Fig. 1. Schematic of surgical telementoring based on a coaxial vision photochromic marking system

Fig. 2. Preparation process and photochromism principle of SP-PLGA film

Fig. 3. Photochromic mark imaging system. (a) Hardware design of the system; (b) optical path diagram of the system

Fig. 4. Function design of CV-PM system. (a) Workflow of CV-PM system; (b) software interface of CV-PM system

Fig. 5. Marking performance of CV-PM system. (a) Color-changing performance of SP-PLGA membrane; (b) laser parameter setting of CV-PM system; (c) photochromic mark maintenance time

Fig. 6. Comparison experiment between photochromic mark and hand drawn mark. (a) Guidance mark drawn by the expert in one of the experimental groups; (b) mark scanned by CV-PM system; (c) guidance mark drawn by the expert in one of the control groups; (d) mark drawn by student with marker; (e) statistical analysis of data

Fig. 7. Experiment of nevus resection surgery for ex-vivo pig skin tissue using CV-PM system. (a) Overall view of remote guidance scenario; (b) mark drawn by the expert on screen; (c) photochromic mark scanned by CV-PM system; (d) scene of local doctor performing the operation; (e) picture after nevus resection; (f) picture after wound suturing