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Low-light images are challenging for both human observation and computer vision algorithms due to low visibility. To address this issue, various image enhancement techniques such as dehazing, histogram equalization, and neural network-based methods have been proposed. However, most existing methods often suffer from the problems of insufficient contrast and over-enhancement while enhancing the brightness, which not only affects the visual quality of images but also adversely impacts their subsequent analysis and processing. To tackle these problems, this paper proposes a low-light image enhancement method called LEFB. Specifically, the low-light image is first transformed into the LAB color space, and the L channel controlling brightness is enhanced using a local contrast enhancement algorithm. Then, the enhanced image is further enhanced using an exposure fusion-based contrast enhancement algorithm, and finally, a bilateral filtering function is applied to reduce image edge blurriness. Experimental evaluations are conducted on real datasets with four comparison algorithms. The results demonstrate that the proposed method has superior performance in enhancing low-light images, effectively addressing problems of insufficient contrast and over-enhancement, while preserving fine details and texture information, resulting in more natural and realistic enhanced images.

Lactobacilli belong to the group of Lactic Acid Bacteria (LAB), extensively utilised in the contemporary food industry. These bacteria are mainly used as natural acidifiers, for the inoculation of bulk quantities of milk and vegetables, in order to produce a variety of fermented products. As such, large quantities of their biomass, produced in cost effective enviromentaly friendly nutrient media, are necessary. Furthermore, during their growth, they naturally produce antimicrobial substances, called bacteriocins or lantibiotics. Due to the constantly developing need for natural food preservatives, bacteriocins deriving from Lactobacilli metabolism, function and activity have been extensively investigated.

The possibility of producing these substances in mass quantities was investigated through several techniques. Three known bacteriocin producing strains of Lactobacilli, were carefully selected, L. plantarum NCIMB 8014, L.casei NCIMB 11970 and L.lactis NCIMB 8586. They were grown into simple batch cultures without pH control, where their physicochemical needs were determined. Through the determination of the optimum nutritional conditions for their propagation an optimised growth medium occurred. A simple, liquid turbidometric method was developed to test the bacteriocin productivity of these strains, on the developed media. The antimicrobial activity and potency of the bacteriocins produced, were tested against the target strain L.delbruckii subsp.lactis NCIMB 8117. In an effort to facilitate the extraction of bacteriocins from the fermented broths it was decided , to fabricate a nutrient medium, that would contain, low molecular weight nitrogen sources and equally support high production of bacteriocins and large yields of biomass.

In order to achieve that, the optimised medium was then filtrated via ultrafiltration membrane modules of 30 and 4 kDa MWCO , in an effort to simplify the medium and facilitate the extraction of the produced substance. The medium’s efficiency in supporting the growth and the bacteriocin production of the bacilli was tested and comparative studies between filtrated and unfiltrated media were done. The filtered medium, containing low molecular weight nutrient sources, was proven to successfully support growth and bacteriocin production.