The Research On Distribution Characteristics Of Moso Bamboo Vascular Bundle Based On YOLO Deep Learning Algorithm

Vascular bundle is the most important structural unit of bamboo that determines the growth of bamboo and properties bamboo-based materials,providing two key functions of bamboo,namely mechanical support and water/nutrition transportation.Therefore,the systematic cognition of the structure-property relationship of vascular bundle is the key to clarifying the complex structure-property relationship of bamboo.For the first time,this paper applies the target detection method in the filed of artificial intelligence deep learning to the filed of bamboos'structure research,and solves the key technical problems regarding automatic detection,positioning,counting,and automatic measurement of relevant morphological parameters.Furthermore,the reasearch systematically studies the variation of inter-plant and intra-plant(radial and axial variation)in above-mentioned characteristic parameters of Moso bamboo(Phyllostachys edulis).The paper studies influence of geographical conditions on the distribution characteristics of vascular bundles of bamboo grown in 12 major producing areas of China.The main conclusions of the paper are as follows:(1)According to the characteristics of the YOLO v3 model,a method of combining fine sandpaper polishing with HD scanner scanning was proposed to quickly obtain stable and high-resolution scanning pictures of bamboo ring.This method can obtain the complete structural information of the entire bamboo ring at one time.In the obtained high-definition pictures,the boundary between the fiber sheath and the basic tissue can be accurately distinguished.The grinding by fine sandpaper also fills the pores in the vascular bundles,such as the vessels and phloem,avoiding the interference of these pores in the automatic calculation of the fiber sheath area.(2)After targeted training and inspection,the YOLO v3 model can quickly identify and binarize the vascular bundles in the high-resolution scanning pictures of internode bamboo ring of Moso bamboo,then obtain the total quantity,distribution density,fiber sheath area,tissue ratio and other structural information of vascular bundles.Compared with the results obtained after manual correction,the prediction accuracy is very high in calculating the number of vascular bundles and the area of fiber sheath after the combined deduplication of more than three sets of subgraphs.The difference is only 0.52±0.23%and 0.31±0.30%.The prediction results of the model are very close to the actual values.(3)The structural information about internode of Moso bamboo at the same height from12 major producing area in China was analyzed.The results show that the total number of vascular bundles in the internode of bamboo ring at the height of 2 m is 6564±668,and the distribution density is 2.63±0.48/mm~2.The total area of fiber sheath is 609±142 mm~2,and the specific tissue volume is 23.84±1.94%.There were significant differences in intra-plant from different producing area,and they were significantly affected by the geographical environment.The distribution density of vascular bundle and the tissue ratio of fiber sheath had a significant linear correlation with the average temperature and latitude within 4 years,but had no significant correlation with the altitude and average precipitation within 4 years.(4)The total number and distribution density of vascular bundles,total area of fiber sheath,tissue ratio and other structural information of the same culm vary significantly with the height of bamboo.The total number of interbamboo vascular bundles and the total area of fiber sheath decreased linearly with the height of bamboos,and the reduced part was mainly Type2 and Type3 vascular bundles containing large vessels.The distribution density of vascular bundle and the tissue ratio of fiber sheath increased with the height of bamboos.(5)Within the same internode,the number of vascular bundles at the lower part where near the bamboo node(distance d<2 cm)is more than other parts of the internode,and the extra parts are mainly Type 1 vascular bundle which played a mechanical supporting role.The distribution density of vascular bundle and the tissue ratio of fiber sheath increased slightly with the height of the position of bamboo.