Multi-channel HDTV system

Details

Inventors: LeGall, Didier J.; Vetterli, Martin;
Assignee: Bell Communications Research, Inc. (Livingston, NJ)
Primary Examiner: Groody; James J.
Assistant Examiner: Lee; Michael H.
Attorney, Agent or Firm: Suchyta; Leonard Charles, Baskerville; Loria J.

A filter bank comprising first and second finite impulse response diamond-shaped filters with finite precision filter coefficients is used to convert a high definition progressive video sequence in a vertical-time representation into an interlaced sequence and a deinterlacing sequence. The interlaced sequence may be used by a low resolution television receiver to display a low resolution television image. The interlaced and deinterlacing sequences may be recombined to perfectly reconstruct the progressive high definition video sequence which then may be used by a high definition television receiver. Thus, the inventive system has the advantage that it enables a single high definition video sequence to be utilized by both high definition television equipment and lower resolution television equipment so that an existing base of consumer television equipment is not rendered obsolete by the introduction of a high definition television sequence.

DETAILED DESCRIPTION OF THE INVENTION Before describing the present invention in detail, it will be helpful to describe some properties of high definition television signals.
FIG.
1 shows a coordinate system defined by time, vertical and horizontal axes.
A plurality of video frames are illustrated with respect to this coordinate system.
The frames may correspond to a progressive or to an interlaced video sequence.
A progressive frame as seen in the vertical-horizontal plane is shown in FIG.
2.
In FIG.
2, each "dot" represents one sample of the video sequence.
As indicated by the dots in FIG.
2, each line in the frame contains signal samples.
Two successive interlaced frames as seen in the vertical-horizontal plane are illustrated in FIGS.
3A and 3B.
In each of the interlaced frames, there are signal samples on every other line, with the odd-numbered lines containing samples in one frame and the even-numbered lines containing samples in the next frame as indicated by the circled l's in FIG.
3A and the circled 2's in FIG.
3B.
Instead of looking at a video signal in the vertical-horizontal representation, it is also possible to consider a video signal in the vertical-time representation.
To consider a video signal in the vertical-time representation, a memory is utilized to store a sequence of the video frames shown in FIG.
1.
FIG.
4A shows a progressive signal in the vertical-time representation and FIG.
4B shows an interlaced signal in the vertical-time representation.
The pattern of samples in FIG.
4B is known as the quincunx pattern.
To go from a progressive sequence as shown in FIG.
4A to an interlaced sequence as shown in FIG.
4B, a quincunx sampler is utilized to remove every other sample from each line of FIG.
4A.
The odd-numbered samples are removed from one line and the even-numbered samples are removed from the next line.
FIG.
5 schematically illustrates a filter system 1 for converting a progressive video sequence into an interlaced sequence and a deinterlacing sequence and for reconstructing the progressive sequence from the interlaced and deinterlacing sequences

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