Surveillance system and method using personal computer

• US 6,480,225 B1
• Filed: 02/25/1999
• Issued: 11/12/2002
• Est. Priority Date: 02/25/1998
• Status: Expired due to Term

• Current Assignee: Hanger Solutions, LLC (IP Investments Group LLC)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Bong-seok
• Primary Examiner(s): Kelley, Chris
• Assistant Examiner(s): SENFI, BEHROOZ M
• Application Number:
  US09/257,180
• Time in Patent Office: 1,356 Days
• Field of Search: 348/153, 348/154, 348/143, 348/155, 345/112, 382/103
• US Class Current: 348/143
• CPC Class Codes: G08B 13/19602 Image analysis to detect motion of the intruder, e.g. by frame subtraction
• 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 7/183 for receiving images from a single remote source

Abstract

A surveillance system and method are disclosed. Two images that occur at a certain time apart are captured. The luminance of each pixel for each image is determined. The change in luminance for each pixel is determined. The number of pixels whose change in luminance exceeds a first threshold is calculated. If this number of pixels exceeding a first threshold exceeds a second threshold, the image is stored as the image has sufficiently changed. Since the present image is stored when there is a movement in the present image compared with the previous image, the cost for storing image data is low. Further, when there is a movement, since the time intervals for capturing images are adjusted according to the extent of the movement, the surveillance operation can be carried out effectively.

Claims

1. A surveillance method, comprising the steps of:

capturing an image from a camera once every predetermined time interval;

calculating luminance values of pixels in the captured image;

counting the number of pixels of a most recently captured image having a sufficiently different luminance value from corresponding pixels of a previously captured image;

permanently storing said most recently captured image when the number of the counted pixels is larger than a predetermined value;

temporarily storing said most recently captured image in a temporary storage unit for comparison with a next, subsequently captured image;

setting said predetermined time interval to a first duration upon permanently storing said most recently captured image prior to capturing a subsequent image; and

setting said predetermined time interval to a second and longer duration when said number of counted pixels is smaller than or equal to said predetermined value prior to capturing a subsequent image.

2. The surveillance method of claim 1, the luminance value calculating step is performed only on pixels selected by a user.

3. The surveillance method of claim 1, said luminance being based on a linear combination of intensities of three primary colors experienced by each pixel during image capturing.