9 research outputs found

    A metric compilation analysis of terrestrial atmospheric turbulence suppression algorithms for use in long range digital video surveillance

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    M.Ing.Atmospheric turbulence (also referred to as optical or heat Scintillation, or heat shimmer) is a particular problem encountered in video surveillance, especially over distances where the target object focused on is over lkm in the distance. Images obtained from video surveillance are commonly required to be of a high quality for object identification and classification. Atmospheric turbulence causes degradation in the image quality through the blurring and a warping of the image, making object identification difficult. Algorithms have and still are being developed to suppress the image turbulence in digital video footage and enhance detail. There is a lack of reliable comparisons among algorithms to provide research direction, methods for identification of the best algorithms for particular applications, identification of useful image processing techniques and a full understanding of the problem. This need and lack of comparisons among the algorithms and atmospheric turbulence degraded videos is identified through the problem identification chapter. A literature study is undertaken in which the source of atmospheric turbulence and models are identified, image processing techniques discussed, filtering of electromagnetic waves reviewed, a review of some equipment, and a discussion of metrics. This is followed by the presentation of a number of atmospheric turbulence suppression algorithms developed by other authors. After a discussion of the algorithm implementations, the experimental design is described for algorithm image quality and performance investigation as well as the effect of optical filters. Experimental results are presented and discussed which provide repeatable results pertaining to the algorithms' image quality and processing requirements. The results allowed identification of the algorithms' strengths and weaknesses, how they compare, and their suitability for real and post processing environments. Efficient performing software components were also able to be identified, particularly Illuminance-Reflectance adjustment. The experiments and results provide a solution to this atmospheric turbulence comparison problem

    Gut microbial signatures in pediatric Crohn's disease vary according to disease activity measures and are influenced by proxies of gastrointestinal transit time: an ImageKids study

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    Introduction: We investigated relationships between disease activity measures and the gut microbiome in children with Crohn’s disease (CD) and how these were confounded by gastrointestinal transit time. Methods: Microbiome was profiled (16S rRNA sequencing) in feces from 196 children with CD. Sixty participants also provided samples after 18 months. Mural inflammation (Pediatric Inflammatory Crohn’s Magnetic Resonance Enterography Index, PICMI), the simple endoscopic score for CD, and the weighted pediatric Crohn’s disease activity index (wPCDAI) were assessed. Fecal calprotectin, plasma C-reactive protein (CRP), and fecal water content (FWC), a proxy of gastrointestinal transit time, were measured too. Results: Microbiome α diversity, clustering, and differential taxa were related to disease status, but varied remarkably by disease activity measure used. The strongest relationships between microbiome and disease activity status were observed using wPCDAI; fewer or no relationships were seen using more objective measures like PICMI. Taxa predictive of disease activity status were dependent on the disease activity measure used with negligible overlap. Active disease was associated with more pathobionts (eg, Viellonella, Enterobacterales) and fewer fiber-fermenting organisms. The effect FWC had on microbiome superseded the effect of active disease for all disease activity measures, particularly with wPCDAI. Accounting for FWC, the differences in microbial signatures explained by disease activity status were attenuated or lost. Conclusions: In CD, microbiome signatures fluctuate depending on the measure used to assess disease severity; several of these signals might be secondary disease effects linked with changes in gut motility in active disease. PICMI appears to be less influenced when studying relationships between microbiome and mural inflammation in CD

    Advances in understanding the fundamental aspects required for successful cryopreservation of Australian flora

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    Australia is host to an amazing diversity of species, many of which require conservation efforts. In vitro culture provides a tool for not only conserving these threatened species but allows for their propagation from limited starting material. Cryopreservation provides the greatest long-term storage option for in vitro cultures and as a conservation tool for other germplasm. However, while cryopreservation has proven capable of delivering viable long-term storage with some plant taxa, the process of deriving protocols is still largely an incremental process. The key to faster and more intuitive optimising of cryopreservation protocols lies with continuing to develop a better understanding of key factors, including issues with plant physiology (such as genetic stability, the composition of the proteome and metabolome, cell membrane characteristics, and antioxidant defences) and how the stresses imposed by cryopreservation (such as the excision damage, desiccation, cryoprotective agent toxicity, ice crystal damage, and cooling to cryogenic temperatures) interact and contribute to the cryocapability of a species. This review focuses on the advances that have been made towards understanding cryogenic stress and how this has led to improved cryopreservation protocols, in the context of cryopreserving Australian flora
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