4.1. Reflectance calibration
This is carried out to account for the background spectral
response of the instrument and the ‘dark’ camera
response. For reflectance measurements, the background
is obtained by collecting a hypercube from a uniform, high
reflectance standard or white ceramic; the dark response is
acquired by turning off the light source, completely covering
the lens with its cap and recording the camera response.
The corrected reflectance value (R) is calculated as follows:
R ¼ ðsample-darkÞ=ðbackground-darkÞ: