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基于光谱反射率的低照度图像增强方法研究

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低照度图像增强技术是机器视觉研究热点之一,Retinex理论模型假设图像是反射分量与光照分量乘积,通过去除或校正光照分量并结合物体的反射特性来恢复图像,被广泛应用在传统算法和深度学习增强模型中.光谱反射率是颜色的指纹,多光谱图像比普通图像的信息量更为丰富.色度学理论和Retinex理论都认为图像的颜色特性取决于反射系数,但光谱反射率是基于仪器测量获得真实的数据,而图像反射分量是基于图像分解假设的数据,目前文献没有从光谱角度对低照度图像增强进行研究.受Retinex理论启发结合深度学习非线性拟合能力,用颜色的光谱反射率代替RetinexNet网络中的图像反射分量,用CIE标准光源的光谱功率分布代替网络中的图像照明分量,提出了一种基于光谱反射率的低照度图像增强方法.首先对图像数据库中正常光照图像进行光谱重建,构建低照度图像与正常光照的多光谱图像数据集.然后训练将低照度图像转换成多光谱图像的深度学习网络模型.任意低照度图像通过网络模型得到多光谱图像,多光谱图像根据色度学理论得到CIEXYZ三刺激值,再通过标准颜色空间转换到RGB颜色空间中显示.该方法在公开LOL数据集上进行训练与测试,结果表明在图像噪声抑制和颜色恢复方面都优于常用方法,证明该方法对低照度图像增强的优越性和有效性.
Research on Low Illumination Image Enhancement Method Based on Spectral Reflectance
Low illumination image enhancement technology is one of the research hotspots of computer vision.The theoretical algorithm of Retinex assumes that the image is the product of the reflection component and the illumination component.It restores the image by removing or correcting the illumination component and combining the reflection component of the object,which is widely used in traditional algorithms and deep learning enhancement models.Spectral reflectance is the fingerprint of color,and multispectral images have more information than RGB images.Colorimetric theory and Retinex theory agree that the color of an image depends on reflection data,but spectral reflectance is obtained based on instrument measurement,and the image reflection component is obtained based on image hypothesis decomposition.The literature has not studied the enhancement of low-light images from the perspective of spectral reflectance.Inspired by Retinex theory and combined with the strong nonlinear fitting ability of deep learning,a low illumination image enhancement method based on spectral reflectance is proposed.The spectral reflectance of color is used to replace the image reflection component in the RetinexNet network,and the spectral power distribution of the CIE standard light source is used to replace the image illumination component in the network.Firstly,the spectral reflectance of normal light images in the image database is reconstructed to build a multispectral image dataset of low illumination and normal light images.Then,the deep learning network model is trained to convert low-illumination images into the multispectral images.Any low illuminance image is obtained from the multispectral image through the network model,and the multispectral image is obtained from the CIEXYZ tristimulus according to the colorimetric theory and then converted to the RGB color space for display through the standard color space.The method is trained and tested on the public LOL dataset,and the results show that this method is superior to the standard methods in image noise suppression and color restoration,which proves the superiority and effectiveness of this method for low illumination image enhancement.

Spectral reflectanceLow illumination image enhancementRetinex theoryDeep learning

麻祥才、曹前、白春燕、王晓红、张大伟

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上海理工大学光电信息与计算机工程学院,上海 200093

上海出版印刷高等专科学校印刷包装工程系,上海 200093

上海理工大学出版印刷与艺术设计学院,上海 200093

光谱反射率 低照度图像增强 Retinex理论 深度学习

国家自然科学基金项目上海理工大学专业学位研究生实践基地项目资助

62205207

2024

光谱学与光谱分析
中国光学学会

光谱学与光谱分析

CSTPCD北大核心
影响因子:0.897
ISSN:1000-0593
年,卷(期):2024.44(3)
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