Fig. 1. Design of zoom endoscopic objective lens with large field. (a) Schematic of lens; (b) view of zoom endoscope; (c) diameter of endoscope; (d) high-magnification view^[17]

Fig. 2. Zoom endoscopic objective lens. (a) Conventional endoscopic view; (b) high-magnification; (c) zoom process^[18]

Fig. 3. Three zoom configurations of the endoscope optics under YZ view^[22]

Fig. 4. Schematic of lens. (a) Tunable liquid lens; (b) capsule endoscope optical system^[23]

Fig. 5. Schematic of scanning patterns. (a) Schematic of spiral scanning^[44]; (b) schematic of Lissajous scanning^[37]

Fig. 6. Endoscopic OCT imaging system. (a) Schematic of the micromotor imaging catheter; (b) schematic of endoscopic OCT imaging system using a swept source laser and micromotor imaging catheter^[45]

Fig. 7. OCT of the normal esophagus.(a) En face OCT image at 240 μm depth. The inset shows an endoscopic view of the esophagus obtained prior to endoscopic OCT imaging; (b) cross-sectional image along the pullback direction; (c) cross-sectional image along the rotary direction^[45]

Fig. 8. Schematic of the tethered capsule and photo of the capsule

Fig. 9. OCT imageof esophagus. (a) Representative cross-sectional image of swine esophagus (inner wall of the tube is cropped out); (b) 3D reconstruction along a 4.5 cm pull-back distance; (c) zoomed-in area of the dotted box in (b). Scale bar is 1 mm^[47]

Fig. 10. Autoimmune cholangitis. (a) Cholangiography shows the biliary stricture (pink arrow); (b) pCLE under the direct view of POCS was performed; (c) cholangioscopy shows a reddish papillogranular surface; (d) pCLE shows a thickened reticular structure in the Paris classification^[48]

Fig. 11. Endoscope system. (a) Photograph of the surgical procedure: 1. commercial endoscope; 2. micromanipulator with the trocar for the fiber bundle; 3. insufflation-pipe. (b) Endoscopic view through the commercial endoscope during the imaging procedure invivo: 1. trocar for the fiber-optic with fiber bundle and blue illumination; 2. intestinal loop; 3. pancreas; 4. liver^[49]

Fig. 12. Image of a fluorescence channel^[49]

Fig. 13. pCLE images of lung tissue of the left upper lobe. Intra alveolar fiber thickness (yellow line), increased density of elastic structures (white arrow), up to disappearance of alveolar structures (yellow arrow), and large drops of intra alveolar secretions (*)^[50]

Fig. 14. Optical path of dual-mode switching endomicroscopic image system^[51]

Fig. 15. Tubula radenomatous polyp. (a) Ordinary eletronic endoscopic image and microscopic fluorecent image; (b) pathologic slice image^[51]

Fig. 16. Schematic diagram of OCT-FL TCE imaging system^[55]

Fig. 17. OCT-FL data display of representative images from swine esophagus, in vivo. (a) Polar and (b) cartesian representation of the same crosssectional scan, depicting 2D grayscale OCT and 1D false color FL data. (c) 3D representation of the cross-sectional OCT map along the axial extension of the esophagus (inverted grayscale: low-to-high as black-to-white). (d) 3D representation of the FL surface map along the axial extension of the esophagus. Scale bars: 1 mm.^[55]

Fig. 18. Experimental setup for autonomous optical biopsy probe scanning and multiscale fusion^[57]

Fig. 19. An example of trans-scale fusion. (a) A macroscale stereo reconstruction; (b) to link with the microscale, by adding the mosaic image to the stereo reconstruction; (c) implementation steps involved for autonomous optical biopsy probe scanning and multiscale fusion^[57]