Method and apparatus for surveillance using an image server

Abstract

Methods and apparatus for an image server surveillance system provide for as control and coordination of cameras that may be widely deployed, analyzing data from multiple cameras, making data available in such a way that it can be efficiently transmitted over a network and can be easily displayed to potentially a large number of users, and displaying and controlling image data by existing client software.

1 . A method for surveillance comprising: 
 capturing a plurality of still frames;    generating, from said plurality of still frames, a sequence of digital image arrays comprising a full frame and a plurality of differential frames;    transmitting said sequence to a camera coordinator;    determining, using said sequence, whether an incident is associated with one or more frames in said sequence;    transmitting said sequence to an image server;    storing said sequence at said image server; and    providing said sequence to one or more clients for viewing by a user.    
   
   
       2 . The method according to  claim 1  wherein said sequence stored at said image server is stored in a format designed for still image display on a client browser.  
   
   
       3 . The method according to  claim 1  wherein said sequence stored at said image server is stored in a format allowing for a pixel to be encoded as a transparent pixel.  
   
   
       4 . The method according to  claim 1  wherein said sequence stored at said image server comprises a full frame and one or more subsequent differential frames wherein pixels in a differential frame with values within a threshold of corresponding pixels in a preceding frame are set to transparent.  
   
   
       5 . The method according to  claim 1  wherein said generating creates a sequence of full and differential frames in a format designed for still image display on a client browser and allowing for a pixel to be encoded as a transparent pixel.  
   
   
       6 . The method according to  claim 5  wherein said sequence is transmitted to said camera coordinator, stored at said camera coordinator, transmitted to said image server, stored at said image server, and viewed by a client all using an image encoding format for still image display on a client browser and allowing for a pixel to be encoded as a transparent pixel.  
   
   
       7 . The method according to  claim 2  wherein said format is the PNG format.  
   
   
       8 . The method according to  claim 2  wherein said format is the GIF format.  
   
   
       9 . The method according to  claim 1  wherein said deriving comprises computing a percentage value for a differential frame indicating a calculated percentage change between said differential frame and a preceding frame.  
   
   
       10 . The method according to  claim 1  wherein said determining comprises comparing a single still frame to a preceding frame.  
   
   
       11 . The method according to  claim 1  wherein said deriving includes computing a percentage value for a differential frame indicating a calculated percentage change between said differential frame and a preceding frame.  
   
   
       12 . The method according to  claim 1  wherein said clients comprise off-the-shelf internet browser software.  
   
   
       13 . The method according to  claim 1  further comprising: 
 storing said sequence at said camera coordinator.    
   
   
       14 . The method according to  claim 1  wherein said storing comprises storage of sequences for which incidents were detected for later transmission as requested by an image server.  
   
   
       15 . The method according to  claim 1  wherein said image server includes a network interface with a high bandwidth capacity allowing for multiple simultaneous client connections.  
   
   
       16 . A method for surveillance comprising: 
 capturing a plurality of still frames as arrays of digital data;    designating a frame in said plurality as a full frame;    for a frame subsequent to said full frame, computing a differential frame wherein a pixel in said differential frame that is within a threshold of a geometrically corresponding pixel in a preceding frame is set to transparent;    for a frame subsequent to said full frame, computing a percentage difference indicating a degree of change of pixels from a preceding frame;    transmitting a full frame, one or more differential frames, and one or more computed percentages to a camera coordinator;    determining that an incident has occurred using rules-based logic to analyze data received from said frame grabber;    storing frame data, image data, and incident data;    transmitting frame data to an image server; and    presenting frame data by said image server to one or more clients for viewing by one or more users.    
   
   
       17 . A method for capturing, analyzing, and presenting image data from one or more digital image capture devices comprising: 
 capturing a plurality of digital image frames;    producing a plurality of sequences, said sequences comprising a full frame followed by one or more differential frames wherein pixels in said differential frames are set to transparent when they have a value within a threshold of a value of corresponding pixels in a preceding frame;    determining whether an incident is associated with one or more frames;    storing said plurality of sequences; and    presenting one or more sequences to a client viewer in response to a viewer's request or when an incident is associated with a sequence.    
   
   
       18 . The method according to  claim 17  wherein said determining comprises computing a percentage of pixels that have changed in one frame from one or more preceding frames.  
   
   
       19 . The method according to  claim 17  wherein said sequence stored at said image server is stored in a format designed for still image display on a client browser.  
   
   
       20 . The method according to  claim 17  wherein said storing comprises storage of sequences for which incidents were detected for later transmission as requested by an image server.