Sub-microstructures of Nephrite from Five Sources Based on Multispectral Imaging and Effect Enhancement

Some collectors and connoisseurs have found that the nephrite from different sources possess different sub-microstructures inside the body, which could become a quite convenient and effective basis for determining provenance. The sub-microstructure of nephrite can be observed by the naked eye under irradiated by strong light. However, the images of original submicrostructure of nephrite were recorded by use of multispectral imaging in our previous work, but the visual effect is not satisfied. Here, the main features of different sub-microstructures will present more distinct by appropriately subtracting the shining strength and then the average filtering is adopted to promote the resolution of sub-microstructure imaging as well as to reduce some image noises. The sub-microstructure images of nephrite from five most common sources have typical inherent characteristics respectively, which are qualified to set up a demonstration for identifying provenances. Furthermore, the shape, size, distribution and name for these different sub-microstructures have been summarized and they will become the basis for future research on the provenance of nephrite including the ancient jade.