Figure 5: FLIM images of healthy skin acquired in vivo by the Imperial College FLIM system incorporated in the DermaInspect . (a) 760 nm excitation wavelength. In the false-colour images, keratinocytes appear green-blue, showing a longer fluorescence lifetime with respect to melanin aggregates corresponding to yellow-red areas with a shorter lifetime value. (b) 760 nm excitation wavelength. Keratinocytes of the basal layer appearing yellow-red because of the presence of pigmentation. (c) 760 nm excitation wavelength. Dermal papillae surrounded by pigmented keratinocytes and melanocytes with low FLIM values. (d) 760 nm excitation wavelength. A hair-follicle with bluish perifollicular cells showing a shorter lifetime.