CA2235102A1 - Method and apparatus for scrambling and descrambling of video signals with edge fill - Google Patents
Method and apparatus for scrambling and descrambling of video signals with edge fillInfo
- Publication number
- CA2235102A1 CA2235102A1 CA 2235102 CA2235102A CA2235102A1 CA 2235102 A1 CA2235102 A1 CA 2235102A1 CA 2235102 CA2235102 CA 2235102 CA 2235102 A CA2235102 A CA 2235102A CA 2235102 A1 CA2235102 A1 CA 2235102A1
- Authority
- CA
- Canada
- Prior art keywords
- video
- location
- sync signal
- active
- colorburst
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Landscapes
- Two-Way Televisions, Distribution Of Moving Picture Or The Like (AREA)
- Television Systems (AREA)
Abstract
A video-scrambling system induces a random wobble i.e., time shifting, in the location of active portion of the video frame, without affecting the horizontal sync signal and colorburst in each video line, thus providing both security and concealment. The security is enhanced by filling in the gap between the nominal beginning of active video and the actual beginning of active video with a synthesized video signal which replicates the adjacent active video using a digitally generated filling pattern.
Also, a random noise overlay further conceals the location of the gap. Additional concealment is provided by wiggling in time the location of the horizontal sync signal using one or two frequencies and also by randomly altering the location of the vertical sync signal. The NTSC digital encoding in accordance with the invention is simplified by using only two channels, chrominance and luminance, and by a heterodyne circuit for chrominance stability. NTSC encoding is enhanced by providing detail normally lost, by use of the chroma channel. Additionally, a non-standard video signal may be provided with a portion of the colorburst on the front porch of the horizontal blanking, thus allowing use of a relatively simple decoder.
Also, a random noise overlay further conceals the location of the gap. Additional concealment is provided by wiggling in time the location of the horizontal sync signal using one or two frequencies and also by randomly altering the location of the vertical sync signal. The NTSC digital encoding in accordance with the invention is simplified by using only two channels, chrominance and luminance, and by a heterodyne circuit for chrominance stability. NTSC encoding is enhanced by providing detail normally lost, by use of the chroma channel. Additionally, a non-standard video signal may be provided with a portion of the colorburst on the front porch of the horizontal blanking, thus allowing use of a relatively simple decoder.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US79589091A | 1991-11-19 | 1991-11-19 | |
| US795,890 | 1991-11-19 | ||
| CA002082675A CA2082675C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002082675A Division CA2082675C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2235102A1 true CA2235102A1 (en) | 1993-05-20 |
| CA2235102C CA2235102C (en) | 2000-01-25 |
Family
ID=25675660
Family Applications (5)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002235101A Expired - Fee Related CA2235101C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
| CA002235097A Expired - Fee Related CA2235097C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
| CA002235099A Expired - Fee Related CA2235099C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
| CA002235102A Expired - Fee Related CA2235102C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
| CA002235100A Expired - Fee Related CA2235100C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
Family Applications Before (3)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002235101A Expired - Fee Related CA2235101C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
| CA002235097A Expired - Fee Related CA2235097C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
| CA002235099A Expired - Fee Related CA2235099C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
Family Applications After (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002235100A Expired - Fee Related CA2235100C (en) | 1991-11-19 | 1992-11-12 | Method and apparatus for scrambling and descrambling of video signals with edge fill |
Country Status (1)
| Country | Link |
|---|---|
| CA (5) | CA2235101C (en) |
-
1992
- 1992-11-12 CA CA002235101A patent/CA2235101C/en not_active Expired - Fee Related
- 1992-11-12 CA CA002235097A patent/CA2235097C/en not_active Expired - Fee Related
- 1992-11-12 CA CA002235099A patent/CA2235099C/en not_active Expired - Fee Related
- 1992-11-12 CA CA002235102A patent/CA2235102C/en not_active Expired - Fee Related
- 1992-11-12 CA CA002235100A patent/CA2235100C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2235100C (en) | 2000-01-25 |
| CA2235101A1 (en) | 1993-05-20 |
| CA2235100A1 (en) | 1993-05-20 |
| CA2235101C (en) | 2001-07-17 |
| CA2235097C (en) | 2000-02-29 |
| CA2235099C (en) | 2000-01-25 |
| CA2235102C (en) | 2000-01-25 |
| CA2235099A1 (en) | 1993-05-20 |
| CA2235097A1 (en) | 1993-05-20 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed | ||
| MKLA | Lapsed |
Effective date: 20041112 |