基于双域和ILoG-CLAHE的矿井红外图像增强算法

Mine infrared image enhancement algorithm based on dual domain and ILoG-CLAHE

针对矿井复杂作业环境导致的红外图像降质,现有红外图像增强算法在实现信噪比和对比度提升的同时易丢失场景细节信息或造成目标边缘模糊的问题,提出了一种基于双域分解耦合改进的高斯-拉普拉斯(ILoG)算子和对比度受限自适应直方图均衡化(CLAHE)(ILoG-CLAHE)的矿井红外图像增强算法。首先,利用双域分解模型将矿井红外图像分解为包含高频信息的细节子图和低频信息的基础子图;其次,利用CLAHE算法对基础子图的亮度、对比度和清晰度进行提升,用以突出监视场景的概貌特征,采用构造的ILoG算子对细节子图进行噪声抑制和边缘锐化,并消除梯度反转现象;然后,通过重构处理后的基础子图和细节子图得到了图像质量改善后的重构图像;最后,设计了一种灰度重分布的Gamma校正函数,对重构图像进行亮度调整,进而得到矿井红外增强图像。通过主观视觉和客观指标对算法进行了性能分析,结果表明:经基于双域和ILoG-CLAHE的矿井红外图像增强算法增强后的矿井红外图像,整体视觉效果和客观指标均得到了较大提升,综合增强性能和鲁棒性更好。相较于原矿井红外图像和6种对比算法(CLAHE算法、双边滤波器(BF)分解与基础子图的CLAHE增强(BF-CLAHE)算法、BF分解与Gamma变换(BF-Gamma)算法、引导滤波与Gamma变换(GF-Gamma)算法、自适应直方图均衡化(AHE)耦合拉普拉斯变换(AHE-LP)算法、基于反锐化掩膜(UM)的图层融合(LF-UM)算法),该算法的综合评价指标值分别提高了0.28,0.11,0.23,0.38,0.57,0.04,0.10,图像亮度、清晰度和对比度均得到了较大提升,并且实现了噪声抑制和边缘锐化,表明该算法适用于矿井复杂作业环境中红外图像的增强处理。

The complex working environment of mine leads to the degradation of the infrared image.The existing infrared image enhancement algorithm is easy to lose the scene details or causes the target edge blur while improving the signal-to-noise ratio and contrast.In order to solve the above problems,a mine infrared image enhancement algorithm based on dual domain decomposition coupling improved Gaussian Laplacian(ILoG)factor and contrast limited adaptive histogram equalization(CLAHE)(ILoG-CLAHE)is proposed.Firstly,the dual domain decomposition model is used to decompose the mine infrared image into a detailed sub-images containing high-frequency information and a basic sub-images containing low-frequency information.Secondly,the CLAHE algorithm is used to improve the brightness,contrast and definition of the basic sub-images to highlight the general features of the monitoring scene.The constructed ILoG operator is used to suppress noise and sharpen edges of detail sub-images and eliminate gradient inversion.Thirdly,the reconstructed image with improved image quality is obtained through the basic sub-image and detail sub-image after reconstruction processing.Finally,a Gamma correction function of gray level redistribution is designed to adjust the brightness of the reconstructed image.The mine infrared-enhanced image is obtained.The performance of the algorithm is analyzed by subjective vision and objective indicators.The results show that the overall visual effect and objective index of the mine infrared image enhanced by the mine infrared image enhancement algorithm based on dual domain and ILoG-CLAHE have been greatly improved.The comprehensive enhancement performance and robustness are better.Compared with the original mine infrared image and the six comparison algorithms,the comprehensive evaluation index values of this algorithm are increased by 0.28,0.11,0.23,0.38,0.57,0.04,and 0.10 respectively.The six algorithms include CLAHE algorithm,bilateral filtering(BF)decomposition and CLAHE enhancement of basic sub-images(BF-CLAHE)algorithm,BF decomposition and Gamma transform(BF-Gamma)algorithm,guided filtering and Gamma transform(GF-Gamma)algorithm,adaptive histogram equalization(AHE)coupled Laplacian transform(AHE-LP)algorithm,and un-sharp mask(UM)based layer fusion(LF-UM)algorithm.The brightness,clarity and contrast of images are greatly improved,and noise suppression and edge sharpening are realized.It shows that the algorithm is suitable for the enhancement of infrared images in the complex working environment of mine.