We report that high lateral resolution and high image quality optical coherence tomography (OCT) imaging can be achieved by the multi-frame superresolution technique. With serial sets of slightly lateral shifted low resolution C-scans, our multi-frame superresolution processing of these special sets at each depth layer can reconstruct a higher resolution and quality lateral image. Layer by layer repeat processing yields an overall high lateral resolution and quality 3D image. In theory, the superresolution with a subsequent deconvolution processing could break the diffraction limit as well as suppress the background noise. In experiment, about three times lateral resolution improvement has been verified from 24.8 to 7.81 μm and from 7.81 to 2.19 μm with the sample arm optics of 0.015 and 0.05 numerical apertures, respectively, as well as the image quality doubling in dB unit. The improved lateral resolution for 3D imaging of microstructures has been observed. We also demonstrated that the improved lateral resolution and image quality could further help various machine vision algorithms sensitive to resolution and noise. In combination with our previous work, an ultra-wide field-of-view and high resolution OCT has been implemented for static non-medical applications. For in vivo 3D OCT imaging, high quality 3D subsurface live fingerprint images have been obtained within a short scan time, showing beautiful and clear distribution of eccrine sweat glands and internal fingerprint layer, overcoming traditional 2D fingerprint reader and benefiting important biometric security applications.
Part of the book: Optical Coherence Tomography and Its Non-medical Applications