Abstract: An image encoder or other image processing apparatus includes a segmentation apparatus for assigning image pixels to regions, in accordance with predetermined criteria. The segmentation apparatus provides a temporally consistent segmentation throughout a motion picture sequence, and comprises: a motion compensation processor for predicting the segmentation for a current frame (F0) upon the basis of the segmentation (S1) of the preceding frame and estimated motion vectors (M); a pixel identifier and reallocator for modifying the predicted segmentation in dependence upon the accuracy of pixel values (F0′) predicted for the current frame on the basis of the motion vectors (M). In particular, for portions of the image where pixel values are not accurately predicted by the motion vectors, it is assumed that the predicted segmentation is invalid, and such portions are re-segmented and merged into the predicted segmentation to obtain the temporally consistent segmentation.

Abstract: An image encoder or other image processing apparatus includes a segmentation apparatus for assigning image pixels to regions, in accordance with predetermined criteria. The segmentation apparatus provides a temporally consistent segmentation throughout a motion picture sequence, and comprises: a motion compensation processor for predicting the segmentation for a current frame (F0) upon the basis of the segmentation (S1) of the preceding frame and estimated motion vectors (M); and a pixel identifier and reallocator for modifying the predicted segmentation in dependence upon the accuracy of pixel values (F0′) predicted for the current frame on the basis of the motion vectors (M). In particular, for portions of the image where pixel values are not accurately predicted by the motion vectors, it is assumed that the predicted segmentation is invalid, and such portions are re-segmented and merged into the predicted segmentation to obtain the temporally consistent segmentation.

Abstract: An interactive television system includes television transmission apparatus (TTA), a transmission path (TPA) and a plurality of television receivers (TRA-1 to TRA-n). The television receivers include a telephone interface (TRT-1 to TRT-n) by which they can communicate with the television transmission apparatus (TTA).The system is arranged to enable interactive games to be played where viewers compete with contestants in a television studio. For a first portion of the program the viewers compete independently and the television receiver accumulates the score. For the final stages of the program viewers with a score above a transmitted threshold are invited to.

Abstract: A method and apparatus for processing an applied signal. The applied signal is low pass filtered via a low pass filter having an input and an output, wherein the filter input and output are coupled to respective inputs of a selection device and respective inputs of a comparator. The comparator compares each of its inputs to one another and produces an output indicating which of its inputs has a lower amplitude. The comparator output is applied to a control input of the selection device such that the selection device will output the signal with the lower amplitude, either the applied signal or the low pass filtered signal.

Abstract: A method of encoding a sequence of images including a moving object, comprises forming an initial template, extracting a mask outlining the object, dividing the template into a plurality (for example sixteen) sub-templates, searching the next frame to find a match with the template, searching the next frame to find a match with each of the sub-templates, determining the displacements of each of the sub-templates with respect to the template, using the displacements to determine affine transform coefficients and performing an affine transform to produce an updated template and updated mask. Encoding is performed at a higher resolution for portions within the outline than for portions outside the outline.

Abstract: A face classification system which receives video data representative of a scene and extracts therefrom data representative of a face which is present in the scene. The facial video data is applied to a homomorphic filter to eliminate the effects of lighting changes in the scene. The positions of the eyes and mouth are located to form two sub-divisions, one in relation to a first line joining the eyes and the other in relation to a second line perpendicular to the first line and passing through the nose. A feature vector which is representative of the face and is rotation, scaling, translation and grey level intensity invariant is then produced by applying a recursive second order sub-division of moments to the filtered data. Such sub-division of moments is constrained to act first on the sub-divisions formed by the aforesaid lines, thereby reducing the effect of noise.

Abstract: A method of tracking a moving object in a scene, for example the face of a person in videophone applications, comprises forming an initial template of the face, extracting a mask outlining the face, dividing the template into a plurality (for example sixteen) sub-templates, searching the next frame to find a match with the template, searching the next frame to find a match with each of the sub-templates, determining the displacements of each of the sub-templates with respect to the template, using the displacements to determine affine transform coefficients and performing an affine transform to produce an updated template and updated mask.

Abstract: A video signal with pre-emphasis is applied via an input to an HD-MAC encoder, the encoded output being applied over a first path to an input of an adder. The encoded signal is also applied via a decoder and a further path comprising a de-emphasis circuit, a mean value estimator circuit and a pre-emphasis circuit, to an input of a difference circuit. The video signal from the encoder input is also applied to a second input to the difference circuit, via a reference path comprising components which correspond to the de-emphasis circuit, mean value estimator, and pre-emphasis circuit in the further path. The difference in the pre-emphasized mean values obtained from the difference circuit is applied via a shuffler and added to the video signal in the first path.

Abstract: A transmitting section of the system according to the invention has transmitting section signal paths for at least three classes of motion, each with a preprocessing circuit (143, 145 and 147) which are provided with means for individually sampling. These sampling means sample in accordance with separate sampling patterns so that each preprocessing circuit (143, 145 or 147) supplies a video signal which is suitable for a display with an optimum distribution of temporal and/or spatial resolution for the associated class of motion. Dependent on the class of motion determined, one of the preprocessing circuits (143, 145 or 147) is coupled to a channel (170). The video signal to be supplied to the channel (170) is therefore a video signal suitable for a display with an optimum distribution of temporal and/or spatial resolution for the given class of motion (FIG. 1A).

Abstract: A receiver for a high definition television signal in which the signal prior to transmission is sub-sampled on a block-by-block basis according to the movement has an input (39) which receives the sub-sampled signal which is applied to a shuffler (40) which shuffles the pixels of blocks in a manner which is the inverse to that performed prior to transmission. The correctly positioned pixels are applied to means (43,44,45) for adaptive switched interpolation filtering capable of providing spatial frequency filter responses which approximate those at the transmitter, for sub-sampling blocks of the interpolated picture are sub-sampled but where pixels adjacent but outside a block are sub-sampled with the same structure as that of the block and for non-adaptive switched interpolation filtering for providing spatial frequency filter responses which substantially correspond to those at the transmitter. An output (46) provides the reproduced high definition television signal.

Abstract: A receiver for a high-definition television signal, in which the signal prior to transmission is sub-sampled on a segmented basis according to the degree of movement, has an input terminal (1) which receives the sub-sampled signal which is applied to an inverse shuffler (2) which shuffles the pixels of each block in a manner which is the inverse to that performed prior to transmission. The output of shuffler (2) is applied to a first delay arrangement (4) which provides one or more delays of an integral number of fields periods and whose delayed and undelayed outputs are applied to an input field selector (6) to produce a changed sequence of fields to that received. The selector output is applied to a processing arrangement (8) in which the signal of changed field sequence is subjected to spatial interpolation and/or temporal interpolation and the resulting interpolated signal applied to a second delay arrangement (10) providing one or more delays of an integral number of fields periods.