An evaluation method of a micro-arrayed multispectral filter mosaic

Abstract

In recent decades, multispectral imaging (MSI) has been approved as an effective tool to detect and discriminate targets in industrial application. A narrowband micro-arrayed multispectral filter mosaic (MSFM) based on MSI technology is proposed to miniaturize MSI instrumentation. There are many reasons to believe that this innovation is going to replace the traditional methods of filtering or dispersing light and bring MSI applications to more industrial fields. However, highly integrated micro pieces of MSFM are arranged periodically, and the spectral profiles of two adjacent pieces cause a spectral interference (SI). To express and estimate the extent of SI, an evaluation method is proposed and its feasibility is reported in this paper. Additionally, the ways reducing the extent of SI are suggested.

Multispectral Filter Arrays: Recent Advances and Practical Implementation

“…The optical filter consists of four narrow-band cells at 540, 577, 650 and 970 nm and is fabricated with traditional multi-film vacuum deposition and modern micro-lithography technologies [ 65 ]. Further, a means of evaluating the spectral interference between adjacent channels is also developed [ 66 ]. Further information and applications are detailed later in a series of articles concerning the detection of erythema and bruising, which are important for the prevention and diagnosis of pressure ulcers [ 67 – 70 ].…”

“…There are mutual interferences that we may quantify. According to previous works [ 66 ], it might be reasonable to determine interference coefficients using this integral ratio: where λa and λb are the wavelength coverage between two filters, λm and λn are related to the effective band of filter j and λc is the wavelength at the intersection of the two filters. The indexes are presented in Table 4 .…”

Spectral Characterization of a Prototype SFA Camera for Joint Visible and NIR Acquisition

“…We compute the interference values, Θ, between each spectral profile pairs in Table 1 . The mutual interferences are quantified, according to previous works [ 50 ] and extended from filters to sensitivities (We modified the integral boundaries so we include the multi-modalities of the sensitivities in the evaluation. ), by determining the interference coefficients computed by using the ratio between overlapping area of two sensitivities over one of these sensitivities, as in Equation (2): where 380 and 1100 are limits of the wavelength interval of interest and is the wavelength at the intersection of and .…”