Fig. 1. Schematic of SSIE. A continuous wave laser is routed through two multimode fibers via speckle generator onto the object. The intrinsic image sensor of the endoscope is used to collect images.

Fig. 2. Characterization of the speckle patterns and the estimated resolution enhancement of SSIE compared to traditional WLE. (a) Schematic of the endoscope with illumination projected at distance d. The field of view should be covered by light from both fibers. (b, c) Numerical simulated Fourier spectra of the speckle patterns at d=3.7 cm and d=7.2 cm, respectively. (d) Theoretical and experimental illumination NA (NA_ill) for various distances d from 1.5 to 10 cm. Focal distance 5.7–10 cm (measured); 1.5–5.7 cm (extrapolation was performed with a power trendline as an exponential curve). (e) Experimentally detected NA (NA_det) for different focal distance d. (f) Estimated SSIE resolution enhancement factor compared to traditional WLE at various focal distances.

Fig. 3. Experimental demonstration of SSIE at 3.7 cm. (a) Diffraction limited endoscopic image of the drop casted stains. (b) SSIE image of the same area in (a). Scale bars in (a-b) are 800 μm. (c–d) Fourier spectra of the images in (a) and (b), respectively. (e–g) Zoom in view of the ground truth, diffraction limited endoscopic image, and SSIE image of the marked area in (a) and (b). Scale bars in (e–g) are 100 μm.

Fig. 4. Experimental demonstration of SSIE at 7.2 cm. Diffraction limited endoscopic image (a) and SSIE super resolution image (b) of a fluorescent object. Scale bars in (a, b) are 600 um. (c, d) Fourier spectra of the images in (a) and (b), respectively.

Fig. 5. Experimental demonstrations of SSIE on curved surface with large depth of field. (a) Photograph of a drop casted rhodamine dye sample on a curved glass surface. (b) A zoom-in review of the marked area in (a) obtained from a stereo microscope. This can be considered as the ground truth of the object. Diffraction limited endoscopic image (c) and the SSIE image (d) of the same object shown in (b). Scale bars in (b–d) are 700 μm.