Autofocusing for tuberculosis detection using fluorescence microscopy

Automated microscopy in the context of tuberculosis (TB) screening aims to reduce the workload on technicians, especially in countries with a high burden of TB. Focusing is a key component of automated microscopy, and the selection of an appropriate autofocus algorithm is task-specific. We examined autofocusing algorithms for fluorescence microscopy of sputum smears for TB screening. Six focus measures, defined in the spatial domain, were applied to stacks of images of auraminestained sputum smears. A maximum difference of 1.21 μm between manually focused and algorithm focused images was obtained for the best performing focus measures. Keywords-autofocus; focus measure; Mycobacterium tuberculosis; z-stack; curve-fitting

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