Endoscopic spectral imagers based on acousto-optic filtration of light

Endoscopic imaging systems are widely used for non-invasive diagnostics of inner tissues for biomedical applications as well as for non-destructive testing of various hard-to-reach industrial objects. Conventional white light endoscopy often does not provide contrast visualization of the inspected objects and quantitative characterization of their differences. In these cases, spectral imaging techniques may be helpful to increase the effectiveness of endoscopic inspection. Acoustooptic (AO) filtration of light is a very promising technique for implementing spectral imaging capabilities. In this paper, we discuss the peculiarities and benefits of conjugating AO tunable filters (AOTF) with rigid borescopes, flexible fiberscopes and video endoscopes. We analyze and compare imaging and spectroscopy capabilities of two alternative technical implementations: AOTF-based tunable light sources and AOTF-based add-on imaging modules. The results of this analysis are confirmed by multiple experiments.