A comparison of motion-compensated interlace-to-progressive conversion methods

摘要

The conversion of interlaced video to progressive format may be carried out in a number of ways, including vertical interpolation, fixed or motion-compensated vertical-temporal interpolation, and approaches based on motion compensation using non-uniform sampling theory. Motion-compensated methods potentially offer the best performance, although the accuracy and reliability of the vectors has a significant impact on their performance. For applications such as display conversion using vectors recovered from an MPEG-2 bitstream, the vectors available may not be of the highest quality. This paper considers several motion-compensated interlace-to-progressive conversion methods, and assesses their performance with both accurate and inaccurate vectors using objective and subjective techniques. The method found to work best uses a motion-compensated three-field vertical-temporal filter, in which the vertical component of the vector is rounded to the nearest even number of picture lines per field period. This method reduced the RMS error of converted picture sequences by almost 20% compared to simple vertical filtering when using vectors from an MPEG-2 bitstream. Conversely, some other motion-compensated methods were found to increase the error by a similar amount.