Fig. 1. Stokes vector measurement system diagram

Fig. 2. Variation trends of Stokes parameters of six kinds of polarized light measured 8 times. (a) 0° linearly polarized light; (b) 45° linearly polarized light; (c) 90° linearly polarized light; (d) 135° linearly polarized light; (e) left-handed circularly polarized light; (f) right-handed circularly polarized light

Fig. 3. Images of polarization uniformity of greenwood. (a) 0° linearly polarized light incident; (b) 45° linearly polarized light incident; (c) 90° linearly polarized light incident; (d) 135° linearly polarized light incident; (e) left-handed circularly polarized light incident; (f) right-handed circularly polarized light incident

Fig. 4. Images of polarization uniformity of reticulated grass. (a) 0° linearly polarized light incident; (b) 45° linearly polarized light incident; (c) 90° linearly polarized light incident; (d) 135° linearly polarized light incident; (e) left-handed circularly polarized light incident; (f) right-handed circularly polarized light incident

Fig. 5. Relationship between incident polarized light and DOPU in leaves of two different plant species. (a) Greenwood; (b) reticulated grass

Fig. 6. Schematic diagram of leaf vein angle of reticulated grass

Fig. 7. DOPU images of stem veins of reticulated grass under different incident light angles

Fig. 8. Polarization uniformity of leaf veins at different incident light angles

Fig. 9. Optical images of different water contents of greenwood

Fig. 10. Images of DOPU of different water contents of greenwood