Abstract: A method and apparatus for detecting and/or tracking one or more colour regions in an image or sequence of images A method of detecting a region having predetermined colour characteristics in an image comprises transforming colour values of pixels in the image from a first colour space to a second colour space, using the colour values in the second colour space to determine probability values expressing a match between pixels and the predetermined colour characteristics, where the probability values range over a multiplicity of values, using said probability values to identify pixels at least approximating to said predetermined colour characteristics, grouping pixels which at least approximate to said predetermined colour characteristics, and extracting information about each group, wherein pixels are weighted according to the respective multiplicity of probability values, and the weightings are used when grouping the pixels and/or when extracting information about a group.

Abstract: A method of representing an object appearing in an image, the method comprising deriving a plurality of view descriptors of the object, each view descriptor corresponding to a different view of the object, and associating the two or more view descriptors, the method comprising indicating for each view descriptor when the respective view corresponds to a view of the object appearing in the image.

Abstract: A method of representing an object appearing in a still or video image, by processing signals corresponding to the image, comprises deriving a plurality of sets of co-ordinate values representing the shape of the object and quantising the co-ordinate values to derive a coded representation of the shape, and further comprises quantising a first co-ordinate value over a first quantisation range and quantising a smaller co-ordinate value over a smaller range.

Abstract: A method of approximating a motion vector for an image block, the method comprising retrieving motion vectors for neighbouring blocks, identifying a predominant value of at least one motion vector characteristic from the motion vectors for the neighbouring blocks, selecting those motion vectors for the neighbouring blocks which have a value which is the same or similar to said predominant value to form a group, and deriving an approximation for the motion vector for the image block from the selected group of motion vectors.

Abstract: A Hough transform based method of estimating N parameters a=(a1, . . . , aN) of motion of a region Y in a first image to a following image, the first and following images represented, in a first spatial resolution, by intensities at pixels having coordinates in a coordinate system, the method including: determining the total support H(Y,a) as a sum of the values of an error function for the intensities at pixels in the region Y; determining the motion parameters a that give the total support a minimum value; the determining being made in steps of an iterative process moving along a series of parameter estimates a1, a2, . . .