基于虚拟模型的水稻冠层叶面积计算方法

水稻冠层的叶面积是分析水稻生长状况的重要参数,传统叶面积统计方法效率较低且误差较大,难以对植株冠层不同高度层的叶面积进行测量。针对传统水稻冠层叶面积统计方法的薄弱点,该文提出一种基于虚拟模型的水稻冠层叶面积计算方法。该方法首先通过田间试验获取的水稻形态参数,建立虚拟水稻模型,然后基于该模型计算植株整体叶面积以及两株水稻在一定株距下不同高度层内叶片面积的大小,从而为水稻种植管理措施的优化提供参考。该文算法与长宽校正法相比,在整株叶面积统计结果上,二者相差在5%左右;每层叶片面积实际测定和仿真结果的比较,两者误差在10%之内。该方法对于水稻冠层叶片面积统计具有一定的实际意义。

Calculation method of rice canopy leaf area based on virtual model

Abstract: Leaf area of the rice canopy is one of the key parameters for rice research and management. Analysis of intercepted light of the rice population and development of the light distribution model based on leaf area analysis on different layers are of great importance. The traditional calculation methods for leaf area are inefficient and with significant bias. Besides, the processes of leaf acquisition often cause damage to the plant, and measurements of the leaf area in different layers are with difficulty. To overcome the weakness of traditional statistical method for leaf area of rice canopy, a new method based on virtual plant model was proposed to calculate the leaf area of rice. The field experiment was firstly conducted to obtain the rice morphological parameters, which were used in the establishment of the virtual rice model. We used two curve equations to construct the profile of the blade. A variety of rice leaves was selected as a sample, and then we analyzed the relationship between contour curve equation parameters and leaf shape parameter by MATLAB. In this way, we can determine the parameters of the virtual leaf contour curve equation. Secondly, we used cylinder with different upper and bottom surfaces to simulate the stem of rice based on the data from field experiment. We constructed the virtual rice model according to the topological structure of leaves and stems. The model was then used to calculate the leaf area for the leaves from different height ranges within the rice canopy, for which the rice individuals were cultivated under different distances, and thus to further support optimization processes for rice cultivation and management. Furthermore, we also calculated the leaf area of a rice using the virtual rice model, and construct different types of virtual rice according to the input parameters. The proposed algorithms were verified with the experiment data. The results of leaf areas obtained from field experiments and virtual plants were compared, which were basically consistent and with minor bias. The leaf area of each plant was measured with the method of the length-width, and that were compared with the simulation results. The calculated results between the algorithms proposed in this paper and the method of the length-width correction differed in 5%. For the stratified leaf area calculation part, the canopy of the selected rice sample was divided into three layers, and the effectiveness of the simulation results was verified by measuring the area of the leaf fragments of the different layers. The actual measurement results of the leaf area of each layer and the simulation results of the algorithm were compared, and the error was within 10%. The method can realize the measurement without destroying the plant, and eliminate the influence of the experiment on the natural environment in the real scene, and reduce the manpower and material resources needed to measure the leaf area and improve the efficiency. This method has a certain practical significance for the rice canopy leaf area statistics.