Abstract: Motion vectors resulting from block matching are corrected for periodic structures by taking a more reliable vector from an edge of a moving object containing the periodic structure. This is done by calculating and comparing different error combinations to identify periodic structures and replacing a current motion vector with one of an adjacent pixel block either from the block to the left or from the block above, which ever yields the smaller error in the current block, or by taking a combination (e.g., mean) of both vectors. Advantageously, artifacts such as phase reversal of information in interpolated fields due to the presence of an erroneous vector in a periodic structure are reduced and very little additional processing is required after the block matching itself.

Abstract: An appearance of a double image around moving objects may be reduced or removed by generating motion compensated 100 Hz fields with the objects in correct positions. When, however, the results of this technique are applied to motion compensated upconversion, objects or parts of the picture which fall outside the range of measurable velocities appear on the upconverted display with a very strong double image, resulting from the display of information in the wrong temporal position generated by uncompensated or `fallback processing`. The subjective strength of the double image may be reduced by low pass filtering in a horizontal direction the components in the new fields of the upconverted signal which cause this double image.

Abstract: The invention discloses a method for coding a video image on a pixel block basis in a transmission system including at least one transmitter and one receiver, where the video image is in one of several possible display formats. The method comprises:(a) defining a first image display format that encompasses each of the several image display formats;(b) dividing the first image format into pixel blocks;(c) assigning labels to the first image format blocks so that they can be individually addressed;(d) selecting a second image display format for the video image that is encompassed by the first image display format; and(e) coding the video image with reference to the individual addresses of the first image format block.A method of decoding transmissions coded by the disclosed coding method is also presented.The invention is applicable to videophones and television transmission systems.

Abstract: Motion compensated video output signal (SO) produced by a soft switching or "fading" (SSW) between the a motion compensated interpolation (MCI) and a "fallback" mode (FFI) (e.g., intra-field), controlled by a "measure of confidence" (CF) in the reliability of the estimated motion vector. The confidence measure includes the following two components, namely: (i) a "basic confidence measure" (e.g., a block based, minimum motion estimation error (BME) and (ii) a measure based on the motion velocity or "speed" of movement of the motion vector or its horizontal (MVX) and vertical components (MVY).

Abstract: A method for estimating motion which calculates a priori for a current image a first field of motion for blocks of a first level resulting from a partition of the image into blocks of a so-called maximum size, on the basis of a symmetric estimation algorithm, using the preceding and following images in the sequence to calculate the displaced inter-raster differences. Then, a second field of motion for blocks resulting from the partition of a block of the first level are calculated, and so on until a level of blocks of a minimum size. The final field of motion results from the selection of the most suited motion vectors from those of the various levels and is directly associated with a quadtree coding tree. Such a method finds particular application to image transmission chains, and in particular high-definition.

Abstract: The method consists in estimating motion by performing a gradient algorithm which minimalizes the mean square deviation of local luminance variations of the present pel of the picture with the pel that is homologous with it in the prior picture, in initializing the execution of the algorithm by displacement values estimated along several directions within the close causal neighborhood of the present pel and in propagating each estimate in the scanning direction if the picture lines.