A Hand-held Mosaicked Multispectral Imaging Device for Early Stage Pressure Ulcer Detection
Journal of Medical Systems
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The technology of color filter arrays (CFA) has been widely used in the digital camera industry since it provides several advantages like low cost, exact registration, and strong robustness. The same motivations also drive the design of multispectral filter arrays (MSFA), in which more than three spectral bands are used. Although considerable research has been reported to optimally reconstruct the full-color image using various demosaicking algorithms, studies on the intrinsic properties of these filter arrays as well as the underlying design principles have been very limited. Given a set of representative spectral bands, the design of an MSFA involves two issues: the selection of tessellation mechanisms and the arrangement/layout of different spectral bands. We develop a generic MSFA generation method starting from a checkerboard pattern. We show, through case studies, that most of the CFAs currently used by the industry can be derived as special cases of MSFAs generated using the generic algorithm. The performance of different MSFAs are evaluated based on their intrinsic properties, namely, the spatial uniformity and the spectral consistency. We design two metrics, static coefficient and consistency coefficient, to measure these two parameters, respectively. The experimental results demonstrate that the generic algorithm can generate optimal or near-optimal MSFAs in both the rectangular and the hexagonal domains