Snell Limited

Snell & Wilcox Limited

British Broadcasting Corporation

Grass Valley Limited

Snell Advanced Media Limited

Martin Weston

Michael James Knee

Barry Flannaghan

William Beningfield Collis

Avigdor Steinberg

Peter Wilson

Steve Dabner

Jonathan Diggins

John O Drewery

Richard Storey

Charles P Sandbank

Keith Steward Hammond

Chris Owen

Simon Longcroft

James Pearson

Simon Auty

In video motion estimation an initial candidate motion vector is generated for each block and a vector error is determined as for example a DFD. Spatial gradients of pixel values are calculated and used to refine the initial candidate motion vector. The relative contribution of the spatial gradients to the refinement process depends on the vector error.

Refining motion vectors in video motion estimation

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.

Method and apparatus for analysing an array of pixel-to-pixel dissimilarity values by combining outputs of partial filters in a non-linear operation

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.

Analysis of stereoscopic images

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.

Repairing scratch impairments to an image

An image or other sample processor has a resampling filter adapted to provide output samples at an output sampling frequency which can be selected to be higher or lower than the input sampling frequency. The width of the resampling filter aperture is scaled according to either the input sampling frequency or the output sampling frequency so as to obtain the wider of the two possible filter apertures.

Re-sampling method and apparatus

Systems and methods of rendering a motion image. Input temporal image-samples are temporally interpolated to create the output sequence and an intentional, periodic motion-judder component that is visible when the output temporal image-samples are displayed is introduced.

Motion image rendering systems and methods

When mixing cutting between video cameras viewing a common scene from different viewpoints, geometric transforms that vary from image to image are applied to one or both camera outputs so as to create an apparent point of view that moves along on a path joining the viewpoints of the cameras.

Processing of images to represent a transition in viewpoint

First image data at a lower sampling frequency is up-sampled in a sampling ratio N:M to a higher sampling frequency in an up-sampling filter; and, second image data at the said higher sampling frequency is down-sampled in a sampling ratio M:N to the said lower sampling frequency in a down-sampling filter where the combination of the up-sampling filter and the down-sampling filter is substantially transparent and every filtered sample is formed from a weighted sum of at least two input samples.

Digital image processing for converting images from one sampling structure to another

Systems and methods of rendering a motion image. A television signal is modified through a sine wave motion judder component to introduce intentional motion judder which can replicate the appearance of cinematic projection. To present 24 frames per second film via a 60 Hz television system with the 'look' of a 72 Hz cinematic projector, a judder oscillator is set to generate a 24 Hz sinewave having a peak amplitude equal to 38.5% of the time difference between 24 Hz frames. The motion-judder component may periodically reverse the apparent direction of motion.

The present invention relates to methods and apparatus for interpolation of images, and in a particular example to de-interlacing of video signals using spatial interpolation. The present invention discloses a method for measuring the slope of a picture portion in which picture gradients are calculated from said selected pixel values and the slope measurement being derived from said gradient values. The invention also discloses a method of spatial interpolation of an array of pixel values, in which interpolated values are dependent upon the measurement of the slope associated with said array. Non-integer slopes can easily be accommodated with the method of the invention.

Image processing

This invention concerns the interpolation of new intermediate images within an existing set of related images, for example views of a scene captured at different times, such as a sequence of film frames or video fields, or views of a scene captured from different camera positions, either simultaneously or in a time sequence. Motion vectors established for pixels or regions in at least one existing image are used to shift those pixels or regions to the output position of the new image. The shifted pixels or regions are combined in dependence on a probability of accuracy measure for the respective motion vector. The probability of accuracy measure may be formed from displaced-field difference measurements. The occlusion of objects is determined and used in forming the probability of accuracy measure.

Method and apparatus for interpolating an image

A method of composite decoding in which the input signal is converted into the frequency domain, and the symmetry of frequency components with respect to the subcarrier frequency is compared. The comparison is varied in dependence upon the frequency being processed. In this way, the separation can be adapted to suit known characteristics of different portions on the input spectrum. This is particularly useful for processing NTSC signals. The allocation of a particular component to chrominance may be biased in dependence upon a measure of the luminance information of the composite signal at a corresponding spatial frequency.

System and method for improved composite decoding

A method of and apparatus for image analysis for picture loss detection in fields or frames in video or film content makes use of different correlation characteristics of picture images and non-picture images to detect picture loss. A measure of self correlation of a plurality of image data samples, and a measure of the correlation of the plurality of image data samples with a mean value are determined, and a positive detection of picture loss is based on a comparison between the two correlation measures.

Method of and apparatus for image analysis

A method of image segmentation using graph-theory techniques, in which pixels of an image are represented by the vertices of a graph. A minimum spanning tree is generated and edges of the tree are successively removed according to a morphological property to leave a spanning forest, trees of which correspond to segments of the image. Selection of edges for removal may depend on an energy function of a tree and on the energy function of trees created by removal of that edge.

Image segmentation based on processing of a graph

A video noise reducer divides a signal into spatial frequency bands and derives both recursively and non-recursively filtered signals for each band. Both signals are processed non-linearly. These signals are combined in ways that vary between the bands to provide a noise signal and a detail signal. A clean video signal with all noise removed is used in the recursive loop. The output signal includes detail enhancement and may have a subjectively pleasant amount of noise added back.

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Petersfield, United Kingdom

Martin Weston