A method for extracting an image of a target fluorophore in a biological material wherein a waveband for the target fluorophore emission overlaps a waveband for autofluorescence emission in the biological material, the method comprising: illuminating the biological material with a first excitation light to induce a first fluorescence emission arising from both autofluorescence of the biological material and fluorescence of the target fluorophore and with a second excitation light to induce a second fluorescence emission arising only from the autofluorescence of the biological material; acquiring a first fluorescence image from the first fluorescence emission and a second fluorescence image from the second fluorescence emission; and processing the first and second fluorescence images to extract a third fluorescence image representing the target fluorophore, wherein relative intensities of the first and second excitation lights with respect to each other are modulated prior to acquiring the first and second fluorescence images, wherein the modulation of the relative intensities comprises: identifying a wavelength region in the first and second fluorescence emissions, wherein the wavelength region is a region where emission arising from the fluorophore is present in the first fluorescence emission and absent in the second fluorescence emission; selecting a waveband outside the wavelength region; calculating at the selected waveband a ratio of relative intensities of the first and second fluorescence emissions with respect to each other; and adjusting the relative intensities of the first and second excitation lights with respect to each other to adjust the corresponding first fluorescence emission, second fluorescence emission or both until a suitable calculated ratio is achieved. illuminating the biological material with a first excitation light to induce a first fluorescence emission arising from both autofluorescence of the biological material and fluorescence of the target fluorophore and with a second excitation light to induce a second fluorescence emission arising only from the autofluorescence of the biological material; acquiring a first fluorescence image from the first fluorescence emission and a second fluorescence image from the second fluorescence emission; and processing the first and second fluorescence images to extract a third fluorescence image representing the target fluorophore, wherein relative intensities of the first and second excitation lights with respect to each other are modulated prior to acquiring the first and second fluorescence images, wherein the modulation of the relative intensities comprises: identifying a wavelength region in the first and second fluorescence emissions, wherein the wavelength region is a region where emission arising from the fluorophore is present in the first fluorescence emission and absent in the second fluorescence emission; selecting a waveband outside the wavelength region; calculating at the selected waveband a ratio of relative intensities of the first and second fluorescence emissions with respect to each other; and adjusting the relative intensities of the first and second excitation lights with respect to each other to adjust the corresponding first fluorescence emission, second fluorescence emission or both until a suitable calculated ratio is achieved. identifying a wavelength region in the first and second fluorescence emissions, wherein the wavelength region is a region where emission arising from the fluorophore is present in the first fluorescence emission and absent in the second fluorescence emission; selecting a waveband outside the wavelength region; calculating at the selected waveband a ratio of relative intensities of the first and second fluorescence emissions with respect to each other; and adjusting the relative intensities of the first and second excitation lights with respect to each other to adjust the corresponding first fluorescence emission, second fluorescence emission or both until a suitable calculated ratio is achieved.