Colorimetrical uncertainty of a hyperspectral imaging microscopy system for assessing whole-slide imaging devices.

A whole-slide imaging (WSI) device is a color medical imaging system whose application in digital pathology is to digitalize stained tissue samples into electronic images for pathologists to diagnose without using a conventional light microscope. Testing the color performance of a WSI device usually implies a color target with known truth that is compared with the device output to estimate color differences. Using stained tissue samples as color targets is challenging because the cellular features cannot be measured with ordinary spectroradiometers unless a hyperspectral imaging microscopy system (HIMS) is used. The goal of this study is to determine the colorimetrical uncertainty of such a reference HIMS that is designed to assess the color performance of WSI devices. A set of optical filters are used for that purpose. The color truth, in terms of spectral transmittance in the visible band, of the optical filters is measured by a reference spectroradiometer. The spectral transmittance is combined with a standard illuminant to generate colorimetrical measures using the CIEXYZ and CIELAB formulas. The differences between the reference HIMS and the reference spectroradiometer are evaluated using the CIE 1976 color difference formulas.