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Video endoscopy allows physicians to visually inspect inner regions of the human body using a camera and only
minimal invasive optical instruments. It has become an every-day routine in clinics all over the world. Recently a
technological shift was done to increase the resolution from PAL/NTSC to HDTV. But, despite a vast literature on invivo
and in-vitro experiments with multi-spectral point and imaging instruments that suggest that a wealth of information
for diagnostic overlays is available in the visible spectrum, the technological evolution from colour to hyper-spectral
video endoscopy is overdue. There were two approaches (NBI, OBI) that tried to increase the contrast for a better
visualisation by using more than three wavelengths. But controversial discussions about the real benefit of a contrast
enhancement alone, motivated a more comprehensive approach using the entire spectrum and pattern recognition
algorithms. Up to now the hyper-spectral equipment was too slow to acquire a multi-spectral image stack at reasonable
video rates rendering video endoscopy applications impossible. Recently, the availability of fast and versatile tunable
filters with switching times below 50 microseconds made an instrumentation for hyper-spectral video endoscopes
feasible. This paper describes a demonstrator for hyper-spectral video endoscopy and the results of clinical
measurements using this demonstrator for measurements after otolaryngoscopic investigations and thorax surgeries. The
application investigated here is the detection of dysplastic tissue, although hyper-spectral video endoscopy is of course
not limited to cancer detection. Other applications are the detection of dysplastic tissue or polyps in the colon or the
gastrointestinal tract.
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