1
Brian A Howell: Video conferencing system. PictureTel Corporation, Fish & Richardson P C, June 16, 1998: US05767897 (240 worldwide citation)

A video conferencing system wherein a director controller is adapted for disposition on a lecture podium. The controller includes an interconnected control section and a video display section for controlling the distribution of generated audio and video information signals among a local and remote s ...


2
John E Bruder: Quantizer control method and apparatus. PictureTel Corporation, Fish & Richardson, February 1, 1994: US05283646 (194 worldwide citation)

A method and apparatus for enabling a real time video encoding system to accurately deliver the desired number of bits per frame, while coding the image only once, updates the quantization step size used to quantize coefficients which describe, for example, an image to be transmitted over a communic ...


3
Brant M Helf, Peter L Chu: Reduction of background noise for speech enhancement. PictureTel Corporation, Fish & Richardson P C, August 27, 1996: US05550924 (125 worldwide citation)

Properties of human audio perception are used to perform spectral and time masking to reduce perceived loudness of noise added to the speech signal. A signal is divided temporally into blocks which are then passed through notch filters to remove narrow frequency band components of the noise. Each bl ...


4
Christopher J Mairs, Anthony M Downes, Roderick F MacFarquhar, Kenneth P Hughes, Alex J Pollitt, John P Batty: Method and system for sharing applications between computer systems. Microsoft Corporation, Picturetel Corporation, Seed and Berry, February 23, 1999: US05874960 (123 worldwide citation)

A method in a computer system for displaying data generated by a shared application on a host computer system on both a host display of the host computer system and a shadow display of a shadow computer systems The host computer system has a window manager for managing windows displayed on the host ...


5
Peter L Chu: Adaptive acoustic echo canceller having means for reducing or eliminating echo in a plurality of signal bandwidths. PictureTel Corporation, Hale and Dorr, April 19, 1994: US05305307 (114 worldwide citation)

An echo cancelling device for reducing acoustic feedback between a loudspeaker and microphone in a full duplex communication system such as a telephone conferencing system. The device includes a whitening filter which flattens the microphone signal's spectrum and reduces its auto-correlation. A firs ...


6
Xiancheng Yuan, Matthew M Bace: Method and apparatus for visual communications in a scalable network environment. PictureTel Corporation, Fish & Richardson P C, October 13, 1998: US05821986 (108 worldwide citation)

A method and apparatus for providing a flexible and scalable videoconferencing system for use in connection with a network provides for scalably encoding an image sequence for transmission onto the network. The encoding enables the encoded image sequence to be decoded at any one of at least two spat ...


7
Richard L Baker, Jeffrey Bernstein, Bernd Girod, Xiancheng Yuan, Edmund Thompson: Hierarchical entropy coded lattice threshold quantization encoding method and apparatus for image and video compression. PictureTel Corporation, Hale and Dorr, September 22, 1992: US05150209 (107 worldwide citation)

A method and apparatus for encoding interframe error data in an image transmission system, and in particular in a motion compensated image transmission system for transmitting a sequence of image frames from a transmitter to a receiver, employ hierarchical entropy coded lattice threshold quantizatio ...


8
Henrique S Malvar: Method and system for adapting a digitized signal processing system for block processing with minimal blocking artifacts. PictureTel Corporation, Lahive & Cockfield, June 28, 1988: US04754492 (105 worldwide citation)

A method and apparatus for processing n-dimensional digitized signals containing at least two adjacent blocks of digitized sample values. The digitized signal is transformed in accordance with a spatial transform operator. The spatial transform operator is characterized by similar size blocks to the ...


9
Peter L Chu, Hong Wang: Method and apparatus for localization of an acoustic source. PictureTel Corporation, Fish & Richardson P C, July 7, 1998: US05778082 (103 worldwide citation)

An acoustic signal processing method and system using a pair of spatially separated microphones to obtain the direction or location of speech or other acoustic signals from a common sound source is disclosed. The invention includes a method and apparatus for processing the acoustic signals by determ ...


10
Larry K Baxter, John J Coffey: Electrical cable interface for electronic camera. PictureTel Corporation, Fish & Richardson, January 23, 1996: US05486853 (103 worldwide citation)

The invention features a video camera system where horizontal and vertical synchronizing signals and a pixel clock signal are generated and added to analog video signals from a video imaging device within an electronic camera head that is connected, via an electrical cable, to a remote host processo ...