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In this paper, we propose a novel image enhancement algorithm via anti-degraded model and L L -based variational retinex (AD- L L VR) for non-uniform illumination endoscopic images. Firstly, a haze-free endoscopic image is obtained by an anti-degraded model named dark channel prior (DCP). For getting a more accurate transmission map, it is refined by using a guided image filtering. Secondly, the haze-free endoscopic image is decomposed into detail and naturalness components by light filtering. Thirdly, a logarithmic Laplacian-based gamma correction (LLGC) is added to the naturalness component for preventing color cast and uneven lighting. Fourthly, we assume that the error between the detail component of the haze-free image and the product of associated reflectance and background illumination follows Gaussian-Laplacian distribution. So, the associated reflectance component can be obtained by using the proposed L L -based variational retinex ( L L VR) model. Finally, the recombination of modified naturalness component and associated reflectance component become the final result. Experimental results demonstrate that the proposed algorithm reveals more details in the background regions as well as other interesting areas and can mostly prevent the color cast. It has a better performance on increasing diagnosis and reducing misdiagnosis than other existing enhancement methods. [ABSTRACT FROM AUTHOR]

Due to the minimal electrochemical oxidation-reduction potential, the potassium (K) metal anode has emerged as a focal in K-ion batteries. However, the reactivity of the K metal anode leads to significant side reactions, particularly gas evolution. Mitigating gas generation from K metal anodes has been a persistent challenge in the field. In this study, we propose a dual protective layer design through pre-treatment of the K metal anode, employing a Bi 2 O 3 modification layer alongside a stable solid electrolyte interface (SEI) formed during the initial charge-discharge cycle, which significantly suppresses gas evolution. Furthermore, we observe that the Bi 2 O 3 modification layer enhances K nucleation due to its strong potassiophilicity when incorporated into the substrate material. The resultant SEI, consisting of dual inorganic layers of Bi-F and K-F formed through the Bi 2 O 3 modification, effectively mitigates side reactions and gas generation while inhibiting dendrite growth. Utilizing a Cu@BO@K host, we achieve a nucleation overpotential as low as 40 mV, with a stability of 1900 h in a Cu@BO@K‖Cu@BO@K cell and a high average Coulombic efficiency of 99.2% in a Cu@BO@K‖Cu cell at 0.5 mA cm -2 /0.5 mA h cm -2 . Additionally, Cu@BO@K‖PTCDA also presents a high reversible capacity of 114 mA g -1 at 100 mA g -1 after 200 cycles. We believe that this work presents a viable pathway for mitigating side reactions in K metal anodes., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)