PRE-ALARM VIDEO BUFFER

• US 20080198268A1
• Filed: 07/09/2007
• Published: 08/21/2008
• Est. Priority Date: 07/13/2006
• Status: Active Grant

• Current Assignee: Axis AB (Canon Inc.)
• Original Assignee: Axis AB (Canon Inc.)
• Inventors: Tullberg, Joacim
• Granted Patent: US 8,384,830 B2
• Time in Patent Office: Days
• US Class Current: 348/659
• CPC Class Codes: H04N 23/66 Remote control of cameras or camera parts, e.g. by remote control devices
• CPC Class Codes: H04N 5/76 Television signal recording
• CPC Class Codes: H04N 5/772 the recording apparatus and the television camera being placed in the same enclosure
• CPC Class Codes: H04N 7/188 Capturing isolated or intermittent images triggered by the occurrence of a predetermined event, e.g. an object reaching a predetermined position signal generation from motion picture films H04N5/253
• CPC Class Codes: H04N 9/8042 involving data reduction

Abstract

The invention relates to a method for buffering a video sequence. The method comprises the acts of:

• • receiving input image frames from an input video stream comprising full image frames and differential image frames,
  • storing said received input image frames, and
  • determining at least one first full image frame based on at least one full image frame of said input image frames, wherein said generated first full image frame is arranged as a first image frame in an presumptive output video sequence.

Claims

1. Method for buffering a video sequence comprising the acts of:

receiving input image frames from an input video stream comprising full image frames and differential image frames,

storing each received input image frame in a video sequence FIFO buffer in response to the receipt of each frame, and

storing at least one full image frame, being related to the video sequence stored in the video sequence FIFO buffer, in a full image FIFO buffer, and

generating an output video sequence by combining at least one of said stored at least one full image frames from the full image frame FIFO buffer with the image frames of the video sequence FIFO buffer.

2. Method according to claim 1, wherein said at least one full image frame stored in the full image frame FIFO buffer is a full image representation of an image frame stored in said video sequence FIFO buffer.

3. Method according to claim 1, wherein said at least one full image frame stored in the full image frame FIFO buffer is a full image representation of an image frame having a short temporal distance to the oldest image frame of the video sequence stored in the video sequence FIFO buffer.

4. Method according to claim 1, wherein the generation of an output video sequence comprises inserting a full image frame from a full image FIFO buffer as the first frame of a video sequence output from a video sequence FIFO buffer comprising full image frames and differential image frames.

5. Method according to claim 1, wherein said generation of an output video sequence is automatically performed upon receipt of a detection signal.

6. Method according to claim 1, further comprising frequently receiving full image frames from a video sequence encoding means outputting the video stream including the input image frames, each full image frame representing a full image version of an image frame of the input image frames, and wherein the storing of at least one full image frame includes storing each of the received full image frames in the full image FIFO buffer in response to the receipt of each full image frame.

7. Method according to claim 1, wherein storing at least one full image frame includes storing a full image frame of said received input image frames in the full image FIFO buffer.

8. Method according to claim 1, wherein said storing of at least one full image frame in a full image FIFO buffer further comprises:

combining at least one image frame of said received input image frames with said at least one full image frame, said at least one image frame of said received input image frames being a differential image and representing a later image frame in the video sequence than the at least one full image frame is representing, and

storing said combined image frames in the full image FIFO buffer.

9. Method according to claim 8, wherein the full image FIFO buffer and the video sequence FIFO buffer stores an equal number of image frames.

10. Method according to claim 8, wherein the full image FIFO buffer stores one image frame.

11. Method according to claim 3, wherein said storing of at least one full image frame in a full image FIFO buffer further comprises:

combining at least one image frame of said received input image frames with said at least one full image frame, said at least one image frame of said received input image frames being a differential image and representing a later image frame in the video sequence than the at least one full image frame is representing, and

storing said combined image frames in the full image FIFO buffer.

12. Method according to claim 11, wherein the full image FIFO buffer stores one image frame.

13. Method according to claim 12, wherein the at least one image frame of said received input image frames or the full image frame of said received input image frame is the oldest image frame in the video sequence FIFO buffer.

22. A computer program, comprising computer program code for performing the steps of the method according to claim 1.

14. Pre-alarm buffer for buffering a video sequence comprising:

a video sequence FIFO buffer arranged to buffer input image frames from an input video stream,

a full image FIFO buffer arranged to buffer at least one full image frame, being related to the video sequence FIFO buffer,

a combiner arranged to combine an image frame from the full image FIFO buffer with the image frames of the first FIFO buffer and generate a pre-alarm video sequence.

15. Pre-alarm buffer according to claim 14, wherein said at least one full image frame stored in the full image frame FIFO buffer is a full image representation of an image frame stored in said video sequence FIFO buffer.

16. Pre-alarm buffer according to claim 14, wherein said at least one full image frame stored in the full image frame FIFO buffer is a full image representation of an image frame having a short temporal distance to the oldest image frame of the video sequence stored in the video sequence FIFO buffer.

17. Pre-alarm buffer according to claim 14, wherein the combiner is arranged to insert a full image frame from a full image FIFO buffer as the first frame of a video sequence outputted from a video sequence FIFO buffer comprising full image frames and differential image frames.

18. Pre-alarm buffer according to claim 14, further comprising a compressed video input arranged to receive a video sequence including full frames and differential frames.

19. Pre-alarm buffer according to claim 14, further comprising a full frame video input arranged to receive a video sequence including only full frames.

20. A video server comprising a pre-alarm buffer according to claim 14.

21. A camera comprising a pre-alarm buffer according to claim 14.

23. Method for generating a pre-alarm video sequence comprising:

inserting a full image frame from a full image FIFO buffer as the first frame of a video sequence outputted from a video sequence FIFO buffer comprising full image frames and differential image frames.

24. Method according to claim 23, wherein the full image frame from the full image FIFO buffer replaces the first image outputted from the video sequence FIFO buffer.

25. Method according to claim 23, wherein the full image frame from the full image FIFO buffer is positioned as the first frame of the video sequence from the video sequence FIFO buffer and making the first frame outputted from the video sequence the second video frame of the resulting video sequence.

26. A computer program, comprising computer program code for generating a pre-alarm video sequence by performing the step of

inserting a full image frame from a full image FIFO buffer as the first frame of a video sequence outputted from a video sequence FIFO buffer comprising full image frames and differential image frames.

27. Computer program according to claim 26, wherein the full image frame from the full image FIFO buffer replaces the first image outputted from the video sequence FIFO buffer.

28. Computer program according to claim 26, wherein the full image frame from the full image FIFO buffer is positioned as the first frame of the video sequence from the video sequence FIFO buffer and making the first frame outputted from the video sequence the second video frame of the resulting video sequence.