the close codes can be selected from the set of available sub-field code words is to select only those video levels having assigned sub-field code words, in which a temporal centre of gravity (CG1, CG2, CG3) for the light generation increases monotonously when the video levels are ordered according to size. Only some exceptions are allowed in the low video level and high video level ranges. <IMAGE> |
