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Due to the non-uniform distribution of lighting systems and the presence of a large amount of dust and mist in the environment during the underground video collection process, there are problems with local light overexposure, insufficient brightness, low contrast, and weak edge information in the monitoring image. In order to solve the above problems, an image enhancement algorithm for non-uniform illumination in underground mines is proposed. This algorithm is based on the improvement of Retinex-Net network structure, which includes three parts: non-uniform illumination suppression module (NLSM), illumination decomposition module (LDM), and image enhancement module (IEM). Among them, NLSM suppresses local non-uniform illumination of artificial light sources in the image. LDM decomposes the image into light and reflection layers. IEM enhances the illumination layer of the image, undergoes gamma correction, and ultimately obtains the enhanced image. Resnet is adopted as the infrastructure of the network in both NLSM and LDM. The channel attention module and spatial attention module in the convolutional attention mechanism are sequentially introduced to enhance the attention to image lighting features and the efficiency of feature selection. The experimental results show the following points. ① MBLLEN, RUAS, zeroDCE, zeroDCE++, Retinex−Net, KinD++, and non-uniform illumination image enhancement algorithms are selected to enhance and qualitatively analyze images in various scenarios (underground transportation environment, single light source roadway, multi light source roadway, ore scenario). The analysis results indicate that non-uniform illumination image enhancement algorithms can avoid excessive enhancement of artificial light source areas. There is no halo or blurring phenomenon in the light source area, and colors are not prone to color deviation. The contrast is moderate, and the visual effect of the image is more realistic. ② The information entropy (IE), average gradient (AG), standard deviation (SD), naturalness image quality evaluator (NIQE), structural similarity (SSIM), and peak signal-to-noise ratio (PSNR) are selected as evaluation indicators to quantitatively compare the quality of image enhancement images. The non-uniform illumination image enhancement algorithm is also in a relatively leading position in various scenarios. ③ The ablation experimental results show the non-uniform illumination image enhancement algorithm achieves optimal results on three evaluation indicators: NIQE, SSIM, and PSNR.

Low-illumination image enhancement technology is a topic of interest in the field of image processing. However, while improving image brightness, it is difficult to effectively maintain the texture and details of the image, and the quality of the image cannot be guaranteed. In order to solve this problem, this paper proposed a low-illumination enhancement method based on structural and detail layers. Firstly, we designed an SRetinex-Net model. The network is mainly divided into two parts: a decomposition module and an enhancement module. Second, the decomposition module mainly adopts the SU-Net structure, which is an unsupervised network that decomposes the input image into a structural layer image and detail layer image. Afterward, the enhancement module mainly adopts the SDE-Net structure, which is divided into two branches: the SDE-S branch and the SDE-D branch. The SDE-S branch mainly enhances and adjusts the brightness of the structural layer image through Ehnet and Adnet to prevent insufficient or overexposed brightness enhancement in the image. The SDE-D branch is mainly denoised and enhanced with textural details through a denoising module. This network structure can greatly reduce computational costs. Moreover, we also improved the total variation optimization model as a mixed loss function and added structural metrics and textural metrics as variables on the basis of the original loss function, which can well separate the structure edge and texture edge. Numerous experiments have shown that our structure has a more significant impact on the brightness and detail preservation of image restoration. [ABSTRACT FROM AUTHOR]

In order to solve the problem of high noise and insufficient feature extraction of Retinex-Net in low-light image enhancement processing, this paper proposes a new network structure. First, the Retinex-Net network was used as the basic model to decompose the input image, and a residual shrinkage network was introduced in the convolutional layer to remove the noise generated during the decomposition process. Then, in order to preserve the details of the image and suppress noise while enhancing the brightness, the enhancement network was divided into three small sub-networks for processing respectively. Finally, the adjusted images were fused to obtain an enhanced image. Compared with the SIRE、LIME、GLADNet、Retinex-Net algorithm, experiments show that the peak signal-to-noise ratio of the images processed by the algorithm in this paper has an avevage increase of 3.48 dB, the mean square error has an avevage increase of 0.082 7, the structural similarity has an avevage increase of 0.146, and the lightness order error has an avevage increase of 271.6.

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Copyright of Journal of Computer Engineering & Applications is the property of Beijing Journal of Computer Engineering & Applications Journal Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)