Fig. 1. Flow chart of insect eggshell processing method

Fig. 2. Comparison of different filtering methods. (a) Original OCT image; (b) median filtering; (c) mean filtering; (d) Gaussian filtering; (e) Wiener filtering

Fig. 3. Images processed by different neighborhood sizes of median filtering. (a) Original OCT image; (b) neighborhood size of 3×3; (c) neighborhood size of 11×11; (d) neighborhood size of 19×19

Fig. 4. Local threshold segmentation method of original OCT images

Fig. 5. Image processing of insect embryo. (a) Original OCT image; (b) filtering; (c) local threshold segmentation(S, eggshell); (d) removal of eggshell image

Fig. 6. Comparison of OCT images before and after eggshell removing, where A represents antenna, Ab represents abdomen, FL represents fore legs, H represents head, HL represents hind legs, and ML represents mid legs. (a) Three-dimensional projection of locust egg on XY plane (include eggshell); (b) three-dimensional projection of locust egg on XY plane (erase eggshell); (c) two-dimensional cross-sectional image of locust egg on XY plane with depth of 0.67 mm; (d) two-dimensional cross-sectional image of locust egg on XY plane with depth of 0.88 mm; (e) two-dimensional cross-sectional image of locust egg on XZ plane (include eggshell); (f) two-dimensional cross-sectional image of locust egg on XY plane(erase eggshell)

Fig. 7. Embryonic development process observed on days 6 to 14 after removal of eggshell, where Y represents yolk, EM represents embryo, Ab represents abdomen, and H represents head