British Telecommunications Public Limited Company

British Telecommunications Corporation

David G Morrison

Michael Erling Nilsson

Li-Qun Xu

Jason Morphett

Charles Nightingale

Michael D Carr

David J Chatting

Andrew P Heron

David O Beaumont

Yongmin Li

Jeremy M Thorne

Ian Parke

Richard C Nicol

Mohammed Granbari

Global motion between frames of a motion-compensated inter-frame encoded video sequence is estimated directly from the motion vectors encoded within the frames. For any particular frame, the motion vectors are first decoded, and a finite number of sets of vectors are selected. An affine or other geometrical transform is then used to generate a motion estimation for each set, and then the least median squared error present in each motion estimation is calculated for each estimation. The motion estimation with the smallest least median squared error is then selected as being representative of the global motion in the image of the frame. A panoramic image generating method and system makes uses of the global motion estimations thus obtained.

Method and system for estimating global motion in video sequences

The invention relates to estimating the global motion between frames of a motion-compensated inter-frame encoded video sequence, directly from the motion vectors encoded within the frames. For any particular frame, a motion estimation is determined from motion vectors direct from the frame's anchor frame to the frame in question. This motion estimation is then checked against pre-determined criteria, and where the criteria are not met, re-estimation along a different route is performed, using the bi-directional motion vectors contained within B-frames. A panoramic image generating method and system which makes uses of the global motion estimations thus obtained is also described.

The present invention concerns the generation of image data, particularly, though not exclusively for motion estimation in the context of video coders employing inter frame differential coding. A method is provided for generating image data using a set of sampled pixels, the sampled pixels being representative of a sampled image, the method including the steps of: (i) at intermediate positions between sampled pixels, interpolating the sampled pixels so as to provide at least one set of interpolated pixels arranged along a plurality of lines, the or each set of interpolated pixels having a respective offset relative to the sampled pixels, and, (ii) storing the or each set of interpolated pixels with a respective address in a memory, the addresses forming an ordered sequence, wherein along a given line, neighbouring interpolated pixels having the same offset are stored with respective addresses that are consecutive to one another in the ordered sequence.

Generating image data

The invention provides a method and system wherein first video images are directly overlaid with remote video images to produce a combined video image which is then displayed to the user and/or stored as appropriate. Preferably at least one of the first and/or remote images is subject to an image processing operation prior to the overlay operation being performed, the image processing operation being such that the scenes contained within the images to be overlaid when processed are separably distinguishable to a user within the combined video image when viewed by the user. The overlay operation is performed such that the scenes contained within the respective video images are substantially in alignment on top of each other. By overlaying the respective first and remote video images as described a single image is obtained within which the respective scenes of the respective first and remote images are still separably distinguishable, but which is still of an appropriate size for display on a screen of limited size without occlusion of one or other of the images.

System and method for combining local and remote images such that images of participants appear overlaid on another in substanial alignment

An image recognition process applied to a photograph is preceded by a pre-processing step which identifies parts of the image which are in focus. The recognition process is then limited to those parts. The pre-processing typically operates by creating a measure of high spatial frequency activity and applying a threshold to them.

Image processing system/network which performs recognition process only upon regions having higher high spatial frequency content

Video transcoder with by-pass transfer of extracted motion compensation

Digital data transcoder with relaxed internal decoder/coder interface

Values, such as a set of coefficients in a transform-based video coder are to be transmitted sequentially in any one of a number of possible preset orders. The order to be selected is the one that results in the largest number of consecutive zeros (or low values) at the end of the sequence. Values are supplied (in an arbitrary sequence) with addresses, in parallel to a bank of assessment sections--one for each preset order--each of which translates the addresses into addresses representing a position in the respective order and records the highest for which the associated value is non-zero. The outputs of the sections are then compared to identify the lowest, and hence the optimum order of transmission.

Data encoding

Two layer video signal coding

Predictive coding and decoding with error drift reduction

Video coder

A television picture transmission system using conditional replenishment employs a scanning rate at the transmitter which differs (for asynchronous operation, slightly; or for operation between systems using different standards, considerably) from the scanning standard at the the receiver. The frame rate conversion is effected by the updating loops at the transmitter or receiver by, respectively, periodically stopping the coding loop for a field or frame so that no data is produced to produce a lower frame rate or periodically repeating a field or frame in the loop without adding any updating data so as to produce a higher frame rate. Resulting variations in data rate are accommodated by utilizing the buffering inherent in conditional replenishment systems. The jerkiness of motion in the received picture resulting from stopping the loop or repeating a field or frame can be reduced by the use of temporal interpolation in the generation of the updating data to anticipate the stopping or repeating of a field or frame, while conversion of the number of lines per frame can be effected by spatial interpolating using a transversal filter.

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Felixstowe, United Kingdom

David G Morrison