Visible and near infrared LCTF-based hyperspectral dermoscope targeting early detection of skin cancer

Abstract

The incidence of skin cancer has increased in the last decades, being one of the most common cancers, but can have a fiveyear survival rate of over 99% if treated early. This work describes a novel hyperspectral dermoscope for early skin cancer detection, able to capture spatial and spectral information in the Visible (VIS) and Near Infrared (NIR) ranges by using Liquid Crystal Tunable Filters (LCTFs). KURIOS-VB1 and KURIOS-XE2 filters were used for VIS and NIR ranges, respectively, providing 136 wavelengths with 5 nm of spectral resolution. A dichroic mirror combines output light paths, illuminating the skin's surface via a fiber optic ring light. Reflected light is captured by a 1.3-megapixel monochrome camera. Additionally, a custom hand-held 3D printed part integrates optics and control circuitry. The proposed characterization method used to optimize the camera exposure time for each wavelength has proven effective in obtaining a flat white reference and gathering information in the range of 450 to 1050 nm and, especially, at critical wavelengths such as the test wavelengths evaluated closer to the limit bands of the LCFTs (450 and 600 nm for VIS, and 750 and 900 nm for NIR).