Fig. 8
Hyperspectral imaging (HSI) of an intact ex vivo pig oesophagus. a Wide-field image, b synthesised RGB image and c absorbance spectra of the pig oesophagus. d–f Images and spectra from the same field of view after methylene blue (MB) staining. Dashed squares in a, d indicate the acquisition area of HSI. Colours in c, f correspond to the coloured squares drawn in b, e, respectively. g Concentration of MB staining estimated by linear spectral unmixing using the average absorption spectrum of normal pig oesophageal tissue and the experimentally measured absorption spectrum of MB as endmembers. h Segmentation of estimated MB concentration according to unmixing values. i Quantification of normalised absorption spectral profile of each segment in h. Solid lines and shaded areas in c, f, i indicate mean value and standard deviation of the absorbance profile, respectively. All hyperspectral images were measured using the internal illumination method
