System for adaptively generating signal in alternate formats as for an EDTV system

• US 4,866,509 A
• Filed: 08/30/1988
• Issued: 09/12/1989
• Est. Priority Date: 08/30/1988
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Guida, Allan A.
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US07/238,238
• Time in Patent Office: 378 Days
• Field of Search: 358/11, 358/12, 358/141, 358/140
• US Class Current: 375/240.25
• CPC Class Codes: H04N 11/28 involving bandwidth reduction, e.g. subsampling
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 7/015 High-definition television systems

Abstract

A video signal generating system develops an encoded video signal representing less than all of the video information. Auxiliary signal generating circuitry develops a pair of auxiliary signals representing in part the remaining video information. A first of the pair of auxiliary signals includes relatively high fidelity signal but with limited bandwidth. The second auxiliary signal includes relatively low fidelity information but has an effective higher bandwidth. Depending upon the information density of the auxiliary information, the first and second auxiliary signals are selected to produce an auxiliary output signal which is combined with the encoded video signal for transmission. A receiver responsive to the transmitted signal separates the video and auxiliary signals. The video and auxiliary signals are decoded and used to generate enhanced display images.

Claims

1. A system for generating a television signal comprising:

a source of video signal information;

means responsive to said video signal information for providing an encoded video signal, said encoded video signal excluding a portion of said video signal information;

means responsive to said video signal information for providing a first auxiliary signal conveying information related to said excluded portion of said video signal information, in a first signal format;

means responsive to said video signal information for providing a second auxiliary signal conveying information related to said excluded portion of said video signal information, in a second signal format;

means responsive to one of said first and second auxiliary signals for selectively providing said first auxiliary signal or said second auxiliary signal, as an auxiliary output signal, depending on the information density of said one of said first and second auxiliary signals; and

means for combining said auxiliary output signal and said encoded video signal to produce said television signal.

2. The system set forth in claim 1 wherein said first auxiliary signal is an analog signal and said second auxiliary signal is a digital signal.

3. The system set forth in claim 1 wherein said source provides progressive scan luminance signal and said means for providing encoded video signal provides interlace scan video signal and wherein said means for providing a first auxiliary signal includes:

delay means responsive to said progressive scan luminance signal for concurrently providing first, second and third luminance signals representing temporally adjacent horizontal lines of luminance signal from three successive field intervals; and

means for combining the first, second and third luminance signals in the relation (x_i -(A_i +B_i)/2) to generate a temporal difference signal representing said first auxiliary signal, where B_i, x_i and A_i represent the amplitudes of the first, second and third luminance signals respectively.

4. The system set forth in claim 3 wherein said delay means includes means for concurrently providing fourth and fifth luminance signals with said first, second and third luminance signals, said fourth and fifth luminance signals representing horizontal lines, respectively, vertically disposed above and below a horizontal line represented by said second luminance signal, and wherein said means for providing said second auxiliary signal includes:

means for combining said second, fourth and fifth signals in the relationship (x_i -(C_i +C_i+1)/2) to produce a vertical difference signal, where C_i and C_i+1 represent the amplitudes of the fourth and fifth luminance signals respectively; and

means responsive to said first auxiliary signal and said vertical difference signal for producing said second auxiliary signal exhibiting first and second states when the magnitude of the first auxiliary signal is greater and lesser than the magnitude of the vertical difference signal respectively.

5. The system set forth in claim 4 wherein said means for providing said second auxiliary signal further includes means for compressing said second auxiliary signal exhibiting first and second states.

6. The system set forth in claim 1 wherein said source provides a progressive scan luminance signal and said means for providing encoded video signal provides interlace scan video signals and wherein said means for providing said first auxiliary signal includes:

means responsive to said progressive scan luminance signal for generating a temporally difference signal representing the difference between progressive scan luminance signal representing a first horizontal line in a first field and the average of progressive scan luminance signal from temporally adjacent second and third horizontal lines in second and third fields, respectively, disposed before and after said first field;

means responsive to said progressive scan luminance signal for generating a vertical difference signal representing the difference between said first horizontal line and the average of progressive scan luminance signals representing fourth and fifth horizontal lines in said first field and vertically disposed on either side of said first horizontal line;

means for comparing said vertical and temporal difference signals for providing said first auxiliary signal exhibiting first and second states when the magnitude of said temporal difference signal is greater and lesser than the magnitude or said vertical difference signal respectively; and

wherein said means for providing a second auxiliary signal includes means responsive to said first auxiliary signal for selectively providing, as said second auxiliary signal, the vertical or temporally difference signal having the smaller magnitude.

7. The system set forth in claim 6 wherein said means for providing said first auxiliary signal further includes means for compressing said first auxiliary signal exhibiting first and second states;

and wherein said means for providing said second auxiliary signal further includes means for compressing said selectively provided vertical and temporally difference signals.

8. The system set forth in claim 6 wherein said first auxiliary signal is in single bit digital sample format and said vertical and temporally difference signals are in multibit digital sample format, and said means for providing said second auxiliary signal further includes means for appending said single bit digital samples of said first auxiliary signal to respective corresponding multibit samples of said selected vertical or temporally difference signal.

9. The system set forth in claim 1 further including a receiver, for receiving said television signal, comprising:

separating means, responsive to received television signal, for separating said encoded video signal and said auxiliary output signal;

video signal decoding means, responsive to said encoded video signal for generating an interlace scan luminance signal;

auxiliary signal decoding means, responsive to separated auxiliary output signal, for recognizing said first and second auxiliary signals and providing a decoded auxiliary signal; and

means, responsive to said interlace scan luminance signal and said decoded auxiliary signal for generating a progressive scan luminance signal.

10. A video signal processing system for processing a television signal including an encoded video signal having luminance and chrominance components in interlace scan format and including an auxiliary signal transmitted in alternative signal formats, said system comprising:

a source of said television signal;

separating means responsive to said television signal for providing separated encoded video and auxiliary signals;

video signal decoding means responsive to said separated encoded video signal for providing an interlace scan luminance signal;

auxiliary signal decoding means responsive to said separated auxiliary signal, for decoding said alternative auxiliary signal formats and providing a decoded auxiliary signal; and

a progressive scan processor, responsive to said interlace scan luminance signal and said decoded auxiliary signal for generating a progressive scan luminance signal.

11. The processing system set forth in claim 10 wherein said alternative signal formats of said auxiliary signal include a first signal format representing a bistate signal which indicates whether said progressive scan processing means will generate additional scan lines more accurately by vertical or temporally interpolation and a second signal format includes an analog signal representing differences between the actual signal values of said additional lines and temporally interpolated lines, and wherein said auxiliary signal decoding means includes:

means, responsive to said separated auxiliary signal, for detecting said first and second alternative signal formats; and

means, responsive to said detecting means and said separated auxiliary signal, for conditioning said auxiliary signal for application to said progressive scan processing means.

12. The system set forth in claim 11 wherein said progressive scan processing means includes:

interpolating means, responsive to said interlace scan luminance signal for concurrently providing vertical and temporal estimates of signal representing additional horizontal lines;

multiplexing means, responsive to a control signal for selectively providing either said vertical or said temporal estimates;

signal combining means having a first input terminal coupled to said multiplexing means, an output terminal and a second input terminal;

signal speed up circuitry, coupled to the output terminal of said signal combining means for time compressing interlace scan line intervals of signal to progressive scan line intervals of signal; and

wherein said means for conditioning said auxiliary signal, includes;

means responsive to said detecting means for selectively coupling signal representing said second signal format or a zero value signal to the second input terminal of said signal combining means when the second and first signal formats are detected respectively, and providing a control signal to said multiplexing means to condition said multiplexing means to provide temporally estimates when said second signal format is detected; and

means responsive to said separated auxiliary signal, for providing as a control signal to said multiplexing means, signal representing said first signal format when said first signal format is detected.

13. The processing system set forth in claim 10 wherein said alternative signal formats of said auxiliary signal include a first signal format representing a bistate signal which indicates whether said progressive scan processing means will generate additional scan lines more accurately by vertical or temporally interpolation, and a second signal format includes a signal representing samples of the smaller of vertical and temporally differences between actual signal values of said additional lines and corresponding vertically and temporally interpolated lines with said bistate signal appended to said samples to indicate whether the sample is a vertical or temporal difference, and wherein said auxiliary signal decoding means includes:

means responsive to said separated auxiliary signal for detecting said first and second alternative signal formats; and

means responsive to said detecting means and said separated auxiliary signal, for conditioning said separated auxiliary signal for application to said progressive scan processing means.

14. The system set forth in claim 13 wherein said progressive scan processing means includes:

interpolating means, responsive to said interlace scan luminance signal for concurrently providing vertical and temporal estimates of signal representing additional horizontal lines;

multiplexing means, responsive to a control signal for selectively providing either said vertical or said temporal estimates;

signal combining means having a first input terminal coupled to said multiplexing means, having an output terminal and a second input terminal;

speed up circuitry coupled to the output terminal of said signal combining means for time compressing interlace scan intervals of signal to progressive scan intervals of signal; and

wherein said means for conditioning said auxiliary signal includes;

means responsive to said detecting means and said separated auxiliary signal for coupling a signal representing said first signal format to said multiplexing means as said control signal and applying a zero value to the second input terminal of said signal combining means when said first signal format is detected; and

means responsive to said detecting means and said separated auxiliary signal, for separating said appended bistate signal from said vertical and temporal difference samples of said second signal format and coupling a signal representing said bistate signal, as a control signal to said multiplexing means, and coupling signal representing said vertical and temporal samples to the second input terminal of said signal combining means, when said second signal format is detected.