An instrument for imaging a region of tissue including a tumour and a non-tumour sub-region spaced-apart from the tumour, the instrument comprising: an illuminator for illuminating the region with two wavelengths of light, including a first wavelength, λ 1, and a second wavelength, λ 2, the illuminator including a polarizer; an imaging detector for generating images of the region based upon the two wavelengths of light, the images being cross-polarized due to the polarizer of the illuminator; and a controller connected to the imaging detector for receiving and storing the images, wherein the images are spectrally-encoded by the controller based on images using the two wavelengths of light to create spectrally-encoded images that illustrate a collagen structure of the region of the tissue, wherein each of the images includes a respective set of pixels, the controller being operative to spectrally encode a first cross-polarized raw image at the first wavelength light with a second cross-polarized raw image at the second wavelength light to create a corrected image and wherein spectrally encoding the images is carried out according to a formula as follows: PXL i, j = β × PXL i, j λ 1 ⊥ − PXL i, j λ 2 ⊥ + 1000 × Δ where: PXL is an abbreviation for pixel value; i is the pixel number in x-direction; j is the pixel number in y-direction; PXL i,j are pixel values of the corrected image, PXL i, j λ 1 ⊥ are pixel values of the first cross-polarized raw image acquired at the first wavelength λ 1; PXL i, j λ 2 ⊥ are pixel values of the second cross-polarized raw image acquired at the second wavelength λ 2; β is a first value defined as β = PXL mean λ 2 PXL mean λ 1; and Δ is a second value defined as: Δ = PXL mean λ 2 − PXL region, mean λ 2 PXL mean λ 2 where: PXL mean λ 2 is a mean pixel value of the second cross-polarized raw image; PXL mean λ 1 is a mean pixel value of the first cross-polarized raw image; and PXL region, mean λ 2 is an average pixel value of a subset of pixels of the cross-polarized image of the second wavelength λ 2, the subset corresponding to the non-tumour sub-region, wherein the two wavelengths of light are selected from the group consisting of: approximately 440 nm light; approximately 550 nm light; approximately 590 nm light; approximately 640 nm light; light in a range of 410 nm to 440 nm; light in a range of 570 nm to 590 nm; and light in a range of 640-730 nm. an illuminator for illuminating the region with two wavelengths of light, including a first wavelength, λ 1, and a second wavelength, λ 2, the illuminator including a polarizer; an imaging detector for generating images of the region based upon the two wavelengths of light, the images being cross-polarized due to the polarizer of the illuminator; and a controller connected to the imaging detector for receiving and storing the images, wherein the images are spectrally-encoded by the controller based on images using the two wavelengths of light to create spectrally-encoded images that illustrate a collagen structure of the region of the tissue, wherein each of the images includes a respective set of pixels, the controller being operative to spectrally encode a first cross-polarized raw image at the first wavelength light with a second cross-polarized raw image at the second wavelength light to create a corrected image and wherein spectrally encoding the images is carried out according to a formula as follows: PXL i, j = β × PXL i, j λ 1 ⊥ − PXL i, j λ 2 ⊥ + 1000 × Δ where: PXL is an abbreviation for pixel value; i is the pixel number in x-direction; j is the pixel number in y-direction; PXL i,j are pixel values of the corrected image, PXL i, j λ 1 ⊥ are pixel values of the first cross-polarized raw image acquired at the first wavelength λ 1; PXL i, j λ 2 ⊥ are pixel values of the second cross-polarized raw image acquired at the second wavelength λ 2; β is a first value defined as β = PXL mean λ 2 PXL mean λ 1; and Δ is a second value defined as: Δ = PXL mean λ 2 − PXL region, mean λ 2 PXL mean λ 2 where: PXL mean λ 2 is a mean pixel value of the second cross-polarized raw image; PXL mean λ 1 is a mean pixel value of the first cross-polarized raw image; and PXL region, mean λ 2 is an average pixel value of a subset of pixels of the cross-polarized image of the second wavelength λ 2, the subset corresponding to the non-tumour sub-region, wherein the two wavelengths of light are selected from the group consisting of: approximately 440 nm light; approximately 550 nm light; approximately 590 nm light; approximately 640 nm light; light in a range of 410 nm to 440 nm; light in a range of 570 nm to 590 nm; and light in a range of 640-730 nm.