Method and system for adjusting dynamic contrast of digital image or video

A dynamic contrast and adjustment method technology, applied in the field of digital imaging, can solve the problems of low brightness and dark images, loss of details, and poor image quality

Active Publication Date: 2014-08-06
SZ DJI TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, no single contrast setting will work for all images
For example, for an image with high overall brightness, the user may choose a Gamma parameter with high brightness or change the contrast setting to enhance the contrast of the image, but when such a setting is used for an image with low brightness, it will Makes the low-brightness parts of the image too dark and loses detail making the image quality poor

Method used

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  • Method and system for adjusting dynamic contrast of digital image or video
  • Method and system for adjusting dynamic contrast of digital image or video
  • Method and system for adjusting dynamic contrast of digital image or video

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Embodiment Construction

[0041] see figure 1 , is a schematic flowchart of a method for adjusting dynamic contrast of a digital image provided by an embodiment of the present invention. Such as figure 1 As shown, the dynamic contrast adjustment method of the digital image comprises the following steps:

[0042] S101: Read a certain frame in an image or video, denoted as I.

[0043] S102: Calculate the brightness histogram of I to obtain the probability density function pdf(·).

[0044] The described calculation brightness histogram, that is, the probability density function pdf(·) refers to the calculation of the number of occurrences of pixels corresponding to the gray level in I to form the distribution of pixel values ​​in I within the entire dynamic range of brightness. Wherein the histogram can be recorded as a vector H=[p 1 ,p 2 ,...,p n ]. This vector satisfies:

[0045] p i =#{(x,y)|I(x,y)=x i};

[0046] where x i represents an arbitrary grayscale. #{(x,y)|I (x，y) =x i} represen...

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Abstract

The invention discloses a method for adjusting the dynamic contrast of a digital image or video. The method comprises the following steps that a frame of image in the digital image or video is read; a pixel brightness value probability cumulative distribution function cdf() of the image is calculated; when the image is a gray level image, the contrast of the current gray level image is adjusted with a relational expression (please see the specific formula in the specification); when the image is a color image, the contrast of the current color image is adjusted with a relational expression (please see the specific formula in the specification), wherein zi=f(Ei), zi is the output pixel value of a pixel point at exposure brightness Ei, f() is a mapping function, Yi is a brightness value, and Ci is one channel in RGB three color channels. The invention further discloses a system for adjusting the dynamic contrast of the digital image or video.

Description

technical field [0001] The invention relates to the field of digital images, in particular to a method and system for adjusting the dynamic contrast of digital images. Background technique [0002] Contrast refers to the measurement of the different brightness levels between the brightest white and the darkest black in an image, and the greater the range of difference, the greater the contrast. Since the dynamic range of the actual scene is often above 100dB, and the sensor elements (CCD or CMOS) used in traditional digital cameras generally only have a dynamic range of about 60dB, this makes the camera's metering system subject to high or low brightness areas. The impact of compressing the quantized grayscale numbers in other areas leads to a decrease in overall contrast and loss of details. [0003] The enhancement of the existing image contrast can be adjusted by using the Gamma (gamma coefficient) parameter of the display, and the image contrast can be adjusted by chang...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N5/202H04N5/57
Inventor 曹子晟梁泰文王铭钰
Owner SZ DJI TECH CO LTD
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