Image restoration in fiber-coupled imagers using space-variant impulse response characterization.

Fiber-coupled image sensors have attracted interest in recent years for high-resolution conformal image transfer, including mapping of the spherical image surface of a monocentric wide-angle lens to one or more flat focal plane sensors. However, image resolution is lost due to fiber bundle defects, moiré from lateral fiber-sensor misalignment, and blur due to the nonzero gap between fiber bundle and the image sensor. Here we investigate whether subpixel impulse response characterization of the strongly shift-variant impulse response can be used with existing image-processing techniques to recover the resolution otherwise lost in image transfer. We show that the submicrometer impulse response is experimentally repeatable, and can be used to recover image data and reveal fine features of the input surface structure of a 2.5 µm pitch fiber bundle.