Tone mapping method for high dynamic range image

A high dynamic range, image tone technology, applied in image enhancement, image data processing, instruments, etc., can solve the problem of insufficient display effect, and achieve the effect of good detail display effect, high dynamic range image and high contrast

Inactive Publication Date: 2014-08-20
广州市捷顺彩印有限公司
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AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a high dynamic range image tone mapping method, which solves the problems of "halo" and insufficient display effect in the existing methods

Method used

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  • Tone mapping method for high dynamic range image
  • Tone mapping method for high dynamic range image

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Embodiment 1

[0056] The high dynamic range image tone mapping method of the present invention is implemented through the following steps and specific parameters:

[0057] Step 1, read the high dynamic range image, convert its floating-point data into integer RGB format data, and then calculate the brightness image L of the high dynamic range image in , and take the logarithm to form the log domain luminance image L, which is calculated as:

[0058] L in =0.299R+0.587G+0.114B,

[0059] L=log(L in +0.00001),

[0060] Step 2, perform multi-scale WLS filtering on L, and estimate the multi-scale illumination component L k (k=1, 2, L), to avoid the phenomenon of "halo" in places with strong contrast between light and dark. It can be expressed as:

[0061] L k =WLS(L,λ k ),

[0062] Among them, the operator WLS( ) means to perform WLS filtering, and λ k Represents the scale factor, whose value determines the illumination component image L k The degree of smoothness, increasing λ k , w...

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Abstract

The invention discloses a tone mapping method for a high dynamic range image. The method comprises the following steps of: firstly, reading the high dynamic range image, and acquiring a log-domain brightness image of the high dynamic range image; secondly, estimating illumination components of the high dynamic range image by multi-scale weighted least squares (WLS) filtering to avoid the phenomenon of halo generated at a high light and shade contrast place; thirdly, recovering brightness components of the high dynamic range image by using a multi-scale Retinex method, eliminating the gray of a 1% part of each of two poles to prevent under-exposure and over-exposure, and adjusting the brightness degree of the image according to a self-adaptive adjustment function; and finally, recovering the color of the high dynamic range image by introducing an index control saturation method. The tone mapping method for the high dynamic range image is applicable to display and output of the high dynamic range image on low dynamic range equipment, generation of the halo can be avoided, and the displayed image has the characteristics of high contrast and good detail reproduction effect.

Description

technical field [0001] The invention belongs to the technical field of digital image processing and is used for reproducing high dynamic range images on low dynamic range display devices, in particular to a high dynamic range image tone mapping method. Background technique [0002] The brightness range of high dynamic range images is generally 0.001cd / m 2 to 100000cd / m 2 between. Because high dynamic range images can well reproduce the rich brightness levels in actual scenes and produce realistic effects, it is being more and more widely used in the fields of film and television, computer games, military, astronomy, and medical testing. Compared with the brightness range of high dynamic range images, the brightness range that many display devices (such as CRT, LCD, projector, etc.) can produce is too narrow. For example, the brightness range produced by ordinary CRT is about 1cd / m 2 to 100cd / m 2 , so using an ordinary monitor to display a high dynamic range image will ca...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G06T5/00
Inventor 张二虎杨慧云
Owner 广州市捷顺彩印有限公司
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