Abstract:  To provide parameters and basis for subsequent studies such as flower phenotypic characteris tics，pollinator interaction，and yield estimation，the diameter and area of sunflower faceplate were meas ured.Through the special background board and shielding board，the image of sunflower faceplate was col lected non-destructively in the field，and the image was automatically transformed.The tip point of the contour of the faceplate was found，and the different radial diameters of the sunflower faceplate were meas ured by the tip wrapping method，to establish the average diameter of the sunflower faceplate.The area of the sunflower disc was established by operations such as texture segmentation，morphological opening and closing operations，and the average diameter of the sunflower disc was calculated.The recommended num ber of sampling measurements for the average diameter of the sunflower faceplate was 32.Prediction mod els for the average diameter and area of sunflower faceplate and disc were established.The results showed that,the determined coefficients of the average diameter prediction models of the sunflower faceplate and disc were 0.991 and 0.999 respectively,and the determined coefficients of the prediction models of the area surrounded by the tip contour of the faceplate and the original contour were 0.942 and 0.935.The tip wrapping method proposed measured the diameter and area of the faceplate with high accuracy and no sensitivity to scale changes．

Key words:  Sunflower faceplate measurement, Diameter, Area, Tip wrapping method, Texture segmentation

摘要： 对向日葵花盘的直径及面积进行测量，为花卉表型特征、传粉媒介相互作用、产量估计等后续研究提供参数和依据。通过特制的背景板和遮挡板在现场非破坏性地采集向日葵的花盘图像，自动进行图像的投影变换；查找花盘轮廓上的尖端点，采用尖端包裹法测量向日葵花盘多个不同径向的直径，确立向日葵花盘的平均直径；通过纹理分割、形态学的开运算和闭运算等操作，确立向日葵圆盘的区域，并计算圆盘的平均直径。推荐向日葵花盘平均直径的最佳采样测量次数是32 次。建立对向日葵花盘和圆盘平均直径、面积的预测模型。结果表明，建立的向日葵花盘、圆盘的平均直径预测模型与实际测量值的决定系数分别达到0.991、0.999，建立的向日葵花盘尖端轮廓、原始轮廓所包围区域的面积预测模型的决定系数分别为0.942、0.935，尖端包裹法测量花盘直径及面积的准确率高，对尺度变化不敏感。

关键词: 向日葵花盘测量, 直径, 面积, 尖端包裹法, 纹理分割