High resolution corneal and single pulse imaging with line field spectral domain optical coherence tomography

Abstract

We report the development of a Spectral Domain Line Field Optical Coherence Tomography (LF-OCT) system, using a broad bandwidth and spatial coherent Super-Continuum (SC) source. With conventional quasi-Continuous Wave (CW) setup we achieve axial resolutions up to 2.1 μm in air and 3D volume imaging speeds up to 213 kA-Scan/s. Furthermore, we report the use of a single SC pulse, of 2 ns duration, to temporally gate an OCT B-Scan image of 70 A-Scans. This is the equivalent of 35 GA-Scans/s. We apply the CW setup for high resolution imaging of the fine structures of a human cornea sample ex-vivo. The single pulse setup is applied to imaging of a coated pharmaceutical tablet. The fixed pattern noise due to spectral noise is removed by subtracting the median magnitude A-Scan. We also demonstrate that the Fourier phase can be used to remove aberration caused artefacts.

Deformation velocity imaging using optical coherence tomography and its applications to the cornea

“…We have previously described the LF-OCT system [ 42 ]. Here we used the iVac CCD camera (frame rate 2 Hz), and 75 mm objective and 100 mm collection achromatic lenses.…”

Optical Coherence Tomography (OCT): Principle and Technical Realization

“…Thus, the read-out of the 2D detector yields the complete information for the entire B-Scan. Experimental line-field SD-OCT systems have been demonstrated for retinal [39] and corneal [40] imaging.…”

Scan-Less Line Field Optical Coherence Tomography, with Automatic Image Segmentation, as a Measurement Tool for Automotive Coatings

“…The details of the LF-OCT used for this study has been previously described [46]. In brief, in order to measure an OCT B-Scan image in a single shot, a line was illuminated on the sample and reference surface, as shown in Figure 1 (left).…”

“…A single (unaveraged) image was taken with the Back Illuminated Charged Couple Device (BI CCD) camera (iVac, Andor, Belfast, UK) and the Fourier phase differential mask method was used to supress aberration induced image artefacts. The band-pass filtered supercontinuum light source provided an axial resolution of 2.1 n G ·µm, the plot of the point spread function is given in Figure 2 of [46]. With a 4f arrangement of 75 mm Achromatic pair (AC) objective (Linnik pair) and 100 mm AC collection lenses, the system's lateral resolution was measured to be 18 µm (United States Air Force 1951 resolution test chart (MIL-STD-150A), line pair width resolved).…”

“…The speed was limited by the mechanical shutter for the CCD camera, with the total illuminating light power physically attenuated accordingly. If required, the acquisition time could be shortened by orders of magnitude by using electronically shuttered CMOS cameras or using a single super-continuum pulse [46]. The 40 s acquisition time for the FF-OCT system would be too long for a practical QA tool.…”