JOURNAL OF NANJING FORESTRY UNIVERSITY ›› 2023, Vol. 47 ›› Issue (3): 19-28.doi: 10.12302/j.issn.1000-2006.202107017

Special Issue: 第三届中国林草计算机应用大会论文精选

Previous Articles     Next Articles

Estimation of total nitrogen in young Aquilaria sinensis based on multi image features

YUAN Ying1(), WANG Xuefeng1,*(), WANG Tian1, CHEN Feifei2, HUANG Chuanteng2, LIN Ling2, DONG Xiaona2   

  1. 1. Research Institute of Forest Resource Information Techniques, CAF, Key Laboratory of Forest Management and Growth Simulation of National Forestry and Grassland Administration, Beijing 100091, China
    2. Hainan Academy of Forestry, Hainan Academy of Mangrove, Haikou 571100, China
  • Received:2021-07-12 Revised:2022-01-07 Online:2023-05-30 Published:2023-05-25
  • Contact: WANG Xuefeng E-mail:paru_salt@163.com;xuefeng@ifrit.ac.cn

Abstract:

【Objective】Multi-image features of young Aquilaria sinensis were extracted using computer vision technology to estimate the total nitrogen content of leaves, providing a new method for rapid and nondestructive measurement of the nitrogen nutritional status of A. sinensis. 【Method】In this study, the best histogram entropy method (KSW entropy method) and morphological processing based on the HIS (Hue-intensity-saturation) color space were used to segment an image of young A. sinensis, and the color, shape and textural features of the image were extracted. Subsequently, the partial least squares (PLS) method was used to reduce the multi-image feature dimensions, and the principal components of the image feature variables were generated. Finally, the Elman neural network (ElmanNN), optimized using the BAS algorithm, was used to estimate the total nitrogen content of young A. sinensis, and the validation results of the model were compared with those of other commonly used models. 【Result】Research showed the following: (1) focusing on the visible image of A. sinensis, the segmentation algorithm based on HIS color space was better than that based on RGB and Lab color space. (2) The PLS algorithm extracted six principal components from the image features, which reduced the dimension of the image features quickly, and effectively eliminated the multicollinearity among the feature variables. (3) The PLS-BAS-ElmanNN model proposed in this study could achieve the adaptive selection of model parameters, and had higher estimation accuracy; for instance, the R2 was 0.740 7 and the root mean square error was only 1.265 3 g/kg. The estimation accuracy of it was slightly higher than that of the PLSR and PLS-GAM models. 【Conclusion】In this study, we proposed an image processing method for young A. sinensis and constructed a PLS-BAS-ElmanNN estimation model that can stably process high-dimensional image data. This provides a new idea for monitoring the nitrogen nutrition status of young A. sinensis and has a very important practical significance for the accurate cultivation of A. sinensis.

Key words: Aquilaria sinensis, total nitrogen, computer vision, BAS-Elman, PLS

CLC Number: