Multimode fiber deep hole imaging based on wavelet polarization fusion.

• A deep-hole imaging method by using MMF is proposed. • Wavelet polarization fusion is applied to deep-hole image reconstruction. • The method achieves reconstruction with a maximum spatial resolution of 3.18 lp/mm. Conventional deep hole imaging uses a camera array as the imaging device, with the lens entering the deep hole to obtain spatial light information for reconstruction. The lens often determines the size of the imaging aperture and it is hard to adapt to different sizes of deep holes, especially elongated ones. This paper proposes a method of the multimode fiber(MMF) deep hole imaging based on wavelet polarization fusion, completed with fiber single-pixel imaging(FSPI) and fiber polarization single-pixel imaging(FPSPI). The system completes three different sizes of deep holes imaging, respectively 8mm × 8mm, 5mm × 5mm, 3mm × 3mm. In addition, the information entropy of each 32 pixels image increases 12.26 % and 11.78 % relative to the original image, which is higher than that of 64 pixels images of the same class, with the spatial resolution of 3.18 lp/mm. The proposed deep hole imaging method based MMF is expected to be applied in pipeline sidewall imaging and deep hole 3D imaging. [ABSTRACT FROM AUTHOR]