## 3 Results and Discussion  
### Specular Reflection Region Inpainting in Hyperspectral Images  
Figure 2a shows the effect of different shapes of specular reflection region mask on inpainting. It was found that rectangle mask did not show a desirable inpainting performance because the pixels that are located along boundary still presented difference of image texture from source region (unaffected region) with sound pixels, which indicated that pixels that are distributing along boundary had influence on image inpainting. However, a more spatially homogeneous texture in target region was synthesized after the application of ellipse mask on account of that more interferential pixels were removed. Apart from visual evaluation, it also displays a highest _PSNR_ value of 51.08 based on ellipse when compared with that of original and rectangle ones (Figure 2b), demonstrating that the ellipse mask was more feasible for spectral image inpainting for green jujube. Figure 2c displays representative spectral images of normal and chilled green jujubes at 480 nm, 580 nm, 680 nm, 780 nm, 880 nm, and 980 nm, respectively, before and after inpainting operation using ellipse mask. The results here indicate that the inpainting operation using Criminisi algorithm could well reconstruct specular reflection region in hyperspectral images both in visible and near-infrared range.  
Figure 2: Effect of different shapes of specular reflection region mask on inpainting performance (**a**), peak signal-to-noise ratio of different shapes of mask (**b**) and spectral images at some representative wavelengths of normal and chilled samples before and after inpainting (**c**) using \(2\times 2\) binning operation (spectral resolution of 1.25 nm).  
Mean Spectra of Different Levels of Chilling Injury at Different Scanning Speeds and Spectral Resolutions  
After the removal of wavelengths with low signal-to-noise ratio (_SNR_) before 430 nm, the remaining wavelengths in the range of 430-1023 nm were used for further analysis. Figure 3 shows the mean spectra of normal, slightly and severely chilling green jujubes under different scanning speeds and spectral resolutions. Local maximum and minimum could be found around 550 nm and 680 nm due to dark green color chlorophyll a absorption. Additionally, the valley around 960 nm was due to water absorption. All of the plots illustrated that a lower reflectance in chilled green jujubes than those of normal ones due to pigment damage and tissue collapse, which resulted in a decreasing of light reflection, thus leading to a lower reflectance in chilled green jujubes than those of normal ones. These different patterns of the reflectance spectra indicated the possibility of identifying normal green jujubes from chilled ones. In addition of that, no notable difference of spectral characteristics over the range of 430-1023 nm could be observed between 8 mm/s and 20 mm/s, implying that a relatively higher scanning speed (20 mm/s) had little impact on the reflectance intensity of green jujubes. When compared with different spectral resolutions, the change pattern of spectral reflectance at two different scanning speeds was similar between them except for spectral resolutions.