Monitoring an environment

1. A method of monitoring an environment, comprising the steps of capturing image data depicting said environment; and

analyzing said image data to identify moving foreground objects; wherein upon identifying an object, the movement of said object is tracked; and

graphical output data is generated providing a representation of said tracked movement superimposed in alignment upon a representation of said environment; wherein

said representation of the environment is said captured image data with portions of said image data visible and other portions masked and varying portions of the visible image data are masked according to the level of access granted to the user.

2. A method according to claim 1 , wherein a background model is created and events are identified by processing said captured image data with reference to said background model.

3. A method according to claim 2 , wherein said representation of the environment is the background model.

4. A method according to claim 1 , wherein a masked image is displayable to an observer in real time.

5. A method according to claim 1 , wherein an operator is provided with access means for viewing a greater proportion of the captured image data upon identification of a moving foreground object.

6. A method according to claim 5 , including logging means for maintaining a log when said access means has been used.

7. A method according to claim 1 , wherein said level of access is authenticated by checking an identifying means for a user.

8. A method according to claim 7 , wherein said identifying means takes the form of a biometric of the user.

9. A method according to claim 1 , wherein said representation of the environment is a diagram of the environment.

10. A method according to claim 9 , wherein the detection of an object being thrown from a predefined window area within said diagram of said environment is identified as a potential event of interest.

11. A method according to claim 1 , wherein an attribute of said graphical output data adapts in response to a detected characteristic of said movement of said object.

12. A method according to claim 1 , wherein said environment is a building and the mask is applied to window areas of said building.

13. A method according to claim 1 wherein said captured image data is stored.

14. A method according to claim 13 , wherein the replaying of said stored captured image requires an access certificate to be obtained.

15. A method according to claim 1 wherein said graphical output data is stored.

16. A computer-readable medium having computer-readable instructions executable by a computer or by a network of computers such that when executing said instructions said computer(s) will perform a method as defined by claim 1 .