Color Restoration of RGBN Multispectral Filter Array Sensor Images Based on Spectral Decomposition.

Chulhee Park,Moon Kang

doi:10.3390/s16050719

Abstract

A multispectral filter array (MSFA) image sensor with red, green, blue and near-infrared (NIR) filters is useful for various imaging applications with the advantages that it obtains color information and NIR information simultaneously. Because the MSFA image sensor needs to acquire invisible band information, it is necessary to remove the IR cut-offfilter (IRCF). However, without the IRCF, the color of the image is desaturated by the interference of the additional NIR component of each RGB color channel. To overcome color degradation, a signal processing approach is required to restore natural color by removing the unwanted NIR contribution to the RGB color channels while the additional NIR information remains in the N channel. Thus, in this paper, we propose a color restoration method for an imaging system based on the MSFA image sensor with RGBN filters. To remove the unnecessary NIR component in each RGB color channel, spectral estimation and spectral decomposition are performed based on the spectral characteristics of the MSFA sensor. The proposed color restoration method estimates the spectral intensity in NIR band and recovers hue and color saturation by decomposing the visible band component and the NIR band component in each RGB color channel. The experimental results show that the proposed method effectively restores natural color and minimizes angular errors.

Highlights

The near-infrared (NIR) is one of the regions closest in wavelength to the radiation detectable by the human eye
We proposes a color restoration method that removes the NIR component in each RGB color channel with an imaging system based on the IR cut-offfilter (IRCF)-removed multispectral filter array (MSFA) image sensor
The input multispectral image was obtained by a camera system with an RGBN image sensor without IRCF, and we used a target visible band image with an IRCF as a reference image

Summary

Introduction

The near-infrared (NIR) is one of the regions closest in wavelength to the radiation detectable by the human eye. Sensors based on silicon (SiO2 ) are sensitive to NIR up to. Surface reflection in the NIR bands is material dependent. Most dyes and pigments used for material colorization are somewhat transparent to NIR. This means that the difference in the NIR intensities is due to the particular color of the material, and to the absorption and reflectance of dyes. The NIR intensity provides the useful information pertinent to material classes rather than the color of that object [1]

Methods

Results

Conclusion