Method for correcting lightness of image
AssigneesSharp Kabushiki Kaisha, Synthesis, Inc.
InventorsNoboru Kubo, Xiaomang Zhang, Hiroyuki Okuhata, Akimasa Niwa
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Abstract
A method is provided for correcting lightness of an image using a multiscale retinex. Lightness of a subject pixel of an original image is corrected using a convolution operation of a surround function and surround pixels with respect to the subject pixel of the original image, and the convolution operation is performed over a plurality of scales. The surround function has a simplified model such that a value of the surround function is changed in a stepwise way along two axes orthogonal to each other.
Claims13
A method for correcting lightness of an image using a multiscale retinex wherein lightness of a subject pixel of an original image is corrected using a convolution operation of a surround function and surround pixels with respect to the subject pixel of the original image, and the convolution operation is performed over a plurality of scales;
- and
- the surround function has a simplified mode such that a value of the surround function is changed in a stepwise way along two axes orthogonal to each other.
A multiscale retinex method for correcting image lightness comprising the steps of:
- selecting a first subject pixel from a plurality of pixels;
- identifying a first plurality of surround pixels related to the first subject pixel;
- and
- correcting the lightness of the first subject pixel using a convolution operation of a surround function and the first plurality of surround pixels over a plurality of scales;
- wherein the surround function has a value which changes in a stepwise manner along two orthogonal axes.
A multiscale retinex method for correcting image lightness comprising the steps of:
- selecting a subject pixel from a plurality of pixels;
- identifying a first plurality of surround pixels related to the subject pixel;
- identifying a second plurality of surround pixels related to the subject pixel;
- and
- correcting the lightness of the subject pixel using one-dimensional convolution operations of a surround function and a selected one of the first plurality of surround pixels over a plurality of scales and a selected one of the second plurality of surround pixels over the plurality of scales.
Dependencies are inferred from the claim text.