Abstract: The present invention relates to an in-vessel or down-hole optical imaging sensor or system for operating in structures which may contain media with different spectral transmission characteristics. The imaging sensor of the present invention selectively emits and/or detects two or more independently controllable wavelengths or wavebands. The imaging sensor comprises an illuminator for emitting radiation of a specified wavelength or waveband through a medium to a target, at least one detector for detecting the radiation deflected by said target and at least one amplifier for providing non-linear amplification of the detector output.

Abstract: The present invention relates to an imaging sensor, particularly for use in oil-filled passages such as wells or pipelines, or for passages containing other similar viscous fluids. There is provided a downhole imaging system which operates in a wavelength region outside the visible band, preferably in the infrared region, to permit penetration of the surrounding fluid medium, e.g., oil. Positioning the optical part of the imaging sensor in a chamber whose walls are transparent to the radiation reduces the path length of the radiation in the oil. The chamber is filled with a material highly transmissive of the radiation.