Abstract: A system for coding video data comprised of one or more frames codes a portion of the video data using a frame-prediction coding technique, and generates residual images based on the video data and the coded video data. The system then codes the residual images using a fine-granular scalability coding technique, and outputs the coded video data and at least one of the coded residual images to a receiver.

Abstract: A camera-based system implements a calibration procedure for determining, for a given system user, calibration information that characterizes the manner in which the user points within the system. The system directs the user to point separately at each point in a set of two or more points at different positions on a display. The system then detects, for each of the points pointed to by the user, a location of a pointing finger of the user in an image generated by each camera in a set of cameras of the system, such that for each of the points the location of the pointing finger and the corresponding point on the display specify a line. The lines associated with the points are then used to compute a reference point or other pointing direction calibration information for the user. The calibration information for the user may be stored with user-identifying information in a database of the system, and is utilized in subsequent pointing direction determinations for that user.

Abstract: The invention relates to a method and device for generating a large static image M(n), such as a sprite or a mosaic, from a video sequence including successive video objects. This method comprises a first step for estimating motion parameters related to the current video object V0(n) of the sequence with respect to the previously generated static image M(n−1), a second step for warping this video object on the basis of the estimated motion parameters, a third step for blending the warped video object thus obtained with the previously generated static image M(n−1), and a fourth step for computing, for each picture element of the current video object, a weighting coefficient WWF(n)[x,y] correlated to the error between the warped video object and the static image M(n−1), the blending formula then taking into account said weighting coefficients.

Abstract: In order to interoperate with all types of transport networks working with packets of constant size, an encapsulation method is proposed to adapt multiplexed data, organized in successive, individually accessible portions, to these networks. Said data are segmented to fit the size of the network packets, and, for matching the last segment of said data to said constant size, a padding step is provided for adding a padding packet to each last segment.

Abstract: A method and arrangement for embedding a watermark in an image are disclosed. The watermark consists of a pseudo-random, dense subset of image pixels, e.g. a pattern of lines (20). A number of salient image pixels (21-26), for example, local extremes, corners or edges, is identified and it is determined whether they lie on (i.e. within a vicinity &dgr; of) the line pattern (21-23) or not (24-26). In an unwatermarked image (FIG. 2A), the number of most salient pixels (21) lying on the watermark is substantially the same as the number of most salient pixels (25,26) not lying on the watermark. The image is watermarked (FIG. 2B) by modifying the saliency of the salient pixels in such a way that a significant majority (21,23) of the most salient pixels (21,23,25) is eventually located within the vicinity of the line pattern.

Abstract: The invention relates to an encoding method for the compression of a video sequence divided into groups of frames decomposed by means of a tridimensional wavelet transform. According to this method, based on the hierarchical subband encoding process SPIHT and applied to the band-pass subbands of a spatio-temporal orientation tree defining the spatio-temporal relationship within the hierarchical pyramid of the obtained transform coefficients, a vectorial DPCM, using either constant prediction coefficients or adaptive ones for taking into account scene changes, is used to separately encode the lowest frequency spatio-temporal subband, and the quantification of the prediction error observed when constructing a spatio-temporal predictor for each vector of transform coefficients having components in each frame of said subband is carried out by means of a scalar or vectorial quantization.

Abstract: A method for motion coding an uncompressed digital video data stream such as an MPEG-2 digital video data stream. The method includes the steps of comparing pixels of a first pixel array in a picture currently being coded with pixels of a plurality of second pixel arrays in at least one reference picture and concurrently performing motion estimation for each of a plurality of different prediction modes in order to determine which of the prediction modes is an optimum prediction mode determining which of the second pixel arrays constitutes a best match with respect to the first pixel array for the optimum prediction mode, and, generating a motion vector for the first pixel array in response to the determining step. The method is implemented in a device such as a motion estimation search system of a digital video encoder.

Abstract: The invention relates to a method of coding a sequence of pictures using a segmentation operation of each of the pictures followed by a coding operation of each of the obtained successive partitions, and to a corresponding system. The system includes a projection circuit (11), for estimating on the basis of the mesh defined for a previous picture a projected mesh made of polygons and corresponding to the current picture, a mesh coding circuit (12, 13, 14, 15) for coding motion and texture associated to the projected mesh, and a texture error detection and coding circuit (16, 17).

Abstract: An implicit surface is defined by a time dependent implicit surface model. From the implicit surface model a first and second mesh of control points of a first and second non-linear coordinate valued functions such as second degree Bezier functions are computed respectively. The first and second non-linear coordinate valued function represent approximations of the implicit surface at a first and second point in time respectively. The points of the first mesh are used as a starting point for computing an approximation of the second mesh of points. The surfaces defined by the first and second non-linear coordinate valued function respectively are rendered for example by approximating each by a respective mesh of flat triangles.

Abstract: A fault tolerant air bag system needs a floating supply, which supply conventionally is made by means of a DC-DC converter with a transformer. By splitting the main energy reserve capacitor (14) into two capacitors (14, 34), and coupling one of the capacitors (34) to the other (14) by means of switches (36, 38) which open during a crash, no transformer is needed any more.

Abstract: The present invention is directed to a variable coding of the bit-planes for a particular source signal. This includes first partitioning or grouping the different bit-planes into embedded sub-signals and then coding each sub-signal. This technique enables an encoder according to the present invention to control and achieve a desired trade-off point between scalability and coding-efficiency. Therefore, in cases where bit or bit-plane level granularity is not required, coding efficiency can be improved by combining two or more bit-planes prior to coding. In addition, since the statistical nature of each bit-plane is different, the level of grouping used across the bit-planes can vary.

Abstract: An image processing method and apparatus are described for rendering two dimensional pixel images composed of triangular image primitives. Prior to their projection into the image plane, each triangle is parameterised with a respective two-dimensional coordinate system with the coordinate axes (s,t) concurrent with respective edges of the triangle and the origin (0,0) coincident with the vertex (V.0) between those edges. A generalised interpolation function, applied in terms of the parameterising (s,t) coordinate system, determines parameter values at positions (P) within the triangle in terms of the two-dimensional coordinate system. These parameter values determine contributions from stored values for one or more attributes, such as surface normal or texturing, stored for each vertex, to give attribute values at each pixel. In a final stage, the per pixel attribute values from all triangles are used to jointly determine an output color for each pixel.

Abstract: In an image processing system for providing two-dimensional pixel images comprised of a purality of polygonal image primitives and a background, the polygonal image primitives representing a three-dimensional object, a Z buffer and a color buffer are cleared by the steps of rendering image primitives relating to foreground in the color buffer (354) and the Z buffer (353); and subsequently scanning the Z buffer and for each pixel, if the Z value is a predetermined background value such as zero (357), clearing the corresponding location in the color buffer to background color (358), and if the Z value is not the predetermined background value, clearing the Z buffer to that predetermined background value (359). In the method, either a Z buffer or a color value is written during the buffer clearing process, but never both. The pixels may be read from cache in groups, the size of a group being selected to maximize the possibility of all consecutive pixels in a group being either foreground or background pixels.

Abstract: A hybrid video encoder which carries out motion estimation and compensation (8) in the transform domain. In such an encoder, the calculation of a prediction block (Ŷ) from previously encoded blocks (Z) stored in the transform-domain frame memory (7) requires a large number of multiplications. This applies particularly to the motion estimation algorithm. In accordance with the invention, only a few DCT coefficients of candidate prediction blocks are calculated, for example, the DC coefficient and some AC coefficients. In a preferred embodiment, the AC coefficients are adaptively selected in dependence upon the motion vector which is being considered. The calculated coefficients of the candidate prediction blocks and the corresponding coefficients of the current input picture block (Y) are then compared to identify the best-matching prediction block.

Abstract: An information stream organized as a sequence of blocks is encoded according to a graceful degradation principle. The stream poses temporal non-uniform data processing requirements. In particular, with respect to a received block one or more blockwise defined control parameters and an associated blockwise processing load are detected. Under control of a processing load for one or more previous blocks, one or more later blocks before processing thereof get an adjustment of one or more of the control parameters. This lowers an expected load for the later block in case of an excessive load, and vice versa when detecting a sub-standard load.

Abstract: The invention relates to a transcoder comprising a drift compensating loop (DCL) for compensating a drift signal (Ei) introduced in the transcoding path by a quantization operation (Q2). This drift compensation loop performs a motion compensation of a signal (F1) issuing from a previous dequantization (IQ1) resulting in a prediction signal (P1). The motion compensation is based on the drift signal stored in a memory unit (MEM). The drift signal and the prediction signal may be conveyed in an interlaced or de-interlaced structure. According to the invention, an AMC unit adapts the motion compensation operation with the de-interlaced or interlaced structures of the drift and prediction signals.

Abstract: The invention relates to a method and device for generating a large static image M(n), such as a sprite or a mosaic, from a video sequence including successive video objects. This method comprises a first step for estimating motion parameters related to the current video object V0(n) of the sequence with respect to the previously generated static image M(n−1), a second step for warping this video object on the basis of the estimated motion parameters, and a third step for blending the warped video object WV0(n) thus obtained with the previously generated static image M(n−1). According to the invention, an additional step for computing, for each picture element of the current video object, a weighting coefficient wWF(n)[x,y] correlated to the error between the warped video object and the static image M(n−1) is provided, and the blending formula now takes into account said weighting coefficients.

Abstract: A method for storing a block of data consisting of N rows and M columns, which includes the step of transposing the block of data by 90° to thereby produce a transposed block of data consisting of M rows and N columns, and, the step of storing the transposed block of data. The transposed block of data is preferably retrieved by using one or more fetch commands, with the number of fetch commands required to retrieve the transposed block of data being less than the number of fetch commands required to retrieve the same data if stored in its original form, thereby reducing memory bandwidth. In a presently contemplated implementation, the block of data is a reference macroblock of decoded MPEG video data that is used in motion compensation operations, and each of the fetch commands is an A×B fetch command, where A represents the number of columns of data and B represents the number of rows of data to be fetched in response thereto, and wherein further, A>B.

Abstract: A basic transcoder, that decodes an encoded data stream and re-encodes it, may be used for locally modifying data in said stream. Said modification is carried out by defining a predicted data stream on the basis of a given modifying data stream and adding to the decoded stream—between the decoding and re-encoding parts of the transcoder—the difference between the modifying data stream and the predicted one. In an improved implementation, the modifying data stream is preprocessed so that it may be obtained in the decoded data stream a local substitution of said modifying data to the decoded ones.

Abstract: The invention relates to a method for generating a large static image M(n), such as a sprite or a mosaic, from a video sequence. This method first comprises, in view of a first accretion step, an estimation of the motion parameters related to the video objects of the sequence, with respect to the previously generated static image. Each video objects is then warped on the basis of said parameters, and the warped video objects are blended with the previously generated static image. According to the invention, said method also comprises (n−1) further accretion steps, but applied this time to the same video sequence considered in the reverse order. Each additional accretion step itself includes a warping sub-step, based on each successive video object considered in said reverse order and on the corresponding motion parameters already estimated, and a blending sub-step, pixel-based or region-based weighting coefficients being then computed in order to be taken into account during the blending steps.