Receiver and channel compatible encoding/decoding system for high definition video

• US 5,561,467 A
• Filed: 03/26/1990
• Issued: 10/01/1996
• Est. Priority Date: 03/26/1990
• Status: Expired due to Fees

• Current Assignee: Nippon Hoso Kyokai
• Original Assignee: Nippon Hoso Kyokai
• Inventors: Suzuki, Shoichi, Kondo, Isao, Hamazumi, Hiroyuki, Tadenuma, Makoto, Yajima, Ryoichi, Kurita, Taiichiro, Yano, Sumio, Yuyama, Ichiro, Nishizawa, Taiji, Kato, Hisakazu, Tanaka, Yutaka, Takeuchi, Yoshio, Honda, Minoru, Kumada, Junji, Gohshi, Seiichi, Okuda, Haruo, Okui, Makoto, Kanatsugu, Yasuaki, Shibuya, Kazuhiko, Izumi, Yoshinori, Enami, Kazumasa
• Primary Examiner(s): Harvey, David E.
• Application Number:
  US07/498,778
• Time in Patent Office: 2,381 Days
• Field of Search: 358/141, 358/142, 358/147, 358/146, 358/11, 358/12, 358/13, 348/426, 348/432, 348/433, 348/434, 348/435, 348/436, 348/437, 348/427, 348/429, 348/430, 348/431
• US Class Current: 375/240.25
• CPC Class Codes: H04N 11/14 in which one signal, modulated in phase and amplitude, conveys colour information and a second signal conveys brightness information, e.g. NTSC-system
• CPC Class Codes: H04N 11/24 High-definition television systems
• CPC Class Codes: H04N 7/007 Systems with supplementary picture signal insertion during a portion of the active part of a television signal, e.g. during top and bottom lines in a HDTV letter-box system
• CPC Class Codes: H04N 7/0122 the input and the output signals having different aspect ratios
• CPC Class Codes: H04N 7/0152 using spatial or temporal subsampling
• CPC Class Codes: H04N 7/0803 using frequency interleaving, e.g. with precision offset
• CPC Class Codes: H04N 7/081 the additional information signals being transmitted by means of a subcarrier
• CPC Class Codes: H04N 9/832 using an increased bandwidth for the luminance or the chrominance signal

Abstract

High resolution vertical and horizontal components of a high definition video signal are combined with a standard broadcast system video signal, such as the NTSC system, in which high frequency horizontal resolution components are sampled and used to modulate at least a first sub-carrier signal. The first sub-carrier is frequency interleaved onto the standard broadcast signal. Vertical high resolution components are time compressed and time division multiplexed onto top and bottom portions of the standard broadcast signal. The modified broadcast signal can be decoded by a standard receiver to display a standard resolution video image, while receivers designed to decode the modified signal can time division demultiplex the vertical high resolution components and demodulate the horizontal high resolution components, combine these components with the standard components, and generate a high definition video image.

Claims

1. An encoder for converting a second television signal with a high resolution and having the larger number of horizontal scanning lines, a broader frequency bandwidth and a larger aspect ratio of a frame relative to a first television signal into a third television signal which is compatible with said first television signal, said encoder comprising:

means for separating a luminance vertical high band component of said second television signal which is higher than a luminance vertical low band component of said second television signal from said second television signal, said luminance vertical high band component of said second television signal corresponding to a central scanning line portion out of said central portion and upper and lower scanning line portions of said first television signal, said central scanning line portion and said upper and lower scanning line portions being divided in the ratio of an aspect ratio of said first television signal to that of said second television signal;

means for converting the number of scanning lines of said second television signal obtained by removing said luminance vertical high band component from said second television signal, into the number of scanning lines in said central portion;

means for frequency-converting a luminance horizontal high band component in the second television signal from said means for converting and having a bandwidth higher than a frequency bandwidth of said first television signal, into a separable signal which is multiplexed to a frequency region higher than the frequency region of a luminance horizontal low band component in said second television signal and is separable on a decoder side;

means for multiplexing said separable signal to a luminance horizontal low band component;

delay means for time-shifting said luminance vertical high band component of said second television signal to said upper and lower scanning line portions; and

means for combining an output from said means for multiplexing with an output from said delay means to obtain said third television signal.

2. An encoder as claimed in claim 1, wherein said first television signal is an NTSC standard television signal.

3. An encoder as claimed in claim 1, wherein said second television signal is produced by converting at least one of the number of scanning lines and a field frequency of a fourth television signal.

4. An encoder as claimed in claim 1, wherein said second television signal has substantially 750 scanning lines, a field frequency of substantially 59.94 Hz, and an aspect ratio of substantially 16:

9.

5. An encoder as claimed in claim 3, wherein said fourth television signal has substantially 1125 scanning lines, a field frequency of substantially 60 Hz, and an aspect ratio of substantially 16:

9.

6. An encoder as claimed in claim 1, wherein said luminance vertical high band component corresponds substantially to 345 central scanning lines in said central scanning line portion of said first television signal.

7. An encoder as claimed in claim 1, further comprising means for generating a carrier for frequency-converting the luminance horizontal high band component into said separable signal, the frequency of said carrier being so determined that the luminance horizontal high band component converted is multiplexed in a frequency-interleaving relationship with said horizontal luminance low band component.

8. An encoder as claimed in claim 7, further comprising:

means for generating a subcarrier;

means for modulating said subcarrier by a color signal of said second television signal; and

means for multiplexing said luminance horizontal low band component in a frequency-interleaving relationship with the subcarrier modulated by said color signal, the frequency of said carrier for converting said luminance horizontal high band component into said separable signal being so determined that the luminance horizontal high band component converted is frequency-interleaved with said luminance horizontal low band component and said subcarrier modulated by said color signal.

9. An encoder as claimed in claim 8, wherein said carrier for frequency-converting said luminance horizontal high band component into said separable signal has a frequency substantially equal to (60n+7.5) (n:

integer).

10. An encoder as claimed in claim 7, further comprising:

means for frequency-dividing said luminance horizontal high band component into first and second high band components; and

means for modulating said first and second high band components with a carrier having a phase off-set at every frame, line and field.

11. An encoder as claimed in claim 8, further comprising:

means for frequency-dividing said luminance horizontal high band component into first and second high band components; and

means for modulating said first and second high band components with a carrier having a phase off-set at every frame, line and field.

12. An encoder as claimed in claim 1, wherein said delay means comprises means for time-compressing the shifted luminance vertical high band component to time-division multiplex the vertical high band components in plural scanning lines.

13. An encoder as claimed in claim 1, wherein said means for separating and said means for converting the number of scanning lines include in common means for obtaining the sum of the two luminance signals in two scanning lines of said second television signals as said luminance vertical low band component, means for obtaining the difference between said two luminance signals as said luminance vertical high band component and means for selectively outputting one of said sum and said difference to form a luminance signal in one scanning line of said third television signal.

14. An encoder as claimed in claim 13, wherein said means for obtaining the difference performs a weighted subtraction of said two luminance signals in a manner that the d.c. components of said two luminance signals are cancelled out.

15. An encoder as claimed in claim 1, wherein said means for combining includes means for setting said output from said delay means at a level lower than the black level of said third television signal so that the output set at said level is combined with said output from said means for multiplexing.

16. An encoder as claimed in claim 1, further comprising:

means for separating a chrominance high band component of said second television signal from the chrominance signal of said second television signal having a bandwidth broader than the bandwidth of the chrominance signal of said first television signal;

means for time-shifting the chrominance high band components separated to said upper and lower scanning line portions; and

means for multiplexing the chrominance high band component time-shifted to the chrominance component in said upper and lower scanning line portions.

17. An encoder as claimed in claim 16, wherein said means for multiplexing includes means for converting the frequency of said chrominance high band component to a frequency having a frequency-interleaving relation with said luminance vertical high band component.

18. An encoder as claimed in claim 17, wherein said chrominance signal of said second television signal has I and Q signals said means for multiplexing includes means for multiplexing the high band components of said I and Q signals to said upper and lower scanning line portions in field sequence.

19. An encoder as claimed in claim 1, further comprising:

means for detecting a motion in said second television signal to output a motion detection signal; and

means for controlling said means for separating in accordance with said motion detection signal so that said luminance vertical high band component is separated from said second television signal when said motion detection signal is outputted.

20. An encoder as claimed in claim 1, further comprising:

means for detecting a motion in said second television signal to output a motion detection signal; and

means for controlling said means for multiplexing so that the multiplexing of said separable signal to said luminance horizontal low band component is suppressed when said motion detection signal is outputted.

21. An encoder as claimed in claim 19, wherein said means for detecting the motion includes:

means for dividing the frequency bandwidth of said second television signal into plural division bandwidths;

means for detecting respective motions in said plural division bandwidths; and

means for combining the results of the detections by said means for detecting the respective motions to judge said motion in said second television signal.

22. An encoder as claimed in claim 20, wherein said means for detecting the motion includes:

means for dividing the frequency bandwidth of said second television signal into plural division bandwidths;

means for detecting respective motions in said plural division bandwidths; and

means for combining the results of the detections by said means for detecting the respective motions to judge said motion in said second television signal.

23. An encoder as claimed in claim 3, further comprising:

a first reverse matrix circuit for forming first non-linear three-primary-color signals from a first non-linear luminance signal and two non-linear color signals of said second television signal,

a reverse gamma correction circuit for converting said first non-linear three-primary-color signals into first linear three-primary-color signals;

a first matrix circuit for converting said first linear three-primary-color signals into a linear luminance signal and two linear chrominance signals;

first band limit filter means for limiting a frequency band for a still picture portion in said linear luminance signal and two linear chrominance signals;

second band limit filter means for limiting a frequency band for a motion picture portion in said linear luminance signal and two linear chrominance signals;

means for detecting a motion in said second television signal to output a motion detection signal;

a selector for selectively outputting one of the outputs from said first and second band limit filters;

a second reverse matrix circuit for converting the output from said selector into second linear three-primary-color signals;

a gamma correction circuit for converting said second linear three-primary-color signals into second non-linear three-primary-color signals;

a second matrix circuit for converting said second non-linear three-primary-color signals into a non-linear luminance signal and two non-linear chrominance signals.

24. An encoder as claimed in claim 3, further comprising:

a first reverse matrix circuit for forming first non-linear three-primary-color signals from a first non-linear luminance signal and two non-linear color signals of said second television signal,

a reverse gamma correction circuit for converting said first non-linear three-primary-color signals into first linear three-primary-color signals;

a first matrix circuit for converting said first linear three-primary-color signals into a linear luminance signal and two linear chrominance signals;

low pass filter means for extracting low band components of said chrominance signals;

a second reverse matrix circuit for converting said low band components of said chrominance signals and said linear luminance signal into second linear three-primary-color signals;

a gamma correction circuit for converting said second linear three-primary-color signals into second non-linear three-primary-color signals;

a second matrix circuit for converting said second non-linear three-primary-color signals into a second non-linear luminance signal;

a third matrix circuit for converting said first non-linear three-primary-color signals into at least first two non-linear chrominance signals; and

low pass filter means for extracting low band components of said first two non-linear chrominance signals to output second two non-linear chrominance signals, said second non-linear luminance signal from said second matrix circuit and said second two non-linear chrominance signals being applied to said means for separating a luminance vertical high band component of said second television signal.

25. An encoder as claimed in claim 3, further comprising:

a motion edge detection filter having;

a first high pass filter in a time axis direction for extracting a luminance high band component in the time axis direction from the luminance signal of said second television signal; and

a second high pass filter in a horizontal direction and/or a vertical direction for extracting a luminance high band component in the horizontal and/or vertical direction of the output from said first high pass filter in the time axis direction to output a motion edge signal; and

an adder for combining said motion edge signal with said luminance signal of said second television signal to output an improved luminance signal.

26. A decoder for decoding the second television signal from the third television signal encoded by an encoder for converting said second television signal with a high resolution and having the larger number of horizontal scanning lines, a broader frequency bandwidth and a larger aspect ratio of a frame relative to the first television signal into said third television signal which is compatible with said first television signal, said decoder comprising:

means for separating a central scanning line portion and upper and lower scanning line portions of said third television signal;

means for extracting a luminance horizontal low band component from said central scanning line portion;

means for extracting a luminance horizontal high band component signal having luminance horizontal high band components multiplexed on the side of said decoder in a frequency region higher than the frequency region of said luminance horizontal low band component, from said central scanning line portion;

means for frequency-converting said luminance horizontal high band component signal into said luminance horizontal high band components arranged in plural frequency regions high than the frequency region of said luminance horizontal low band component;

means for combining said luminance horizontal high band components with said luminance horizontal low band component to obtain a broad-band luminance horizontal signal;

a first scanning line number conversion means for converting the number of scanning lines of said broad-band luminance horizontal signal into the number of scanning lines of said second television signal;

a second scanning line number conversion means for converting the number of scanning lines of the signals in the upper and lower scanning line portions into signals having scanning lines, the number of which is equal to the number of scanning lines of said second television signal; and

means for combining the outputs from said first and second scanning line number conversion means with each other.

27. A decoder as claimed in claim 26, wherein said first television signal is an NTSC standard television signal.

28. A decoder as claimed in claim 26, wherein said second television signal has substantially 750 scanning lines, a field frequency of substantially 59.94 Hz and an aspect ratio of substantially 16:

9.

29. A decoder as claimed in claim 26, further comprising means for demultiplexing and time axis expanding said signals in the upper and lower scanning line portions which are time-division multiplexed.

30. A decoder as claimed in claim 29, wherein a high band component of a color signal is multiplexed to said upper and lower scanning line portions in a frequency interleaving relationship and said second scanning line number conversion means comprises a comb filter for removing said high band component of said color signal, said comb filter having characteristics corresponding to said frequency interleaving relationship.

31. A decoder as claimed in claim 26, wherein said means for frequency-converting said luminance horizontal high band component signal comprises a comb filter having characteristics corresponding to a frequency interleaving relationship between said luminance horizontal high band components in said predetermined frequency region and for outputting said luminance horizontal high band components and a demodulator for frequency-converting the output from said comb filter into said plural frequency regions.

32. A decoder as claimed in claim 26, wherein said luminance horizontal high band components are obtained by four-field multiplexing on the side of said encoder, and said means for frequency-converting said luminance horizontal high band component signal comprises means for sub-sampling said luminance horizontal high band components by an offset sub-sampling pulse having a relation with the correlation between four fields and a demodulator for frequency-converting the output from said comb filter into said plural frequency regions.

33. A decoder as claimed in claim 26, further comprising:

means for decoding chrominance high band components of chrominance signals I and Q contained in the separated upper and lower scanning line portions;

means for time-shifting said chrominance high band components decoded; and

means for combining the shifted high band components with chrominance low band components of said chrominance signals I and Q contained in the separated central scanning line portion to form color signals with a broader frequency band.

34. A decoder as claimed in claim 33, wherein said chrominance high band components are multiplexed to each other in said upper and lower scanning line portions in a frequency interleaving relationship on the side of said encoder, and further comprising a comb filter for separating said chrominance high band components from said upper and lower scanning line portions, said comb filter having characteristics corresponding to said frequency interleaving relationship;

and a demodulator for frequency converting the separated chrominance high band components into a frequency band of said chrominance high band component.

35. A decoder as claimed in claim 33, wherein said chrominance high band components of said I and Q signals are multiplexed sequentially field by field on the side of said encoder, and further comprising means for selectively outputting said chrominance high band components of said I and Q signals in field sequence;

means for frequency converting chrominance high band components selectively outputted into predetermined frequency bands, respectively; and

means for combining chrominance high band components frequency-converted with chrominance low band components of said I and Q signals, respectively.

36. A decoder as claimed in claim 26, further comprising:

motion detection means for detecting a portion of said third television signal where a picture moves to output a motion detection signal; and

means for controlling said means for frequency-converting said luminance horizontal high band component signal to enable the outputs from said means for frequency-converting said luminance horizontal high band component signal when said motion detection means outputs said motion detection signal.

37. A decoder as claimed in claim 33, further comprising:

motion detection means for detecting a portion of said third television signal where a picture moves to output a motion detection signal; and

means for controlling said means for decoding chrominance high band components of chrominance signals I and Q to enable the outputs from said means for decoding chrominance high band components of chrominance signals I and Q when said motion detection means outputs said motion detection signal.

38. A decoder as claimed in claim 26, further comprising:

means for controlling said first and second scanning line number conversion means in accordance with said motion detection signal from said motion detection means.

39. A decoder as claimed in claim 26, further comprising means for detecting phase information with respect to a zero crossing point of a color burst signal in said third television signal;

and

means for regenerating a synchronizing signal in accordance with the phase information detected.

40. A decoder as claimed in claim 39, wherein said means for detecting the phase information includes means for generating a puke at a zero crossing point of a subcarrier at a predetermined position in said color burst signal television signal.

41. A decoder as claimed in claim 39, wherein said means for detecting phase information includes:

an A/D converter for converting said third television signal to output a sampled value sampled at a sampling phase;

means for synchronously separating a horizontal synchronizing pulse from said third television signal;

means for generating a pulse indicative of a position of a zero crossing point of a subcarrier at a predetermined position in said color burst signal in said third television signal;

means for calculating said phase information in accordance with a sampled value at said position of said zero crossing point and sampled values at positions adjacent to said position of said zero crossing point positions from said A/D converter; and

means for feeding-back said phase information calculated to said sampling phase in said A/D converter.

42. A decoder as claimed in claim 39, wherein said means for detecting phase information includes edge detection means for detecting whether a zero crossing point of a subcarrier at a predetermined position in said color burst signal in said third television signal has a positive or negative edge;

and said means for regenerating includes means for regenerating a carrier having a frequency of M×

f_h /2 (M;

integer, f_h ;

horizontal synchronizing frequency) in accordance with the phase information from said means for detecting phase information and the information detected by said edge detection means.

43. A broad bandwidth television signal transmission system having an encoder for converting a second television signal with a high resolution and having the larger number of horizontal scanning lines, a broader frequency bandwidth and a larger aspect ratio of a frame relative to a first television signal into a third television signal which is compatible with said first television signal, and a decoder for decoding a second television signal from a third television signal encoded by an encoder for converting said second television signal with a high resolution and having the larger number of horizontal scanning lines, a broader frequency bandwidth and a larger aspect ratio of a frame relative to a first television signal into said third television signal which is compatible with said first television signal, said system comprising on the transmitter side:

means for separating a luminance vertical high band component of said second television signal which is higher than a luminance vertical low band component of said second television signal from said second television signal, said luminance vertical high band component of said second television signal corresponding to a central scanning line portion out of said central portion and upper and lower scanning line portions of said first television signal, said central scanning line portion and said upper and lower scanning line portions being divided in the ratio of an aspect ratio of said first television signal to that of said second television signal;

means for converting the number of scanning lines of said second television signal obtained by removing said luminance vertical high band component from said second television signal, into the number of scanning lines in said central portion;

means for frequency-converting a luminance horizontal high band component in the second television signal from said means for converting and having a bandwidth higher than a frequency bandwidth of said first television signal, into a separable signal which is multiplexed to a frequency region higher than the frequency region of a luminance horizontal low band component in said second television signal and is separable on a decoder side;

means for multiplexing said separable signal to a luminance horizontal low band component;

delay means for time-shifting said luminance vertical high band component of said second television signal to said upper and lower scanning line portions;

means for combining an output from said means for multiplexing with an output from said delay means to obtain said third television signal; and

transmitting means for modulating a carrier signal by said third television signal from said means for combining and for transmitting the modulated carrier signal; and

said system further comprising on the receiver side;

receiving means receiving the transmitted modulated carrier signal and for demodulating the third television signal therefrom;

means for separating a central scanning line portion and upper and lower scanning line portions of said third television signal;

means for extracting a luminance horizontal low band component from said central scanning line portion;

means for extracting a luminance horizontal high band component signal having luminance horizontal high band components multiplexed on the side of said decoder in a frequency region higher than the frequency region of said luminance horizontal low band component, from said central scanning line portion;

means for frequency-converting said luminance horizontal high band component signal into said luminance horizontal high band components arranged in plural frequency regions high than the frequency region of said luminance horizontal low band component;

means for combining said luminance horizontal high band components with said luminance horizontal low band component to obtain a luminance horizontal signal;

a first scanning line number conversion means for converting the number of scanning lines of said luminance horizontal signal into the number of scanning lines of said second television signal;

a second scanning line number conversion means for converting the number of scanning lines of the signals in the upper and lower scanning line portions into signals having scanning lines, the number of which is equal to the number of scanning lines of said second television signal; and

means for combining the outputs from said first and second scanning line number conversion means with each other.

44. A broad bandwidth television signal transmission system as claimed in claim 43, wherein said modulated carrier signal is transmitted through a cable transmission system.

45. A broad bandwidth television signal transmission system as claimed in claim 43, wherein said modulated carrier signal is transmitted through a wireless transmission system.

46. A broad bandwidth television signal transmission system as claimed in claim 43, further comprising:

means for combining an audio signal relating to said second television signal in combination with said third television signal, so that said carrier signal is modulated by the combined signal; and

means for extracting the audio signal; and

means for extracting the audio signal from the received modulated carrier signal.

47. A broad bandwidth television signal recording/reproducing system having an encoder for converting a second television signal with a high resolution and having the larger number of horizontal scanning lines, a broader frequency bandwidth and a larger aspect ratio of a frame relative to a first television signal into a third television signal which is compatible with said first television signal, and a decoder for decoding a second television signal from a third television signal encoded by an encoder for converting said second television signal with a high resolution and having the larger number of horizontal scanning lines, a broader frequency bandwidth and a larger aspect ratio of a frame relative to a first television signal into said third television signal which is compatible with said first television signal, said system comprising on the recording side:

means for separating a luminance vertical high band component of said second television signal which is higher than a luminance vertical low band component of said second television signal from said second television signal, said luminance vertical high band component of said second television signal corresponding to a central scanning line portion out of said central portion and upper and lower scanning line portions of said first television signal, said central scanning line portion and said upper and lower scanning line portions being divided in the ratio of an aspect ratio of said first television signal to that of said second television signal;

means for converting the number of scanning lines of said second television signal obtained by removing said luminance vertical high band component from said second television signal, into the number of scanning lines in said central portion;

means for frequency-converting a luminance horizontal high band component in the second television signal from said means for converting and having a bandwidth higher than a frequency bandwidth of said first television signal, into a separable signal which is multiplexed to a frequency region higher than the frequency region of a luminance horizontal low band component in said second television signal and is separable on a decoder side;

means for multiplexing said separable signal to a luminance horizontal low band component;

delay means for time-shifting said luminance vertical high band component of said second television signal to said upper and lower scanning line portions;

means for combining an output from said means for multiplexing with an output from said delay means to obtain said third television signal; and

recording means for recording said third television signal from said means for combining on a recording medium; and

said system further comprising on the reproducing side;

reproducing means for reproducing the third television signal from said recording medium;

means for separating a central scanning line portion and upper and lower scanning line portions of said third television signal;

means for extracting a luminance horizontal low band component from said central scanning line portion;

means for extracting a luminance horizontal high band component signal having luminance horizontal high band components multiplexed on the side of said decoder in a frequency region higher than the frequency region of said luminance horizontal low band component, from said central scanning line portion;

means for frequency-converting said luminance horizontal high band component signal into said luminance horizontal high band components arranged in plural frequency regions high than the frequency region of said luminance horizontal low band component;

means for combining said luminance horizontal high band components with said luminance horizontal low band component to obtain a luminance horizontal signal;

a first scanning line number conversion means for converting the number of scanning lines of said luminance horizontal signal into the number of scanning lines of said second television signal;

a second scanning line number conversion means for converting the number of scanning lines of the signals in the upper and lower scanning line portions into signals having scanning lines, the number of which is equal to the number of scanning lines of said second television signal; and

means for combining the outputs from said first and second scanning line number conversion means with each other.

48. A broad bandwidth television signal recording/reproducing system as claimed in claim 47, wherein said recording medium is a magnetic disc.

49. A broad bandwidth television signal recording/reproducing system as claimed in claim 47, wherein said recording medium is an optical disc.

50. A broad bandwidth television signal recording/reproducing system as claimed in claim 47, wherein said recording medium is a magnetic tape.

51. A broad bandwidth television signal recording/reproducing system as claimed in claim 47, further comprising:

means for recording said audio signal on said recording medium; and

means for reproducing the recorded audio signal from said recording medium.