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In low-light environments, the amount of light captured by the camera sensor is reduced, resulting in lower image brightness. This makes it difficult to recognize or completely lose details in the image, which affects subsequent processing of low-light images. Low-light image enhancement methods can increase image brightness while better-restoring color and detail information. A generative adversarial network is proposed for low-quality image enhancement to improve the quality of low-light images. This network consists of a generative network and an adversarial network. In the generative network, a multi-scale feature extraction module, which consists of dilated convolutions, regular convolutions, max pooling, and average pooling, is designed. This module can extract low-light image features from multiple scales, thereby obtaining richer feature information. Secondly, an illumination attention module is designed to reduce the interference of redundant features. This module assigns greater weight to important illumination features, enabling the network to extract illumination features more effectively. Finally, an encoder-decoder generative network is designed. It uses the multi-scale feature extraction module, illumination attention module, and other conventional modules to enhance low-light images and improve quality. Regarding the adversarial network, a dual-discriminator structure is designed. This network has a global adversarial network and a local adversarial network. They determine if the input image is actual or generated from global and local features, enhancing the performance of the generator network. Additionally, an improved loss function is proposed by introducing color loss and perceptual loss into the conventional loss function. It can better measure the color loss between the generated image and a normally illuminated image, thus reducing color distortion during the enhancement process. The proposed method, along with other methods, is tested using both synthesized and real low-light images. Experimental results show that, compared to other methods, the images enhanced by the proposed method are closer to normally illuminated images for synthetic low-light images. For real low-light images, the images enhanced by the proposed method retain more details, are more apparent, and exhibit higher performance metrics. Overall, compared to other methods, the proposed method demonstrates better image enhancement capabilities for both synthetic and real low-light images. [ABSTRACT FROM AUTHOR]

With the rapid development of the fifth-generation (5G) wireless system, the explosive growth of transmitted data raises higher requirements for high-performance surface acoustic wave (SAW) devices as filters and duplexers. (100) AlN/(100) ZnO/diamond layered structures are theoretically simulated by finite element method (FEM) to investigate the Rayleigh SAW propagation properties, including phase velocity, electromechanical coupling coefficient K2, and temperature coefficient of frequency (TCF). Three types of layered structures with different interdigital transducers (IDTs) arrangements, which are IDTs/(100) AlN/(100) ZnO/diamond, (100) AlN/IDTs/(100) ZnO/diamond, and (100) AlN/(100) ZnO/IDTs/diamond structures, are considered in the simulations. The results show that the Sezawa mode exhibits larger K2 than the other modes. We found that the (100) AlN/IDTs/(100) ZnO/diamond structure exhibited better SAW properties, including high K2 and appropriate phase velocity. [ABSTRACT FROM AUTHOR]

This paper proposes a transversal dual-band wideband bandpass filter (BPF) with two transmission paths. We introduced two short coupled lines as the ideal 180° phase shift structure to realize the additional transmission path. A highly selective passband can be achieved by obtaining transmission zeros through a lateral signal cancellation mechanism. Using the classical odd/even mode analysis, seven modes can be excited for the dual-wideband structure. The fractional bandwidth of the first wide passband can reach 107% for multi-service applications. The presented transversal BPF with dual wideband is fabricated for verification. Good agreement between experimental results and simulation predictions validates the effectiveness of the proposed design methodology. [ABSTRACT FROM AUTHOR]