Abstract: A method of analyzing an array of pixel-to-pixel dissimilarity values to identify a pixel which has a low pixel-to-pixel dissimilarity value and which has neighboring pixels which have a low pixel-to-pixel dissimilarity value; the method comprising filtering the pixel-to-pixel dissimilarity values and varying the spatial extent of the filter aperture in dependence upon a picture spatial activity measure.

Abstract: To control loudness during a junction between different types of broadcast content, such as a junction between programme and commercial or promotional content, representative loudness values for content respectively before (P) and after (C) the junction are received from a playout automation system. A time-varying gain control is applied before and after the junction in order to smooth loudness around the junction. The audio gain is smoothly increased prior to the junction to a gain (P+C)/2P times higher than the original gain value. Then, the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value. After the junction, the gain is returned smoothly to the original value.

Abstract: To detect the presence of a logo in a search image, the positions of edges, in an image of the logo and in the search image, are represented by ratios of distances between the respective edge and a plurality of preceding edges. This can be carried out both horizontally and vertically. A sequence of edges at a selected position in the logo image is then compared with sequences of edges from a plurality of positions in the search image, and the position of the logo in the search image is determined from the position of a match between the respective sequences of edges.

Abstract: The invention relates to the analysis of characteristics of audio and/or video signals for the generation of audio-visual content signatures. To determine an audio signature a region of interest for example of high entropy—is identified in audio signature data. This region of interest is then provided as an audio signature with offset information. A video signature is also provided.

Abstract: In for example the assignment of motion vectors, an array of pixel-to-pixel dissimilarity values is analyzed to identify a pixel which has a low pixel-to-pixel dissimilarity value and which has neighboring pixels which have a low pixel-to-pixel dissimilarity value. The pixel-to-pixel dissimilarity values are filtered with a filter aperture decomposed into two or more sectors with partial filters applied respectively to each sector. Outputs of the partial filters are combining by a non-linear operation, for example taking the minimum from diametrically opposed sectors.

Abstract: Apparatus is provided for processing a switched audio signal output received from a crosspoint router having a plurality of inputs and a plurality of outputs, there being a control signal that defines which of the plurality of inputs is to be routed by the crosspoint router to which of the plurality of outputs. A control unit receives the control signal and serves to identify a route change in the control signal. An instantaneous value of the switched audio signal prior to the route change is stored. A signal processing unit then combines the stored value with values of the switched audio signal after the route change to form a processed audio signal that changes smoothly.

Abstract: A method of enhancing the perceived sharpness of an image by controlling a spatial interpolation process. A pixel value spatial gradient measure is formed and used to generate a map of modified pixel positions. In this map, the pixel spacing is reduced when the gradient measure is high. By using this map of modified pixel positions to control an otherwise conventional interpolation process, an output image is formed having a perceived sharpness which is greater than that of the unmodified output of the interpolation process.

Abstract: For re-timing sampled data, input data samples at an input data rate are stored in a FIFO buffer and output at an output data rate according to an output clock that is locked to the input data rate in dependence on a loop-filtered measure of the fill level of the said buffer. The frequency of the output clock is additionally controlled by an estimate of the input data rate.

Abstract: To control loudness during a junction between different types of broadcast content, such as a junction between programme and commercial or promotional content, representative loudness values for content respectively before (P) and after (C) the junction are received from a playout automation system. A time-varying gain control is applied before and after the junction in order to smooth loudness around the junction. The audio gain is smoothly increased prior to the junction to a gain (P+C)/2P times higher than the original gain value. Then, the gain is reduced shortly before the junction to a value (P+C)/2C times lower than the original gain value. After the junction, the gain is returned smoothly to the original value.

Abstract: A watermark encoder receives a current video image together with current metadata associated with the current image. A metadata delay also makes available to the watermark decoder delayed metadata associated respectively with four or more of the preceding. Then the watermark encoder modifies pixel values of the current image not only to encode the current metadata but also the delayed metadata. At a decoder, if metadata for the current image is corrupted or missing, it can be recovered from one of the succeeding images.

Abstract: An image manipulation process is controlled by a spatial periodicity measure formed for an image or an image block by measuring the sparseness of the two-dimensional spatial frequency spectrum of the image on a scale of zero to unity in which a two-dimensional spatial frequency spectrum having all equal values has a sparseness of zero and in which a two-dimensional spatial frequency spectrum having only one non-zero value has a sparseness of unity. Sparseness may be measured by allocating values of the spectrum to frequency bins and counting the number of bins that contain non-zero values; comparing values of the spectrum with a threshold and counting the number of values that exceed the threshold; or forming a function of the mean-square value and the mean value of the spectrum values.

Abstract: A motion estimator has a spatial sub-sampler to receive input images; at least one motion estimator determining motion vectors between input images and sub-sampled motion vectors between sub-sampled images; an up-sampler for up-sampling the sub-sampled motion vectors; and a selector for providing a motion vector output by selecting between the motion vectors and the (up-sampled) sub-sampled motion vectors, according to motion vector confidence.

Abstract: To generate a warning that a stereoscopic image sequence has been synthesized from a 2D image sequence, a video processor correlates left-eye image data and right-eye image data to identify any sustained temporal offset between the left-eye and right-eye image data. A measure of sustained correlation between a measured spatial distribution of horizontal disparity and a spatial model can also be used to generate the warning.

Abstract: A method of identifying the left-eye and the right-eye images of a stereoscopic pair, comprising the steps of comparing the images to locate an occluded region visible in only one of the images; detecting image edges; and identifying a right-eye image where image edges are aligned with a left hand edge of an occluded region and identifying a left-eye image where more image edges are aligned with a right hand edge of an occluded region.

Abstract: A method for repairing scratch impairments in which brightness values for a set of points within a narrow region of the impaired input image that is aligned with an expected scratch direction are modified in a scratch repair process; and the scratch repair process is controlled in dependence upon the relationship between the impaired brightness values and corresponding modified brightness values.

Abstract: An image manipulation process is controlled by a spatial periodicity measure formed for an image or an image block by measuring the sparseness of the two-dimensional spatial frequency spectrum of the image on a scale of zero to unity in which a two-dimensional spatial frequency spectrum having all equal values has a sparseness of zero and in which a two-dimensional spatial frequency spectrum having only one non-zero value has a sparseness of unity. Sparseness may be measured by allocating values of the spectrum to frequency bins and counting the number of bins that contain non-zero values; comparing values of the spectrum with a threshold and counting the number of values that exceed the threshold; or forming a function of the mean-square value and the mean value of the spectrum values.

Abstract: Resampling a spatially sampled attribute of an image, for example up- or down-conversion, in which contributions to a symmetrical FIR resampling filter from positions outside the image—that is to say where the filter aperture extends beyond an image edge—are obtained by copying values from positions inside the image. This can conveniently be done by modifying filter coefficients.

Abstract: An adaptive low pass filtering process with a filter delay DA is conducted in parallel with reference low pass filtering process with a filter delay DR which is greater than DA. The error is measured between a delayed version of the adaptive process output and the reference process output. Filter parameters of the adaptive process are controlled to minimize the error.

Abstract: The temporal sampling pattern of a sequence of images that represents a moving scene is classified into classes of temporal sampling patterns including “film”, “video” and “still”. Pixels in each image in the said sequence are classified according to the relationship between signed inter-image pixel-value differences f1 and f2 between that image and, respectively, the preceding and succeeding images in the sequence. An initial classification for each pixel may be refined in accordance with the relative numbers of pixels of the image initially classified into each class.

Abstract: The intended display aspect-ratio for video is determined automatically by analyzing an image to identify image blocks resulting from prior block-based processing of the video; comparing horizontal and vertical dimensions of those image blocks with horizontal and vertical dimensions of the image, with black border regions excluded as necessary; and determining from that comparison a display aspect ratio for the video.