Method and apparatus for detecting motion in MPEG video streams

1. A method of detecting an abandoned object in a video image comprising the steps of: connecting an MPEG compliant encoder to a video source that provides video images; storing a reference video frame; obtaining the current video image frame; determining the motion compensation for the current video image frame versus the reference video frame; comparing the motion compensation to a threshold value; compressing the current video image; storing an indication in the compressed video image that an abandoned object has been detected if the motion compensation is greater than the threshold value; starting a timer when the motion compensation is greater than the threshold value; continuing to increment the timer for each current video frame that has a motion compensation greater than the threshold value; resetting the timer if a current video frame has a motion compensation less than the threshold value; comparing the timer to a predetermined period of time; and indicating that an abandoned object has been detected if the timer is greater than the predetermined period of time.

2. A method of detecting the removal of an object in a video image comprising the steps of: connecting an MPEG compliant encoder to a video source that provides video images; storing a reference video frame containing an object to be monitored; defining a zone of interest around the object to be monitored; obtaining the current video image frame; determining the motion compensation for the current video image frame in the zone of interest versus the reference video frame zone of interest; comparing the motion compensation to a threshold value; compressing the current video image; storing an indication in the compressed video image that the removal of the object to be monitored has been detected if the motion compensation is greater than the threshold value;

starting a timer when the motion compensation is greater than the threshold value; continuing to increment the timer for each current video frame that has a motion compensation greater than the threshold value; resetting the timer if a current video frame has a motion compensation less than the threshold value; comparing the timer to a predetermined period of time; and indicating that the removal of the object to be monitored has been detected if the timer is greater than the predetermined period of time.

3. An apparatus for detecting an abandoned object in a video image comprising: an encoder adapted to be connected to a video image source, said encoder providing compressed video images including an MPEG compliant motion compensation between two video images and comprising a first memory for storing the current video image frame and a processor; a second memory for storing a reference video image; said processor determining the motion compensation for the current video image stored in said first memory with the reference video image stored in said second memory, comparing said motion compensation with a threshold value, and providing an indication in the compressed image for the current frame that an abandoned object has been detected if the motion compensation is greater than the threshold value; a timer and wherein said processor is adapted to start said timer when the motion compensation is greater that the threshold value, to allow the timer to continue to increase provided that the motion compensation for each subsequent current video image has a motion compensation greater than the threshold value and to compare the timer to a predetermined time, and to provide an indication in the compressed image for the current frame that an abandoned object has been detected if the timer is greater than the predetermined time.

4. An apparatus for detecting the removal of an object in a video image comprising: an encoder adapted to be connected to a video image source, said encoder providing compressed video images including an MPEG compliant motion compensation between two video images and comprising a first memory for storing the current video image frame and a processor; a second memory for storing a reference video image containing an object to be monitored; said processor being adapted to allow a zone of interest to be defined around the object in the reference image and determining the motion compensation for the zone of interest in the current video image stored in said first memory with the zone of interest in the reference video image stored in said second memory, comparing said motion compensation with a threshold value, and providing an indication in the compressed image for the current frame that the removal of the object has been detected if the motion compensation is greater than the threshold value; a timer and wherein said processor is adapted to start said timer when the motion compensation is greater that the threshold value, to allow the timer to continue to increase provided that the motion compensation for each subsequent current video image has a motion compensation greater than the threshold value and to compare the timer to a predetermined time, and to provide an indication in the compressed image for the current frame that the removal of the object has been detected if the timer is greater than the predetermined time.

5. An apparatus as recited in claim 3 wherein said motion compensation is a motion vector.

6. An apparatus as recited in claim 3 wherein said motion compensation is a sum of the absolute values of the distortion between the frames.

7. An apparatus as recited in claim 4 wherein said motion compensation is a motion vector.

8. An apparatus as recited in claim 4 wherein said motion compensation is a sum of the absolute values of the distortion between the frames.