Method for event initiated video capturing and a video camera for capture event initiated video

• US 8,676,027 B2
• Filed: 07/15/2011
• Issued: 03/18/2014
• Est. Priority Date: 07/16/2010
• Status: Active Grant

• Current Assignee: Axis AB (Canon Inc.)
• Original Assignee: Axis AB (Canon Inc.)
• Inventors: Hugosson, Fredrik
• Primary Examiner(s): JONES, HEATHER RAE
• Application Number:
  US13/183,942
• Publication Number:
  US 20120014659A1
• Time in Patent Office: 977 Days
• Field of Search: None
• US Class Current: 386/228
• CPC Class Codes: G08B 13/19669 Event triggers storage or change of storage policy
• CPC Class Codes: G08B 13/19676 Temporary storage, e.g. cyclic memory, buffer storage on pre-alarm
• 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

Abstract

A method and a video camera for recording an event initiated video sequence includes storing captured video frames in a video buffer, detecting a first event, and in response, initiating a video sequence recording session for recording of a video sequence in a non-volatile memory. Pre-event video frames and post-event video frames related to the first event are recorded, where the post-event time period starts at the detection of the first event. A first event delay time period is started in response to the expiration of the post-event time period. The video sequence recording session is closed if a delay period expires and no other event process is in progress.

Claims

1. Method for recording an event initiated video sequence, the method comprising:

continuously capturing video frames;

temporarily storing video frames in a video buffer;

detecting a first event;

initiating, in response to the detection of the first event, a video sequence recording session for recording of a video sequence in a non-volatile memory;

recording, in response to the detection of the first event, in the non-volatile memory, pre-event frames of the captured video data present in the buffer;

recording, in the non-volatile memory, post-event frames of the video data captured during a post-event time period related to the first event, the post-event time period starting at the detection of the first event;

starting a first event delay time period in response to the expiration of the post-event time period of the first event;

detecting a second event after expiration of the post-event time period of the first event and before expiration of the first event delay time period;

recording, in response to detection of the second event, in the non-volatile memory, frames from the video buffer representing a time period starting at the expiration of the post-event time period of the first event and ending at the detection of the second event;

recording, in the non-volatile memory, frames of the video data captured during a post-event time period related to the second event, the post-event time period starting at the detection of the second event; and

closing the video sequence recording session if a delay period expires and no other event process is in progress, wherein an event process includes recording pre-event frames, recording post-event frames, and an event delay time period, and wherein the delay period is a period counted from the expiration of a post-event time period.

2. Method according to claim 1, wherein the size of the video buffer substantially corresponds to the predetermined number of pre-event frames.

3. Method according to claim 2, wherein the number of pre-event frames to be recorded is defined by at least two parameters, wherein the first parameter is an arbitrary value defining the desired amount of video preceding the event and the second parameter is a latency period corresponding to the time difference between an occurrence of an event and a detection of the same event.

4. Method according to claim 1, wherein the video buffer is a First In First Out type.

5. Method according to claim 1, wherein the initiating a video sequence recording session comprises setting up a file in the non-volatile memory to include the recorded video session and wherein the closing the video sequence recording session comprises closing the file.

6. Method according to claim 1, wherein the capturing video frames, the temporarily storing video frames in a video buffer, the detecting a first event, the initiating a video sequence recording session, the recording pre-event frames of the first event, the recording post-event frames of the first event, the detecting a second event, the recording pre-event frames of the second event, the recording post-event frames of the second event, and the closing the video sequence recording session, are all performed at a camera.

7. Method according to claim 1, wherein the non-volatile memory is arranged in a camera.

8. Method according to claim 1, wherein the buffer is arranged in a camera and the non-volatile memory is arranged in a device connecting to the camera via a network, and wherein the initiating a video sequence recording session comprises setting up a video stream over the network and a file in the non-volatile memory to transfer the video stream over the network and storing the recorded video session in the file, and wherein the closing the video sequence recording session comprises the act of closing the file and the video stream.

9. Method according to claim 1, wherein a detected event is one event type of a plurality of event types and wherein the method further comprises indicating the event type of any detected event and retrieving values specifying the predetermined number of pre-event frames the predetermined number of post-event frames of the indicated event type.

10. Video camera arranged for event initiated recording of video sequences, the video camera comprising:

an image sensor arranged to continuously capture video frames;

a video buffer arrange to temporarily store video frames;

an event detector;

a video sequence recording session initiator arranged to initiate, in response to a detection of a first event, a video sequence recording session for recording of a video sequence in a non-volatile memory;

a pre-event recorder arranged to record, in response to the detection of the first event, in the non-volatile memory, a number of pre-event frames of the captured video data present in the buffer;

a post-event recorder arranged to record, in the non-volatile memory, post-event frames of the video data captured during a post-event time period related to a detected event, the post-event time period starting at the detection of the first event and ranging a number of post-event frames;

an event delay timer arranged to time an event delay time period starting at a point in time of an expiration of a post-event time period;

wherein the pre-event recorder is further arranged to record, in response to the detection of a subsequent event within the event delay time, in the non-volatile memory, frames from the video buffer representing a time period starting at the expiration of the post-event time period of the event and ending at the detection of the subsequent event; and

a video sequence recording session closer arranged to close the video sequence recording session if a delay period expires and no other event process is in progress, wherein an event process includes recording pre-event frames, recording post-event frames, and an event delay time period.

11. Video camera according to claim 10, wherein the size of the video buffer substantially corresponds to a maximal number of pre-event frames.

12. Video camera according to claim 11, wherein the number of pre-event frames is defined by at least two parameters, wherein the first parameter is an arbitrary value defining the desired amount of video preceding the event and the second parameter is a latency period corresponding to the time difference between an occurrence of an event and a detection of the same event.

13. Video camera according to claim 10, wherein the video buffer is a First In First Out type.

14. Video camera according to claim 10, wherein the video sequence recording session initiator is further arranged to set up a file in the non-volatile memory to include the recorded video session and wherein the video sequence recording session closer is further arranged to close the file.