Frame switcher and method of switching, digital camera and monitoring system

• US 6,791,602 B1
• Filed: 04/20/2000
• Issued: 09/14/2004
• Est. Priority Date: 04/30/1999
• Status: Expired due to Term

• Current Assignee: Security Video Camera Systems Inc. (Wi-LAN Inc.)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Shinohara, Toshiaki, Sasaki, Yuhi
• Primary Examiner(s): DIEP, NHON THANH
• Application Number:
  US09/553,150
• Time in Patent Office: 1,608 Days
• Field of Search: H04/N.592, H04/N.591, 348/153, 348/159, 348/705, 386/109, 386/46, 386/52
• US Class Current: 348/159
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/4223 Cameras H04N23/00 takes precedence
• CPC Class Codes: H04N 21/4334 Recording operations recording of a television signal H04N5/76; arrangements for recording or accumulating broadcast information or broadcast-related information H04H60/27
• CPC Class Codes: H04N 21/43615 Interfacing a Home Network, e.g. for connecting the client to a plurality of peripherals home Audio Video Interoperability [HAVI] data switching networks H04L12/2805
• CPC Class Codes: H04N 21/43632 involving a wired protocol, e.g. IEEE 1394 high-speed IEEE 1394 serial bus H04L12/40052
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 5/268 Signal distribution or switching
• CPC Class Codes: H04N 7/181 for receiving images from a plurality of remote sources

Abstract

A plurality of digital cameras that are synchronized are connected to a switcher, thus constructing a digital monitoring system in which image signals from the cameras are switched and received. A method of switching the image signals includes the steps of setting transmission timings and transmission cycles of I frames from the digital cameras, buffering the image signals of one cycle from the cameras, and extracting necessary I frames from the buffered image signals. Even though the digital image signals include frames depending upon other frames such as P frame and B frame, the I frames are received by switching operation.

Claims

1. A digital monitoring system comprising MPEG cameras that are synchronized and a switcher, wherein said cameras are provided to set transmission timings and transmission cycle times of I frames, and said switcher is provided to buffer image signals of one cycle from said cameras and extract the I frames from the buffered image signals to a necessary extent.

2. A digital monitoring system comprising MPEG cameras that are synchronized and a switcher, wherein said cameras are provided to set transmission timings and transmission cycle times of I frames, and said switcher is provided to buffer image signals of once cycle from said cameras and extract the I frames from the buffered image signals to a necessary extent, the transmission timings of I frames from said cameras being shifted.

3. A digital monitoring system comprising MPEG cameras that are synchronized and a switcher, wherein said cameras are provided to set transmission timings and transmission cycle times of I frames, and said switcher as provided to switch image signals from said cameras in accordance with the transmission timings of I frames, the transmission timings of I frames from said cameras being shifted.

4. A digital monitoring system comprising MPEG cameras that are synchronized and a switcher, wherein said cameras are provided set transmission timings and transmission cycle times of I frames, and said switcher is provided to switch image signals from said cameras in accordance with the transmission timings of I frames, the transmission timings of I frames from said cameras being shifted and only the I frames from said cameras being transmitted on a single channel in a time sharing manner.

5. A method of switching image signals comprising the steps of:

providing a plurality of cameras for producing digital image signals, which are synchronized;

providing a switcher for switching the image signals from said cameras;

setting the synchronization of said cameras so that transmission timings and transmission cycle times of I frames are simultaneously performed; and

buffering the image signals of one cycle from said cameras and extracting necessary I frames from the buffered image signals by switching operation.

6. A method of switching image signals comprising the steps of:

providing a plurality of cameras for producing digital image signals, which are synchronized;

providing a switcher for switching the image signals from said cameras;

setting synchronization of said cameras so that transmission timings and transmission cycle times of I frames are simultaneously performed; and

buffering the image signals of one cycle from said cameras and extracting necessary I frames from the buffered image signals by switching operation with the transmission timings of I frames being shifted among said cameras.

7. A method of switching image signals comprising the steps of:

providing a plurality of cameras for producing digital image signals, which are synchronized;

providing a switcher for switching the image signals from said cameras;

setting synchronization of said cameras so that transmission timings of I frames are different from each other and transmission cycle times of I frames are identical with each other; and

transmitting the I frames in synchronization with the different transmission timings of I frames with the timings being shifted among said cameras by switching operation.

8. A method of switching image signals comprising the steps of:

providing a plurality of cameras for producing digital image signals, which are synchronized;

providing a switcher for switching the image signals from said cameras;

setting synchronization of said cameras so that transmission timings of I frames are different from each other and transmission cycle times of I frames are identical with each other; and

transmitting only the I frames in synchronization with the different transmission timings of I frames by switching operation with the timings being shifted among said cameras and sharing a signal channel by said cameras in a time division manner.

9. A digital camera comprising:

imaging means for picking up images;

digitizing means for converting an image signal produced by said imaging means into a digital signal;

timing control means for controlling a transmission timing of I frame of the image signal;

setting means for setting a timing of said timing control means and a transmission cycle of the I frame; and

transmitting means for transmitting the image signal, whereby the I frame of the image signal is transmitted with a predetermined timing.

11. A digital camera according to claim 9, further comprising setting means for setting synchronization of a plurality of digital cameras so that transmission timings of I frames are simultaneously performed and transmission cycle times of I frames are identical with each other.

12. A digital camera according to claim 9, further comprising setting means for setting synchronization of a plurality of digital cameras so that transmission timings of I frames are different from each other and transmission cycle times of I frames are identical with each other.

10. A digital camera comprising:

imaging means for picking up images;

digitizing means for converting an image signal produced by said imaging means into a digital signal;

I frame extracting means for extracting a necessary I frame from the image signal;

timing control means for controlling a transmission timing of I frame of the image signal;

setting means for setting a timing of said timing control means and a transmission cycle of I frame; and

transmitting means for transmitting the image signal, whereby the I frame of the image signal is transmitted with a predetermined timing.

18. A digital camera according to claim 10, further comprising setting means for setting synchronization of a plurality of digital cameras so that transmission timings of I frames are simultaneously performed and transmission cycle times of I frames are identical with each other.

19. A digital camera according to claim 10, further comprising setting means for setting synchronization of a plurality of digital cameras so that transmission timings of I frames are different from each other and transmission cycle times of I frames are identical with each other.

13. A switcher comprising:

receiving means for receiving image signals from a plurality of cameras for producing digital image signals, which are synchronized;

buffer means for temporarily storing the image signals of one cycle received from said cameras;

I frame extracting means for extracting only necessary I frames from the stored image signals in said buffer means;

timing control means for controlling an operation timing of said I frame extracting means;

setting means for setting a timing of said timing control means; and

transmitting means for transmitting the image signals, whereby the I frames of the image signals are extracted from said buffer means and transmitted with a predetermined timing.

14. A switcher according to claim 13, wherein said setting means sets said cameras so that transmission timings of I frames are simultaneously performed and transmission cycle times of I frames are identical with each other.

17. A switcher according to claim 13, wherein said setting means sets synchronization of said cameras so that transmission timings of I frames are different from each other and transmission cycles of I frames are identical with each other.

15. A switcher comprising:

receiving means for receiving image signals from a plurality of cameras for producing digital image signals, which are synchronized;

channel switching means for switching channels on which the image signals are received to a channel on a camera for transmitting an I frame;

timing control means for controlling a switching timing of said channels in said channel switching means;

setting means for setting a timing of said timing control means; and

transmitting means for transmitting the image signals, whereby the I frames of the image signals are received and transmitted with a predetermined timing.

16. A switcher according to claim 15, further comprising buffer means for storing part of I frame data of the image signals received from said cameras.

20. A switcher according to claim 15, wherein said setting means sets synchronization of said cameras so that transmission timings of I frames are different from each other and transmission cycles of I frames are identical with each other.

21. A switcher according to claim 16, wherein said setting means sets synchronization of said cameras so that transmission timings of I frames are different from each other and transmission cycles of I frames are identical with each other.