Abstract: A method and system for monitoring assets using radio frequency tags is provided that includes a plurality of primary tags. Each primary tag stores an identification of each linked tag associated with the primary tag. The primary tag receives a polling event and transmits a query message for linked tags within an operational range of the primary tag. Each linked tag receiving the query message transmits a response message that includes an identification of the linked tag. The primary tag receives the response messages and compares the identifications in the response messages to the identifications stored for each linked tag. Based on the comparison, the primary tag determines a monitored asset status.

Abstract: A networked digital security system is disclosed that preferably includes a centralized administrator web server coupled via a communication network such as the Internet to a plurality of customer servers and a plurality of customer work stations. The centralized web server advantageously provides a point of control and management of the networked digital security system. The customer servers and customer work stations are preferably located at the customer's monitored sites. The customer servers are coupled to one or more intelligent camera units, which are preferably fully integrated intelligent units that gather, analyze, and transmit video, audio, and associated detected alarm event information to their associated customer server and the administrator web server. The camera units also include an intelligent automatic gain controller, an encoder buffer controller, and a network bandwidth priority controller. The system supports several compression algorithm standards.

Abstract: An access control system includes a plurality of door control systems each associated with an access door and including a relay control for operating the access door and a transmitter for eliciting a radio response from a tag at the access door. The response includes a tag ID and an access door ID. A receiver is operable to receive radio responses from tags at a plurality of access doors. An access door controller is coupled to the receiver and operable to receive the tag ID and the access door ID included in each radio response received by the receiver. The access controller determines whether access by the tag at the access door is authorized and controls the relay door to permit authorized access.

Abstract: A radio frequency tag accepts a received signal received by an antenna and demodulates that signal into a digital output using a comparator. The received signal is forwarded to a first comparator input. A threshold voltage generator generates a threshold voltage signal and forwards that signal to a second comparator input. The comparator compares the two inputs and generates a digital output based on the comparison.

Abstract: The invention provides a method, and related apparatus, for improved compression of video images by determining optimum compression points using pixel-to-pixel slope comparison techniques and relaxable length limits. The method converts a digitized analog video signal into its piecewise linear equivalent, and then reduces the data stream by preserving only the break points. The linear segments may be as short as one pixel. After a predetermined slope length has been reached, the improved pointing technique combines length-limited points if the slopes of the corresponding linear segments are identical.

Abstract: A data transmission system includes a reader transceiver and one or more tag transceivers. The reader transmits an activation signal to a tag. The tag selectively transmits a response signal to the reader at a specific time determined by a detected level of communications channel activity. The detector operates in a low-power standby state until the time it receives the activation signal, and then operates in an active state. The invention further incorporates a technique to maintain an extremely low power state to the tag during quiescent mode while retaining full sensitivity to reader activation signals. The reader transceivers are of a modular architecture with each module operating independently, yet in concert with the others. The modules are interconnected in a media independent method and can interact remotely with other modules.

Abstract: The invention enables processing of a time-varying video image in a manner that blurs (or "smears") the time-varying portion or portions of the video image as successive frames of video data are processed. Such smearing is particularly useful in reducing the choppiness and jerkiness that degrades the viewability of the time-varying portions of a displayed video image when the frame rate is low. The invention blends corresponding video data components from a current video frame and a previous video frame to achieve the smearing effect. The invention enables the degree to which the video data from each of the frames affects the processed video data to be varied. The exact blending can be based upon, for example, the magnitude of the frame rate. Further, in processing each video frame, each of a set of related video data components can be processed serially to enable the invention to be implemented more compactly and inexpensively.