Images taken under low light conditions tend to suffer from poor visibility, which can decrease image quality and even reduce the performance of downstream tasks. It is hard for a CNN-based method to learn generalized features that can recover normal images from the ones under various unknown low light conditions. We propose to incorporate the contrastive learning into an illumination correction network to learn abstract representations to distinguish various low light conditions in the representation space, with the purpose of enhancing the generalizability of the network. Considering that light conditions can change the frequency components of the images, the representations are learned and compared in both spatial and frequency domains to make full advantage of the contrastive learning. Additionally, a grayscale self-weight perception method is used to preproccess the images to reduce the complexity of the model in coping with the uneven distribution of image illumination. The proposed method is evaluated on LOL and LOL-V2 datasets, and the results show that the proposed method achieves better qualitative and quantitative results compared with other state-of-the-art methods.
Topological insulators (TIs) are theoretically predicted to be promising candidate materials for broadband photodetection from the visible to the infrared (IR). As a 3DTI, Bi2Te3 has reattracted greater interest in recent years. Here, we report a study on a self-powered organic/inorganic photodetector based on N-type Bi2Te3 thin films and P-type pentacene heterojunction with wideband response from 450 nm to 1550 nm. In addition, the optimized responsivity reaches 14.89 A W-1 , with the corresponding eternal quantum effciency of 2840%. These excellent properties prove that the combination with low molecular weight organic matter is the future direction for the preparation of high performance photodetectors by TIs. The findings represent a fundamental form scenario for advancement of the next-generation highperformance array photodetectors and highly integrated optoelectronic products.
Photodetector that use three dimensional (3D) Dirac Semimetal have received considerable attention because Dirac Semimetal is regarded as an ideal candidate electrode material. In this work, organics is steamed by heat on Cd3As2 thin film is used in the field of photoelectric detection. Surprisingly, the photodetector shows excellent photo response properties from 405 nm to 1550 nm. The device exhibiting high photocurrent responsivity (407 mA/W) and external quantum efficiency (58.7 %) at the wavelength of 808 nm, which Ri is more than six times than pure Cd3As2 thin film devices. Most interestingly, the NIR photocurrent responsivity of this device can reach 53.1 mA/W. Overall, the broadband photodetector based on using organics and 3D Cd3As2 Dirac semimetal thin film heterojunction is proved to better performance for photoelectric application. Moreover, organics/Cd3As2 thin film heterojunction also has advantage in low cost array devices. The use of Cd3As2 thin film and organics opens up a new path for the practical application of Dirac Semimetal materials.
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