Fig. 1

Optical design of the hyperspectral endoscope. The system is assembled using a clinically approved endoscope with an integrated illumination fibre, to deliver optical excitation to the sample at the distal end of the endoscope, and an imaging fibre bundle, to relay image information back to the proximal end of the endoscope. Illumination is provided either by coupling a white LED to the illumination fibre (internal illumination method), or by directly illuminating a halogen light source to the scene (external illumination method). Line-scan hyperspectral data are acquired using sCam, a CCD coupled to the spectrograph, whereas wide-field image data are acquired using wCam, a monochrome or colour CMOS camera for image registration purposes. Left inset shows the arrangement of the spectrometer and sCam. Right inset shows details of the distal end of the endoscope. CCD charge coupled device, CMOS complementary metal oxide semiconductor, L1–3 lens, Obj1–2 objective lens, BS beam splitter