Compositing video image data

Claim 3

A method according to claim 1 , wherein said color-space coordinates represent positions on an orthogonal set of axes and said distance is calculated from the sum of each component squared.

Claim 4

A method according to claim 2 , wherein said control value is calculated from the square root of said sum.

Claim 5

A method according to claim 1 , wherein color-space coordinates are transformed onto an alternative set of orthogonal axes.

Claim 6

A method according to claim 4 , wherein said transformation is performed with reference to said background base color.

Claim 7

A method according to claim 1 , wherein said background base color is determined from a set of manually selected colors.

Claim 8

A method according to claim 6 , wherein said background base color is derived by forming a convex hull around said selected colors.

Claim 9

A method according to claim 1 , wherein said control value is used to suppress color in areas of color spill.

Claim 10

A method according to claim 1 , wherein said control value is used to generate a keying signal.

Claim 11

Image data compositing apparatus including means for merging first image data with second image data in which the first image data and the second image data are obtained separately and each has a plurality of pixels and each pixel is represented by three color components defining a position within a color-space, comprising: (a) means for identifying a background base color to be replaced in the first image; (b) calculating means for calculating distance in three-dimensional color-space between a foreground input color in the first image and said background base color; and (c) means for producing a control value in relation to said calculated distance, wherein: (i) the control value is used to merge the first image data with the second image data; (ii) the control value indicates that a first image data pixel is part of background to be replaced if the calculated distance is within a tolerance zone; (iii) the control value indicates the first image data pixel is part of required foreground if the calculated distance is outside of a softness zone; and (iv) the control value indicates a level of blending if the calculated distance is within the softness zone.

Claim 12

Image data compositing apparatus including means for merging first image data with second image data in which the first image data and the second image data are obtained separately and each has a plurality of pixels and each pixel is represented by three color components defining a position within a color-space, comprising: (a) means for identifying a background base color to be replaced in the first image; (b) calculating means for calculating distance in three-dimensional color-space between a foreground input color in the first image and said background base color; and (c) means for producing a control value in relation to said calculated distance, wherein: (i) the control value is used to merge the first image data with the second image data; (ii) the control value indicates that a first image data pixel is part of background to be replaced if the calculated distance is within a tolerance zone; (iii) the control value indicates the first image data pixel is part of required foreground if the calculated distance is outside of a softness zone; and (iv) the control value indicates a level of blending if the calculated distance is within the softness zone.

Claim 13

Apparatus according to claim 10 , including means for calculating said distance as the sum of each component squared, wherein said components are defined on an orthogonal set of axes.

Claim 14

Apparatus according to claim 11 , wherein said calculating means is configured to calculate the square root of said sum.

Claim 15

Apparatus according to claim 10 , including means for transforming said color-space coordinates onto an alternative set of orthogonal axes.

Claim 16

Apparatus according to claim 13 , wherein said means for performing said transformation is configured to perform said transformation with reference to said background base color.

Claim 17

Apparatus according to claim 10 , including manually operable means for selecting said background base-color.

Claim 18

Apparatus according to claim 15 , including means for deriving a background base color with reference to a convex hull constructed around selected colors.

Claim 19

Apparatus according to claim 10 , including means for suppressing color signals in areas of color spill under the control of said control value.

Claim 20

Apparatus according to claim 10 , including means for keying video signals in response to said control signal.