A Compatible High-Definition Television System Using the Noise-Margin Method of Hiding Enhancement Information

W. F. Schreiber, E. H. Adelson, A. B. Lippman, Gong Rongshu, P. Monta, A. Popat, H. Sallic, P. Shen, A. Tom, K. Zangi, A. N. Netravali

This article discusses a receiver-compatible extended-definition television (EDTV) system using a new method of hiding extra information in a normal video signal. It is found that when video signals are transmitted in the usual over-the-air channels, if the signal-to-noise ratio (SNR) is satisfactory at the receiver, it is actually higher than required in some spatial-frequency bands, creating a “noise margin” in which extra information can be inserted, appearing on the NTSC receiver as a very small amount of high-frequency noise. On a special EDTV receiver, the second signal is detected independently, combined with the first signal, and displayed at high resolution. The method does require a channel SNR high enough to make good NTSC pictures; however, an adequate SNR is required for any method of transmitting high-quality NTSC-compatible EDTV/HDTV images through analog channels. As an alternative to transmitting side panels, a wide aspect ratio on the EDTV display is achieved by discarding a portion of the height of the transmitted image as displayed on a normal receiver, having previously ensured that the areas so discarded are free of significant content. Finally, the excess vertical and temporal chrominance resolution of NTSC is utilized for adding digital audio and for increasing the horizontal chrominance resolution.

Print ISSN
Published
1989-12
Content type
Original Research
DOI
10.5594/J03939