A generic method for generating multispectral filter arrays

Abstract

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 multi-spectral filter arrays (MSFA), in which more than three color bands are used (e.g. visible and infrared). Although considerable research has been reported to optimally reconstruct the full-color image using various interpolation algorithms, studies on the intrinsic properties of these filter arrays as well as the underlying design principles have been very limited. In this paper, we identify the properties a CFA should possess and extend the design philosophy to MSFA. Based on these discussions, we develop a generic MSFA generation method starting from a checkerboard pattern with both rectangular and hexagonal tessellations. By manipulating this pattern through a combination of decomposition and subsampling steps, we can generate MSFAs that satisfy all the design requirements. We show, through case studies, that most of the CFAs currently used by the industry can be derived as special cases. To evaluate the performance of MSFAs, we design a metric, referred as the static coefficient (SC), to measure the uniformity of MSFAs.