Sony United Kingdom Limited

Sony Corporation

James Edward Burns

Nicholas Ian Saunders

Robert Mark Stefan Porter

Karl James Sharman

Morgan W David

Martin Rex Dorricott

Clive Henry Gillard

John W Richards

Shima R Varsani

Tsuneo Morita

James J Galt

Stephen Mark Keating

Jonathan Living

Ahmad Sadjadian

Timothy Stuart Roberts

Andrew Campbell

An image processing apparatus generating output pixel values with respect to pixels of an input image selected in accordance with an image feature direction in the input image and including a comparing mechanism comparing blocks of pixels of the input image, the blocks disposed with respect to a pixel position under test so that a correlation between the blocks would indicate an image feature direction applicable to that pixel position; and a validating mechanism detecting whether an image feature direction may be used to interpolate an output pixel value at the pixel position under test. The validating mechanism: (i) detects whether a detected image feature direction for the pixel position under test meets one or more predetermined directional criteria; and (ii) detects whether pixel values in image regions disposed with respect to the pixel position under test in accordance with possible image feature directions meet one or more predetermined pixel value criteria.

Alias avoidance in image processing

An image processing apparatus in which output pixels of an output image are generated with respect to input pixels of an input image, a first subset of the output pixels being identical to respective input pixels and a second subset of the output pixels being derived from respective groups of one or more input pixels. The apparatus includes a spatial filter arrangement for filtering the second subset of pixels, the filter not being applied to filter the first subset of output pixels, the filter arrangement having a response such that high spatial frequencies are attenuated in the output image.

Scan conversion image filtering

A method of image processing for image conversion, comprises the steps of calculating a difference measure of the difference in pixel values between corresponding blocks of a current image field and a preceding image field, calculating a variability measure of the variability of pixel values from at least one of said corresponding blocks, determining whether the difference measure exceeds the variability measure, and if the difference measure exceeds the variability measure, then setting an inter-image mixing value for each pixel in the corresponding block of the current image field to indicate that the current image field should not be mixed with the preceding image field at that pixel position.

Motion adaptive image processing

A method of image processing for converting interlaced images to progressive scan images comprises the steps of generating a motion dependent mixing value for determining the extent to which a preceding image field should be mixed with a current intra-field interpolated image field at a given pixel position, comparing the generated mixing value with a preceding historical mixing value, and if the comparison indicates an increase in motion, using the generated mixing value; otherwise, if the comparison indicates a decrease in motion, temporally filtering the generated mixing value prior to use.

A method of image processing for conversion of an image in a sequence of images comprises the steps of associating pixels of an image with respective motion values indicative of a degree of inter-image motion for each pixel; adjusting the motion value of each pixel based upon the motion value of a secondary pixel found within a first region of a first predetermined size substantially centered upon each respective pixel, said secondary pixel being that whose associated motion value is indicative of the greatest motion of any pixel in the first region; adjusting the motion value of each pixel based upon the motion value of a secondary pixel that lies within a second region of a second predetermined size substantially centered upon each respective pixel, said secondary pixel being that whose associated motion value is indicative of the least motion of any pixel in the second region; categorizing each pixel as a static pixel or a motion pixel according to its respective associated motion value, and then selecting respectively either a first conversion process or a second conversion process for a pixel dependant upon whether that pixel is categorized as a static pixel or a motion pixel.

Apparatus and method of motion adaptive image processing

An image processing method for image conversion by combining two or more source values based on a mixing parameter to generate an output pixel value. A metric is calculated for a selected pixel at a given image field based on the directly preceding image field and a spatially interpolated version of the given image field at the selected pixel position. The selected pixel is categorized based on the metric as providing an indeterminate, unreliable, or reliable basis for a determination of motion at that pixel. The mixing parameter for the selected pixel is adjusted based on the categorization of the pixel.

An image processing apparatus includes a first motion detector, a second motion detector and a conversion selector. The first motion detector detects motion to a first level of spatial frequency sensitivity. The second motion detector detects motion to a second level of spatial frequency sensitivity greater than the first level of spatial frequency sensitivity to detect smaller amounts of motion than the first motion detector. The conversion selector selects contributions from at least one of a first conversion process and a second conversion process for a given point in an image dependant upon whether motion is detected by the first motion detector at the given point or not. The conversion selector operates independently of the second motion detector if a degree of motion within the image or a part thereof including the given point detected by the first motion detector does not exceed a threshold amount.

A data compression apparatus for performing data compression on input data comprises a quantisation parameter estimation arrangement for deriving an estimated value of a quantisation parameter used in a previous compression/decompression cycle applied to the input data, by detecting rounding effects in data values of at least a subset of the input data; and a parameter selection arrangement, responsive to the quantisation parameter estimation arrangement for selecting a quantisation parameter for use in compression of the input data.

Data compression

Decoders A and B decode MPEG-2 bitstreams A and B. A switch (S ) switches from decoded stream A to decoded stream B to achieve a splice. The resulting bitstream is re-encoded in an encoder . A new GOP is defined beginning at the splice. The new GOP is defined by picture type decision rules which may the effect of changing the GOP compared to the GOPs of streams A and B. The new GOP provides a prediction of the position in stream B where the occupancy value of stream C should coincide with that of B. A target for the new number of bits in the new GOP is calculated dependent on the difference between the occupancy value of stream C at the splice and a prediction of the occupancy of stream B at the predicted position. The occupancy value of stream C is controlled in accordance with the target so that it tends towards the occupancy value of stream B at the predicted position.

Signal processing

Data compression apparatus for compressing an input data unit to produce an output data unit in accordance with a desired data quantity of the output data unit, the degree of compression being determined by a compression control variable having a range of possible values. A trial encoder compresses successive sections of the input data unit in accordance with a trial group of two or more values of the compression control variable. A data quantity detector detects the trial data quantities generated by each trial encoding of the sections of the input data unit and selects a base compression control variable applicable to the input data unit on the basis of the detected trial data quantities, in order to comply with the desired data quantity. An allocator allocates a compression control variable for use in final encoding each section of the input data unit to generate the output data unit, the allocator being comparable to determine whether to use the base compression control variable or another possible value of the compression control variable for the current section.

Video data compression apparatus for compressing images of an input video signal on a block-by-block basis comprises a block analyser for analysing each block of an image to be compressed to detect a degree of difference between pixels within that block; a data quantity allocator for allocating target output data quantities for the compression of each block, the target data quantities being dependent on the detected degrees of pixel difference of the blocks; and a data compression encoder for compressing each block in accordance with the target output data quantity associated with that block.

Video data compression

Decoders A and B decode MPEG-2 bitstreams A and B and re-encoders and re-encode them as bitstreams A and B comprising only I frames. A switch (S1) switches from recoded stream A to recoded stream B to achieve a splice A /B . The spliced bitstream is stored in an I-frame store ( ). The stored bitstream A /B is re-encoded in an encoder . A new transitional GOP is defined beginning at the splice. The new GOP is defined by picture type decision rules which may change the length of the transitional GOP compared to the GOPs of streams A and B. The transitional GOP provides a prediction of the position in stream B where the occupancy value of stream C should coincide with that of B. A target for the new number of bits in the new GOP is calculated dependent on the difference between the occupancy value of stream C at the splice and a prediction of the occupancy of stream B at the predicted position. The occupancy value of stream C is controlled in accordance with the target so that it tends towards the occupancy value of stream B at the predicted position. In another version, the target is updated at regular intervals throughout the GOP, and the change allowed is limited.

Signal processor

Image data decompression apparatus and method for receiving data words comprising a first sub-word and a second sub-word, at least some possible values of the first sub-word specifying a run of at least m instances of a predetermined data value, corresponding second sub-words specifying a number of instances of the predetermined data value in a range from at least m instances. The apparatus includes a first decoder for decoding the first sub-words to detect whether a current first sub-word specifies a run of at least m instances of the predetermined value, and a second decoder for decoding the second sub-words to generate output decoded data. The apparatus also includes a data counter for counting output decoded data from the second decoder, an adder, responsive to detection of a data error in a current second sub-word, for adding to a count of the data counter an amount corresponding to a lowest number m of instances of the predetermined data value specified by the corresponding first sub-word, and a partial code detector, responsive to a second sub-word having only a portion thereof corrupted by an error therein for detecting the number of instances of the predetermined data value more than the number of instances specified by the first sub-word indicated by an uncorrupted portion thereof, and for controlling the adder to add to the count of the data counter the number of instances specified by the uncorrupted portion of the second sub-word.

Image data compression and decompression using both a fixed length code

Video down-conversion apparatus in which lines of successive output video field are interpolated from lines of respective input video fields, the apparatus being selectively operable to interpolate each output field from an input field of either field polarity so that the successive output video fields can maintain a regular odd-even field polarity sequence even if there is a discontinuity in the field polarity sequence of the input video fields.

Video down-conversion

Motion compensated video signal processing apparatus comprises a subsampler for horizontally subsampling an input digital video signal, to generate a subsampled video signal; a motion vector processor for generating motion vectors from the subsampled video signal; and a motion compensated video processor for processing the input digital video signal according to the motion vectors, to generate an output digital video signal.

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Basingstoke, United Kingdom

James Edward Burns