Computer graphics processing and selective visual display system – Computer graphics processing – Attributes
Reexamination Certificate
2000-12-22
2004-08-10
Zimmerman, Mark (Department: 2671)
Computer graphics processing and selective visual display system
Computer graphics processing
Attributes
C345S421000, C345S441000, C345S427000, C345S620000, C348S154000, C348S159000
Reexamination Certificate
active
06774905
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method and a device for managing image information in a monitoring system, in which the management of image information comprises both processing of image information and transmission of processed image information. The invention also relates to a monitoring module and a computer program product.
BACKGROUND ART
Monitoring of various public places, installations and premises is becoming increasingly important as they contain increasingly valuable equipment such as, for example, computers which in turn contain information that is very important to the owner, and perhaps also confidential. There is also a need for monitoring, for example, of baggage at airports and also in private dwellings. It is normally desirable for the monitoring information to be displayed immediately and accurately in order to enable the appropriate measures to be taken quickly.
In order to meet these needs, there are different types of monitoring systems. One type of monitoring system according to prior art technique normally comprises a monitoring center and a number of monitoring modules. Each monitoring module is connected to the monitoring center via communication cables. A monitoring module can comprise a video camera and an infrared detector which are connected to each other via a cable. It operates by the infrared detector detecting a movement and the video camera recording an image. The recorded image is then sent to the monitoring center. A problem with infrared detectors is that they are relatively easy to mislead, which makes the monitoring unreliable. For example, a sheet of glass can be placed in front of the detector, which means that heat changes are not detected and the video camera will not start recording. A further problem with this type of monitoring system is that in many cases the recorded images do not provide sufficient information about what caused the alarm. This can occur when, for example, alarm situations which have been caused by high temperatures or sabotage are not caught by the camera. As a result, there remains uncertainty as to whether it is a genuine alarm.
In order to solve this problem, it has been proposed that images should be recorded continually. The recorded image can be compared with a reference image, which is normally a background image of the area which is being monitored. If there is any difference between these images and if a change has occurred in a recorded image, these images are transmitted to a manned monitoring center. A system operator at the monitoring center looks at the transmitted image and from that makes a decision regarding the monitoring situation. A number of situations which the infrared detector would not detect will be detected by this method. A disadvantage of this technique is that a lot of information must be transmitted, as there are many situations, such as changes in lighting conditions, which can cause changes in the recorded image. It takes a long time to transmit the image. Before the transmission is carried out, the image or images are compressed using, for example, JPEG or MPEG. A transmission, which is a video transmission of consecutive images of the monitoring site, is limited to a certain number of images per second. If a mobile telephone of the GSM type with a transmission speed of 9.6 kbit/s is used as the receiver for the monitoring information, it can take 20-100 seconds before the transmitted image becomes clear and decipherable. By means of compression of the images, it is possible to reduce this to 3-4 seconds per image. If there is further compression, the image becomes so unclear that events become difficult or even impossible to make out. This means that if the degree of compression is increased in order to reduce the bandwidth, the image quality finally becomes so poor that it is not possible to draw the correct conclusions from the image. As an alternative, the image frequency can be reduced and fewer images sent. However, this does not provide satisfactory monitoring, as much can happen between two consecutive images and here too it can be difficult to draw conclusions about actual movements. Problems also arise when it is wished to store monitoring information in the monitoring module. In order to be able to store all the information which is needed to determine whether there is an alarm situation, a large storage capacity is required, which results in the equipment being expensive and its complexity increasing.
Patent application WO 98/28706 describes a security system which comprises a number of cameras which are arranged to record images and to transmit these images to a monitoring station in which digital image processing is carried out. The monitoring station carries out processing to determine whether there is an alarm situation or not, and if there is an alarm situation a signal is forwarded indicating whether it is a human-related alarm or an unknown alarm.
U.S. Pat. No. 5,666,157 describes a monitoring system which detects unusual events, which can be movements which are interpreted as personal attacks. Recorded images are analyzed, objects are detected and the movement characteristics of the object are calculated. Based on the movement characteristics, a decision is reached which indicates to what extent a movement is judged to have a criminal intention.
SUMMARY OF THE INVENTION
An object of the invention is therefore to make possible reliable and cost-effective monitoring.
This and other objects which will be apparent from the following description are achieved by a method for managing image information in a monitoring system, which monitoring system comprises at least one monitoring module for monitoring a monitored location and a remote recipient unit, comprising the steps of recording an image of the monitored location by means of the monitoring module, segmenting a distinct region in the monitoring module by comparing the recorded image with a reference image, creating an outline shape in the monitoring module which represents the edge of the distinct region, transmitting data which represents the outline shape to the recipient unit, recreating the outline shape in the recipient unit by means of the said transmitted data, and displaying the outline shape visually in the recipient unit.
The monitoring module can continually record images of the monitored location. The monitored location is limited among other things by the components of the monitoring module for recording images. If a change has occurred in a recorded image in comparison to a reference image, such as a person or an animal having entered the image, this object is segmented by means of a number of different algorithms. The reference image is created with one or more algorithms from one or more previous images, one or more background images of the monitored location or a combination of both. The advantage of the comparison is that moving objects can be processed further and stationary objects, such as tables and chairs, which are in the monitored location can be excluded. This means that a distinct region contains interesting information about events in the monitored location. An object which is segmented from an image is represented by this distinct region.
An outline shape is created. An outline shape is a stylized representation of the edge of the distinct region. Data representing this outline shape occupies little bandwidth and is therefore suitable for transmission. The recipient unit is the unit which receives data representing the outline shape and processes it in an appropriate way. The monitoring module and the recipient unit interpret the transmitted information in the same way. They have the same mathematical model of the outline shape. That is to say that the monitoring module processes the outline shape in accordance with a mathematical model and produces data representing the outline shape and transmits this data to the recipient unit. The recipient unit which receives the data can, if so required, have knowledge of which mathematical model is used and can recreate
Elfving Mats
Merheim Christian
Rodman Andreas
Nguyen Kimbinh T.
Wespot AB
Zimmerman Mark
LandOfFree
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