Abstract: The present invention concerns the generation of image data, particularly, though not exclusively for motion estimation in the context of video coders employing inter frame differential coding. A method is provided for generating image data using a set of sampled pixels, the sampled pixels being representative of a sampled image, the method including the steps of: (i) at intermediate positions between sampled pixels, interpolating the sampled pixels so as to provide at least one set of interpolated pixels arranged along a plurality of lines, the or each set of interpolated pixels having a respective offset relative to the sampled pixels, and, (ii) storing the or each set of interpolated pixels with a respective address in a memory, the addresses forming an ordered sequence, wherein along a given line, neighbouring interpolated pixels having the same offset are stored with respective addresses that are consecutive to one another in the ordered sequence.

Abstract: A portable or other video communications device has a display 106 and camera 111. It provides a user with feedback as to his position in relation to the camera, with a head location unit 113 serving to modify (at 105) the displayed incoming picture—e.g. by degrading its quality and/or shifting it—if the user's head is off-centre. The location and modification can alternatively be located elsewhere in a remote device or intervening network. A preferred arrangement employs centre-weighted compression.

Abstract: Values, such as a set of coefficients in a transform-based video coder are to be transmitted sequentially in any one of a number of possible preset orders. The order to be selected is the one that results in the largest number of consecutive zeros (or low values) at the end of the sequence. Values are supplied (in an arbitrary sequence) with addresses, in parallel to a bank of assessment sections--one for each preset order--each of which translates the addresses into addresses representing a position in the respective order and records the highest for which the associated value is non-zero. The outputs of the sections are then compared to identify the lowest, and hence the optimum order of transmission.

Abstract: A method of coding a video signal for transmission includes the steps of coding data representing the video signal by a base layer coding operation which includes base layer quantizer having a base layer quantization step size to provide coded video data for transmission; deriving inverse-coded video data by carrying out an inverse base layer coding operation on the coded video data; deriving difference data from the data representing the video signal and the inverse coded video data; and coding the difference data by an enhancement layer coding operation only when the energy of the difference data exceeds a variable threshold, the threshold being inversely proportional to the base layer quantization step size.

Abstract: A predictive coder, e.g., a hybrid DCT interframe predictive video decoder, reduces the tendency of long-term bias error in the decoded difference signal to accumulate in a predictor (7) by periodically alternating the polarity of the bias error relative to the contents of the predictor. Inverse discrete cosine transform (IDCT) stage (6) in a receiver is bracketed by switchable invertors (9a,9b) which, when operating, invert the signal into IDCT stage (6) and then reinvert the signal, plus error, out of IDCT stage (6), thereby inverting the error relative to the difference signal. Control means (10), e.g., a pseudo-random number generator, switches the invertors (9a,9b) in and out periodically such that, over several frames, each block spends an equal amount of time in "normal" and "inverted" modes.

Abstract: A coder assembles bursts of blocks of image data (e.g. transform coded coefficients) and associated overhead data into a sequence of data which are then transmitted. Both the transform coded coefficients and the overhead data are initially stored in separate FIFO memory stores (21), (22). The blocks of transform coded coefficients have a `last coefficient` flag accompanying the last coefficient, and the overhead information contains a unique word SWITCH, after the header information but before the `end-of-block` flag. The `last coefficient` flag and the SWITCH word are recognized by a toggle controller (29) which controls the reading of the stores so that the coefficient data and overhead data are selectively passed to a buffer (30) in a desired sequence. The buffer (30) is followed by a variable length coder (31) which supplies the output of the coder at a constant bit rate.

Abstract: A poultry litter is disclosed in two preferred embodiments: compacted peat in fragments ranging in nominal diameter from 1/8 of an inch to 11/2 inches, and compacted peat fragments combined with a conventional litter material such as wood shavings, with the peat accounting for at least ten percent of the mixture weight. In this latter case, the peat fragments preferably have nominal diameters no greater than 1/8 of an inch. Preferably the peat is of the reed sedge type, with a pH of from 3.5 to 4.5, and a moisture content of no more than fifty percent by weight. For enhanced capacity to absorb moisture and dust control, the peat fragments are provided with a coating of a feed grade petroleum based oil, vegetable oil or animal fat.

Abstract: A binder ingredient for pelleted feeds comprising a direct binding agent present as a dry thin film layer or coating upon a solid particle of organic nutrient-filler. The dry thin film layer or coating comprises a water soluble lignin sulfonate such as calcium lignin sulfonate, while the organic nutrient-filler comprises granular dried reed sedge peat. The binder is mixed with the feed ingredients in a desired range, such as in the range of approximately 2 percent by weight, to form a pelleted feed.

Abstract: A television picture transmission system using conditional replenishment employs a scanning rate at the transmitter which differs (for asynchronous operation, slightly; or for operation between systems using different standards, considerably) from the scanning standard at the the receiver. The frame rate conversion is effected by the updating loops at the transmitter or receiver by, respectively, periodically stopping the coding loop for a field or frame so that no data is produced to produce a lower frame rate or periodically repeating a field or frame in the loop without adding any updating data so as to produce a higher frame rate. Resulting variations in data rate are accommodated by utilizing the buffering inherent in conditional replenishment systems.

Abstract: A coder assembles bursts of blocks of image data (e.g. transform coded coefficients) and associated overhead data into a sequence of data which are then transmitted. Both the transform coded coefficients and the overhead data are initially stored in separate FIFO memory stores (21), (22). The blocks of transform coded coefficients have a `last coefficient` flag accompanying the last coefficient, and the overhead information contains a unique word SWITCH, after the header information but before the `end-of-block` flag. The `last coefficient` flag and the SWITCH word are recognized by a toggle controller (29) which controls the reading of the stores so that the coefficient data and overhead data are selectively passed to a buffer (30) in a desired sequence. The buffer (30) is followed by a variable length coder (31) which supplies the output of the coder at a constant bit rate.