Hier finden Sie wissenschaftliche Publikationen aus den Fraunhofer-Instituten.

Spatio-temporal subsampling and transform coding of HDTV signals

: Schamel, G.


Image communication 2 (1990), Nr.3, S.305-18
ISSN: 0923-5965
Fraunhofer HHI ()
data compression; encoding; filtering and prediction theory; high definition television; picture processing; video signals; spatio-temporal subsampling; 3d subsampling; transform coding; HDTV signals; two-stage coding system; digitized interlaced source signal; motion-adaptive filter structure; television signal; quincunx sampling pattern; energy concentration; entropy calculation; coding efficiency; data reduction; modified threshold coding algorithm; 140 mbit/s

A two-stage coding system for reducing the usually high data rate of an HDTV signal to less than 140 Mbit/s is described. Three-dimensional subsampling is used to reduce the number of samples of the digitized interlaced source signal. A motion-adaptive filter structure adjusts the three-dimensional spectrum of the television signal to some reduced region which is supported by the quincunx sampling pattern. The visibility of the transition between different spatial resolutions is decreased by 3D-filtering of slowly moving areas. As a result of subsampling, the sampling frequency is halved. Transform coding of the remaining samples is then performed. The quincunx sampling structure is rotated within blocks of 8 by 8 to result in a rectangular block structure. Different possibilities for transforming the quincunx sampled field have been investigated and compared in terms of energy concentration, entropy calculation and coding efficiency. A data reduction of the transform coefficients is sought in the range of four and five. A modified threshold coding algorithm is used to code the coefficients.