| 摘要 |
Apparatus for spatially interpolating between lines of a digital video signal, to produce interpolated lines, comprises a supersampler (11) that horizontally interpolates between samples of the video signal to produce a supersampled signal comprising the original samples and at least one interpolated sample located between each adjacent pair of original samples. Block matching circuits (SD(-4) to SD(+4)) each determine, for each sample of the supersampled signal, the extent of matching between two blocks of N X M samples of the supersampled signal (where N is the number of lines and M is the number of samples), the two blocks being vertically offset from one another in opposite directions with respect to a line to be interpolated, and being horizontally offset from one another in opposite directions with respect to a predetermined sample position (X). Each block matching circuit (SD(-4) to SD(+4)) operates as set forth for a respective different horizontal offset, including zero offset and offsets on opposite sides of zero, whereby a respective value of the extent of matching is produced for each horizontal offset. A selector (26) is responsive to the respective values produced by the block matching circuits (SD(-4) to SD(+4)) to select, for each sample of the line to be interpolated, from a plurality of gradient vectors each associated with a respective one of the different horizontal offsets, the gradient vector associated with the horizontal offset that produces the greatest extent of matching between the two blocks. A variable direction spatial interpolator (14, 16, 18, 38, 40, 42, 44, 46) spatially interpolates the video signal. The direction of interpolation of the spatial interpolator is controlled, for each sample it generates, in accordance with the gradient vector selected for said predetermined sample position (X) corresponding to that generated sample. |
