TV picture motion vector measurement by correlation of pictures
AssigneeBritish Broadcasting Corporation
InventorGraham A. Thomas
Life of this patent
Estimating the term…
Abstract
A correlation surface is derived by phase correlating two pictures selectively displaced in the X and Y directions. The illustrative surface shows a large peak at zero displacement, corresponding to a stationary background, and a fairly large peak corresponding to a moving object, the X, Y position of the peak indicating the magnitude (pixels per field period) and direction of the motion vector. A set of motion vectors is thus determined and testing is then carried out, on a pixel by pixel basis or pixel block by pixel block basis, to determine which of the motion vectors gives the best match in deriving the second picture from the first. The motion vector thus assigned may be used in temporal interpolation of the pictures.
Claims27
A machine method of TV picture motion measurement, comprising a first step of correlating first and second pictures to determine correlation as a function of selective displacement, thereby to determine a plurality of peak correlation values corresponding to respective motion vectors, and a second step of testing for each of a plurality of elementary areas of the pictures which of these motion vectors gives the best fit in deriving one of the pictures from the other, and wherein said second step comprises the following operations:
- (a) an elementary area of a picture is derived from said first picture using each of said motion vectors determined in said first step, thereby to form a set of derived elementary areas corresponding to said motion vectors respectively;
- (b) each derived elementary area is compared with the corresponding elementary error as a sum over the elementary areas of the magnitudes of the differences between corresponding points of said elementary areas;
- (c) that one of said motion vectors which results in the smallest comparison error is selected as giving the best fit in deriving said elementary area of said second picture from said elementary area of said first picture;
- (d) repeating operations (a), (b) and (c) for each of said plurality of elementary areas.
Dependencies are inferred from the claim text.