Methods for matching dynamic range of image signals

A dynamic range and image signal technology, applied in image communication, color signal processing circuit, color TV components, etc., can solve the problems of poor dynamic range matching and affecting image quality, etc.

Active Publication Date: 2009-09-23
成都恒图科技有限责任公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to solve the problem in the prior art that the dynamic range of the digital image in the computer and the dynamic range of the digital output device do not match well and affect the image quality, and provide a dynamic range matching method for the image signal. processing to match the dynamic range of digital output devices to achieve high-quality image output

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  • Methods for matching dynamic range of image signals
  • Methods for matching dynamic range of image signals
  • Methods for matching dynamic range of image signals

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Embodiment 1

[0112] The method for matching the dynamic range of an image signal includes the following steps:

[0113] a. Extracting the normalized luminance signal of the input image signal;

[0114] The specific method of this step is as follows:

[0115] a1. For all pixels of the input image signal in RGB color space, compare the maximum value of each primary color to find the maximum value I max .

[0116] a2. Divide the signal value of each pixel by the above maximum value, that is, normalize the input image signal to a signal in the interval [0, 1];

[0117] a21. If the input image signal is a nonlinear signal, convert it to a linear signal, this step is an optional step, and the conversion may not be performed.

[0118] a3. Convert the color space, convert the I(x, y) value representing the image signal into the Lum(x, y) value representing the image brightness signal and the C(x, y) value of the color signal, thereby obtaining the brightness signal and the color signal of the i...

Embodiment 2

[0198] This embodiment is mainly aimed at fast stretching for an image representing each RGB color channel with a small number of bits such as 8 bits, so as to speed up the processing process.

[0199] a. Extracting the normalized luminance signal of the input image signal;

[0200] The specific method of this step is as follows:

[0201] a1. For all pixels of the input image signal in RGB color space, compare the maximum value of each primary color to find the maximum value I max .

[0202] a2. Divide the signal value of each pixel by the above maximum value, that is, normalize the input image signal to a signal in the interval [0, 1];

[0203] a21. If the input image signal is a nonlinear signal, convert it to a linear signal, this step is an optional step, and the conversion may not be performed.

[0204] a3. Convert the color space, convert the I(x, y) value representing the image signal into the Lum(x, y) value representing the image brightness signal and the C(x, y) v...

Embodiment 3

[0254] In this embodiment, after the luminance signal of the input image signal is extracted, the area block is used to preliminarily adjust the luminance signal and then weighted and average the processing method to make it match the dynamic range of the output digital device.

[0255] Specific steps are as follows:

[0256] a. Extracting the normalized luminance signal of the input image signal;

[0257] The specific method of this step is as follows:

[0258] a1. For all pixels of the input image signal in RGB color space, compare the maximum value of each primary color to find the maximum value I max

[0259]a2. Divide the signal value of each pixel by the above maximum value, that is, normalize the input image signal to a signal in the interval [0, 1];

[0260] a21. If the input image signal is a nonlinear signal, convert it to a linear signal, this step is an optional step, and the conversion may not be performed.

[0261] a3. Convert the color space, convert the I(x...

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Abstract

The invention provides methods for matching the dynamic range of image signals, in particular relates to methods for processing the image signals, aims at solving the problem of influenced image quality of the prior art, which is caused by the reason that the dynamic range of a digital image in a computer can not be well matched with the dynamic range of digital output equipment. The invention mainly adopts two methods: in the first method, the brightness signal of the image signal is extracted and then is processed by the steps of blurring, adjustment, stretching transformation, and the like, and detail signals in the brightness signal are correspondingly processed, so that the dynamic range of the digital image can be matched with the dynamic range of digital equipment; or in the second method, the brightness signal of the image signal is extracted and is divided into regional blocks; after being initially adjusted, the brightness signal of pixel in each regional block is processed by the operation of weighted average, so that the dynamic range of the digital image can be matched with the dynamic range of digital equipment. The methods can be used for processing the digital image so as to output high quality images.

Description

technical field [0001] The invention relates to an image signal processing method, in particular to a method for matching the dynamic range of an input image signal and an output digital device. Background technique [0002] Digital images are usually stored in different bits (bits) on computers, such as 8 bits, 16 bits, and 32 bits to represent each RGB color channel, so they have different dynamic ranges (dynamic range is defined here as image or The ratio of the highest signal to the lowest signal in the system). Similarly, different digital devices such as monitors, projectors, and printers also have different dynamic ranges. [0003] When a digital image is displayed or printed on a digital device, often due to the mismatch of the dynamic range, the displayed or printed image does not have good brightness, contrast and details, so it does not have high image quality. Contents of the invention [0004] The purpose of the present invention is to solve the problem in t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04N5/14H04N5/57H04N9/64
Inventor 段江
Owner 成都恒图科技有限责任公司
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