The quality of field-rate conversion improves significantly with motio
n-compensation techniques. It becomes possible to interpolate new fiel
ds at their correct temporal position. This results in smooth motion p
ortrayal without loss of temporal resolution. However, motion vectors
are not always valid for every pixel or object in an image. Therefore,
visible artifacts occur wherever such wrong vectors are used on the i
mage. One effective method to solve this problem is the use of non-lin
ear filtering. In this method, a wrongly interpolated pixel is either
substituted or averaged with neighbouring pixels. In this paper we int
roduce and evaluate a new and very robust upconversion algorithm which
is based on the non-linear filtering approach. It is unique in that i
t estimates motion vector reliability and uses this information to con
trol the filtering process. This algorithm outperforms others in its c
lass, especially when we have complex image sequences.