Patent EP0396229A2 successfully refreshed from Google Patents.
EP0396229A2
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Spatial interpolation of digital video signals
Assignee: Sony Corp
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Filing: 1990-03-07
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Granted: —
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Expires: 2010-03-07
Abstract
Abstract 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.
Inventors
- 👤 David Andrew Dougall
- 👤 Gavin Alexander Walker
- 👤 James Hedley Wilkinson
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 14:56
CPC Classifications
H; H04; H04N; H04N19/00; H04N19/50; H04N19/59; G; G06; G06T; G06T3/00; G06T3/40; G06T3/4007; G06T3/403; H04N7/00; H04N7/01; H04N7/0117; H04N7/012; H04N7/0135; H04N7/014
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
281 words
A method of spatially interpolating between lines of a digital video signal to produce interpolated lines, the method comprising the steps of: horizontally interpolating (11) 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; determining (SD(-4) to (SD(+4)), 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), the determining step being carried out for a plurality of different horizontal offsets, including zero offset and at least one offset on each side of zero, so as to produce a respective value of the extent of matching for each horizontal offset; selecting (26), 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; and spatially interpolating (14, 16, 18, 38, 40, 42, 44, 46) between samples of the video signal in different lines thereof to generate samples of the interpolated line, the direction of interpolation of spatial interpolation being controlled, for each sample generated, in accordance with the gradient vector selected for said predetermined sample position (X) corresponding to that generated sample.
Claim 2
Independent Claim
281 words
A method of spatially interpolating between lines of a digital video signal to produce interpolated lines, the method comprising the steps of: horizontally interpolating (11) 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; determining (SD(-4) to (SD(+4)), 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), the determining step being carried out for a plurality of different horizontal offsets, including zero offset and at least one offset on each side of zero, so as to produce a respective value of the extent of matching for each horizontal offset; selecting (26), 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; and spatially interpolating (14, 16, 18, 38, 40, 42, 44, 46) between samples of the video signal in different lines thereof to generate samples of the interpolated line, the direction of interpolation of spatial interpolation being controlled, for each sample generated, in accordance with the gradient vector selected for said predetermined sample position (X) corresponding to that generated sample.
Claim 3
Dependent Claim
79 words
A method according claim 1, wherein: said selection step (26) is carried out for each sample of the supersampled signal and said spatial interpolation step (14, 16, 18, 38, 40, 42, 44, 46) is performed upon the supersampled signal, whereby a sample of an interpolated line is generated for each sample of the supersampled signal; and those generated samples other than those that correspond in horizontal position to the original samples of the digital video signal are discarded (50).
Claim 4
Dependent Claim
75 words
A method according to claim 1 or claim 2, wherein, for at least some of said horizontal offsets, said determining step (SD(-4) to (SD(+4)) is carried out for a plurality of said blocks of respective different sizes, and the resultant plural values of the extent of matching for each horizontal offset are combined, to form a single value of the extent of matching for each horizontal offset, prior to said selection step being carried out.
Claim 5
Dependent Claim
28 words
A method according to claim 3, wherein the plurality of blocks of different sizes all have the same value of N and have respective different values of M.
Claim 6
Dependent Claim
29 words
A method according to claim 4, wherein there are four blocks of different sizes, the values of M for the four blocks being 3, 5, 7 and 9, respectively.
Claim 7
Independent Claim
12 words
A method according to any one of the preceding claims, wherein N=3.
Claim 8
Independent Claim
24 words
A method according to any one of the preceding claims, wherein the gradient vectors selected for successive samples are low pass spatially filtered (28).
Claim 9
Independent Claim
79 words
A method according to any one of the preceding claims, wherein the value of a generated sample of an interpolated line is predicted (66) from values of other generated samples in the same line and, if the actual value of the generated sample does not fall within a range of values determined by the predicted value, the generated sample is at least partially replaced by a sample generated by vertically filtering (62) between samples of the digital video signal.
Claim 10
Independent Claim
36 words
A method according to any one of the preceding claims, which spatially interpolates between the lines of a field of a digital video signal to form interpolated lines disposed midway between the lines of the field.
Claim 11
Dependent Claim
59 words
A method according to claim 9, wherein the local degree of motion of a picture represented by the digital video signal is sensed (112) and, if the degree of motion is less than a predetermined value, the generated samples of the interpolated lines are at least partially replaced by samples generated by temporally filtering (110) the digital video signal.
Claim 12
Dependent Claim
338 words
Apparatus for spatially interpolating between lines of a digital video signal to produce interpolated lines, the apparatus comprising: supersampling means (11) operative to horizontally interpolate 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; a plurality of block matching circuits (SD(-4) to SD(+4)) each operative to 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 being operative as set forth for a respective one of plurality of different horizontal offsets, including zero offset and at least one offset on each side of zero, whereby a respective value of the extent of matching is produced for each horizontal offset; selector means (26) responsive to said respective values produced by the block matching circuits 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; and a spatial interpolator (14, 16, 18, 38, 40, 42, 44, 46) operative to spatially interpolate between samples of the video signal in different lines thereof, to generate samples of the interpolated line, the direction of interpolation of the spatial interpolator being variable and the spatial interpolator being connected to the selector means so that the direction of interpolation of the spatial interpolator is controlled, for each sample generated thereby, in accordance with the gradient vector selected for said predetermined sample position (X) corresponding to that generated sample.
Claim 13
Dependent Claim
338 words
Apparatus for spatially interpolating between lines of a digital video signal to produce interpolated lines, the apparatus comprising: supersampling means (11) operative to horizontally interpolate 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; a plurality of block matching circuits (SD(-4) to SD(+4)) each operative to 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 being operative as set forth for a respective one of plurality of different horizontal offsets, including zero offset and at least one offset on each side of zero, whereby a respective value of the extent of matching is produced for each horizontal offset; selector means (26) responsive to said respective values produced by the block matching circuits 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; and a spatial interpolator (14, 16, 18, 38, 40, 42, 44, 46) operative to spatially interpolate between samples of the video signal in different lines thereof, to generate samples of the interpolated line, the direction of interpolation of the spatial interpolator being variable and the spatial interpolator being connected to the selector means so that the direction of interpolation of the spatial interpolator is controlled, for each sample generated thereby, in accordance with the gradient vector selected for said predetermined sample position (X) corresponding to that generated sample.
Claim 14
Dependent Claim
98 words
Apparatus according claim 11, wherein: the selector means (26) is operative to carry out said selection for each sample of the supersampled signal and the spatial interpolator (14, 16, 18, 38, 40, 42, 44, 46) is operative to perform said spatial interpolation upon the supersampled signal, whereby the spatial interpolator generates a sample of an interpolated line for each sample of the supersampled signal; and the apparatus includes subsampling means (50) operative to discard those samples generated by the spatial interpolator other than those that correspond in horizontal position to the original samples of the digital video signal.
Claim 15
Dependent Claim
81 words
Apparatus according to claim 11 or claim 12, wherein at least some of said block matching circuits (SD(-4) to SD(+4)) are operative to determine the extent of matching for a plurality of said blocks of respective different sizes and to combine the resultant plural values of the extent of matching for the associated horizontal offset to form a single value of the extent of matching for each horizontal offset, prior to the selector means effecting said selection of a gradient vector.
Claim 16
Dependent Claim
27 words
Apparatus according to claim 13, wherein the plurality of blocks of different sizes all have the same value of N and have respective different values of M.
Claim 17
Dependent Claim
28 words
Apparatus according to claim 14, wherein there are four blocks of different sizes, the values of M for the four blocks being 3, 5, 7 and 9, respectively.
Claim 18
Dependent Claim
12 words
Apparatus according to any one of claims 11 to 15, wherein N=3.
Claim 19
Dependent Claim
27 words
Apparatus according to any one of claims 11 to 16, including a low pass spatial filter (28) operative to filter the gradient vectors selected for successive samples.
Claim 20
Dependent Claim
97 words
Apparatus according to any one of claims 11 to 17, including a vertical filter (62) operative to effect vertical filtering between samples of the digital video signal, and a horizontal predictor (66) operative to predict the value of a generated sample of an interpolated line from values of other generated samples in the same line and, if the actual value of the generated sample does not fall within a range of values determined by the predicted value, to cause the generated sample to be at least partially replaced by a sample generated by the vertical filter (62).
Claim 21
Dependent Claim
39 words
Apparatus according to any one of claims 11 to 18, which is operative to spatially interpolate between the lines of a field of a digital video signal to form interpolated lines disposed midway between the lines of the field.
Claim 22
Dependent Claim
65 words
Apparatus according to claim 19, including motion sensor means (112) operative to sense the local degree of motion of a picture represented by the digital video signal and, if the degree of motion is less than a predetermined value, to cause the generated samples of the interpolated lines to be at least partially replaced by samples generated by temporally filtering (110) the digital video signal.
References Cited (Backward Citations)
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