Progressive versus Interlaced Coding

Interlaced versus progressive scanning is an important issue when dealing with digital television. Not only because the change from analog to digital communication may be seen as an opportunity to move to other formats, but also because of the well-known artifacts of interlaced scanning (interline twitter, line crawling, and field aliasing) compared to the natural way of representing two-dimensional images as the progressive format does. However, digital broadcasting has to face the problem of transmitting twice the number of pels of the progressive format. It is the purpose of this article to study this problem, and especially to check if the increased vertical and temporal correlations of the progressive pictures provide a significant improvement in the bit-rate reduction efficiency. In that case, progressive scanning may also be used as an intermediate transmission format to improve the compression performances of interlaced sequences.