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US 9,288,462 B2Granted
Conversion of an image to a transparency retaining readability and clarity of detail while automatically maintaining color information of broad areas
AssigneeiMatte, Inc.
InventorsPaul E. Vlahos, Arie Berman
Life of this patent
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Abstract
The present invention converts an image into a transparency, or “foreground image”, on which the readability of text and other detail is preserved after compositing with a background, while maintaining color information of broad areas of the image.
Claims10
A method for converting an image into a transparency, or foreground image with matte for compositing with a background image, comprising:
- a) determining an edge level for each pixel in a foreground image,
- b) interpreting the determined edge levels as opacity levels for pixels of the foreground image, said opacity levels ranging from fully transparent at a first edge level, to fully opaque at a second edge level, to form a matte and a foreground transparency, wherein said first edge level is less than said second edge level;
- and
- c) compositing said foreground transparency with said background image, wherein said interpreting of the determined edge levels as said opacity levels is performed to preserve the readability of text and other detail in said foreground image after said compositing.
1 more element
A system for converting an image into a transparency, or foreground image with matte, on which the readability of text and other detail is preserved after compositing over a background image, comprising:
- a) a low pass filter unit configured to receive a foreground image signal;
- b) an absolute difference unit coupled to said low pass filter unit and configured to receive said foreground image signal and a low pass filtered version of said foreground image signal and to calculate an absolute difference between said foreground image signal and said low pass filtered version of said foreground image signal;
- c) a multiplier coupled to said absolute difference unit configured to receive said absolute difference and multiply said absolute difference by an opacity scaling factor to convert said absolute difference to an opacity level between 0 and a number greater than wherein 0 represents complete transparency and 1 represents complete opacity;
- d) a clip unit coupled to said multiplier to replace said opacity level if greater than 1 to an opacity level equal to 1;
- e) a complementing unit coupled to said clip unit to calculate a complement to said opacity level output by said clip unit;
- f) a second multiplier coupled to said complementing unit configured to receive said complemented opacity level and multiply said complemented opacity level by a transparency scaling factor to convert said complemented opacity level to a transparency level between 0 and a number greater than wherein 0 represents complete opacity and 1 represents complete transparency;
- g) a second clip unit coupled to said second multiplier to replace said transparency level if greater than 1 to a transparency level equal to 1 to generate a transparency matte signal;
- h) a difference unit configured to receive said foreground image signal and a background image signal and calculate a difference between said background image signal and said foreground image signal;
- i) a third multiplier coupled to said second clip unit and said difference unit and configured to multiply said calculated difference by said transparency matte signal to generate a product signal;
- j) an adder unit coupled to said third multiplier and configured to receive said foreground signal and add said foreground signal to said product signal to generate a composite signal having a red component level, a green component level and a blue component level;
- k) a third clip unit coupled to said adder unit to convert each of said red component level, said green component level and said blue component level if less than 0 to 0;
- and
- l) a fourth clip unit coupled to said third clip unit to replace each of said red component level, said green component level and said blue component level if greater than a predetermined maximum value with said predetermined maximum value.
10 more elements
Dependencies are inferred from the claim text.