Patent ID: 7739332

Claim:
A method of responding to a first request to view a current image from a selected one of a plurality of cameras at different locations, the first request received over a first network, the method comprising: assigning a first image server among a plurality of image servers to handle the first request, each of said plurality of image servers having associated therewith an image cache storing images from a first number of said plurality of cameras, and further having associated therewith a request cache, wherein the request cache stores information about prior requests to retrieve updated images from at least a second number of said plurality of cameras; checking the image cache of the first image server to determine whether an image from the selected camera has recently been written into the image cache of the first image server; if an image from the selected camera has recently been written into said image cache of the first image server, providing said image from said image cache of the first image server, in response to the first request; if no image from the selected camera has recently been written into said image cache of the first image server, checking the request cache of the first image server to determine whether there is a pending prior request to retrieve an updated image from said selected camera; if checking the request cache of the first image server indicates that there is no pending prior request to retrieve an updated image from said selected camera, then: issuing a second request to retrieve an updated image from the selected camera; waiting until the updated image is received by the first image server from the selected camera, in response to the second request; and providing the updated image in response to the first request; if checking the request cache of the first image server indicates that an updated image from said selected camera has recently been requested, then: waiting until the updated image from the selected camera is received by the first image server; and providing the updated image in response to the first request.