Methods and apparatus for defining contours in colored images
First Claim
1. A method of defining a contour in a coloured image to separate a selected region having a selected colour or colours from other regions wherein a colour component content of each pixel of said coloured image is defined by digital data at a first resolution, the method comprisinga) Defining at least one region of said coloured image containing colours which are to be located in said selected region;
- b) For each of said pixels in said defined region(s) deriving a digital colour component representation at a second resolution higher than said first resolution by combining said colour component content of one or more adjacent pixels with said colour component content of said pixel;
c) Designating each of said digital colour component representations at said second resolution derived in step b as a "selected colour value"; and
,d) Performing an edge following algorithm to define said contour within said coloured image including deriving said digital colour component representation at said second resolution for each of said pixels under consideration in the same manner as in step (b), determining whether each of said digital colour component representations at said second resolution is one of said selected colour values, and designating one of said pixels as lying on said contour by reference to the arrangement of neighbouring pixels having said selected colour values.
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Abstract
A method and apparatus for defining a contour in a colored image to separate a selected region having a selected color or colors from other regions when the color component content of each pixel of the image is defined by digital data at a first resolution. The method comprises defining a region of the image containing colors which are to be located in the selected region and for each of the pixels in the defined region deriving a digital color component representation at a second resolution higher than the first resolution by combining color component data from one or more adjacent pixels. Each digital color component representation at a second resolution is then designated as a selected color value. An edge following algorithm is performed to define a contour within the image by deriving a digital color component representation at a second resolution for each pizel under consideration, as before, determining whether each digital color component representation is a selected color value and designating a pixel as lying on the contour by reference to the arrangement of neighboring pixels having selected color values.
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Citations
9 Claims
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1. A method of defining a contour in a coloured image to separate a selected region having a selected colour or colours from other regions wherein a colour component content of each pixel of said coloured image is defined by digital data at a first resolution, the method comprising
a) Defining at least one region of said coloured image containing colours which are to be located in said selected region; -
b) For each of said pixels in said defined region(s) deriving a digital colour component representation at a second resolution higher than said first resolution by combining said colour component content of one or more adjacent pixels with said colour component content of said pixel; c) Designating each of said digital colour component representations at said second resolution derived in step b as a "selected colour value"; and
,d) Performing an edge following algorithm to define said contour within said coloured image including deriving said digital colour component representation at said second resolution for each of said pixels under consideration in the same manner as in step (b), determining whether each of said digital colour component representations at said second resolution is one of said selected colour values, and designating one of said pixels as lying on said contour by reference to the arrangement of neighbouring pixels having said selected colour values. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Apparatus for defining a contour in a coloured image to separate a selected region having a selected colour or colours from other regions wherein a colour component content of each pixel of said coloured image is defined by digital data at a first resolution, the apparatus comprising a first store for storing said digital data at said first resolution;
- and processing means for
a) Defining at least one region of said coloured image containing colours which are to be located in said selected region; b) For each of said pixels in said defined region(s) deriving a digital colour component representation at a second resolution higher than said first resolution by combining said colour component content of one or more adjacent pixels with said colour content of said pixel; c) Designating each of said digital colour component representations at a second resolution derived in step b as a "selected colour value"; and
,d) Performing an edge following algorithm to define said contour within said coloured image including deriving said digital colour component representation at said second resolution for each of said pixels under consideration in the same manner as in step (b), determining whether each of said digital colour component representations at a second resolution is one of said selected colour values, and designating one of said pixels as lying on said contour by reference to the arrangement of neighbouring pixels having said selected colour values. - View Dependent Claims (9)
- and processing means for
Specification