The quality of sunflower seed usually influences the load and product quality. The plumpness, expressing as the percent of the kernel and shell (%), is a crucial indicator reflecting the vigor of the sunflower seed. Investigations were carried out to measure the plumpness of intact sunflower seed by the use of terahertz (THz) transmittance imaging. The THz data of the worms, defects, and sound sunflower seeds were scanned using a THz time-domain transmittance imaging system. Followed THz imaging, the shell and kernel of the sample were separated carefully and recorded RGB images as the reference. Compared with the shell, the absorption coefficients and time domain signals of the kernel showed a significant difference in 0.5–2.0 THz. The characteristic images in 0.5–2.0 THz and control groups of 0.5–1.0, 1.0–1.5, and 1.5–2.0 THz were extracted, and the defects, kernel, and shell could be discriminated clearly in 0.5–2.0 THz. The models of the plumpness were developed between the THz and RGB images processed by the threshold segmentation. The determination coefficient and root mean square error of prediction (RMSEP) were 0.91 and 4% for an independent prediction set, respectively. The results suggested that use of THz transmittance imaging in measurement of plumpness of the intact sunflower seed was feasible. In addition, THz imaging provided a novel quality assessment solution for the coated samples.

中文翻译：

---

使用太赫兹透射成像测量完整向日葵种子的饱满度

葵花籽的质量通常会影响装载量和产品质量。饱满度以籽粒和壳的百分比（％）表示，是反映向日葵种子活力的关键指标。进行了研究，以通过太赫兹（THz）透射成像来测量完整向日葵种子的饱满度。使用THz时域透射成像系统扫描蠕虫，缺陷和葵花籽的THz数据。在太赫兹成像之后，仔细分离样品的壳和核，并记录RGB图像作为参考。与外壳相比，内核的吸收系数和时域信号在0.5–2.0 THz之间显示出显着差异。提取了0.5–2.0 THz和对照组0.5–1.0、1.0–1.5和1.5–2.0 THz的特征图像，缺陷，核和壳可以在0.5–2.0 THz的范围内清晰地区分。在阈值分割处理的THz和RGB图像之间建立了饱满度模型。独立预测集的确定系数和预测均方根误差（RMSEP）分别为0.91和4％。结果表明，使用太赫兹透射率成像测量完整向日葵种子的饱满度是可行的。此外，太赫兹成像为涂层样品提供了一种新颖的质量评估解决方案。独立预测集分别为91％和4％。结果表明，使用太赫兹透射率成像测量完整向日葵种子的饱满度是可行的。此外，太赫兹成像为涂层样品提供了一种新颖的质量评估解决方案。独立预测集分别为91％和4％。结果表明，使用太赫兹透射率成像测量完整向日葵种子的饱满度是可行的。此外，太赫兹成像为涂层样品提供了一种新颖的质量评估解决方案。