Plant height is an important trait linked to yield potential and phenotyping; hence, a method for measuring plant height with sufficient temporal and spatial resolutions is required. Furthermore, a low-cost and easy-to-use method is desirable for practical application in agricultural fields. In previous studies, methods for measuring plant height have only fulfilled one or a few of these requirements, and there have been very few studies that have attempted to fulfill all the above requirements in one method. The current study proposes a low-cost plant height measurement system using a commercial time-lapse camera to capture seasonal and year-to-year variations in plant height that represent plant heights at the site scale. The system’s performance was tested in a rice field in Japan for two growing seasons. Plant heights were determined to the nearest 1-cm in height from the camera images by referencing a scale bar that was erected next to the four target plants. The obtained plant heights were corrected for vertical distortion (referred to as the ‘displacement effect’ in the main text), and those were compared with the direct height measurements for each the target plant and site-scaled plant heights that were averaged from 10 samples. For both cases, good agreement between the captured and referenced plant heights was obtained. The system was able to reflect detailed seasonal variations in the plant heights including the maximum heights and the times at which they occurred as well as year-to-year differences. Consequently, the developed system appears to fulfill all the necessary requirements for practical measurement of plant height on-site in agricultural fields.

中文翻译：

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使用延时相机精确连续测量农田中的植物高度

株高是与产量潜力和表型相关的重要性状；因此，需要一种具有足够时间和空间分辨率的测量植物高度的方法。此外，在农业领域的实际应用中需要一种低成本且易于使用的方法。在以往的研究中，测量植物高度的方法只满足了这些要求中的一个或几个，很少有研究试图用一种方法来满足上述所有要求。目前的研究提出了一种低成本的植物高度测量系统，使用商业延时相机来捕捉植物高度的季节性和年度变化，这些变化代表了现场规模的植物高度。该系统的性能在日本的稻田中进行了两个生长季节的测试。通过参考在四个目标植物旁边竖立的比例尺，将植物高度确定为与相机图像最接近的 1 厘米高度。对获得的株高进行垂直变形校正（正文中称为“位移​​效应”），并将其与每个目标植物的直接高度测量值和10个样本平均的定点株高进行比较. 对于这两种情况，捕获的植物高度和参考的植物高度之间都获得了良好的一致性。该系统能够反映植物高度的详细季节性变化，包括最大高度和它们发生的时间以及年际差异。最后，