基于热传导小波变换的低照度图像增强方法

Low-Light Image Enhancement based on Heat Conduction Wavelet Transform

  • 摘要: 低光环境中拍摄的图像普遍存在着色彩损失、细节失真与噪声干扰等问题,严重制约了其在自动驾驶、目标检测、人脸识别等下游视觉任务中的应用性能。为了克服这些问题,本文提出一种融合视觉热传导机制与频域建模的低照度图像增强方法。该方法利用视觉热传导机制,实现从局部到全局的平滑增强。同时结合频域方法,针对性地强化细节信息。最终在提升色彩真实性的同时,有效恢复受噪声影响的纹理特征。具体而言,采用小波变换在不丢失信息的情况下进行下采样,将特征分解为高低频分量,以支持针对性设计。为了有效地对低照度图像上的全局和局部信息进行联合建模,提出了一种低频增强块,通过并行视觉热传导模块和状态空间模块来专注于恢复低频子带的信息。此外,为了有效地恢复高频子带中所包含的边缘纹理信息,并抑制噪声干扰,提出了高频增强块,利用增强后的低频信息对高频信息进行校正,有效地恢复出正确的高频细节。实验结果表明,本文方法所增强的低照度图像跟目前最先进的方法相比,无论是在视觉的主观感知还是客观的评价指标上(在LOL-v1数据集上比目前最先进的方法分别提高了0.34 dB的PSNR、0.10的SSIM)都取得了较好的结果。

     

    Abstract: Images captured under low-light conditions commonly suffer from color distortion, loss of detail, and noise interference, which severely degrade performance in downstream vision tasks such as autonomous driving, object detection, and face recognition. To address these challenges, we propose a low-light image enhancement method that integrates the visual heat conduction mechanism with frequency-domain modeling. This method leverages the visual heat conduction mechanism to achieve smoothing enhancement from local to global scales. Concurrently, it integrates a frequency-domain approach to selectively reinforce detail information. Ultimately, this strategy improves color authenticity while effectively recovering texture features degraded by noise. Specifically, we employ wavelet transform to perform information-preserving downsampling and decompose features into low- and high-frequency components, enabling targeted design for each subband.To effectively model both global and local information in low-light images, we propose a low-frequency enhancement block that employs parallel visual heat conduction and state space modules to specifically recover the low-frequency subband. Furthermore, to effectively recover edge and texture details embedded in the high-frequency subband while suppressing noise interference, we introduce a high-frequency enhancement block that leverages the enhanced low-frequency information to refine the high-frequency components, thereby accurately restoring genuine high-frequency details. Experimental results show that, compared with state-of-the-art method, the low-light images enhanced by our approach achieve better performance both in terms of visual quality and objective metrics—specifically, (on the LOL-v1 dataset, our method improves PSNR by 0.34 dB and SSIM by 0.10).

     

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