Spatial resolution performance and object detection improvement with a multiple-wavelength NIR light transmission scanner

A multiple-wavelength near-infrared (NIR) imaging device has been constructed. The scanner utilizes transmitted through the objects NIR light at five different wavelengths in the interval of 900nm-1600nm. The scanning is realized by a consecutive positioning of Hamamatsu G9203-256D InGaAs linear image sensor sliding close to the scanned object and results in a set of five object´s images. The scanned region has a rectangular shape with dimensions of 50mm × 80mm. A system of polarizers ensures scanning of the objects in polarized NIR light as well. The number of object images obtained at different wavelengths and at different angles of the transmitted NIR light makes possible the application of a multivariate image analysis (MIA) in order to reveal tissue objects whose NIR light absorption exhibits slight deviations from the rest of the media. In this article we present results from the spatial resolution measurements conducted with the scanner as well as a spectral analysis of the transmittance of NIR in some mice tissues. A multivariate image analysis has been conducted on NIR images of mice tumor tissues taken at different wavelengths. The resulted images from the MIA projection back compare well with the observations from alternative methods.