METHOD FOR IMPROVING DIGITAL IMAGES Russian patent published in 2007 - IPC G06T5/00 H04N1/409 

FIELD: digital processing of images, possible use for improving digital colored or halftone image.

SUBSTANCE: in accordance to invention, filtration of noises is performed, correction of global contrast is realized, brightness component is extracted from image as maximal one out of R, G, B components, local correction parameters are determined for light and dark tones, bilateral filtration of image brightness is performed, dark and light tones are corrected in brightness channel. Correction of dark image tones is performed due to addition to brightness channel of result of multiplication of difference between image of details in dark tones and brightness, inversion of result of bilateral filtration, raised to certain power, which determines width of tone spectrum, and amplification coefficient of dark tones, while image of details in dark tones is a function of ratio of brightness of original image and filtered image. Correction of light image tones is performed due to subtraction from brightness channel of difference between result of multiplication of brightness and image of details in light tones, result of bilateral filtration of brightness, raised to certain power which determines width of tone spectrum, and light tones weakening coefficient, while image of details in light tones is a function of ratio of filtered image and brightness of original image, image correction result is converted to RGB color system.

EFFECT: ensured correction of global contrast, local correction of light and dark tones, suppression of noises with a certain increase of image detail.

9 cl, 16 dwg