Near-infrared Colorized Imaging Technologies and Their Fundus Camera Applications

Abstract

This study proposes to adapt the fundus camera for use as a personal healthcare tool. The proposed system uses near-infrared light to avoid blinding the subject and three-wavelength near-infrared imaging to acquire colorized fundus images. First, the optical system with the fundus camera was tested using a three-plate near-infrared snapshot camera. Subsequently, image processing and denoising techniques, including tracking and image integration, were applied to reduce the blur caused by biological scattering. Furthermore, a single-chip three-wavelength near-infrared-compatible image sensor is required for device miniaturization, for which a dielectric multilayer Fabry-Perot bandpass filter was adopted as its transmission wavelength can be easily controlled. In this study, the optical design of the dielectric multilayer structure, the fabrication process of the mosaic filter, and the chip mounting technology are investigated. The demosaicing process and color space conversion corresponding to the spectral response characteristics of the fabricated image sensor are also discussed.