Method and apparatus for backlight compensation of an image
First Claim
1. A method for backlight compensation of an image, comprising:
- generating an image histogram of an image to be processed;
judging whether the image to be processed requires backlight compensation according to the image histogram;
if the image to be processed requires the backlight compensation, determining a first luminance boundary value A used for performing the backlight compensation and a second luminance boundary value C used for performing positive or negative backlight compensation; and
performing backlight compensation for the image to be processed according to the first luminance boundary value A and the second luminance boundary value C;
wherein judging whether the image to be processed requires the backlight compensation includes;
obtaining a luminance level of L1 a pixel point corresponding to a crest value of a highest peak with a maximum crest luminance and a luminance level L2 of a pixel point corresponding to a crest value of a second highest peak whose crest luminance level is lower than an average luminance of the image histogram, anddetermining that the image to be processed requires the backlight compensation if L1−
L2>
K, wherein K is a fixed luminance difference and K>
0.
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Accused Products
Abstract
A method and an apparatus for processing images are disclosed. The method includes: generating an image histogram of an image to be processed; judging whether the image to be processed requires backlight compensation according to the image histogram; if the image to be processed requires backlight compensation, determining a first luminance boundary value A used for deciding whether to perform backlight compensation and a second luminance boundary value C used for deciding whether to perform positive or negative backlight compensation; and performing backlight compensation for the image to be processed according to the first luminance boundary value A and the second luminance boundary value C. The method is simple and universally applicable. After backlight compensation, the contrast of the image is high, and the image is free from background overexposure and image layering. The image photographed in a backlight environment is processed properly.
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Citations
8 Claims
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1. A method for backlight compensation of an image, comprising:
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generating an image histogram of an image to be processed; judging whether the image to be processed requires backlight compensation according to the image histogram; if the image to be processed requires the backlight compensation, determining a first luminance boundary value A used for performing the backlight compensation and a second luminance boundary value C used for performing positive or negative backlight compensation; and performing backlight compensation for the image to be processed according to the first luminance boundary value A and the second luminance boundary value C; wherein judging whether the image to be processed requires the backlight compensation includes; obtaining a luminance level of L1 a pixel point corresponding to a crest value of a highest peak with a maximum crest luminance and a luminance level L2 of a pixel point corresponding to a crest value of a second highest peak whose crest luminance level is lower than an average luminance of the image histogram, and determining that the image to be processed requires the backlight compensation if L1−
L2>
K, wherein K is a fixed luminance difference and K>
0. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An apparatus for backlight compensation of an image, comprising:
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an image histogram generating unit, adapted to generate an image histogram of an image to be processed; a backlight compensation judging unit, adapted to judge whether the image to be processed requires backlight compensation according to the image histogram of the image to be processed; a backlight compensation parameter generating unit, adapted to generate a first luminance boundary value A and a second luminance boundary value C for the backlight compensation if the backlight compensation judging unit determines that the image to be processed requires the backlight compensation; and a backlight compensation unit, adapted to perform the backlight compensation for the image to be processed according to the first luminance boundary value A and the second luminance boundary value C generated by the backlight compensation parameter generating unit; wherein the backlight compensation parameter generating unit comprises; a first boundary value generating unit, connected to the backlight compensation judging unit and the backlight compensation unit and adapted to generate the first luminance boundary value A and the second luminance boundary value C according to the image histogram and a first function generating unit, connected to the first boundary value generating unit and the backlight compensation unit, and adapted to generate a first compensation function and a second compensation function according to the first luminance boundary value A and the second luminance boundary value C generated by the first boundary value generating unit wherein the first compensation function and the second compensation function are designed the backlight compensation for the image to be processed.
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Specification