Method to obtain data cubes of low intensity intrinsic spectral images when imaging under high illumination conditions without the use of filters

A method to obtain data cubes of low intensity intrinsic spectral images when imaging under high illumination conditions with an image capturing device without the use of filters, said method comprising:

• determining exposure, focus and defocus settings for an image capturing device, wherein said settings are determined in relation to a spatial field of view of a target of interest;
• obtaining from said image capturing device a focused data cube and a defocused data cube of an empty field of view having minimal spatial features of low intensity, wherein said focused and defocused data cubes are obtained with the determined exposure, focus and defocus settings of said image capturing device;
• obtaining associated spectrum for each pixel in the spatial array of the focused data cube and the defocused data cube of said empty field of view, respectively, and subtracting across the wavelength range, the associated spectrum of the defocused data cube of said empty field of view from the associated spectrum of the focused data cube of said empty field of view in order to obtain a Residual spectra for each pixel in the spatial array;
• and
• adding, pixel by pixel, said Residual spectra to a defocused spectra in a defocused data cube of said target of interest to obtain an adjusted reference spectra and further subtracting, pixel by pixel, said adjusted reference spectra from a focused spectra in a focused data cube of said target of interest, effectively obtaining an intrinsic spectral image having a focused target data cube with each of its pixels associated with an intrinsic spectrum of said target of interest.