Calibrated autofluorescence imaging for classification of tissue and detection of early cervical cancer

We report a calibrated fluorescence imaging technique by taking the ratio of the fluorescence image to the cross- polarized reflection image. The imaging technique has been applied to tissue examination in vivo. The results show that the inhomogeneity of fluorescence excitation and collection across the irregular surface of the examined tissue is calibrated to a great extent. It is demonstrated that different tissue can be clearly separated endoscopically and in vivo based on the calibrated fluorescence signal at the sites of oral cavity, oropharynx and cervix.