一种用于局部低照度水下图像的自适应增强方法

针对局部低照度导致的水下图像细节丢失以及使用现有的水下图像整体增强方法产生的增强过度现象,提出一种基于改进Retinex-Net的水下图像增强方法.通过基于HSV空间颜色阈值的图像二值化获取图像任意位置的低照度区域;利用卷积神经网络对图像的低照度区域学习与分解,并对分解结果进行端对端训练;在增强网络中运用U-Net,构...     

基于深度注意力机制的低照度图像增强方法

复杂环境下的低照度图像具有光照分布不均、多光源叠加作用等特点,导致增强后的图像真实性不足、图像噪声增加等问题。针对低照度图像的特点,提出了一种基于深度注意力机制的低照度图像增强方法。设计生成对抗全局自注意力低照度增强网络（GSLE-GAN）以实现低照度图像的增强。在生成器中设计并使用注意力模块,提高模型对于光照分布特点的提取能力以及生成图像的真实性,采用局部鉴别器与全局鉴别器共同作用的方式使图像具有更丰富的细节信息,使用非配对数据及对模型进行训练,以提升模型的鲁棒性并进一步保证生成图像的真实性。通过对比实验,证明了文中所提方法的优越性,并在目标检测任务中证明了方法的有效性。     

一种基于生成对抗网络与注意力机制的可见光和红外图像融合方法

针对低照度可见光图像中目标难以识别的问题,提出了一种新的基于生成对抗网络的可见光和红外图像的融合方法,该方法可直接用于RGB三通道的可见光图像和单通道红外图像的融合。在生成对抗网络中,生成器采用具有编码层和解码层的U-Net结构,判别器采用马尔科夫判别器,并引入注意力机制模块,使得融合图像可以更关注红外图像上的高强度信息。实验结果表明,该方法在维持可见光图像细节纹理信息的同时,引入红外图像的主要目标信息,生成视觉效果良好、目标辨识度高的融合图像,并在信息熵、结构相似性等多项客观指标上表现良好。     

基于线阵扫描成像的太赫兹图像超分辨率重建

针对太赫兹扫描成像设备存在的图像清晰度差、边缘模糊等问题,提出了一种基于生成对抗网络的太赫兹图像超分辨率重建算法。首先,在处理太赫兹图像时引入限制对比度自适应直方图均衡方法,有效解决了太赫兹图像对比度低的问题;其次,在生成对抗网络的基础上,提出了一种基于增强注意力机制的残差生成对抗网络,实现了太赫兹扫描图像的超分辨率重建,提升了图像纹理和细节的重建能力;最后利用频谱归一化的U-net网络对生成器生成的重建图像进行判别,增强了训练的稳定性。实验结果表明,提出的太赫兹图像超分辨率重建算法将太赫兹线阵相机所成太赫兹图像的边缘强度提高了7%,峰值信噪比提高了13%,平均梯度提高了12%,结构相似度提高了14%,验证了该算法的优越性和有效性。     

一种改进CycleGAN的低照度图像增强网络

为了提高CycleGAN对低照度图像增强后的细节分辨能力,提高图像整体的视觉质量,提出了一种改进CycleGAN的低照度图像增强算法.该网络的生成器由低光照增强模块和亮度均衡处理模块组成,用以学习低照度图像到正常照度图像的特征映射.以多尺度卷积和残差空洞卷积构建基于U-Net的低光照增强模块,提高网络对增强后图像细节信...     

多输入融合对抗网络的水下图像增强

针对水下图像出现对比度低、颜色偏差和细节模糊等问题,提出了多输入融合对抗网络进行水下图像增强。该方法主要特点是生成网络采用编码解码结构,通过卷积层滤除噪声,利用反卷积层恢复丢失的细节并逐像素进行细化图像。首先,对原始图像进行预处理,得到颜色校正和对比度增强两种类型图像。其次,利用生成网络学习两种增强图像与原始图像之间差异的置信度图。然后,为减少在生成网络学习过程中两种增强算法引入的伪影和细节模糊,添加了纹理提取单元对两种增强图像进行纹理特征提取,并将提取的纹理特征与对应的置信度图进行融合。最后,通过构建多个损失函数,反复训练对抗网络,得到增强的水下图像。实验结果表明,增强的水下图像色彩鲜明并且对比度提升,评价指标UCIQE均值为0.639 9,NIQE均值为3.727 3。相比于其他算法有显著优势,证明了该算法的良好效果。     

基于卷积分析稀疏表示和相位一致性的低照度图像增强

针对低照度图像存在的对比度低、视觉效果差等问题,提出一种基于卷积分析稀疏表示和相位一致性的低照度图像增强方法.该方法基于Retinex模型,在估计照度图像时采用卷积分析稀疏表示进行约束,所用滤波器一部分人工设定,一部分由样本训练自动获得;在计算反射图像时利用单演相位一致性特征,施加相位一致性残余最小约束来恢复细节;通过联合约束并进行优化,得到的反射图像即为最终的增强结果.对大量低照度图像进行实验,并与当前先进方法相比,结果表明,本文方法不仅提高了图像的亮度与对比度,增强了细节,而且在多个客观评价指标上都优于其他方法.     

基于任务解耦的低照度图像增强方法

低照度条件下拍摄的照片往往存在亮度低、颜色失真、噪声高、细节退化等多重耦合问题,因此低照度图像增强是一个具有挑战性的任务.现有基于深度学习的低照度图像增强方法通常聚焦于对亮度和色彩的提升,导致增强图像中仍然存在噪声等缺陷.针对上述问题,本文提出了一种基于任务解耦的低照度图像增强方法,根据低照度图像增强任务对高层和低层特征的不同需求,将该任务解耦为亮度与色彩增强和细节重构两组任务,进而构建双分支低照度图像增强网络模型（Two-Branch Low-light Image Enhancement Network,TBLIEN）.其中,亮度与色彩增强分支采用带全局特征的U-Net结构,提取深层语义信息改善亮度与色彩;细节重构分支采用保持原始分辨率的全卷积网络实现细节复原和噪声去除.此外,在细节重构分支中,本文提出一种半双重注意力残差模块,能在保留上下文特征的同时通过空间和通道注意力强化特征,从而实现更精细的细节重构.在合成和真实数据集上的广泛实验表明,本文模型的性能超越了当前先进的低照度图像增强方法,并具有更好的泛化能力,且可适用于水下图像增强等其他图像增强任务.     

基于深度学习的多帧遥感降质图像三维重建算法

为提升多帧遥感降质图像对比度以及图像质量,提出一种基于深度学习的多帧遥感降质图像三维重建算法。采用三角函数变换方法并结合高通滤波器,增强多帧遥感降质图像对比度;再以包含生成器和判别器的生成对抗网络为基础,在判别器中引入自注意力层,设计自注意力机制残差模块,生成自注意力生成对抗网络模型;最后将增强后的图像输入模型进行学习和训练,获取多帧遥感降质图像的全局特征后,实现多帧遥感降质图像三维重建。测试结果表明,所提算法具有较好的多帧遥感降质图像增强能力,能够提升图像对比度,并且渗透指数（PI）均在0.92以上,重构效果良好。     

基于多尺度生成对抗网络的运动散焦红外图像复原

红外热成像系统在夜间实施目标识别与检测优势明显,而移动平台上动态环境所导致的运动散焦模糊影响上述成像系统的应用。该文针对上述问题,基于生成对抗网络开展运动散焦后红外图像复原方法研究,采用生成对抗网络抑制红外图像的运动散焦模糊,提出一种针对红外图像的多尺度生成对抗网络(IMdeblurGAN)在高效抑制红外图像运动散焦模糊的同时保持红外图像细节对比度,提升移动平台上夜间目标的检测与识别能力。实验结果表明:该方法相对已有最优模糊图像复原方法,图像峰值信噪比(PSNR)提升5%,图像结构相似性(SSIMx)提升4%,目标识别YOLO置信度评分提升6%。     

Low-light image enhancement via deep Retinex decomposition and bilateral learning

Low-light images enhancement is a challenging task because enhancing image brightness and reducing image degradation should be considered simultaneously. Although existing deep learning-based methods improve the visibility of low-light images, many of them tend to lose details or sacrifice naturalness. To address these issues, we present a multi-stage network for low-light image enhancement, which consists of three sub-networks. More specifically, inspired by the Retinex theory and the bilateral grid technique, we first design a reflectance and illumination decomposition network to decompose an image into reflectance and illumination maps efficiently. To increase the brightness while preserving edge information, we then devise an attention-guided illumination adjustment network. The reflectance and the adjusted illumination maps are fused and refined by adversarial learning to reduce image degradation and improve image naturalness. Experiments are conducted on our rebuilt SICE low-light image dataset, which consists of 1380 real paired images and a public dataset LOL, which has 500 real paired images and 1000 synthetic paired images. Experimental results show that the proposed method outperforms state-of-the-art methods quantitatively and qualitatively.     

基于分数阶Retinex的低照度图像增强方法

低照度彩色图像增强在生活中起着重要作用,传统的低照度彩色图像增强算法往往会引起图像的不同程度失真。为了增强低照度彩色图像而又不引起图像失真,本文提出了一种新的低照度图像自适应对比度增强算法。将分数阶微积分、传统Retinex变分法与分段对数变换饱和度增强法相结合,构造一种新的分数阶Retinex图像增强算法。实验结果表明,该方法具有增强图像对比度的同时又能保持边缘和纹理细节的能力。与传统低照度图像增强算法相比,能突出图像的细节纹理信息,同时图像色度和亮度也有明显改善。     

密集残差网络红外图像超分辨率重构

单幅红外图像超分辨率重构算法作为红外图像分辨率提升应用的关键技术,近年来得到了广泛的研究。为了提高红外图像的分辨力,提出了一种基于残差密集对抗式生成网络的单幅红外图像分辨力提升方法。与以往基于对抗式生成网络的分辨力提升方法不同,本文方法的新颖性主要包含两个方面。首先,在网络架构方面进行改进,以提高性能。设计密集残差网络作为对抗式生成网络的生成网络,充分利用了低分辨率图像的有效特征。在生成网络中引入了一种连续内存机制,以利用密集的剩余块。其次,将Wasserstein-GAN作为损失函数,对判别网络模型进行修正,以达到稳定训练的目的。利用红外高分辨率图像数据集进行了大量的实验,结果表明,该方法在客观评价和主观评价方面均优于目前最新的方法。     

基于多通道GAN的图像去噪算法

针对图像采集和传输过程中所产生噪声导致后续图像处理能力下降的问题,提出基于生成对抗网络(GAN)的多通道图像去噪算法。所提算法将含噪彩色图像分离为RGB三通道,各通道基于具有相同架构的端到端可训练的GAN实现去噪。GAN生成网络基于U-net衍生网络以及残差块构建,从而可参考低级特征信息以有效提取深度特征进而避免丢失细节信息;判别网络则基于全卷积网络构造,因而可获得像素级分类从而提升判别精确性。此外,为改善去噪能力且尽可能保留图像细节信息,所构建去噪网络基于对抗损失、视觉感知损失和均方误差损失这3类损失度量构建复合损失函数。最后,利用算术平均方法融合三通道输出信息以获得最终去噪图像。实验结果表明,与主流算法相比,所提算法可有效去除图像噪声,且可较好地恢复原始图像细节。     

Event-guided low light image enhancement via a dual branch GAN

In the low light conditions, images are corrupted by low contrast and severe noise, but event cameras capture event streams with clear edge structures. Therefore, we propose an Event-Guided Low Light Image Enhancement method using a dual branch generative adversarial networks and recover clear structure with the guide of events. To overcome the lack of paired training datasets, we first synthesize three datasets containing low-light event streams, low-light images, and the ground truth normal-light images. Then, in the generator network, we develop an end-to-end dual branch network consisting of a image enhancement branch and a gradient reconstruction branch. The image enhancement branch is employed to enhance the low light images, and the gradient reconstruction branch is utilized to learn the gradient from events. Moreover, we develops the attention based event-image feature fusion module which selectively fuses the event and low-light image features, and the fused features are concatenated into the image enhancement branch and gradient reconstruction branch, which respectively generate the enhanced images with clear structure and more accurate gradient images. Extensive experiments on synthetic and real datasets demonstrate that the proposed event guided low light image enhancement method produces visually more appealing enhancement images, and achieves a good performance in structure preservation and denoising over state-of-the-arts.     

Underwater image enhancement based on conditional generative adversarial network

Underwater images play an essential role in acquiring and understanding underwater information. High-quality underwater images can guarantee the reliability of underwater intelligent systems. Unfortunately, underwater images are characterized by low contrast, color casts, blurring, low light, and uneven illumination, which severely affects the perception and processing of underwater information. To improve the quality of acquired underwater images, numerous methods have been proposed, particularly with the emergence of deep learning technologies. However, the performance of underwater image enhancement methods is still unsatisfactory due to lacking sufficient training data and effective network structures. In this paper, we solve this problem based on a conditional generative adversarial network (cGAN), where the clear underwater image is achieved by a multi-scale generator. Besides, we employ a dual discriminator to grab local and global semantic information, which enforces the generated results by the multi-scale generator realistic and natural. Experiments on real-world and synthetic underwater images demonstrate that the proposed method performs favorable against the state-of-the-art underwater image enhancement methods.     

Global attention retinex network for low light image enhancement

Most low-light image enhancement methods only adjust the brightness, contrast and noise reduction of low-light images, making it difficult to recover the lost information in darker areas of the image, and even cause color distortion and blurring. To solve the above problems, a global attention-based Retinex network (GARN) for low-light image enhancement is proposed in this paper. We propose a novel global attention module which computes multiple dimensional information in the channel attention module to help facilitate inference learning. Then the global attention module is embedded into different layers of the network to extract richer shallow texture features and deep semantic features. This means that the rich features are more conducive to learning the mapping relationship between low-light images to normal-light images, so that the detail recovery of dark regions is enhanced in low-light images. We also collected a low/normal light image dataset with multiple scenes, in which the images paired as training set can succeed to be applied to low-light image enhancement under different lighting conditions. Experimental results on publicly available datasets show that our method has better effectiveness and generality than the state-of-the-art methods in terms of evaluations metrics such as PSNR, SSIM, NIQE, Entropy.     

采用深度学习与图像融合混合实现策略的低照度图像增强算法

提出了一种采用深度学习与图像融合混合实现策略的低照度图像增强算法.首先,利用照射分量预测模型直接基于输入的低照度图像快速地估计出其最佳照射分量并在Retinex模型框架下获得一张整体上适度曝光图像;其次,将低照度图像本身及它的过曝光图像作为适度曝光图像的修正补充图像参与融合;最后,采用局部结构化融合和色度加权融合机制技术将制备好的3张待融合图像进行融合以获得最终的增强图像.实验数据表明:本文算法相较于各种主流对比算法在主客观图像质量评价指标上均有显著优势,在局部图像结构细节上具有更好的边缘保持和颜色保真效果.     

DSE-Net: Deep simultaneous estimation network for low-light image enhancement

This paper presents a novel approach for low-light image enhancement. We propose a deep simultaneous estimation network (DSE-Net), which simultaneously estimates the reflectance and illumination for low-light image enhancement. The proposed network contains three modules: image decomposition, illumination adjustment, and image refinement module. The DSE-Net uses a novel branched encoder–decoder based image decomposition module for simultaneous estimation. The proposed decomposition module uses a separate decoder to estimate illumination and reflectance. DSE-Net improves the estimated illumination using the illumination adjustment module and feeds it to the proposed refinement module. The image refinement module aims to produce sharp and natural-looking output. Extensive experiments conducted on a range of low-light images demonstrate the efficacy of the proposed model and show its supremacy over various state-of-the-art alternatives.